keerthikoganti/dfm-manufacturability-augmented

text string	topic string	source string	good_bad_practice string	reasoning_type string	feature_type string	source_link string	manufacturing_type string	potential_prompt_type string	explanation string	good_bad_label int64
Use filleted internal corners in pockets; sharp corners require secondary EDM or hand work.	Internal Corners	Hubs CNC Design Guide	Good	Rule-based	Corner	https://www.hubs.com/knowledge-base/how-design-parts-cnc-machining/	CNC Machining	Geometry Fix	End mills leave a radius; designing for that radius avoids expensive secondary operations.	1
Align bend lines in the same direction where possible to minimize setups.	Bend Planning	Groover Manufacturing	Good	Strategy-based	Bend	https://www.wiley.com/en-us/Fundamentals%2Bof%2BModern%2BManufacturing%3A%2BMaterials%2C%2BProcesses%2C%2Band%2BSystems%2C%2B7th%2BEdition-p-00007087	Sheet Metal	Process Planning	Reduces handling and simplifies tooling.	1
Over-designing parts with unnecessary curves or tight tolerances significantly increases machining cost without improving function.	Machining Efficiency	Modus Advanced	No	Rule-based	Geometry / Machining	https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications	CNC Machining	Informational	Excessive detail forces smaller tools, more setups, and complex toolpaths. Recognizing which geometric details serve real performance needs prevents wasted time and cost.	0
Is access restricted during assembly?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Small features may be allowed, but the diameter in any region should not be less than 0.030 in. (0.76mm).	Feature Size	Protolabs ‚ Turning guidelines	Yes	Rule-based	Small Feature	https://www.protolabs.com/services/cnc-machining/cnc-turning/design-guidelines/	CNC Turning	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Is the noise level unacceptable?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	General DFM	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Clearly differentiate between reference dimensions and toleranced dimensions using parentheses or drawing conventions.	Reference Dims	Xometry Drawing Best Practices	Good	Rule-based	Dimension	https://www.xometry.com/resources/design-guides/technical-drawing-best-practices/	General	Drawing Hygiene	Reference dimensions should not drive inspection or machining; clarity prevents misuse.	1
Are there packaging materials that are considered standard that are not being used?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	Material Selection	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Using standard materials aligns with existing supplier capabilities and ensures availability and cost efficiency. It also facilitates easier replacement and compliance with company or industry standards.	1
Bends ¬± 1 degree	Tolerances	Protolabs ‚ Basic Design Guidelines	Yes	Rule-based	Bend	https://www.protolabs.com/help-center/basic-design-guidelines/	Sheet Metal	Ask-Back	Missing tolerance can cause rework and fit issues.	1
“Future DFM tools will predict manufacturing yield and generate optimized designs automatically.”	AI-driven DFM	NextPCB	Yes	Conceptual	System	https://www.nextpcb.com/blog/dfm-checklist-and-hqdfm-practice	Smart Manufacturing	Educational Prompt	Suggest integrating predictive yield estimation into the workflow.	1
Don’t fake dimensions or holes — always model what’s real.	Design Accuracy	Reddit Interview	No	Rule-based	Geometry	https://www.reddit.com/r/AskEngineers/comments/i76pqo/to_all_the_pros_what_are_some_general_best/	Machining / Assembly	Informational	Mismatched models and drawings create manufacturing errors and loss of trust.	0
The most common tolerance standards ... are defined by ISO 2768 and ISO 286.	Tolerances	Xometry ‚ Whitepaper	Yes	Fact	General	https://xometry.pro/wp-content/uploads/2023/07/UK-mastering-CNC-tolerances-1.pdf	CNC Machining	Ask-Back	Missing tolerance can cause rework and fit issues.	1
Reduce total part count by combining functions when feasible.	Assembly Simplification	Analogy Design	Yes	Strategy-based	Assembly Efficiency	https://www.analogydesign.co/blog/dfm-checklist	Assembly / Joining	Ask-Back	Each additional part increases assembly time, inventory, and potential failure points.	1
Can multiple parts be combined into one to reduce the number of parts in the assembly?	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Combining multiple parts into one simplifies the assembly process and reduces potential failure points. It also improves structural integrity and reduces costs associated with fasteners and assembly labor.	1
Avoid sharp, zero-radius bends; if a sharp appearance is needed, use post-machining or chamfering.	Sheet Metal - Sharp Bends	Xometry Sheet Metal Bending Tips	Yes	Material-Limit-Based	Bend	https://xometry.pro/en/articles/sheet-metal-bending-design-tips/	Sheet Metal	Warning	Sharp bends concentrate stress and can crack, especially in stainless and high-strength alloys.	1
Align features with main machining axes to reduce repositioning.	Machining Orientation	Shalin Designs	Yes	Strategy-based	Orientation	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	CNC Machining	Ask-Back	Axis alignment minimizes fixture setups and improves tolerance control.	1
Select datum features that represent real functional mating surfaces, not arbitrary model edges.	Datums	ASME Y14.5	Good	Principle-based	Datum	https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing	General	Drawing Check	Functional datums ensure that tolerances relate directly to how the part assembles and works.	1
Are there any parts that can be confused with other parts of similar shape?	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Use casting for complex forms that are costly to machine.	Process Selection	Shalin Designs	Yes	Strategy-based	Process	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	Casting	Ask-Back	Casting simplifies manufacturing of complex geometries in fewer steps.	1
Integrate datum features for alignment during inspection and assembly.	Quality Control	Shalin Designs	Yes	Principle-based	Datum	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	QA / Assembly	Ask-Back	Reference datums enable consistent measurement and precise mating.	1
Design with standard sheet thicknesses/gauges instead of custom values.	Sheet Metal - Standard Gauges	General Sheet Metal Practice	Yes	Cost-based	Wall	https://geomiq.com/sheet-metal-design-guide/	Sheet Metal	Auto-Suggest	Standard gauges are cheaper and widely available; custom thickness increases lead time and cost.	1
Choose mono-material assemblies to simplify recycling and end-of-life separation.	Sustainability	Analogy Design	Yes	Principle-based	Material Lifecycle	https://www.analogydesign.co/blog/dfm-checklist	Sustainable Design	Ask-Back	Using similar material types eliminates complex disassembly steps and supports circular economy goals.	1
Model clearances for snap fits and joints that account for printer tolerance (e.g., 0.2–0.4 mm gaps).	3D Printing - Clearance	General FDM Tolerance Practice	Yes	Empirical	Joint	https://xometry.pro/en/articles/fdm-design-tips/	FDM 3D Printing	Auto-Suggest	Perfectly mating solids in CAD may fuse in print; designed clearance is required for moving parts.	1
Use interlocking features to avoid separate fasteners in assembly.	Assembly Design	Shalin Designs	Yes	Strategy-based	Interlock	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	Assembly	Informational	Interlocks improve precision and simplify assembly without screws.	1
Can parts be combined for multiple uses?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Combining multiple parts into one simplifies the assembly process and reduces potential failure points. It also improves structural integrity and reduces costs associated with fasteners and assembly labor.	1
Maintain sufficient radius at the base of bosses and ribs to avoid stress hot spots.	Injection Molding - Boss/Rib Fillets	Fictiv Injection Molding Design Guide	Yes	Mechanics-based	Boss/Rib	https://www.fictiv.com/wp-content/uploads/2021/07/IM-Design-Guide-ebook.pdf	Injection Molding	Auto-Suggest	Fillets spread out stress and improve flow into these junctions.	1
Does master carton not use the optimum retail package arrangement for pallet, blank size and cube efficiency?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	Packaging / Handling	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Optimizing packaging structure reduces material use, labor time, and shipping costs. It also enhances product protection, ease of unpacking, and consumer experience.	1
Keep bridges relatively short; for long spans, add intermediate support or change the geometry.	3D Printing - Bridges	General FDM Printing Practice	Yes	Physical Limitation	Bridge	https://ultimaker.com/learn/design-for-fff-3d-printing-maximize-your-success/	FDM 3D Printing	Diagnostic	Long bridges can droop, causing poor surface quality and dimensional error.	1
Aerospace applications demand balancing weight optimization with manufacturability.	Industry-Specific DFM	Modus Advanced	Yes	Conceptual	Material / Structural	https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications	Aerospace Manufacturing	Informational	Ultra-light designs often push tolerance limits. Awareness of manufacturing constraints ensures feasible production.	1
Keep slot widths ≥ tool diameter (often at least 1–2 mm) so they can be machined with standard end mills.	CNC - Slot Width	Hubs CNC Machining Guide	Yes	Manufacturing Constraint	Slot	https://www.hubs.com/guides/cnc-machining/	CNC Machining	Auto-Suggest	Slots narrower than the tool cannot be machined and require special micro tooling.	1
Ensure adequate draft and clearance on slide features if undercuts cannot be eliminated.	Injection Molding - Slides	Stratasys Direct IM Design Guidelines	Yes	Manufacturing Constraint	Slide	https://info.stratasysdirect.com/rs/626-SBR-192/images/Stratasys_Direct_Design_Guidelines_Injection_Molding_201907.pdf	Injection Molding	Diagnostic	Slides need room to move and clear the plastic; poor design causes sticking or damage.	1
Simplify fillet count—uniform radii reduce CAM tool changes.	Machining Optimization	Shalin Designs	Yes	Rule-based	Fillet	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	CNC Machining	Informational	Uniformity allows reusing same cutter, improving process flow.	1
Avoid pockets deeper than 3× tool diameter to reduce chatter and tool breakage.	CNC - Pocket Depth	General CNC DFM Practice / Xometry CNC Guide	Yes	Physical Limitation	Pocket	https://geomiq.com/cnc-design-guide/	CNC Machining	Auto-Suggest	Deep, narrow pockets cause chatter and tool deflection, making machining slow and inaccurate.	1
AI suggestions must include confidence levels and assumptions to be trusted in engineering workflows.	AI Explainability	Industry Interview	Good	Principle-based	Assistant	Interview	General	AI Trust	Engineers need transparency to evaluate manufacturability advice.	1
Datums establish a frame of reference for measurement.	Datums	GD&T Basics ‚ Datums	Yes	Principle-based	Datum	https://www.gdandtbasics.com/datums/	GD&T	Educational Prompt	Without datums, measurements are ambiguous.	1
Use joints that permit welding in the flat position when possible.	Weld Position	Lincoln Electric ‚ Weld design	Yes	Heuristic	Joint	https://www.lincolnelectric.com/en/Support/welding-resources	Welding	Heuristic Suggestion	Flat positions produce higher quality and productivity.	1
Do not rely on very tiny engraved text; keep stroke widths and character heights comfortably above tool diameters.	CNC - Engraving	General CNC DFM Practice	Yes	Manufacturing Constraint	Text	https://geomiq.com/cnc-design-guide/	CNC Machining	Warning	Very fine text requires micro tools, which are slow and fragile.	1
Are there parts design that do not allow for proper location and alignment?	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Are there concerns with the comfort and the safety of the seating compartment?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Evaluating potential safety hazards early in design prevents injury and ensures compliance with safety standards. It also reduces liability and promotes user trust.	1
Avoid extremely thin roofs over large cavities; add ribs or increase thickness.	3D Printing - Roof Thickness	General FDM Practice	Yes	Structural	Wall	https://xometry.pro/en/articles/fdm-design-tips/	FDM 3D Printing	Diagnostic	Thin horizontal surfaces over voids may sag or show severe drooping between supports.	1
Check model sanity before fabrication ‚ basic DFM rules can prevent avoidable errors.	Design Verification	Interview	Yes	Checklist-based	Model	null	General DFM	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Snap-fit joints are a very simple, economical and rapid way of joining two parts without fasteners or tools.	Snap-Fits	Hubs ‚ Injection molding guide	Yes	Fact	Snap-fit	https://www.hubs.com/guides/injection-molding/	Injection Molding	Heuristic Suggestion	Potential DFM concern; verify against context.	1
List datums in feature control frames in the order of how the part is functionally located in the assembly.	Datum Precedence	Hubs GD&T Article	Good	Principle-based	Datum	https://www.hubs.com/knowledge-base/what-is-geometric-dimensioning-and-tolerancing/	Assembly	Design Intent Prompt	Datum order should reflect physical assembly and inspection setup, not arbitrary coordinate axes.	1
Ask for help if you’re stuck — don’t waste hours on simple modeling issues.	Collaboration	Reddit Interview	Yes	Principle-based	Communication	https://www.reddit.com/r/AskEngineers/comments/i76pqo/to_all_the_pros_what_are_some_general_best/	CAD	Ask-Back	Teams move faster when designers seek guidance early instead of guessing.	1
Use LMC for features that protect minimum material conditions such as wall thickness or clearance.	Material Condition	ASME Y14.5	Good	Principle-based	Feature of Size	https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing	Machining	Design Check	LMC is useful where excess material could block flow, clearance, or access even if size is within limits.	1
Align CAD design choices with the intended process (molding, casting, forging).	DFM Integration	Shalin Designs	Yes	Principle-based	Process Fit	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	General Manufacturing	Ask-Back	Process-aware design ensures cost-effective manufacturability and quality consistency.	1
Keep thread lengths to what is structurally needed; excessive thread depth wastes machining time.	Threads	Xometry CNC Design Guide	Bad	Heuristic	Thread	https://www.xometry.com/resources/design-guides/	CNC Machining	Cost Optimization	Beyond a certain engagement length, additional threads add little strength but add cost.	0
Do any parts or assemblies require a special environment during manufacturing? (i.e. dust proofing, grounding, etc.)	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
“Move DFM to the front of the process and use automated tools to handle complexity.”	Early DFM Integration	NextPCB	Yes	Strategy-based	Process	https://www.nextpcb.com/blog/dfm-checklist-and-hqdfm-practice	PCB Manufacturing	Checklist	Verify that manufacturability checks are run before design freeze.	1
In injection molding, keep nominal wall thickness as uniform as possible throughout the part.	Wall Uniformity	Protolabs Injection Molding Tips	Good	Principle-based	Wall	https://www.protolabs.com/resources/design-tips/plastic-injection-molding-design-tips/	Injection Molding	Warp Analysis	Non-uniform walls cool unevenly, causing warpage, sink marks, and residual stresses.	1
The nominal distance between fasteners is 4D.	Fastener Spacing	NASA ‚ Fastener Design Manual	Yes	Rule-based	Pattern	https://psfeg.com/wp-content/uploads/2014/01/NASA_RP-1228.pdf	Assembly/Fastening	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Common design practice is to use a nominal edge distance of 2D from the fastener hole centerline.	Edge Distance	NASA ‚ Fastener Design Manual	Yes	Rule-based	Hole	https://psfeg.com/wp-content/uploads/2014/01/NASA_RP-1228.pdf	Assembly/Fastening	Heuristic Suggestion	Potential DFM concern; verify against context.	1
How to model and verify a countersink in your CAD design	Countersink	SendCutSend ‚ Video	Yes	Educational	Countersink	https://sendcutsend.com/education/video/adding-countersinking-to-your-parts/	Sheet Metal	Direct Check	Non-standard angles may not match fasteners.	1
Are there opportunities for more cost-effective components? (i.e. speaker size, cheaper PCB, battery quantity, etc.)	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Electronics / Wiring	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Managing wire harness complexity and PCB design ensures efficient assembly and maintenance. Clear labeling and color coding minimize wiring errors and improve serviceability.	1
Include 1–2° of draft on core and cavity surfaces in molded parts.	Draft	Protolabs IM Tips	Good	Rule-based	Draft	https://www.protolabs.com/resources/design-tips/plastic-injection-molding-design-tips/	Injection Molding	Teaching Prompt	Draft improves ejection and reduces drag marks. This rule is often taught explicitly in sophomore-level manufacturing courses.	1
Use consistent internal fillet radii throughout the part to reduce tool changes and machining cost.	CNC - Standardization	Xometry CNC Machining Design Guide	Yes	Cost-based	Fillet	https://xometry.pro/wp-content/uploads/2023/07/EN-CNC-Machining-Design-Guide.pdf	CNC Machining	Auto-Suggest	Standardizing radii lets the shop use fewer tools and shorter programs.	1
Multiple surfaces ¬± 0.030 in.	Tolerances	Protolabs ‚ Basic Design Guidelines	Yes	Rule-based	General	https://www.protolabs.com/help-center/basic-design-guidelines/	Sheet Metal	Ask-Back	Missing tolerance can cause rework and fit issues.	1
The maximum depth of holes we recommend is 4 x the nominal diameter.	Hole Depth	Hubs ‚ CNC video	Yes	Rule-based	Hole	https://www.hubs.com/videos/design-cnc-machining/	CNC Milling	Direct Check	Deep holes risk tool deflection and poor chip evacuation.	1
Apply perpendicularity to features that must be square to a datum, such as mounting faces.	Perpendicularity	Xometry GD&T Guide	Good	Rule-based	Surface	https://www.xometry.com/resources/blog/what-is-gdt-and-how-is-it-used/	Machining	Design Check	Perpendicularity creates a tolerance zone around a theoretical 90° orientation, aiding assembly fit.	1
Avoid placing ejector pins on cosmetic or sealing surfaces whenever possible.	Ejection	Protolabs Injection Molding Tips	Bad	Principle-based	Surface	https://www.protolabs.com/resources/design-tips/plastic-injection-molding-design-tips/	Injection Molding	DFM Warning	Ejector marks on visible or sealing areas can cause appearance issues and leaks.	0
Use positional tolerances for hole patterns instead of tight linear dimensions.	GD&T	ASME Y14.5 via Shigley	Good	Principle-based	Hole Pattern	https://www.mheducation.com/highered/product/shigleys-mechanical-engineering-design-nisbett.html	Machining	Tolerance Optimization	Position controls functional fit with looser individual dims.	1
Smooth coatings can prevent gasket adhesion; slight surface texture often improves bonding.	Surface Preparation	Modus Advanced	Yes	Heuristic	Surface Finish	https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications	FIP Dispensing	Informational	Adhesion relies on mechanical grip as well as chemistry. Over-polished surfaces reduce wetting and cause delamination.	1
Avoid excessive draft angles that distort part geometry.	Draft Optimization	Shalin Designs	No	Heuristic	Draft Angle	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	Molding	Informational	Too much draft changes fit and can affect structural or aesthetic alignment.	0
Avoid aspect ratios of height to diameter > 3:1 for unsupported bosses in CNC milling.	Bosses	Groover Manufacturing	Bad	Heuristic	Boss	https://www.wiley.com/en-us/Fundamentals%2Bof%2BModern%2BManufacturing%3A%2BMaterials%2C%2BProcesses%2C%2Band%2BSystems%2C%2B7th%2BEdition-p-00007087	CNC Machining	Stability Check	Tall slender bosses vibrate and are easily damaged.	0
Add lead-in chamfers at tapped holes to guide screws and reduce cross-threading.	Lead-In	Protolabs Design Tips	Good	Heuristic	Edge	https://www.protolabs.com/resources/design-tips/	CNC Machining	Assembly Aid	Chamfers improve assembly ergonomics and protect thread starts from damage.	1
Are there parts that do not nest properly?	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Select materials with adequate machinability ratings for the chosen manufacturing process.	Material Selection	Groover Manufacturing	Good	Principle-based	Material	https://www.wiley.com/en-us/Fundamentals%2Bof%2BModern%2BManufacturing%3A%2BMaterials%2C%2BProcesses%2C%2Band%2BSystems%2C%2B7th%2BEdition-p-00007087	CNC Machining	Material Check	Poor machinability increases tool wear and cycle time.	1
Design bosses for screws with supporting ribs rather than solid thick cylinders.	Bosses	Malloy Plastic Part Design	Good	Principle-based	Boss	https://www.hanser-elibrary.com/doi/book/10.3139/9783446433748	Injection Molding	Feature Optimization	Reduces sink while preserving strength around screws.	1
The distance between two ribs should be 2 ‚ 3X the nominal wall thickness.	Ribs Spacing	SOLIDWORKS Blog ‚ Cardinal rules	Yes	Rule-based	Rib	https://blogs.solidworks.com/solidworksblog/2015/02/the-cardinal-rules-of-designing-injection-molded-plastic-parts.html	Injection Molding	Direct Check	Thick ribs cause sink and warpage.	1
Use relief cuts at the ends of complex bend intersections to reduce tearing.	Relief Cuts	SendCutSend Bending Guide	Good	Heuristic	Relief	https://sendcutsend.com/guidelines/bending/	Sheet Metal	Detail Check	Relief prevents material from stretching and cracking.	1
Review CAD models with manufacturing partners before final release.	Collaboration	Shalin Designs	Yes	Principle-based	Review Process	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	General	Ask-Back	Early joint reviews catch design flaws before they reach the shop floor, saving cost and lead time.	1
Avoid thin walls less than two extrusion widths in FDM printing.	Wall Thickness	Prusa Knowledge Base	Bad	Fact	Wall	https://help.prusa3d.com/	Additive	Feature Validation	Too-thin walls are fragile and may not slice correctly.	0
Protolabs provides a range of internal bend radius tooling options between 0.01 in. and 1 in.	Bend Radius Tooling	Protolabs ‚ Sheet metal toolkit	Yes	Capability	Bend	https://www.protolabs.com/resources/design-for-sheet-metal-fabrication-toolkit/	Sheet Metal	Heuristic Suggestion	Potential DFM concern; verify against context.	1
The radius of the corner will be half the diameter of the cutting tool.	Internal Corners	Fictiv ‚ CNC design guide	Yes	Rule-based	Corner	https://www.fictiv.com/articles/fictiv-cnc-machining-design-guide	CNC Milling	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Blind holes machined with a drill have a conical floor (135o angle).	Drilled Holes	Hubs ‚ CNC video	Yes	Fact	Hole	https://www.hubs.com/videos/design-cnc-machining/	CNC Milling	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Minimize the number of separate adjustment points in a mechanism; design for fixed, repeatable alignment.	Adjustments	Shigley's Mechanical Engineering Design	Good	Principle-based	Mechanism	https://www.mheducation.com/highered/product/shigleys-mechanical-engineering-design-nisbett.html	Assembly	Reliability Prompt	Fewer adjustments mean fewer opportunities for misalignment during assembly or service.	1
Use profile to control both size and location of non-cylindrical bosses or tabs instead of complex coordinate schemes.	Profile	ASME Y14.5	Good	Principle-based	Boss	https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing	Machining	Geometry Control	Profile simplifies specification of non-standard shapes and improves inspection clarity.	1
Critical features should remain accessible to standard metrology tools to prevent custom gauge development.	Inspection Design	Modus Advanced	Yes	Rule-based	QA / Accessibility	https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications	General Manufacturing	Ask-Back	Deep cavities or blind holes require specialized probes. Designing with access in mind saves time and equipment cost.	1
Minimize secondary operations like polishing, trimming, or drilling.	Process Optimization	Analogy Design	Yes	Strategy-based	Manufacturing Operations	https://www.analogydesign.co/blog/dfm-checklist	Multi-Process	Informational	Each post-process adds labor and tolerance variation. Integrating finish quality into the initial process improves yield.	1
Choose machining tolerances around ±0.005" unless tighter is required.	Machining Standards	Shalin Designs	Yes	Rule-based	Tolerance	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	CNC Machining	Informational	Industry-standard tolerances balance cost with precision.	1
Use texture-friendly draft and avoid small, deep recesses that are hard to polish.	Injection Molding - Surface Finish	Xcentric Mold Designing for Plastics	Yes	Manufacturing Constraint	Surface	https://xcentricmold.com/designing-for-plastics/	Injection Molding	Auto-Suggest	Recessed or undercut surfaces are hard to polish or texture, raising tooling cost.	1
“Ensure cross-functional collaboration between design, engineering, and manufacturing.”	Team Integration	6Sigma.us	Yes	Principle-based	Process	https://www.6sigma.us/six-sigma-in-focus/design-for-manufacturing-dfm/	General Manufacturing	Ask-Back	Confirm multi-disciplinary review sign-offs before release.	1
Avoid specifying unnecessarily tight tolerances (e.g., ±0.01 mm) on non-critical dimensions.	CNC - Tolerancing	Hubs CNC Machining Guide	Yes	Cost-based	General	https://www.hubs.com/guides/cnc-machining/	CNC Machining	Diagnostic	Tighter tolerances require slower machining, inspection, and sometimes secondary operations.	1
A +/- 1 degree tolerance on all bend angles is generally acceptable in the industry.	Bend Angles	Geomiq ‚ Sheet metal guide	Yes	Rule-based	Bend	https://geomiq.com/sheet-metal-design-guide/	Sheet Metal	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Can product components be easily detached or damaged by consumer?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	General DFM	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Avoid abrupt wall thickness transitions; use tapers or fillets to blend.	Wall Transitions	Malloy Plastic Part Design	Good	Principle-based	Wall	https://www.hanser-elibrary.com/doi/book/10.3139/9783446433748	Injection Molding	Teaching Prompt	Smooth transitions reduce stress and cosmetic defects. This rule is often taught explicitly in sophomore-level manufacturing courses.	1
chatbots may miss nuanced design reasoning ‚ physical intuition and edge cases matter.	Limitations	Interview	No	Conceptual	Assistant	null	/Software	Ask-Back	Preference-based; confirm desired level of automation.	0
Radiused corners are required, and must be larger than the cutter to be used.	Internal Corners	Fictiv ‚ CNC design guide	Yes	Rule-based	Corner	https://www.fictiv.com/articles/fictiv-cnc-machining-design-guide	CNC Milling	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Use standardized components and tools wherever possible.	Standardization	Analogy Design	Yes	Rule-based	Parts / Procurement	https://www.analogydesign.co/blog/dfm-checklist	Assembly / Machining	Informational	Off-the-shelf fasteners, bearings, or switches reduce lead time and ensure replaceability.	1
Can the product be secured in a less labor intensive method?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	General DFM	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Keep minimum flange length at least 4× material thickness to allow proper contact with tooling.	Sheet Metal - Flange Length	Protolabs Sheet Metal Design Guidelines	Yes	Manufacturing Constraint	Flange	https://www.protolabs.com/services/sheet-metal-fabrication/design-guidelines/	Sheet Metal	Auto-Suggest	Short flanges don’t engage the press brake die properly and may deform or slip.	1
Avoid designs that require many side actions or lifters; simplify to straight-pull molds where possible.	Injection Molding - Undercuts	Stratasys Direct IM Design Guidelines	Yes	Cost-based	Undercut	https://info.stratasysdirect.com/rs/626-SBR-192/images/Stratasys_Direct_Design_Guidelines_Injection_Molding_201907.pdf	Injection Molding	Warning	Side actions and lifters add cost, complexity, and risk of mechanical failure in the mold.	1
Verify accessibility for cutters and inspection probes in all orientations.	Accessibility	Shalin Designs	Yes	Rule-based	Reachability	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	Machining	Ask-Back	Poor access increases cycle time or may make features unmachinable.	1
Holes and slots should be at least 6X MT from each other.	Feature Spacing	Xometry ‚ Sheet Metal Design Guide (PDF)	Yes	Rule-based	Hole/Slot	https://cdn2.hubspot.net/hubfs/340051/Design_Guides/Xometry_DesignGuide_SheetMetal.pdf	Sheet Metal	Heuristic Suggestion	Potential DFM concern; verify against context.	1
Reduce undercuts and overhangs that require special tooling.	Tooling Complexity	Shalin Designs	No	Rule-based	Undercut	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	Molding / Machining	Informational	Side actions and custom tools add setup and maintenance time.	0
Ensure proper dimensioning in cast parts to prevent shrinkage issues.	Casting Design	Shalin Designs	Yes	Rule-based	Dimensioning	https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm	Casting	Informational	Poor dimension control leads to porosity or misalignment in castings.	1
Avoid chain dimensioning for critical features; dimension from common datums instead.	Dimensioning	ASME Y14.5	Bad	Rule-based	Dimension	https://www.asme.org/codes-standards/y14-standards	General	DFM Warning	Chain dimensions accumulate tolerance stack-up; datum-based dimensions localize variation.	0
Are there any mechanisms of the product that may not meet life-cycle requirement?	Packaging	Quality-One DFM/A Sample Checklist	Yes	Checklist	General DFM	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	Simplifying complex mechanisms improves reliability and reduces the risk of assembly errors or part failure. It enhances manufacturability and minimizes maintenance or repair time.	1
Can irregular parting lines be eliminated?	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	Assembly / Ergonomics	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1
Are there any missing surface finishes/textures?	Product Design - General	Quality-One DFM/A Sample Checklist	Yes	Checklist	General DFM	https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx	General Manufacturing	Ask-Back	This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.	1

Use filleted internal corners in pockets; sharp corners require secondary EDM or hand work.

Internal Corners

Hubs CNC Design Guide

Good

Rule-based

Corner

https://www.hubs.com/knowledge-base/how-design-parts-cnc-machining/

CNC Machining

Geometry Fix

End mills leave a radius; designing for that radius avoids expensive secondary operations.

1

Align bend lines in the same direction where possible to minimize setups.

Bend Planning

Groover Manufacturing

Good

Strategy-based

Bend

https://www.wiley.com/en-us/Fundamentals%2Bof%2BModern%2BManufacturing%3A%2BMaterials%2C%2BProcesses%2C%2Band%2BSystems%2C%2B7th%2BEdition-p-00007087

Sheet Metal

Process Planning

Reduces handling and simplifies tooling.

1

Over-designing parts with unnecessary curves or tight tolerances significantly increases machining cost without improving function.

Machining Efficiency

Modus Advanced

No

Rule-based

Geometry / Machining

https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications

CNC Machining

Informational

Excessive detail forces smaller tools, more setups, and complex toolpaths. Recognizing which geometric details serve real performance needs prevents wasted time and cost.

0

Is access restricted during assembly?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Small features may be allowed, but the diameter in any region should not be less than 0.030 in. (0.76mm).

Feature Size

Protolabs ‚ Turning guidelines

Yes

Rule-based

Small Feature

https://www.protolabs.com/services/cnc-machining/cnc-turning/design-guidelines/

CNC Turning

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Is the noise level unacceptable?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

General DFM

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Clearly differentiate between reference dimensions and toleranced dimensions using parentheses or drawing conventions.

Reference Dims

Xometry Drawing Best Practices

Good

Rule-based

Dimension

https://www.xometry.com/resources/design-guides/technical-drawing-best-practices/

General

Drawing Hygiene

Reference dimensions should not drive inspection or machining; clarity prevents misuse.

1

Are there packaging materials that are considered standard that are not being used?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

Material Selection

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Using standard materials aligns with existing supplier capabilities and ensures availability and cost efficiency. It also facilitates easier replacement and compliance with company or industry standards.

1

Bends ¬± 1 degree

Tolerances

Protolabs ‚ Basic Design Guidelines

Yes

Rule-based

Bend

https://www.protolabs.com/help-center/basic-design-guidelines/

Sheet Metal

Ask-Back

Missing tolerance can cause rework and fit issues.

1

“Future DFM tools will predict manufacturing yield and generate optimized designs automatically.”

AI-driven DFM

NextPCB

Yes

Conceptual

System

https://www.nextpcb.com/blog/dfm-checklist-and-hqdfm-practice

Smart Manufacturing

Educational Prompt

Suggest integrating predictive yield estimation into the workflow.

1

Don’t fake dimensions or holes — always model what’s real.

Design Accuracy

Reddit Interview

No

Rule-based

Geometry

https://www.reddit.com/r/AskEngineers/comments/i76pqo/to_all_the_pros_what_are_some_general_best/

Machining / Assembly

Informational

Mismatched models and drawings create manufacturing errors and loss of trust.

0

The most common tolerance standards ... are defined by ISO 2768 and ISO 286.

Tolerances

Xometry ‚ Whitepaper

Yes

Fact

General

https://xometry.pro/wp-content/uploads/2023/07/UK-mastering-CNC-tolerances-1.pdf

CNC Machining

Ask-Back

Missing tolerance can cause rework and fit issues.

1

Reduce total part count by combining functions when feasible.

Assembly Simplification

Analogy Design

Yes

Strategy-based

Assembly Efficiency

https://www.analogydesign.co/blog/dfm-checklist

Assembly / Joining

Ask-Back

Each additional part increases assembly time, inventory, and potential failure points.

1

Can multiple parts be combined into one to reduce the number of parts in the assembly?

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Combining multiple parts into one simplifies the assembly process and reduces potential failure points. It also improves structural integrity and reduces costs associated with fasteners and assembly labor.

1

Avoid sharp, zero-radius bends; if a sharp appearance is needed, use post-machining or chamfering.

Sheet Metal - Sharp Bends

Xometry Sheet Metal Bending Tips

Yes

Material-Limit-Based

Bend

https://xometry.pro/en/articles/sheet-metal-bending-design-tips/

Sheet Metal

Warning

Sharp bends concentrate stress and can crack, especially in stainless and high-strength alloys.

1

Align features with main machining axes to reduce repositioning.

Machining Orientation

Shalin Designs

Yes

Strategy-based

Orientation

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

CNC Machining

Ask-Back

Axis alignment minimizes fixture setups and improves tolerance control.

1

Select datum features that represent real functional mating surfaces, not arbitrary model edges.

Datums

ASME Y14.5

Good

Principle-based

Datum

https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing

General

Drawing Check

Functional datums ensure that tolerances relate directly to how the part assembles and works.

1

Are there any parts that can be confused with other parts of similar shape?

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Use casting for complex forms that are costly to machine.

Process Selection

Shalin Designs

Yes

Strategy-based

Process

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

Casting

Ask-Back

Casting simplifies manufacturing of complex geometries in fewer steps.

1

Integrate datum features for alignment during inspection and assembly.

Quality Control

Shalin Designs

Yes

Principle-based

Datum

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

QA / Assembly

Ask-Back

Reference datums enable consistent measurement and precise mating.

1

Design with standard sheet thicknesses/gauges instead of custom values.

Sheet Metal - Standard Gauges

General Sheet Metal Practice

Yes

Cost-based

Wall

https://geomiq.com/sheet-metal-design-guide/

Sheet Metal

Auto-Suggest

Standard gauges are cheaper and widely available; custom thickness increases lead time and cost.

1

Choose mono-material assemblies to simplify recycling and end-of-life separation.

Sustainability

Analogy Design

Yes

Principle-based

Material Lifecycle

https://www.analogydesign.co/blog/dfm-checklist

Sustainable Design

Ask-Back

Using similar material types eliminates complex disassembly steps and supports circular economy goals.

1

Model clearances for snap fits and joints that account for printer tolerance (e.g., 0.2–0.4 mm gaps).

3D Printing - Clearance

General FDM Tolerance Practice

Yes

Empirical

Joint

https://xometry.pro/en/articles/fdm-design-tips/

FDM 3D Printing

Auto-Suggest

Perfectly mating solids in CAD may fuse in print; designed clearance is required for moving parts.

1

Use interlocking features to avoid separate fasteners in assembly.

Assembly Design

Shalin Designs

Yes

Strategy-based

Interlock

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

Assembly

Informational

Interlocks improve precision and simplify assembly without screws.

1

Can parts be combined for multiple uses?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Combining multiple parts into one simplifies the assembly process and reduces potential failure points. It also improves structural integrity and reduces costs associated with fasteners and assembly labor.

1

Maintain sufficient radius at the base of bosses and ribs to avoid stress hot spots.

Injection Molding - Boss/Rib Fillets

Fictiv Injection Molding Design Guide

Yes

Mechanics-based

Boss/Rib

https://www.fictiv.com/wp-content/uploads/2021/07/IM-Design-Guide-ebook.pdf

Injection Molding

Auto-Suggest

Fillets spread out stress and improve flow into these junctions.

1

Does master carton not use the optimum retail package arrangement for pallet, blank size and cube efficiency?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

Packaging / Handling

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Optimizing packaging structure reduces material use, labor time, and shipping costs. It also enhances product protection, ease of unpacking, and consumer experience.

1

Keep bridges relatively short; for long spans, add intermediate support or change the geometry.

3D Printing - Bridges

General FDM Printing Practice

Yes

Physical Limitation

Bridge

https://ultimaker.com/learn/design-for-fff-3d-printing-maximize-your-success/

FDM 3D Printing

Diagnostic

Long bridges can droop, causing poor surface quality and dimensional error.

1

Aerospace applications demand balancing weight optimization with manufacturability.

Industry-Specific DFM

Modus Advanced

Yes

Conceptual

Material / Structural

https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications

Aerospace Manufacturing

Informational

Ultra-light designs often push tolerance limits. Awareness of manufacturing constraints ensures feasible production.

1

Keep slot widths ≥ tool diameter (often at least 1–2 mm) so they can be machined with standard end mills.

CNC - Slot Width

Hubs CNC Machining Guide

Yes

Manufacturing Constraint

Slot

https://www.hubs.com/guides/cnc-machining/

CNC Machining

Auto-Suggest

Slots narrower than the tool cannot be machined and require special micro tooling.

1

Ensure adequate draft and clearance on slide features if undercuts cannot be eliminated.

Injection Molding - Slides

Stratasys Direct IM Design Guidelines

Yes

Manufacturing Constraint

Slide

https://info.stratasysdirect.com/rs/626-SBR-192/images/Stratasys_Direct_Design_Guidelines_Injection_Molding_201907.pdf

Injection Molding

Diagnostic

Slides need room to move and clear the plastic; poor design causes sticking or damage.

1

Simplify fillet count—uniform radii reduce CAM tool changes.

Machining Optimization

Shalin Designs

Yes

Rule-based

Fillet

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

CNC Machining

Informational

Uniformity allows reusing same cutter, improving process flow.

1

Avoid pockets deeper than 3× tool diameter to reduce chatter and tool breakage.

CNC - Pocket Depth

General CNC DFM Practice / Xometry CNC Guide

Yes

Physical Limitation

Pocket

https://geomiq.com/cnc-design-guide/

CNC Machining

Auto-Suggest

Deep, narrow pockets cause chatter and tool deflection, making machining slow and inaccurate.

1

AI suggestions must include confidence levels and assumptions to be trusted in engineering workflows.

AI Explainability

Industry Interview

Good

Principle-based

Assistant

Interview

General

AI Trust

Engineers need transparency to evaluate manufacturability advice.

1

Datums establish a frame of reference for measurement.

Datums

GD&T Basics ‚ Datums

Yes

Principle-based

Datum

https://www.gdandtbasics.com/datums/

GD&T

Educational Prompt

Without datums, measurements are ambiguous.

1

Use joints that permit welding in the flat position when possible.

Weld Position

Lincoln Electric ‚ Weld design

Yes

Heuristic

Joint

https://www.lincolnelectric.com/en/Support/welding-resources

Welding

Heuristic Suggestion

Flat positions produce higher quality and productivity.

1

Do not rely on very tiny engraved text; keep stroke widths and character heights comfortably above tool diameters.

CNC - Engraving

General CNC DFM Practice

Yes

Manufacturing Constraint

Text

https://geomiq.com/cnc-design-guide/

CNC Machining

Warning

Very fine text requires micro tools, which are slow and fragile.

1

Are there parts design that do not allow for proper location and alignment?

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Are there concerns with the comfort and the safety of the seating compartment?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Evaluating potential safety hazards early in design prevents injury and ensures compliance with safety standards. It also reduces liability and promotes user trust.

1

Avoid extremely thin roofs over large cavities; add ribs or increase thickness.

3D Printing - Roof Thickness

General FDM Practice

Yes

Structural

Wall

https://xometry.pro/en/articles/fdm-design-tips/

FDM 3D Printing

Diagnostic

Thin horizontal surfaces over voids may sag or show severe drooping between supports.

1

Check model sanity before fabrication ‚ basic DFM rules can prevent avoidable errors.

Design Verification

Interview

Yes

Checklist-based

Model

null

General DFM

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Snap-fit joints are a very simple, economical and rapid way of joining two parts without fasteners or tools.

Snap-Fits

Hubs ‚ Injection molding guide

Yes

Fact

Snap-fit

https://www.hubs.com/guides/injection-molding/

Injection Molding

Heuristic Suggestion

Potential DFM concern; verify against context.

1

List datums in feature control frames in the order of how the part is functionally located in the assembly.

Datum Precedence

Hubs GD&T Article

Good

Principle-based

Datum

https://www.hubs.com/knowledge-base/what-is-geometric-dimensioning-and-tolerancing/

Assembly

Design Intent Prompt

Datum order should reflect physical assembly and inspection setup, not arbitrary coordinate axes.

1

Ask for help if you’re stuck — don’t waste hours on simple modeling issues.

Collaboration

Reddit Interview

Yes

Principle-based

Communication

https://www.reddit.com/r/AskEngineers/comments/i76pqo/to_all_the_pros_what_are_some_general_best/

CAD

Ask-Back

Teams move faster when designers seek guidance early instead of guessing.

1

Use LMC for features that protect minimum material conditions such as wall thickness or clearance.

Material Condition

ASME Y14.5

Good

Principle-based

Feature of Size

https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing

Machining

Design Check

LMC is useful where excess material could block flow, clearance, or access even if size is within limits.

1

Align CAD design choices with the intended process (molding, casting, forging).

DFM Integration

Shalin Designs

Yes

Principle-based

Process Fit

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

General Manufacturing

Ask-Back

Process-aware design ensures cost-effective manufacturability and quality consistency.

1

Keep thread lengths to what is structurally needed; excessive thread depth wastes machining time.

Threads

Xometry CNC Design Guide

Bad

Heuristic

Thread

https://www.xometry.com/resources/design-guides/

CNC Machining

Cost Optimization

Beyond a certain engagement length, additional threads add little strength but add cost.

0

Do any parts or assemblies require a special environment during manufacturing? (i.e. dust proofing, grounding, etc.)

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

“Move DFM to the front of the process and use automated tools to handle complexity.”

Early DFM Integration

NextPCB

Yes

Strategy-based

Process

https://www.nextpcb.com/blog/dfm-checklist-and-hqdfm-practice

PCB Manufacturing

Checklist

Verify that manufacturability checks are run before design freeze.

1

In injection molding, keep nominal wall thickness as uniform as possible throughout the part.

Wall Uniformity

Protolabs Injection Molding Tips

Good

Principle-based

Wall

https://www.protolabs.com/resources/design-tips/plastic-injection-molding-design-tips/

Injection Molding

Warp Analysis

Non-uniform walls cool unevenly, causing warpage, sink marks, and residual stresses.

1

The nominal distance between fasteners is 4D.

Fastener Spacing

NASA ‚ Fastener Design Manual

Yes

Rule-based

Pattern

https://psfeg.com/wp-content/uploads/2014/01/NASA_RP-1228.pdf

Assembly/Fastening

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Common design practice is to use a nominal edge distance of 2D from the fastener hole centerline.

Edge Distance

NASA ‚ Fastener Design Manual

Yes

Rule-based

Hole

https://psfeg.com/wp-content/uploads/2014/01/NASA_RP-1228.pdf

Assembly/Fastening

Heuristic Suggestion

Potential DFM concern; verify against context.

1

How to model and verify a countersink in your CAD design

Countersink

SendCutSend ‚ Video

Yes

Educational

Countersink

https://sendcutsend.com/education/video/adding-countersinking-to-your-parts/

Sheet Metal

Direct Check

Non-standard angles may not match fasteners.

1

Are there opportunities for more cost-effective components? (i.e. speaker size, cheaper PCB, battery quantity, etc.)

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Electronics / Wiring

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Managing wire harness complexity and PCB design ensures efficient assembly and maintenance. Clear labeling and color coding minimize wiring errors and improve serviceability.

1

Include 1–2° of draft on core and cavity surfaces in molded parts.

Draft

Protolabs IM Tips

Good

Rule-based

Draft

https://www.protolabs.com/resources/design-tips/plastic-injection-molding-design-tips/

Injection Molding

Teaching Prompt

Draft improves ejection and reduces drag marks. This rule is often taught explicitly in sophomore-level manufacturing courses.

1

Use consistent internal fillet radii throughout the part to reduce tool changes and machining cost.

CNC - Standardization

Xometry CNC Machining Design Guide

Yes

Cost-based

Fillet

https://xometry.pro/wp-content/uploads/2023/07/EN-CNC-Machining-Design-Guide.pdf

CNC Machining

Auto-Suggest

Standardizing radii lets the shop use fewer tools and shorter programs.

1

Multiple surfaces ¬± 0.030 in.

Tolerances

Protolabs ‚ Basic Design Guidelines

Yes

Rule-based

General

https://www.protolabs.com/help-center/basic-design-guidelines/

Sheet Metal

Ask-Back

Missing tolerance can cause rework and fit issues.

1

The maximum depth of holes we recommend is 4 x the nominal diameter.

Hole Depth

Hubs ‚ CNC video

Yes

Rule-based

Hole

https://www.hubs.com/videos/design-cnc-machining/

CNC Milling

Direct Check

Deep holes risk tool deflection and poor chip evacuation.

1

Apply perpendicularity to features that must be square to a datum, such as mounting faces.

Perpendicularity

Xometry GD&T Guide

Good

Rule-based

Surface

https://www.xometry.com/resources/blog/what-is-gdt-and-how-is-it-used/

Machining

Design Check

Perpendicularity creates a tolerance zone around a theoretical 90° orientation, aiding assembly fit.

1

Avoid placing ejector pins on cosmetic or sealing surfaces whenever possible.

Ejection

Protolabs Injection Molding Tips

Bad

Principle-based

Surface

https://www.protolabs.com/resources/design-tips/plastic-injection-molding-design-tips/

Injection Molding

DFM Warning

Ejector marks on visible or sealing areas can cause appearance issues and leaks.

0

Use positional tolerances for hole patterns instead of tight linear dimensions.

GD&T

ASME Y14.5 via Shigley

Good

Principle-based

Hole Pattern

https://www.mheducation.com/highered/product/shigleys-mechanical-engineering-design-nisbett.html

Machining

Tolerance Optimization

Position controls functional fit with looser individual dims.

1

Smooth coatings can prevent gasket adhesion; slight surface texture often improves bonding.

Surface Preparation

Modus Advanced

Yes

Heuristic

Surface Finish

https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications

FIP Dispensing

Informational

Adhesion relies on mechanical grip as well as chemistry. Over-polished surfaces reduce wetting and cause delamination.

1

Avoid excessive draft angles that distort part geometry.

Draft Optimization

Shalin Designs

No

Heuristic

Draft Angle

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

Molding

Informational

Too much draft changes fit and can affect structural or aesthetic alignment.

0

Avoid aspect ratios of height to diameter > 3:1 for unsupported bosses in CNC milling.

Bosses

Groover Manufacturing

Bad

Heuristic

Boss

https://www.wiley.com/en-us/Fundamentals%2Bof%2BModern%2BManufacturing%3A%2BMaterials%2C%2BProcesses%2C%2Band%2BSystems%2C%2B7th%2BEdition-p-00007087

CNC Machining

Stability Check

Tall slender bosses vibrate and are easily damaged.

0

Add lead-in chamfers at tapped holes to guide screws and reduce cross-threading.

Lead-In

Protolabs Design Tips

Good

Heuristic

Edge

https://www.protolabs.com/resources/design-tips/

CNC Machining

Assembly Aid

Chamfers improve assembly ergonomics and protect thread starts from damage.

1

Are there parts that do not nest properly?

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Select materials with adequate machinability ratings for the chosen manufacturing process.

Material Selection

Groover Manufacturing

Good

Principle-based

Material

https://www.wiley.com/en-us/Fundamentals%2Bof%2BModern%2BManufacturing%3A%2BMaterials%2C%2BProcesses%2C%2Band%2BSystems%2C%2B7th%2BEdition-p-00007087

CNC Machining

Material Check

Poor machinability increases tool wear and cycle time.

1

Design bosses for screws with supporting ribs rather than solid thick cylinders.

Bosses

Malloy Plastic Part Design

Good

Principle-based

Boss

https://www.hanser-elibrary.com/doi/book/10.3139/9783446433748

Injection Molding

Feature Optimization

Reduces sink while preserving strength around screws.

1

The distance between two ribs should be 2 ‚ 3X the nominal wall thickness.

Ribs Spacing

SOLIDWORKS Blog ‚ Cardinal rules

Yes

Rule-based

Rib

https://blogs.solidworks.com/solidworksblog/2015/02/the-cardinal-rules-of-designing-injection-molded-plastic-parts.html

Injection Molding

Direct Check

Thick ribs cause sink and warpage.

1

Use relief cuts at the ends of complex bend intersections to reduce tearing.

Relief Cuts

SendCutSend Bending Guide

Good

Heuristic

Relief

https://sendcutsend.com/guidelines/bending/

Sheet Metal

Detail Check

Relief prevents material from stretching and cracking.

1

Review CAD models with manufacturing partners before final release.

Collaboration

Shalin Designs

Yes

Principle-based

Review Process

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

General

Ask-Back

Early joint reviews catch design flaws before they reach the shop floor, saving cost and lead time.

1

Avoid thin walls less than two extrusion widths in FDM printing.

Wall Thickness

Prusa Knowledge Base

Bad

Fact

Wall

https://help.prusa3d.com/

Additive

Feature Validation

Too-thin walls are fragile and may not slice correctly.

0

Protolabs provides a range of internal bend radius tooling options between 0.01 in. and 1 in.

Bend Radius Tooling

Protolabs ‚ Sheet metal toolkit

Yes

Capability

Bend

https://www.protolabs.com/resources/design-for-sheet-metal-fabrication-toolkit/

Sheet Metal

Heuristic Suggestion

Potential DFM concern; verify against context.

1

The radius of the corner will be half the diameter of the cutting tool.

Internal Corners

Fictiv ‚ CNC design guide

Yes

Rule-based

Corner

https://www.fictiv.com/articles/fictiv-cnc-machining-design-guide

CNC Milling

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Blind holes machined with a drill have a conical floor (135o angle).

Drilled Holes

Hubs ‚ CNC video

Yes

Fact

Hole

https://www.hubs.com/videos/design-cnc-machining/

CNC Milling

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Minimize the number of separate adjustment points in a mechanism; design for fixed, repeatable alignment.

Adjustments

Shigley's Mechanical Engineering Design

Good

Principle-based

Mechanism

https://www.mheducation.com/highered/product/shigleys-mechanical-engineering-design-nisbett.html

Assembly

Reliability Prompt

Fewer adjustments mean fewer opportunities for misalignment during assembly or service.

1

Use profile to control both size and location of non-cylindrical bosses or tabs instead of complex coordinate schemes.

Profile

ASME Y14.5

Good

Principle-based

Boss

https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing

Machining

Geometry Control

Profile simplifies specification of non-standard shapes and improves inspection clarity.

1

Critical features should remain accessible to standard metrology tools to prevent custom gauge development.

Inspection Design

Modus Advanced

Yes

Rule-based

QA / Accessibility

https://www.modusadvanced.com/resources/blog/design-for-manufacturing-checklist-manufacturing-readiness-assessment-for-critical-applications

General Manufacturing

Ask-Back

Deep cavities or blind holes require specialized probes. Designing with access in mind saves time and equipment cost.

1

Minimize secondary operations like polishing, trimming, or drilling.

Process Optimization

Analogy Design

Yes

Strategy-based

Manufacturing Operations

https://www.analogydesign.co/blog/dfm-checklist

Multi-Process

Informational

Each post-process adds labor and tolerance variation. Integrating finish quality into the initial process improves yield.

1

Choose machining tolerances around ±0.005" unless tighter is required.

Machining Standards

Shalin Designs

Yes

Rule-based

Tolerance

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

CNC Machining

Informational

Industry-standard tolerances balance cost with precision.

1

Use texture-friendly draft and avoid small, deep recesses that are hard to polish.

Injection Molding - Surface Finish

Xcentric Mold Designing for Plastics

Yes

Manufacturing Constraint

Surface

https://xcentricmold.com/designing-for-plastics/

Injection Molding

Auto-Suggest

Recessed or undercut surfaces are hard to polish or texture, raising tooling cost.

1

“Ensure cross-functional collaboration between design, engineering, and manufacturing.”

Team Integration

6Sigma.us

Yes

Principle-based

Process

https://www.6sigma.us/six-sigma-in-focus/design-for-manufacturing-dfm/

General Manufacturing

Ask-Back

Confirm multi-disciplinary review sign-offs before release.

1

Avoid specifying unnecessarily tight tolerances (e.g., ±0.01 mm) on non-critical dimensions.

CNC - Tolerancing

Hubs CNC Machining Guide

Yes

Cost-based

General

https://www.hubs.com/guides/cnc-machining/

CNC Machining

Diagnostic

Tighter tolerances require slower machining, inspection, and sometimes secondary operations.

1

A +/- 1 degree tolerance on all bend angles is generally acceptable in the industry.

Bend Angles

Geomiq ‚ Sheet metal guide

Yes

Rule-based

Bend

https://geomiq.com/sheet-metal-design-guide/

Sheet Metal

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Can product components be easily detached or damaged by consumer?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

General DFM

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Avoid abrupt wall thickness transitions; use tapers or fillets to blend.

Wall Transitions

Malloy Plastic Part Design

Good

Principle-based

Wall

https://www.hanser-elibrary.com/doi/book/10.3139/9783446433748

Injection Molding

Teaching Prompt

Smooth transitions reduce stress and cosmetic defects. This rule is often taught explicitly in sophomore-level manufacturing courses.

1

chatbots may miss nuanced design reasoning ‚ physical intuition and edge cases matter.

Limitations

Interview

No

Conceptual

Assistant

null

/Software

Ask-Back

Preference-based; confirm desired level of automation.

0

Radiused corners are required, and must be larger than the cutter to be used.

Internal Corners

Fictiv ‚ CNC design guide

Yes

Rule-based

Corner

https://www.fictiv.com/articles/fictiv-cnc-machining-design-guide

CNC Milling

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Use standardized components and tools wherever possible.

Standardization

Analogy Design

Yes

Rule-based

Parts / Procurement

https://www.analogydesign.co/blog/dfm-checklist

Assembly / Machining

Informational

Off-the-shelf fasteners, bearings, or switches reduce lead time and ensure replaceability.

1

Can the product be secured in a less labor intensive method?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

General DFM

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Keep minimum flange length at least 4× material thickness to allow proper contact with tooling.

Sheet Metal - Flange Length

Protolabs Sheet Metal Design Guidelines

Yes

Manufacturing Constraint

Flange

https://www.protolabs.com/services/sheet-metal-fabrication/design-guidelines/

Sheet Metal

Auto-Suggest

Short flanges don’t engage the press brake die properly and may deform or slip.

1

Avoid designs that require many side actions or lifters; simplify to straight-pull molds where possible.

Injection Molding - Undercuts

Stratasys Direct IM Design Guidelines

Yes

Cost-based

Undercut

https://info.stratasysdirect.com/rs/626-SBR-192/images/Stratasys_Direct_Design_Guidelines_Injection_Molding_201907.pdf

Injection Molding

Warning

Side actions and lifters add cost, complexity, and risk of mechanical failure in the mold.

1

Verify accessibility for cutters and inspection probes in all orientations.

Accessibility

Shalin Designs

Yes

Rule-based

Reachability

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

Machining

Ask-Back

Poor access increases cycle time or may make features unmachinable.

1

Holes and slots should be at least 6X MT from each other.

Feature Spacing

Xometry ‚ Sheet Metal Design Guide (PDF)

Yes

Rule-based

Hole/Slot

https://cdn2.hubspot.net/hubfs/340051/Design_Guides/Xometry_DesignGuide_SheetMetal.pdf

Sheet Metal

Heuristic Suggestion

Potential DFM concern; verify against context.

1

Reduce undercuts and overhangs that require special tooling.

Tooling Complexity

Shalin Designs

No

Rule-based

Undercut

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

Molding / Machining

Informational

Side actions and custom tools add setup and maintenance time.

0

Ensure proper dimensioning in cast parts to prevent shrinkage issues.

Casting Design

Shalin Designs

Yes

Rule-based

Dimensioning

https://shalindesigns.com/blog/optimize-cad-models-with-design-for-manufacturing-dfm

Casting

Informational

Poor dimension control leads to porosity or misalignment in castings.

1

Avoid chain dimensioning for critical features; dimension from common datums instead.

Dimensioning

ASME Y14.5

Bad

Rule-based

Dimension

https://www.asme.org/codes-standards/y14-standards

General

DFM Warning

Chain dimensions accumulate tolerance stack-up; datum-based dimensions localize variation.

0

Are there any mechanisms of the product that may not meet life-cycle requirement?

Packaging

Quality-One DFM/A Sample Checklist

Yes

Checklist

General DFM

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

Simplifying complex mechanisms improves reliability and reduces the risk of assembly errors or part failure. It enhances manufacturability and minimizes maintenance or repair time.

1

Can irregular parting lines be eliminated?

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

Assembly / Ergonomics

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1

Are there any missing surface finishes/textures?

Product Design - General

Quality-One DFM/A Sample Checklist

Yes

Checklist

General DFM

https://quality-one.com/uploads/2017/03/DFMA-Sample-Checklist.xlsx

General Manufacturing

Ask-Back

This checklist item prompts engineers to consider manufacturability, cost efficiency, and reliability in early design. Addressing it prevents downstream issues during assembly, testing, or production.

1