CAD quote and DFM review
Prepare a CAD package that lets an engineer review manufacturability, clarify the quote and identify the decisions that affect cost, lead time and part acceptance.
A quote review connects the model to the delivered part
A CAD file describes geometry. A useful manufacturing review also needs the material, quantity, finish, inspection, fit and use that give the geometry meaning.
Geometry
What is the part?
Send the native or neutral CAD, revision and any assembly or mating geometry needed to understand interfaces.
Requirement
What must it do?
Name loads, environment, fit, appearance, quantity and the features that cannot change.
Evidence
How will it pass?
Define inspection, material records, finish acceptance and any customer or regulatory forms before the route is priced.
Build a quote package with one source of truth
Conflicting files create a false sense of precision. Put the released CAD, drawing and requirements in a package whose revision and units are unambiguous.
Check your quote package
0 of 9 reviewed
Mark each item when you have addressed it, or confirmed that it does not apply to this order.
Your checks stay on this page until it is reloaded. This is a preparation aid; the manufacturing review resolves the open requirements.
| Item | Include | Common gap |
|---|---|---|
| 3D model | STEP or the requested native format, named with revision and units | A model that omits the mating part, material condition or intended orientation. |
| 2D drawing | Datums, tolerances, threads, surface finish, material, notes and revision | A drawing with tight defaults but no statement of which features control function. |
| Assembly context | Mating parts, fasteners, keep-outs and the assembly direction | A single component that hides the actual fit or tool-access requirement. |
| Quantity and schedule | Prototype, pilot or repeat quantity plus target need date | A one-off request used to infer production economics. |
| Acceptance | Inspection, certifications, finish sample and packaging requirements | “Full inspection” without features, sample size or records. |
What an engineer should review before pricing
The review should locate manufacturability risk early, while a design change is still cheaper than a rework or an inspection dispute.
The corner limits the cutter
In this plan view, a pocket with a larger internal radius admits a larger cutter. Give the cutter room to arc around the corner; a relief can clear a square mating part.
The holder also needs clearance
In section, a long tool must clear the pocket mouth with its shank and holder. A shorter reach reduces deflection; changing the corner alone may not clear the holder.
Schematic views, not to scale. The manufacturing plan must match the part geometry and material.
| Review area | Questions | Output |
|---|---|---|
| Process | Does CNC, sheet metal, additive, molding or a hybrid route fit the geometry and quantity? | A route assumption and any alternatives worth comparing. |
| Tool access | Can standard tools reach pockets, holes, threads and finish-critical faces? | Features to open, radius, split or sequence differently. |
| Tolerances | Which dimensions control mating, sealing, motion or load? | A short critical-feature list and a realistic general tolerance. |
| Material | Is the named grade available and compatible with the process and environment? | A confirmed alloy/polymer condition or a documented alternate. |
| Finish | What is cosmetic, masked, conductive, corrosion-critical or fit-critical? | Finish sequence, sample and post-finish dimensions. |
Ask questions that change the manufacturing decision
A DFM question is useful when its answer changes the model, process, inspection or acceptance plan. General reassurance does not resolve a feature-level risk.
- Ask for the controlling feature. “Which feature drives the extra operation?” is more useful than “Can you make this cheaper?”
- Ask for a standard alternative. Request a standard tool, radius, thickness, hardware or finish that preserves the requirement.
- Ask what changes after finishing. Clarify dimensions, masking, colour, texture and inspection state after the final operation.
- Ask how the first part will be accepted. Agree the drawing revision, sample, instruments, report and disposition path before release.
The CNC DFM cost guide gives machining-specific change examples; this page applies the same review logic across processes.
Choose the route from function, quantity and change risk
A quote is a decision about a complete part, not a price for a file. Keep the design flexible when the requirement is still moving; lock the route when the design and acceptance evidence are stable.
| Situation | Compare | Keep visible |
|---|---|---|
| One or a few prototypes | CNC, additive and sheet routes that can validate the critical feature quickly | What the prototype proves and what it cannot prove about production. |
| Pilot or low volume | Batch economics, inspection, finish repeatability and change control | Which requirements are now stable enough to freeze. |
| Recurring production | Repeatability, material supply, tooling, process capability and records | The approved recipe, revision and response to process changes. |
| Complex assembly | One-piece geometry versus several manufacturable parts and assembly operations | Datums, fasteners, service access and inspection ownership. |
Review the quote as a set of assumptions
The quote should make its assumptions visible: material and condition, process, quantity, finish, inspection, lead-time basis and any exclusions. That makes two quotes comparable and makes a later revision traceable.
Learn from a first article
Use representative geometry, material and finishing to verify the properties that matter before repeating the order.
Control the production recipe
Record material product, build settings, orientation, finishing and inspection criteria. Confirm changes before the next batch.
Schematic illustrations; not to scale. Confirm the design for the chosen material, process and final use.
A lower price can reflect a different finish, tolerance, inspection plan, material condition or delivery assumption. Compare like-for-like requirements before comparing totals.
If the supplier proposes a change, record it against the model and drawing. An accepted DFM suggestion becomes part of the released configuration only when the design owner approves it.
Move from quote to first article without losing the review
The handoff should carry the final files, requirements and decisions into production. A first article or representative sample then tests the feature that mattered in the review.
Design the mating pair
Clearance is the hole diameter minus the shaft diameter. Both parts contribute to the final fit.
Allow for the worst case
Minimum clearance = smallest hole − largest shaft. A nominal gap alone does not guarantee free movement.
Schematic illustrations; not to scale. Confirm the design for the chosen material, process and final use.
- Name the release. Carry CAD, drawing, material, finish and inspection revisions into the order and report.
- Inspect the critical path. Measure the fit, sealing, datum, appearance or load feature that drove the quote choice.
- Close the loop. Record approved deviations and update the design or process before the next batch.
For quality records and FAI terminology, see the inspection and certifications guide.
Frequently asked questions
What files do I need for a manufacturing quote?
Provide the released CAD with units and revision, a drawing when tolerances or notes matter, mating geometry or assembly context, material and condition, quantity, finish, schedule and inspection or certification requirements.
What does a DFM review check?
It checks whether the geometry, process, tools, material, tolerances, finish, inspection and quantity fit together. A useful review identifies the feature that creates risk and gives a change or clarification that preserves function.
Should I send a 2D drawing with a STEP file?
Send both when the drawing carries tolerances, datums, finishes, threads, notes or acceptance requirements that the model does not contain. Make the revision relationship explicit.
Why do two quotes for the same CAD differ?
They may assume different material conditions, process routes, tolerances, setups, finishes, inspection packages, quantities, lead times or shipping terms. Normalize those assumptions before judging the price.
Who owns a DFM change suggested during quoting?
The design owner should approve any change to geometry or requirements. Record the accepted revision so the quote, production file and inspection report refer to the same released configuration.
Sources and further reading
- Protolabs: designing for speed in CNC machiningIllustrates why an early CAD review can identify setups, tool access, tolerances and process choices.
- Protolabs: sheet metal fabrication design guidelinesShows the kinds of bend, feature-distance, hardware and finish questions a sheet-metal review should resolve.
- ISO: ISO 9001 quality management systemsQuality-system context for documented review and controlled changes; certification status must be verified separately.
Make the quote review part of the released design.
Upload your CAD and drawing with the material, quantity, finishing and critical dimensions. Confirm the manufacturing route before production.