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Aluminum Stamping DFM and RFQ Guide
An aluminum stamping RFQ is ready for tooling review only when it identifies the exact alloy, temper and product form; the features that can move after forming; the surfaces that must remain protected; the permitted burr and edge condition; and the inspection evidence that will release samples and production lots. “Aluminum part” is not a usable material specification, and a finished CAD model does not tell a stamper how the buyer will judge springback, pickup marks, flatness or fit.
This guide is for OEM engineers, sourcing teams and supplier-quality reviewers buying custom aluminum stampings. It turns common forming risks into drawing and RFQ decisions. It does not prescribe a universal bend radius, die clearance, lubricant, press, tolerance or process window. Those choices depend on the released material, geometry, tool concept, surface requirement and validation plan.
Start with alloy, temper and incoming stock—not a generic material name
Alloy and temper describe different parts of the material condition. Two sheets both called aluminum can respond differently during blanking, bending or drawing because their chemistry, temper, thickness tolerance, surface condition and rolling direction differ. A substitution that looks harmless on a purchase order can change forming load, edge behavior, springback, marking or the evidence needed for approval.
The Aluminum Association maintains the alloy and temper designation system in ANSI H35.1/H35.1M and publishes separate mill-product tolerance resources. ISO 6361-1 addresses technical conditions for inspection and delivery of wrought aluminum sheet, strip and plate. These documents help a buyer define the incoming product; they do not select a grade for a particular stamped part and do not prove Zhengna Technology compliance with a customer specification.
| Material input | What the RFQ should state | Why it affects tooling or acceptance |
|---|---|---|
| Alloy and temper | Exact designation, approved source or controlled alternative route | Formability, strength, springback and surface response can change |
| Product form | Coil, strip or sheet; thickness and width; any applicable mill tolerance standard | Stock variation influences feed, clearance, forming and measurement baselines |
| Rolling direction | Whether grain direction is controlled relative to bends, clips or visible surfaces | Orientation can affect bend behavior and how parts nest in strip |
| Surface condition | Finish, protective film, acceptable handling marks and visible zones | The forming route and material handling may need different controls |
| Traceability | Required material document, lot identity and substitution approval | Sample evidence is not comparable when the material state changes silently |
Define springback as a part-state and measurement problem
Springback is the elastic movement that remains after forming load is removed. It does not occur as one uniform angle correction across every feature. Open flanges, return bends, curved walls, embossed areas and asymmetric sections can move differently. Tool compensation may improve one dimension while shifting another, so the drawing needs to identify the interfaces that matter rather than simply requesting “control springback.”
State when and how the part is measured. A free-state part on a surface plate, a part located by functional datums and a part restrained in its mating assembly are not the same condition. If a bracket must fit two locating points, show those points and the permitted restraint. If a flatness or profile callout applies before or after a finishing operation, say so. The supplier then has a defined target for tool tryout, fixture design and inspection.
- Mark the functional datums. Identify the faces, holes, tabs or clips that establish assembly position.
- Separate free-state and assembled requirements. Do not use an assembly fixture to hide unacceptable free-state movement unless the drawing permits that condition.
- Connect bends to material direction. Record rolling direction where it is controlled and show which bends or formed features are sensitive.
- Use staged evidence. Review the first tool samples, the adjusted tool state and a repeatable run rather than accepting one manually selected part.
- Freeze the accepted baseline. Link the released tool revision, material state, inspection fixture and approved drawing revision.
Galling and pickup are surface-system risks
During sliding contact, aluminum can transfer to a tool surface. The resulting pickup may score later parts, change local friction or build until the formed shape shifts. Treating every line as a cosmetic defect or every lubricant change as a complete fix misses the system: contact pressure, sliding distance, tool finish and condition, material surface, lubrication, debris and cleaning all interact.
The buyer should define which surfaces are functional, cosmetic or hidden; which marks are unacceptable; whether protective film is allowed; and whether cleaning, coating or joining follows stamping. The supplier can then review tool material or treatment, polish direction, lubrication strategy, maintenance triggers and handling without promising that one standard setup fits every alloy and geometry.
| Observed issue | Questions before changing the process | Evidence worth retaining |
|---|---|---|
| Repeating score at one feature | Does the mark follow a tool contact path, an edge, debris or a specific station? | Part location, station, tool condition and material-lot record |
| Pickup grows during the run | Did friction, lubrication, tool surface or cleaning frequency change? | Run sequence, maintenance point and before/after samples |
| Random handling marks | Are parts sliding, nesting or contacting metal after ejection? | Container, separator, transfer and packing review |
| Finish defect after secondary processing | Was the surface already damaged, contaminated or dimensionally out before finishing? | Inspection at the handoff between stamper and finisher |
Specify burrs and edges by function
“No burr” is not a measurable drawing requirement. Blank and pierced edges have a direction, and their condition can affect assembly force, electrical contact, wire or seal damage, coating coverage, handling safety and dimensional inspection. Identify the allowed burr side, critical edges and any edge-break requirement. If a hole or slot is checked after deburring or finishing, state the applicable part condition.
Do not let a general edge note override a feature that needs a different rule. A locating hole, contact tab and hidden trim edge may justify different limits and methods. The inspection plan should name the measurement or comparison method, sample stage and reaction when an edge condition drifts. Tool-maintenance evidence is useful because an edge trend may warn of wear before the part fails another dimension.
Protect visible and functional surfaces through the complete route
A surface requirement belongs to the full material-to-packaging route. A sheet may arrive within its mill condition and still be damaged during feeding, forming, part ejection, washing, stacking or shipment. Mark Class A or otherwise controlled areas on the drawing, define the viewing or comparison method, and state whether tool contact, draw lines, orange peel, dents, scratches, adhesive residue or rub marks matter to function or appearance.
If anodizing, conversion coating, plating, painting, bonding or welding follows stamping, clarify which dimensions and appearance rules apply before and after that step. Do not assume that a finish hides forming damage or that a pre-finish dimension remains unchanged. The separate stamped-parts finishing RFQ guide explains how to control zones, masking and post-finish dimensions without implying that Zhengna Technology performs every secondary process in-house.
Use mill-product tolerances as incoming inputs, not finished-part acceptance
ISO 6361-3 specifies shape and dimensional tolerances for cold-rolled aluminum strip used in general engineering applications. ISO 6361-4 addresses sheet and plate. Those standards concern the incoming mill product within their scope. They do not automatically define the finished stamping's hole position, formed profile, flange angle, flatness, surface appearance or assembly fit.
The RFQ should therefore separate three layers: the stock specification, the formed-part drawing, and the process or inspection evidence. If stock width or thickness is critical to a progressive strip, state the permitted source and tolerance reference. If the finished part has a profile or flatness requirement, define its datums, free or restrained condition, measurement fixture and stage. If a feature will be coated, say whether the final dimension is measured after finishing.
Plan tool trials around decisions, not sample counts alone
A first tool trial should answer named questions. Does material feed consistently? Are bend angles and formed profiles approaching the released requirement? Where are pickup, scoring, distortion or edge risks appearing? Can the proposed datum and gauge strategy produce repeatable results? A large pile of samples does not answer those questions if the tool revision, material lot and process state are not recorded.
For each approval stage, define the drawing revision, sample quantity, material state, tool revision, features to report, appearance reference, assembly check, packaging expectation and approval owner. Record temporary adjustments and deviations separately. A hand-tuned sample may be useful for diagnosis, but it should not be presented as evidence that an ongoing production route is stable.
Aluminum stamped-part RFQ checklist
| RFQ field | Minimum useful input |
|---|---|
| Controlled files | 2D drawing, 3D model, revision, units, governing-file rule and marked critical features |
| Material | Alloy, temper, product form, thickness, source/substitution rule, rolling-direction requirement and material records |
| Functional geometry | Datums, mating parts, bend directions, free or restrained measurement state, profile/flatness and edge orientation |
| Surface and edge | Visible/functional zones, acceptable marks, protective film rule, burr side, edge break and handling limits |
| Secondary route | Finishing, cleaning, joining or assembly responsibility; before/after-process dimensions; masking or surface restrictions |
| Tooling and approval | Tool ownership, trial stages, change approval, maintenance evidence and disposition of pre-change stock |
| Inspection | Method, fixture, sampling, material/lot identity, capability evidence when required and reaction to nonconformance |
| Commercial inputs | Prototype and production quantities, annual forecast, launch timing, delivery location, packaging and required documents |
Where Zhengna Technology fits
Zhengna Technology reviews made-to-drawing stamped-part RFQs through material, geometry, tooling, forming, burr, surface, inspection and delivery requirements. For an aluminum part, send the exact alloy and temper or the controlled approval route rather than asking the supplier to infer material from the application. Feasibility remains subject to the released drawing, stock availability, tool concept, process trials and agreed validation.
Use the custom stamping parts commercial page for capability and quotation context. The stamping material-selection checklist covers cross-material decisions, and the progressive stamping supplier-audit checklist covers general tooling and batch-control review. Review the quality-control context, then use the contact page to describe the project and arrange controlled drawing transfer through the agreed sales channel.
This page does not claim a standard aluminum alloy, temper, bend radius, tolerance, press capacity, die life, lubricant, inspection frequency, surface-treatment route, certification, MOQ or lead time. The project quotation and approved quality plan govern those points.
Frequently asked questions
What should an aluminum stamping RFQ specify first?
Start with the controlled drawing and model, exact alloy and temper, product form and thickness, rolling-direction requirement, functional datums, critical bends and interfaces, surface zones, burr direction, secondary processes, quantities and the evidence required for approval.
Can one springback allowance be used for every aluminum stamped feature?
No. Springback depends on the actual material state, geometry, forming sequence, tool contact and restraint. Define the functional geometry and measurement condition, then use tool trials and recorded adjustments to establish the accepted process.
How should galling or pickup risk be addressed?
Review the complete contact system: tool surface and condition, contact pressure and sliding path, material surface, lubrication, debris, cleaning and handling. Define the surfaces and marks that matter, then retain evidence linking the symptom to a station, tool condition and material lot.
Does an aluminum mill tolerance standard define the finished stamped part?
No. Standards such as ISO 6361-3 and ISO 6361-4 define shape and dimensional tolerances for certain incoming strip, sheet or plate products. The finished part still needs its own drawing, datum, free or restrained state, process stage and inspection method.
What does the workshop image prove?
It is representative evidence of a Zhengna Technology precision press workshop. It does not prove a particular aluminum grade, tool, tolerance, output rate, inspection result or customer approval.
Sources and review boundary
- The Aluminum Association — standards and alloy registration resources
- ANSI H35.1/H35.1M — alloy and temper designation systems
- ISO 6361-1:2011 — technical conditions for inspection and delivery
- ISO 6361-3:2014 — strip shape and dimensional tolerances
- ISO 6361-4:2014 — sheet and plate shape and dimensional tolerances
Published and reviewed: July 26, 2026 by Zhengna Technology. Sources structure material and inspection questions; they do not establish a Zhengna Technology certification, process approval or project result.