Key takeaways
- PPAP is an evidence pack, not a form. The forming process, the finish and the material all need to be inside it.
- Traceability starts at the wire heat number and has to follow the part through forming, welding and plating.
- Most automotive wireform changes are small process changes that nobody classifies as a change.
- A run at rate proves capacity and reveals handling problems that a sample batch hides.
What an automotive programme expects
An automotive wireform is usually a small part with a large paper trail. The programme expects a documented process, a first article that covers every dimension on the drawing, a control plan for the run, and a record that links the delivered part back to the wire that made it. None of that is unusual, but formed wire adds a complication: the process is a set of bends, and bends move.
The programme also expects change control. A new wire supplier, a different temper, a re-sequenced bend or a moved plating line can change springback, load and fatigue life without changing the drawing. The supplier has to know which of those events counts as a change and notify before the part ships.
The PPAP elements that matter for formed wire
A full PPAP has many elements, and a wireform does not need to treat them all equally. The ones that carry real information for this process are the design record, the process flow, the first article, the control plan, the measurement system check, the run at rate and the part submission warrant.
The design record is the drawing at the correct revision, including the general tolerance and any customer specific requirements. The process flow should name straightening, forming, any welding or threading, stress relief, finishing and inspection. The first article should report every ballooned dimension plus the functional calls, which for a spring or contact means load at a stated length rather than a set of linear dimensions alone.
- Design record at the current revision, with all customer specific calls
- Process flow diagram that matches the route on the floor
- Dimensional results for every ballooned feature, plus material and performance results
- Control plan naming the check, the frequency, the gauge and the reaction plan
- Measurement system study for the gauges that decide pass or fail
- Run at rate result at the quoted cycle time and staffing
- Part submission warrant signed against the actual submission level
Traceability from heat to part
Traceability in a wireform programme usually means four links: the wire heat or lot, the forming lot, the finishing lot and the despatch lot. A mill certificate identifies the heat. The forming lot ties a quantity of parts to a reel or a set of reels. The finishing lot ties the batch to a plating or coating record. The despatch lot ties the carton to the customer and the date.
The weak link is often the reel change. If two reels of the same grade but different heats are loaded on the same run, the parts are a mixed lot unless the change is recorded. Decide whether mixed heats are acceptable. If they are, the record must show both certificates. If they are not, the run has to stop at the reel change and the lot has to be separated.
A heat number on a certificate is not traceability
Traceability is the link between that number and the carton in the customer's warehouse. Test the link by picking a delivered carton and walking backwards to the mill certificate. If the walk needs an email, the system is incomplete.
What counts as a change
Most suppliers have a change procedure for a drawing revision. Fewer have one for the events that actually move a wireform: a new wire mill, a different temper within the same grade, a change in straightening settings, a new set of bend pins, a re-sequenced bend, a different plating line, or a move to another machine. Each of these can change the part without touching the drawing.
The practical rule is that anything which can change springback, load, stress or corrosion protection is a change. Classify it before it happens, agree the evidence with the customer, and do not ship until the evidence is accepted. A change that is discovered after shipment is a containment event, not a notification.
| Change | Notify before | Evidence to agree |
|---|---|---|
| Wire mill or distributor | Order placement | Mill certificate and a first article comparison |
| Grade or temper | Quotation | Material certificate, load and fatigue review |
| Bend sequence or tool set | First off | Dimensional and load results on the new setup |
| Machine or plant move | Planning | Process flow, control plan and run at rate |
| Plating source or thickness | Batch booking | Thickness, adhesion and bake records |
| Weld or secondary operation | Process design | Pull or shear results and a revised control plan |
| Packing or label format | Before despatch | Label sample and carton check |
The list is a starting point. Customer specific requirements may add events, and the stricter list always applies.
Run at rate is a capacity test and a handling test
A run at rate takes the quoted cycle time and proves it with the real staffing, the real handling and the real inspection. For a formed wire part, the interesting failures are rarely at the press. They are at the reel change, the tangle, the manual unload and the pack station. A part that runs at cycle time for ten minutes but tangles every two hundred pieces does not have the capacity in the quote.
Run the test long enough to see at least one reel change if the volume justifies it. Record the output, the scrap, the downtime reason and the inspection results. If the line needs a second operator to keep up, the quoted piece price is wrong, and the programme will find out in the first month of production.
Annual requalification and record retention
Many programmes require an annual layout inspection or a periodic requalification. For a wireform, that should include the full dimensional report, a load check at the stated length, a plating thickness check and a visual standard. It is also the moment to re-check the control plan against what the floor actually does.
Record retention is usually defined by the customer, and it is often longer than the life of the programme. Keep the material certificates, first articles, control plans, calibration records and non-conformance history together, indexed by part number and lot. A record that cannot be found during an audit is treated as a record that does not exist.
The gaps that show up most often
The first gap is a first article that reports dimensions but not function. A spring that measures correctly and delivers the wrong load at the installed height has not been approved, it has been measured. The second is a control plan that names a check nobody performs, which is worse than no check because it looks like control.
The third is a change that was treated as maintenance. A new set of bend pins, a re-set straightener or a swapped reel is often recorded in a maintenance log rather than a change log. Ask to see both logs and compare them. The difference between the two is usually where the un-notified change is hiding.
Frequently asked questions
Does a wireform need a full PPAP?
It depends on the customer and the submission level. Many programmes ask for a full pack for a new part, then a reduced pack for a change. The forming process, material and finish still need to be covered, because those are the variables that move a formed wire part.
What is the traceability unit for a wireform?
Usually the forming lot, tied to one or more wire heats and to a finishing batch. The lot size should be small enough that a problem can be contained without scrapping a year of stock. Agree the lot definition with the customer before the first run.
Is a new wire supplier a change that needs notification?
Yes on most automotive programmes. A different mill can change cast, helix, surface condition and springback even when the grade and diameter are nominal. Treat it as a change and agree the evidence before the first shipment.
How long should PPAP records be kept?
Follow the customer requirement, which is often the life of the programme plus a defined period. Keep the records indexed by part and lot so they can be produced during an audit without a search through personal folders.
Sources and further reading
- AIAG Production Part Approval Process, 4th edition
- IATF 16949:2016, Automotive quality management system standard
- ISO 2768-1:1989, General tolerances, linear and angular dimensions
Qumek Engineering Desk
Engineering team
The engineering team behind Qumek drawings, DFM notes, tolerances and inspection standards. Every guide is reviewed against the drawings and processes used on live programmes.
Building an automotive wireform submission?
Send the drawing and the customer specific requirements. The engineering desk will map the PPAP elements to the forming and finishing route.
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