Short answer: First-off and last-off checks help buyers confirm that a stamped part lot started correctly and did not drift before completion. The RFQ should define setup approval, CTQ dimensions, burr checks, finish condition, sample count, retained samples, record format, reaction rules, and whether restart checks are needed after coil changes, tool maintenance, or press stops.
First article inspection proves an initial controlled sample. Production lots need a different question: did this run start in control, stay in control, and end with acceptable parts? First-off and last-off checks make that decision visible before parts are packed and shipped.
Use this page with the મેટલ સ્ટેમ્પિંગ control plan checklist, first article inspection checklist, AQL sampling plan guide, and run-at-rate validation guide.
Lot release checks to define
| Check point | Why it matters | RFQ evidence |
|---|---|---|
| First-off | Confirms setup, tool position, feed, and inspection method before the run continues. | Approved first pieces, measured CTQs, operator signoff, and time stamp. |
| Restart check | Coil change, die adjustment, or press stop can change the process. | Trigger list, sample count, and approval responsibility. |
| In-process check | Detects drift before the end of the lot. | Frequency, features, gage, SPC rule, and reaction plan. |
| Last-off | Shows the run ended without unchecked drift or tool wear. | Last-piece measurements, retained samples, defect review, and release record. |
Separate lot release from launch approval
A lot release check does not repeat the full first article package. It focuses on the features most likely to move during routine production: hole location, bend angle, formed height, burr growth, cutoff tab, plating appearance after handling, part count, label, and packaging condition. The buyer should identify CTQ features instead of asking the સપ્લાયર to measure everything every time.
For high-volume tools, first-off and last-off records also help diagnose complaints. If a shipped lot has a burr, missing feature, scratch, or mixed revision, the record should show whether the issue was present at start, appeared during the run, or happened during packing. This works best when lot labels connect to material, tool, operator, and inspection records through the lot traceability guide.
Define restart triggers clearly
Some variation happens after a stop, coil change, die sharpening, sensor adjustment, material splice, feeder correction, or operator shift change. If the control plan does not say when to re-check parts, a સપ્લાયર may treat the lot as one continuous run even when the process changed.
Restart checks should match risk. A simple bracket may need a few dimensions and appearance checks. A small terminal may need burr side, carrier cutoff, contact height, plating condition, and reel orientation. If the tool has known drift risk, connect the release plan to the tooling maintenance audit checklist and require evidence after maintenance.
RFQ details to include
- Drawing, revision, CTQ list, material, finish, burr limits, cosmetic zones, and functional inspection features.
- First-off sample count, last-off sample count, restart trigger list, in-process check frequency, and approval responsibility.
- Gage, fixture, CMM, optical check, force test, resistance test, or visual sample used for each feature.
- Record format, retained sample rule, lot label format, operator signoff, date, time, press, tool number, and material lot.
- Reaction plan when first-off fails, last-off fails, or an in-process check detects drift.
- Normal lot size, release quantity, annual volume, shipment cadence, and report documents required with each lot.
How to compare સપ્લાયર answers
A strong answer names the specific features checked at start, during production, and at the end. It also explains what happens after a stop or adjustment. A weak answer only says quality inspection is performed.
Ask for a sample record before production starts. A blank form often reveals whether the સપ્લાયર understands the drawing, gage, revision, lot traceability, and release responsibility. If a buyer wants records with every shipment, that requirement should be priced before the first order.
Send drawings, CTQ features, lot size, release cadence, and record needs through the contact page. Use the RFQ form to request first-off and last-off checks when lot drift could stop assembly.
FAQ
What is a first-off check in stamping?
It is the approval of initial production pieces after setup to confirm the tool, material, feed, and inspection method are ready to run.
Why keep last-off samples?
Last-off samples help show whether the run ended in control and provide evidence if a later complaint suggests drift or tool wear.
Does first-off replace first article inspection?
No. First article approval is usually a launch or tooling approval step. First-off checks are routine lot release controls.
What should be included in a lot release RFQ?
Include CTQ features, sample counts, restart triggers, gage method, record format, retained samples, lot labels, volume, and shipment cadence.