DEMO — fictional range. Local brief only, NOT SENT. No personal data is collected or transmitted.
BATCH
Two batches a month apart have to work together.
For parts bought in quantity, the useful question is not whether one piece is correct but whether batch forty matches batch one. A batch record is what answers it.
- Batch identifier
- Which run, on which machine, on which day
- Material heat
- Which heat the batch was made from, not just the grade
- Tool changes
- When tooling was replaced during the run, and why
- First and last piece
- Measured, because they differ by the amount the tool wore
- Sample size
- How many pieces were checked, and how they were chosen
- Gauge used
- Which gauge, and when it was last calibrated
- Non-conformance
- What was rejected, and what happened to it
- Retained sample
- A piece kept from the batch, for as long as the agreement says
Why the first and last piece matter most
They bracket the run. A report that measures a piece from the middle of a batch says nothing about where the tool was when the run started or finished, and tool wear is the thing that moves.
What a first article cannot tell you.
Whether the run held. A first article is made before the run, often deliberately carefully, and it is the easiest piece in the batch to get right.
The question worth asking instead.
Which dimension moved most between the first and last piece of the last batch. A supplier who can answer that has measured their own process rather than their sample.