Terminal Block Sample Approval: Record Deviations Before the Order
A sample arrives, it looks right, and the order is released. Months later the production batch is found to differ from the sample in a way nobody wrote down — a plating finish, an entry chamfer, a marking position — and there is no record to settle it. The problem is not the sample. It is that approval was given without a baseline to approve against.
This guide covers how to define the baseline, what to record for each sample, how to handle deviations, and what sample approval does not cover. Feed-through blocks and other families are listed in the product range.
Quick answer: Approve a sample against a written baseline — your drawing, the supplier's drawing, or a physical reference with a revision. Record every deviation, decide who accepts it, and state what the approval covers. State in the order how sample approval relates to production release and how batch conformity will be checked.
In this guide
- Define the baseline first
- What to record for each sample
- Deviations and disposition
- What sample approval does not cover
- Handover to incoming inspection
- FAQ: Frequently Asked Questions
- Next steps: send the baseline with the request
Define the baseline first
The baseline is the agreed drawing, specification or physical reference used to check the sample. Without one, comparison happens in memory, and memory is not auditable.
Choose one of these, and say which:
- Your drawing, issued to the supplier with a revision number.
- The supplier's drawing, accepted by you in writing before the sample is made.
- A physical reference, such as the part currently in use, with a photograph, measurements and a date.
- A combination, where your drawing covers the interface and the supplier's covers the internals, with the split stated explicitly.
What to record for each sample
| Item | What to record | Example of a usable entry |
|---|---|---|
| Sample identification | Supplier's sample reference and date | Sample 2026-10-A, received 12 Oct |
| Baseline reference | Document and revision | Illustrative drawing TB-001, rev B |
| Dimensions checked | Which dimensions, with the measured values | Pitch 9.5 mm; length 92.4 mm |
| Material and appearance | Colour, surface, marking position | Black; marking as drawing |
| Functional checks | What was operated or checked | Screw travel, entry, retention on rail |
| Deviations | Numbered list, or "none" | DEV-01 plating duller than sample |
| Disposition | Accept, accept with limitation, or reject | DEV-01 accepted for this order |
| Approval statement | Who approved and what it covers | Approved for the sample; batch to be produced to the same drawings |
| Attachments | Photographs and the marked-up drawing | Photographs 1–6; drawing marked |
Deviations and disposition
A deviation is any difference from the baseline, including a difference that does not matter. Recording it costs a line; not recording it can cost a batch.
- Number each deviation, so it can be referenced in later correspondence.
- Describe what is different, not what it looks like: "entry chamfer not present" rather than "edge looks sharper".
- State the disposition: accepted, accepted with a limitation, or rejected with the required action.
- Say who decided, and on what basis — appearance, function, measurement or the supplier's explanation.
- State whether the deviation is a one-off or expected in production. This is the sentence that prevents the dispute later.
- Do not accept a deviation silently by failing to mention it. Record who accepted each deviation and whether the decision applies to production.
What sample approval does not cover
| Common assumption | What the approval actually covers | What it does not cover |
|---|---|---|
| "The sample was fine, so the batch will be fine" | That the sample matched the baseline on the recorded points | Batch equivalence, unless the order states that the approved sample defines the batch and says how it is verified |
| "We approved the part" | The part as described by the baseline document and revision | A later revision of the drawing, which requires the approval to be revisited |
| "The supplier signed it off" | The supplier's confirmation of what can be met | The buyer's responsibility for defining the requirement |
| "It passed inspection" | The points that were checked, by the method recorded | Points that were not checked, such as material or plating, unless they were in the record |
| "We do not need incoming checks now" | Nothing about later deliveries | Drift between batches, which is why incoming inspection continues |
Handover to incoming inspection
Sample approval is only useful if the receiving function can use it.
- Pass the approved drawing and the deviation list to incoming inspection, with the sample reference.
- Identify the characteristics to check on each delivery, and how: dimension, appearance, function or documentation.
- State the sampling and the acceptance rule for each characteristic, however simple.
- Keep the approved sample accessible, ideally together with its photograph set, so the comparison does not rely on a person's memory.
- Record what to do with a nonconforming delivery: quarantine, notify, and record the reference of the batch concerned.
FAQ: Frequently Asked Questions
Is sample approval enough before mass production?
It is enough to establish that the sample met the baseline, provided the baseline was documented and the approval statement says what it covers. It does not automatically make every subsequent batch identical, so the order should state how batch equivalence is checked and what happens if a delivery differs.
What should I do if the sample has a deviation I can accept?
Record it as a numbered deviation, give it a disposition, state who accepted it and whether it is expected to recur in production, and keep the record with the drawing. Accepting a deviation without recording it means the same difference will be raised again on the first delivery.
How do I compare a sample with a drawing practically?
Mark the drawing with the dimensions and features you actually check, measure the sample and write the values down, then photograph the sample from the same angles each time. The purpose is a repeatable comparison: the same dimensions, the same method and the same photographs for every sample and every batch.
Next steps: send the baseline with the request
The request and the baseline go together.
- Send the drawing the sample should match, with its revision.
- State what will be checked and who will check it.
- State what happens after approval — whether the sample defines the batch or whether batch equivalence has to be demonstrated.
- Ask for the supplier's drawing of the sample, so both files describe the same part.
- Browse the full catalogue — start from the product range and the feed-through terminal block family.
When requesting a sample from Antong, include the written requirements and ask for the drawing of the proposed item. Because dimensions and materials differ between series, confirm the drawing revision and the characteristics to be checked before the sample is produced. Send your baseline and requirements through the contact page.
Continue reading
- How to Choose Terminal Blocks: Current, Wire Size & Pitch
- Terminal Block Terminology: Glossary for Buyers & Engineers
- Terminal Block RFQ Template
References & standards
- ISO 9001 describes quality management system requirements. Use the agreed inspection plan and approval record to define checks for the specific part.
- IEC 60947-7-1 covers certain copper-conductor terminal blocks for industrial or similar use. Check which standard and edition apply to the proposed model and use its datasheet and drawing for declared values.
- Antong product documentation — ask for the current datasheet and drawing for the proposed model. Browse the product range to identify a family.
The table shows example entries. Record the actual measurements, drawing revision and disposition for each sample.