First-article approval: how to present a first batch so the buyer signs off

A first batch gets signed off quickly when the buyer's quality engineer can check it without picking up the phone. It takes three things in the box and in the email. The first is a dimensional report that follows the numbered drawing. The others are a few photographs of the critical features and a one-page note on what was made and where you were unsure. Ask the buyer which format, which dimensions and how many pieces they want before you cut metal. A good part with a confusing report still sits in the incoming-inspection rack.

Ask before you cut the first piece

The person who approves your first lot is not the person who ordered it. Purchase placed the order. A supplier quality engineer, or whoever runs incoming inspection, decides whether the lot is used. Ask purchase for that person's name on the day the order arrives, and send them a short message before the first-off is machined.

"Before we machine the first pieces of part 7741, revision B, could you confirm six things? One: your first-article format, or may we use ours? Two: how many pieces to measure fully, and how many to send? Three: which features are critical for you? Four: do you need the mill certificate, and certificates for anodising or heat treatment? Five: how should the measured pieces be tagged and packed? Six: who signs the approval, and where should the report go?"

A quality engineer has reason to answer this message, because it saves them a rejection. If one does not reply, send your own plan in writing and say you will follow it unless told otherwise.

The approval pack, item by item

Lay it out in this order, because it is the order the engineer checks in.

• Ballooned drawing. The buyer's drawing with every dimension, tolerance and note numbered, showing the revision you machined to.
• Dimensional report in balloon order. For each number: the specified value, the tolerance, the measured value on each piece, the instrument used, and a clear OK or not OK.
• Material certificate from the mill or the stockist, with a heat number that matches the bar, plate or casting you used.
• Certificates for outside work, such as hardness after heat treatment or coating thickness, from the vendor who did it.
• Three to five photographs, described below.
• Tagged pieces, marked FA-1, FA-2 and so on to match the report columns, packed apart from the rest of the lot.
• The covering note, on top of everything.

The covering note

This is the page owners skip, and it is the one that gets read first. Keep it to what the engineer needs to start.

First article: part 7741, revision B, aluminium manifold block
Lot: 50 pieces. FA-1 to FA-5 tagged and fully measured.
Measured: all 42 balloons on FA-1 to FA-5 (CMM and hand gauges, listed in report)
Material: plate certificate attached, heat number matches
Outside work: anodising, thickness certificate attached
Observations:
  Balloon 17, port depth: FA-3 was 0.05 mm deep. Reworked; new reading attached.
  Balloon 29, M10 thread: checked with GO/NO-GO gauge only, no measured value.
Question: edge break at balloon 33 is not specified. We used 0.3 x 45 degrees.
Contact for queries: (name and phone)

The rule for the observations line is simple. Anything you are unsure of goes in. Anything out of tolerance goes in with a request for a written deviation. A buyer who finds a hidden problem stops trusting the whole report. A buyer who is told can decide, and the decision is on record.

Photographs that answer a question

Each photograph should save the engineer a step. The whole part on a plain sheet with a steel rule beside it. A close view of each critical feature: the sealing face, the thread, the bore. The tagged pieces in their packing. The label on the box.

Leave out the machine shots. They belong in your capability sheet, and our post on a photo and video routine for a machine shop covers those.

Imagine: a Hubballi machine shop and its first manifold blocks

Imagine a VMC shop on Gokul Road, Hubballi, that wins its first order from a maker of hydraulic power packs in Chennai: 50 aluminium manifold blocks. The details are illustrative.

The blocks were good. The paperwork was not. The shop sent the CMM printout in the machine's own order, with no ballooned drawing and no tags. One port on one block was slightly deep, and nobody mentioned it. The quality engineer could not match readings to features, found the deep port on their own, and put the lot on hold. The power pack line waited, and purchase rang the owner.

Putting it right took a day. The shop sent a ballooned drawing, re-sorted the report into balloon order and tagged five pieces. A covering note declared the deep port, the rework and the new reading. The lot was approved on the second submission. For every new part since, the six questions go out with the order acknowledgement, and the observations line is never left blank.

When a lighter pack is enough

Not every buyer wants the full set. A small machine builder ordering ten brackets may want two pieces checked on three dimensions and a material certificate. A thick file only annoys them. Ask, and send what they ask for.

Where the buyer has its own format, use it exactly, even if yours is neater. A form they recognise is approved faster than a better one they do not.

Medical device, aerospace and defence buyers are another matter. Their approvals follow sector rules that differ by customer and change over time. Ask for the full document list in writing, and let the buyer's quality team tell you what applies to your part.

Save the six questions before the next new order

Make the covering note a template now. Then save the six questions as a message and send them before the first-off on the next new part. The first lot is only one gate in a CNC shop's approval, and the CNC machining and precision engineering section walks through the rest. If a lot of yours is sitting in someone's inspection rack right now, or you want the pack and note built into your sales collateral, tell us what you need.