Capability
Rapid prototyping & first articles
One part, measured and reported, before anyone commits to a hundred. Finding a problem on part one is a conversation. Finding it on part sixty of a run is a write-off.
Two different questions
A prototype and a first article prove different things
A prototype answers a design question: does this shape do what it is meant to do. It can be rough in places that do not matter yet, because the point is to learn something before the drawing is final. A first article answers a process question instead: does this shop's setup, on this drawing, produce the part the print describes, dimension for dimension.
Running a first article before the rest of a production run is cheaper than discovering a process problem partway through it, because a first article catches a setup mistake at the cost of one part instead of the whole run. This bracket is the part a first article report would be written against: adjustment slots, a filleted gusset standing in for a weld, and a datum face everything else is measured from. Drag it, and tap a numbered callout to see what gets checked.
- Prototype. Proves the design. Checked by fit, function and a general look at the dimensions. Can be rough where it does not matter yet.
- First article. Proves the process. Every toleranced dimension on the released print is measured and recorded on the actual part.
- Production run. Repeats the process the first article already proved, at the quantity the job actually needs.
Interactive
Plan your path
How settled the design is, and how many parts you need, both change the sensible path.
Iteration planner
Set the design stage and the quantity to see the recommended path.
How settled is the design?
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Interactive
What a first article report actually proves
Four things get checked. Each one has an honest limit to what it tells you.
Checked. Every toleranced dimension on the print, measured on this specific part with the tool the tolerance calls for: calipers, micrometer, bore gauge or CMM.
Does not prove. That the next part off the same program measures the same. One part is a single reading, not a distribution.
Checked. The material certificate and heat lot match what the drawing calls out, and, where specified, the hardness after heat treatment.
Does not prove. Fatigue life or long-term corrosion performance. Those are properties of the alloy you chose, not something one inspection tests.
Checked. The router that was actually run is written down: the fixture, the work-holding, the program and the tool list, so the same part can be run the same way again.
Does not prove. Cycle time or cost at full volume. A first article is machined carefully once, not at production pace.
Checked. If more than one first article is run, the variation between those parts from the same setup.
Does not prove. Long run capability, from a single part or two. A real capability figure needs a larger sample than a first article provides.
Questions we get asked before a first run
What is the difference between a prototype and a first article?
A prototype proves the design works. A first article proves the machining process reproduces a settled drawing. They ask different questions, which is why a design still in progress usually starts with a prototype, not a first article.
Can I skip straight to a first article?
If the drawing is already settled, yes: a first article on that print is enough to confirm this shop reproduces it before the rest of the run is cut. If the design itself is still the open question, a prototype first is the faster way to an answer.
How many parts does a first article inspection cover?
Typically one part, measured in full against the print. If you want to see part to part variation as well as the dimensions themselves, a small pilot batch measured the same way covers that too. See the Repeatability tab above for what that does and does not tell you.
What do I get at the end of a first article?
A written record of what was measured against the drawing, so the setup that produced it can be trusted for the run and rerun the same way later. Talk to us at quote about the format you need it in.