· 2 min read
From drawing to delivered weldment, the eight steps
What actually happens to your drawing between the enquiry and the truck, and which of the eight steps is the one that decides the other seven.
A contract weldment passes through the same eight steps whether it is one bracket or a forty-piece series. Knowing which step you are in is useful, because the cost of changing something rises sharply after the third one and again after the fifth.
One, enquiry
The drawing arrives, with the quantity, the material, the finish and the date. Files go to a private store, not a public bucket, and are read only by the people quoting the job.
Two, drawing review
This is the step that decides the other seven. The production office and the welding coordinator read the drawing together for weldability, weld preparations, tolerances, accessibility for the torch and whether the part can be held while it is welded. Most of what comes back to you as a question comes back here, and every question answered at this stage is one that does not become a deviation later.
Three, quotation
A written quotation for the drawing as reviewed: the price, the date, what is included, and the documentation that will ship with the part. If the review found something that makes the part expensive to build, this is where you hear which detail and what a change would save.
Four, first article
On a new drawing the first piece is built and inspected in full, welds and dimensions, before the series runs. It is the cheapest place to find a disagreement between the drawing and the part, because at this point exactly one of them exists.
Five, production
Cutting on the laser, forming on the press brake, welding to a written procedure under the certified EN ISO 3834-2 system, and machining after welding wherever a face has to be flat or a bore has to be true. The order is not decided by the drawing; it is decided by what the part will do as it cools.
Six, inspection
Visual weld inspection to EN ISO 17637 against the EN ISO 5817 level the execution class calls for, and dimensional measurement, on the arm where the geometry needs it. Non-destructive testing beyond the visual is done where the drawing asks for it or on request.
Seven, documentation
Whatever the order asked for, assembled with the delivery rather than sent later: procedure specifications and their qualification records, welder qualifications, material inspection documents, the inspection record. Ask for this at enquiry, not at delivery: some of it has to be produced while the part is being made and cannot be reconstructed afterwards.
Eight, delivery
Machined faces protected, the structure loaded for the transport agreed in the quotation. Oversize loads are agreed per job rather than assumed.
If you take one thing from this list, take step two. A drawing review is half an hour of two people reading, and it is the only step where a change is free.