What to Include in a Welded Assembly Drawing
An assembly drawing defines the finished welded part. Overall dimensions, reference faces, joint types and what gets checked decide whether it can be built as drawn.
A component drawing and an assembly drawing answer different questions. The component drawing says what to cut. The assembly drawing says what the finished welded part has to be. Sending only the first one leaves the second to be guessed at the bench.
The finished part
Start with the dimensions that only exist once the parts are welded together: overall length, width and height, the position of mounting points, and any diagonal that proves the assembly is square. These are the dimensions a welder works to, and the ones an inspector checks.
Where a dimension is functional, mark it. An assembly where every dimension carries equal weight gives the bench no way to prioritise when a tolerance stack has to be resolved.
The reference face
Say which face is the datum. A frame can be built square to any of its faces, and the one the installation uses is not always the one that looks obvious on the print. This single note prevents a delivery argument.
The component list
A bill of materials at component level, with each part identified by a drawing number or a mark, and the quantity per assembly. It makes the difference between an assembly order and a puzzle.
State what you are supplying. Purchased hardware, castings, bearings or customer supplied parts belong on the list with their source, because they affect the schedule and the scope.
Joints, without inventing procedure
Describe the joint: which members meet, where the weld runs, and which side is visible. A symbol on the drawing or a written description of the joint both work. What KorFab does not do is write the welding procedure for a customer design, and a request does not need to include one for the assembly to be quoted.
Where the joint repeats on every piece in a run, that repetition is the reason a programmed path becomes viable, which is covered in what a programmed weld path means for repeated parts.
Fit up and inspection
- Any requirement on square, flatness or twist across the finished assembly.
- Whether the assembly is checked against a mating part or a fixture.
- The finish, and which surfaces are visible after installation.
- How the finished part is identified and how it is packed.
What makes the package reviewable
Assembly drawing with overall dimensions and reference face, component drawings, the component list with quantities, joint description and finish. That package lets the review say whether the assembly can be built as drawn instead of discovering it after the first one is welded.