When this applies
- Frames, bases, skids, guards and brackets
- One to a few dozen assemblies
- Structures combining cut, formed and machined parts
- Equipment built to suit a specific installation
Say which dimensions matter after welding
Heat moves metal. A drawing that tolerances everything equally forces the fabricator to guess, and usually to add cost as insurance. Identify the mounting-hole pattern, the flatness of a mating face or the overall length that must hold, and allow the rest to be nominal.
- Critical post-weld dimensions and datums
- Faces machined after welding
- Flatness requirements and how they are checked
- Whether stress relief is required
Weld specification
State weld sizes, types and locations rather than leaving them to interpretation. Say whether welds must be continuous or stitched, whether they must be ground flush, and whether any inspection beyond visual is required.
Fixturing and repeat orders
Fixtures built for the first batch make the second cheaper and more consistent. Ask whether fixturing is included in the price, who owns it and whether it is retained for reorders.
RFQ checklist
Include these in your request and suppliers can quote without a round of questions.
- Assembly drawing plus part drawings or models
- Material grades and section sizes
- Weld symbols, sizes and inspection requirements
- Critical post-weld dimensions
- Finish, quantity and delivery location