Write a metal fabrication RFQ with usable drawings

A fabricated part is defined by drawing revision, material, process, finish and the interfaces that matter. Asking for “a bracket like this photo” shifts too much engineering judgement to the supplier. A precise brief still leaves room for a supplier to propose a more efficient process.

Define the requirement

Attach dimensioned drawings with units, tolerances for critical features, material requirements, finish and expected annual or initial volume. Identify mating parts and load conditions. If welding, coating or heat treatment is required, say where it applies and what evidence must be supplied.

Questions to send with the RFQ

Ask suppliers to flag design features that increase cost or create inspection difficulty. Request a first article and a measurement report for critical dimensions. Clarify whether tooling, fixtures and post-processing are included in the quoted price.

Review the answer

Compare fabrication methods and their effect on function. A proposed change to a hole, bend radius or coating thickness may be valuable, but it should appear as a documented deviation. Check that every quote references the same drawing version.

An example to adapt

For a hypothetical mounting bracket, the bolt pattern and load path are essential, while a cosmetic edge profile may be negotiable. Mark those priorities on the drawing and request separate pricing for any suggested simplification.

Decision before sending

Ask the design owner to mark which dimensions control assembly and which are merely descriptive. A supplier may offer a cheaper method if it understands the true constraints, but it should not change a mating interface without approval. For a first article, compare the measurement report with the actual fitting trial. Keep both in the file: dimensions provide reproducibility, while physical fit reveals integration issues that the drawing may not have captured.

Source context

NIST explains how CAD files carry parts, assemblies, dimensions and tolerances into manufacturing and inspection. Send one controlled drawing set and identify the features that will be measured after fabrication; decorative finish and dimensional acceptance need separate checks.