What "qualified" means for made-to-drawing work

A contract manufacturer can own CNC machines, welding robots and a large floor and still miss the details that matter on your drawing. Qualification is the work of confirming that the shop can make your parts, to your specification, with evidence you can audit. The check is not a single certificate. It is a pattern of equipment, procedures, records and openness that lets you audit them before an order is placed.

This matters most when you are buying parts that will carry loads, mate with other components or ship straight to a final assembly line. A crane mast, a pump chassis, a hydraulic tank and a conveyor frame all need different processes, but the qualification questions are similar. If the supplier cannot explain how a given weld or machined surface will be controlled, the quotation is only a price, not a plan.

Workshop checks before you shortlist

Start with the shop itself, not the brochure. For made-to-drawing structural work, the limiting factors are usually size, access and repeatability.

Crane capacity and bed size

Ask for the maximum single-piece weight the shop can lift, the hook height and the largest work envelope it can machine or weld without repositioning. A drawing that fits on paper may not fit through the door or under the crane hook. For large welded assemblies, also ask whether the shop has a dedicated trial-assembly area, because trying to fit a 12-metre frame in a 10-metre bay reveals problems only after delivery.

Welding and thermal cutting

Look for the processes your drawing actually needs: SMAW, GMAW, FCAW, SAW, plasma, laser or oxy-fuel cutting. Then ask how each procedure is qualified. AWS D1.1, Structural Welding Code - Steel, requires either prequalified welding procedure specifications that follow the code's joint details and parameter limits, or WPSs supported by procedure qualification records from tested samples. The same code requires welders to demonstrate their ability through performance qualification records before working on production joints. AWS D1.1 and the AISC Steel Solutions Center describe these requirements in detail.

Machining envelope and measurement

CNC travel, table size and spindle power define what the shop can finish in-house. How it checks results matters just as much. Ask whether dimensional inspection uses a CMM, a laser tracker, a total station or manual gauges, and which tolerance classes and GD&T symbols the inspectors routinely work to. ISO 1101 covers geometrical tolerancing; ISO 9013 classifies thermal-cut quality for material thicknesses from 3 mm to 300 mm.

Surface treatment and handling

Shot blasting, painting, galvanizing and export crating each need space and controlled sequences. A shop that welds well but has no covered paint bay may push your parts through a subcontractor without telling you unless you ask.

Documentation to review before award

Certificates help, but the records behind them matter more.

Quality management scope

ISO 9001 is a useful baseline, but read the certificate scope. If welding is central to your part and the scope only lists general metalwork, ask why. For fusion welding, ISO 3834 defines comprehensive, standard and elementary quality requirements. The TWI standards guide explains that ISO 5817 sets quality levels B, C and D for weld imperfections, while ISO 6520-1 classifies the imperfections themselves.

WPSs, PQRs and welder qualifications

Ask for examples of qualified welding procedures that cover the materials, thicknesses, positions and processes on your drawing. Cross-check that the welders who will work on your order hold current performance qualifications for those same variables. Continuity records matter too: under AWS D1.1 a welder stays qualified only if he or she uses each process at least once within every six-month window.

Material traceability

Request how material certificates will be linked to your parts. EN 10204 Type 3.1 or 3.2 certificates are common for structural steel, depending on the project risk. If traceability is required, confirm whether the shop marks individual plates and retains heat numbers through cutting, welding and final inspection.

Inspection and test plan

A supplier that has run similar work will propose an ITP that lists hold points, witness points, inspection methods and acceptance criteria before production starts. The plan should name the NDT methods, the extent of testing and the certification of the personnel performing it. ISO 9712 covers qualification of NDT personnel.

How to compare two candidate suppliers

Once you have the same information from each shop, compare against your drawing, not against each other.

First, check coverage. One supplier may quote lower because it plans to subcontract machining or NDT; another may quote higher because it keeps both in-house. Both can work, but the responsibility must be clear.

Second, look at evidence density. A supplier that can show recent PQRs, continuity logs, CMM reports and material certificates is easier to audit than one that promises to generate them after award.

Third, ask how change orders are handled. Drawings evolve. A supplier with documented revision control and a formal technical query process will waste less time later.

Fourth, visit if you can. A video call through the workshop is better than no call. Look for clean material segregation, labelled welding consumables, clear work-in-progress areas and recent calibration labels on measuring equipment.

What to put in your RFQ so the audit is worth it

The supplier can only be as precise as your package. Send a frozen drawing revision, a material specification, quantities and a delivery schedule. State the codes and standards that apply, the weld quality level you need, the NDT extent and the inspection evidence format. If you want material certificates, export crating, surface treatment or trial assembly, say so explicitly.

Also state what you will supply yourself: buyout parts, fasteners, seals, hydraulic components or sub-assemblies. Boundary mistakes are a common source of cost overruns. The more your RFQ defines responsibility, the more useful the supplier qualification exercise becomes.

Realjet supplies custom machinery component manufacturing based on customer drawings, specifications and delivery requirements. If you are evaluating suppliers for a welded, machined or assembled part, we can review your drawing package and propose a scope that matches your inspection and documentation expectations.