What does secondary process mean in fabrication?

In a laser cutting shop, cutting is the primary process. Everything that happens to the part afterwards is a secondary process. The common ones fall into a few groups:

• forming: folding or bending on a press brake, rolling
• holes and threads: drilling, tapping, countersinking, pressing in nuts and studs
• edge finishing: deburring, grinding, tumbling
• joining: welding, riveting, assembly
• coatings: powder coating, wet painting, galvanising, anodising, zinc plating

Some are done in-house. Others, such as galvanising and anodising, usually go to a specialist, which shops call outside processing or subcontract work.

How are secondary processes priced?

Each secondary process is priced on whatever drives its cost:

• per feature: tapping, countersinking and hardware insertion, charged per hole or per insert
• by surface area: powder coating and painting, charged per square metre or square foot, counting both sides
• by weight: hot-dip galvanising, charged per kilogram or pound
• by time: folding (setup plus time per bend) and welding (time, or length of weld)
• by supplier price: outside processing, with handling, freight and a markup added

A worked example, for 50 brackets 200 x 100 mm (about 8 x 4 in) in 3 mm (about 1/8 in) mild steel, each with two folds, four tapped M6 holes and a powder coat:

• folding: one setup, then 100 bends
• tapping: 200 holes
• powder coating: 0.2 x 0.1 x 2 sides = 0.04 m² per part, so about 2 m² (21.5 ft²) for the job
• galvanising instead: about 0.47 kg (1 lb) per part, so about 24 kg (52 lb) for the job

None of those numbers come from the cut. They come from the part's features, area and weight, which is why secondary processes are easy to underquote by eye.

Why does a secondary process matter?

Customers would rather buy finished parts from one supplier than send laser-cut blanks to three other shops. A fabricator that can fold, tap and coat wins work a cut-only shop can't, and the extra steps often earn better margin than the cutting.

They're also where quotes go wrong. Cutting is measured from the drawing, but secondary processes are often added as a guess or a flat allowance. Underprice the tapping on a part with 30 holes, or forget that powder coating is charged on both sides, and the job can lose money even though the cutting was priced correctly. Coaters and galvanisers often have minimum charges too, which matter on small orders.

In-house vs outside processing

Work done in-house costs machine time and labour. Work sent out costs the supplier's price plus everything around it:

• freight or a delivery run each way
• handling, packing and paperwork
• extra lead time, often several days, which has to be added to the quoted delivery date
• risk, if parts come back damaged or the wrong colour

Most shops add a markup to outside processing to cover this. Whatever the figure, set it once and apply it on every quote, so two estimators don't price the same powder coat differently.

Secondary processes and quoting

A quote for finished parts has to price each secondary process from the part itself: its holes, area, weight and bends. In Tempus Tools, secondary processes are set up once with your own rules (per feature, by area, by weight, or a custom formula) and priced automatically. Folding is calculated from the longest fold and the number of folds, which drive tool sets, setup and press time. Everything lands on the same quote as the cutting.

Further reading: Are secondary processes costing you money or adding to your profit?