In capacity subcontracting, the buyer knows how to make the part, generally has the skills and the machines, but lacks availability: machines fully booked, a workload peak, a deadline to meet, a machine breakdown. It then entrusts part of production to a subcontractor who works to its drawings and specifications and acts as an extension of its workshop. It contrasts with specialist subcontracting, where you call on know-how you do not have.
It typically covers processes common in workshops: machining, turning, sheet metal cutting and bending, welding. Examples: an SME whose lathes are fully booked has two hundred shafts made by a turning workshop; a machine builder outsources the blanking and bending of its covers for a busy quarter; a general engineering workshop passes part of its batches to a fellow workshop during a peak of activity. The parts, designed by the buyer, can be shared between several interchangeable workshops, hence strong competition on price, lead time and reliability.
For the buyer, the benefit is flexibility: adapting production to workload without investing. The risks are quality (a precise specification and incoming inspection are needed), dependence and the confidentiality of drawings. For the workshop, it is a way to fill its order book, at the price of more irregular activity that is more exposed to pressure on prices. A lasting relationship, backed by a forecast volume, gives both parties security.
In a quote request
Supply a complete file (drawing, 3D model, material, tolerances, inspections): the workshop will have only that to understand the need. State quantities per batch, the frequency, the firm delivery date, and specify whether the material is supplied or bought by the workshop. State the level of quality expected (self-inspection, report, first article) and any framework order. See the guide choosing an industrial subcontractor.