GlossaryKind of term: Cost and economicsOne-off and small batch
What are one-offs and small batches?
A one-off is a single copy of a part and a small batch a handful to a few dozen; in both, few parts carry all of the one-off costs.
A one-off is a single copy of a part: a prototype, a spare, a jig or a replacement part for a machine. A small batch is a handful to a few dozen; where the line falls differs per shop and per part. What marks both is not the number itself but that one-off costs weigh heavily against the cost per piece.
How do one-offs and small batches work in practice?
Setup happens per batch, programming in principle once per part and revision, and the first-part check often per batch. A one-off carries those costs in full; in a batch of ten each part takes a share. So the price per piece of a one-off can be a multiple of the batch price without the part being any harder. Material does not scale linearly either: a minimum purchase length or saw loss can weigh relatively heavily on a single part. At larger quantities a different route can pay off, such as a dedicated fixture or a bar feeder, which shifts the comparison further. Pricing setup as a fixed percentage on cycle time makes one-off costs scale with quantity, so small quantities can come out too low and large ones too high against the actual setup time.
What are one-offs and small batches often confused with?
A small batch is not a repeat order: a repeat order can be small, but it reuses the program and often the workholding, so its one-off costs can come out lower. Nor is a one-off the same as a prototype: a prototype is a purpose, a one-off a quantity; a prototype can come as a small batch and a one-off can be a spare.
How do you see one-offs and small batches in Blake?
In Blake material, machining, finishing, setup and programming are separate lines, per piece and per batch. The quantity breaks show the cost estimate per piece for each quantity asked, so you see what the one-off costs do per piece. More on estimating.
Frequently asked questions
Why are one-off machined parts so expensive?
Because setup, programming and checking the first part take roughly the same time for one part as for a batch. A one-off carries those costs in full; a batch spreads them over the parts.
How do I explain a small-batch price to a customer?
Show the quantity breaks: material and machining per piece stay roughly the same on the same route, while the one-off costs per piece fall as the quantity grows. The customer then sees where the price comes from.
Is a one-off cheaper if I already have the program?
Usually, on the same revision and the same machine. A saved program and known workholding save programming time and part of the setup. Setting up itself and checking the first part remain.