Buyers coming from casting or injection moulding often ask a machining supplier for the minimum order quantity and are surprised by the answer.
There is usually no hard minimum
Machining does not require a mould. There is no five-figure tool to amortise before the first good part appears. That is why most machining suppliers, including us, will quote a quantity of one.
What there is instead is setup: programming, fixturing, tool selection, first article. That cost is real, and it is spread across whatever quantity you order.
How the curve actually behaves
For a typical machined part the price per piece falls steeply from 1 to about 10, moderately from 10 to around 100, and then flattens. Beyond a few hundred pieces the remaining reductions come from process changes — dedicated fixtures, bar feeding, running unattended — rather than from spreading setup.
This shape has a practical consequence: the jump from 1 to 5 pieces often costs very little extra. If you are prototyping and think you might iterate, ordering a handful rather than a single piece is frequently the cheapest insurance available.
Where a minimum does appear
Some situations do create a floor:
- Material stocking. If your alloy or section is not held, the mill's minimum purchase can set a quantity.
- Outsourced finishing. Anodising and plating lines usually have a minimum batch charge. A run of three parts may be charged as if it were thirty.
- Heat treatment. Same logic — furnace time is charged by the load.
If your part needs any of these, ask specifically whether the finishing minimum is driving the price. Sometimes ordering slightly more is cheaper in total than ordering fewer.
Repeat orders are where the money is
The second order of the same part should always be cheaper than the first, because the programming and fixturing already exist. If a supplier quotes you the same unit price on a repeat order with no changes, that is a fair question to raise.
Ask at the outset: what is the repeat price, and how long do you keep the program and fixtures? A supplier who holds them for you is worth more than one who is a few percent cheaper on the first run.
Practical advice for a first order
Order the quantity you need plus a small allowance, ask for the price break at two or three quantities so you can see the curve, and confirm what the repeat price would be. Those three numbers tell you more about a supplier's cost base than any amount of negotiation on the first figure.
