Quantity changes the price per part more than anything
Before the first good part comes off a machine, someone has to program it, set it up, build fixtures and check the first piece. That work costs about the same whether you order one part or a thousand.
On a single part, setup can be most of the price. Spread across a large run, it becomes a small slice of each part. If you are not sure how many you need, ask for prices at two or three quantities so you can see where the price per part levels off.
Some processes need tooling before the first part
Injection molding, die casting, stamping and some cable and harness work need a mold, die or fixture built first. That is a one-time cost, and it can be large.
Tooling pays off when you need a lot of parts, because each part after that is cheap. For prototypes and small runs, machining, sheet metal or 3D printing usually costs less overall, even though each part costs more.
The process sets the starting point
The same part can often be machined, printed, cast, molded or bent from sheet. Each one has a different setup cost and a different cost per part, and the best choice changes with quantity.
Matching the process to the volume is often the biggest single saving on a project. It is also the easiest one to miss if you only ask one type of shop for a price.
Material and how much gets cut away
Material cost is more than the price per pound. It includes how big a block or bar the part starts from, how much of it gets machined away, and whether the material is easy to buy.
Common aluminum and steel grades are usually easy to get. Specialty alloys, certified material and unusual plastics can add cost and weeks of lead time. If more than one material would work, say so. See the materials guide for what fits each process.
Tolerances and inspection
Tighter tolerances mean slower, more careful work and more time measuring. Keeping tight numbers only on the features that need them is one of the easiest ways to lower cost without changing how the part works.
The tolerances guide covers this in more detail.
Finishing, hardware and assembly
Every extra step adds handling, and some steps go out to a specialty shop. These all add to the price:
- Anodizing, plating, powder coat and other finishes
- Threaded inserts, pressed pins and other hardware
- Assembly, testing and kitting
- Custom packaging and labeling
None of these are bad. Just list them up front so the quote covers the real job.
Electronics and bought parts
When a project includes connectors, wire, electronic components or other bought parts, their price and availability become part of the cost. A part on allocation or a long lead time can drive the schedule and the price more than the custom work does.
A bill of materials with acceptable alternates gives the most room to find stock and keep cost down.
Paperwork and requirements
Some jobs need more than parts in a box. Material certifications, first article reports, full inspection reports, special packaging and Made in USA requirements all take time and should be part of the quote.
Tell us early. Adding them after the quote usually costs more than including them from the start.
Lead time
Rush jobs can mean overtime, jumping the line or paying for faster shipping and outside services. If your date has some give in it, say so. A flexible date often lowers the price.
How to get a quote you can actually use
The more of this you send, the closer the first quote will be to the final price:
- Quantity now, and what you expect later
- What the part does and what it connects to
- Which features are critical
- Material, finish and any required paperwork
- When you need it, and whether that date can move
Use the CNC quote checklist before you send files, and the guide to comparing quotes when the prices come back.