CNC machining transforms raw material into precision parts with repeatability and tight tolerances that manual processes simply can't match. Whether you need a single prototype or thousands of units, understanding what's actually included—and what costs extra—keeps you from surprises. Here's what you need to know before requesting quotes.
What Core Services Are Included
Most CNC machining shops include the basics: part design review, material sourcing, machine setup, and the actual cutting/milling work. You're paying for machine time, operator expertise, and the overhead of running a production facility. The quoted price typically covers turning, milling, boring, drilling, or tapping operations depending on your part geometry.
What often isn't included is anything beyond the finished raw part. Secondary operations, finishing, and quality checks are usually add-ons or quoted separately.
Material Selection and Sourcing
You can either supply your own material stock or have the shop source it. Providing material yourself can save 10–20% on costs, but you'll need to handle storage, handle shipping delays, and accept liability if material arrives defective.
Most shops charge a sourcing fee (typically $50–200 per order) plus material cost at market rates. Common CNC materials include:
- Aluminum ($8–15/lb) — fastest to machine, lowest cost
- Steel ($12–20/lb) — stronger, takes longer to cut
- Stainless steel ($15–30/lb) — corrosion resistance adds machine time
- Brass/copper ($10–25/lb) — good machinability, higher material cost
- Plastics (PEEK, Delrin, acrylic) ($20–50/lb) — varies widely by polymer
Scrap material from your part is almost never refunded; it's factored into overhead.
Setup, Programming, and CAM
Every job requires CAM (computer-aided manufacturing) programming—converting your CAD file into machine instructions. This is where turnaround time hits.
Simple parts with standard features (holes, pockets, basic geometry) take 2–4 hours to program. Complex parts with undercuts, tight tolerances, or multiple setups can take 8–20+ hours. Many shops include basic programming in their quote, but custom or intricate CAM work may add $200–800 to your order.
Machine setup—clamping the part, running test cuts, verifying dimensions—typically takes 30 minutes to 2 hours depending on part complexity. Some shops roll this into their hourly rate; others charge a separate setup fee ($100–300 per setup).
Tolerance and Quality Control
Standard CNC tolerances are ±0.005" on most dimensions—no charge for that. Tighter tolerances (±0.002" or better) require additional time, temperature-controlled environments, or hand-finishing, which adds 15–40% to the cost.
Most shops include basic dimensional checks with go/no-go gauges. Certified inspection reports, CMM (coordinate measuring machine) verification, or SPC (statistical process control) documentation cost extra: typically $50–300 depending on the part count and complexity.
Surface Finishing and Secondary Operations
Raw CNC parts have sharp edges and a functional but rough surface finish. Adding any finish is separate:
- Deburring (removing sharp edges): $0.50–2 per part
- Anodizing (aluminum): $2–8 per part, plus 2–3 week lead time
- Powder coating: $4–15 per part
- Plating (nickel, chrome, zinc): $3–12 per part
- Polishing or hand finishing: $1–5 per part (or hourly labor)
Threading, tapping, drilling, and other secondary cuts add $0.50–3 per operation depending on size and material.
Lead Times and Expediting
Standard lead time runs 3–4 weeks for small batches of straightforward parts. Complex jobs or high volumes can stretch to 6–8 weeks. Rush fees typically run 25–50% surcharge for 1–2 week turnaround, and 50–100% for expedited (next-week) delivery.
When comparing quotes, always ask specifically: Does the lead time include programming, or just machine time? Are setup delays factored in?
How to Compare Quotes Effectively
Request quotes with clear specifications: material, quantity, required tolerances, any secondary operations, and your target delivery date. A vague request gets a vague estimate. Three-quote minimum is standard practice—you'll spot outliers and overpriced shops quickly.
Platforms like Mercoly help you compare trusted CNC machining providers side by side with transparent timelines and pricing, removing the guesswork from vendor selection.
Frequently Asked Questions
Q: Why do some CNC shops quote significantly lower than others for the same part? A: Machine capacity, material supplier relationships, automation level, and whether they're accounting for programming and setup all vary. Lowest price doesn't mean best value—check included services, lead times, and quality guarantees.
Q: Do I need to pay for a prototype or sample run first? A: Many shops offer single-piece or low-quantity runs at a per-unit cost 30–100% higher than production volume, but no tooling or setup fees. Use prototypes to validate your design before committing to larger orders.
Q: What happens if your part design has a machining problem? A: Reputable shops flag manufacturability issues during CAM review and suggest design changes. Some charge a design consultation fee ($100–300); others flag issues free if you're quoting with them formally.
Compare quotes from verified CNC machining providers on Mercoly to find the right fit for your project timeline and budget.