Non-Standard CNC Machining Pricing: How Custom Parts Cost Is Calculated

When you need a custom non-standard part — something that doesn't fit a standard catalog or off-the-shelf design — getting a fair CNC quote can feel like a guessing game. The truth is, non-standard parts are priced using the same variables as standard parts. The difference is that each variable has a wider range depending on your specific design requirements.

Material Cost for Non-Standard Parts

Raw material is usually the most straightforward part of any CNC machining quote. But non-standard parts often require non-standard material sizes, which means more waste and potentially longer lead times to source the right stock. Standard material prices per kilo:

• Aluminum 6061/7075: $3-5/kg — low to moderate cost
• Steel (1018, 4140, 304/316 stainless): $1-8/kg — moderate range
• Titanium (Grade 2/5): $35-50/kg — high cost, slow machining
• Engineering plastics (PEEK, PTFE, Delrin): variable by grade

A recent client came to us with a titanium bracket that required custom-sized stock. The standard titanium bar was 50mm diameter, but their part needed 65mm. We sourced the non-standard stock, but the material cost was 40 percent higher than if they had designed around an available size. A small DFM adjustment on their next revision saved them that premium.

Machining Time

This is the biggest cost driver for any non-standard CNC part. Because the geometry is unique, there's no existing program to pull from. Everything is programmed from scratch. Typical machine rates:

• 3-axis CNC milling: $35-55/hour
• 4/5-axis CNC milling: $55-85/hour
• CNC turning: $30-50/hour
• Swiss CNC machining: $45-75/hour

Complex geometry — deep cavities, thin walls, tight internal corners, multi-axis contouring — increases cycle time significantly. A simple block with holes might take 10 minutes. A complex aerospace bracket with thin wall sections could take 6 hours.

Setup and Programming

Every custom part requires CAM programming, fixture design, and machine setup from scratch. For simple non-standard parts, this is minimal. For complex multi-operation parts, it's substantial. And unlike standard parts where you might amortize setup across thousands of units, custom runs are often small — which means setup cost per part is higher.

Tolerance and Quality Control

Standard ±0.1mm tolerances don't add cost. But non-standard parts often have tighter requirements because they're designed for specific mating interfaces. Going to ±0.01mm adds cost due to:

• Slower feed rates and lighter cuts
• Additional CMM inspection time
• Higher scrap rates
• Specialized tooling

Surface Finishing

Non-standard parts often need custom finishing based on their application. Options range from basic clear anodize (most economical) to hard coat anodize, passivation, nickel plating, and powder coating. Each adds process time and cost.

How to Get the Best Non-Standard CNC Quote

• Provide a complete 3D CAD model in STEP or IGES format
• Specify tight tolerances only on mating surfaces — the rest can run standard
• Consolidate multiple part numbers into one order to share setup costs
• Ask about standard material alternatives before finalizing your design

Contact Us

At AOOM Technology, we handle non-standard CNC parts every day. With 60+ machines, ISO 9001 certification, and over 15 years of experience, we provide free DFM analysis on every quote. Send your CAD files to chen@aoomtech.com for a detailed breakdown within 24 hours.