How much does it cost to get something CNC machined?
1. Basic concepts of CNC machining
CNC (Computer Numerical Control) machining is a process that uses programmed machine tools to manufacture high-precision parts. It is widely used in the automotive, aerospace, medical equipment and other fields. Its cost is determined by multiple factors, including design complexity, material selection, and mass production.
2. Core factors affecting CNC machining costs
Material cost
Material type: Metals (such as aluminum, stainless steel, and titanium alloys) are more expensive than plastics and have different processing difficulties. For example, aluminum is the first choice due to its easy processing and low cost, while titanium alloys are twice as expensive due to their high hardness and low thermal conductivity.
Material machinability: Difficult-to-process materials (such as stainless steel and titanium) require longer time and special tools, which increases costs.
Design and complexity
Geometric complexity: Complex designs (such as deep cavities, thin walls, and sharp corners) require multiple clamping and special tools, which prolongs the processing time.
Tolerance requirements: Standard tolerances (metal ±0.1mm, plastic ±0.25mm) do not require additional fees, but tolerances of ±0.005mm require precision grinding, which increases the cost by 40-200 yuan/hour.
Surface treatment: Sandblasting, polishing, anodizing and other processes are charged on demand. For example, polishing requires manual grinding, and the cost is twice that of the original surface.
Processing time and equipment
Working hours: CNC machine tools are usually charged by the minute, about 80-120 yuan/minute, and five-axis machine tools are more expensive.
Equipment type: Three-axis machine tools are low-cost, and five-axis machine tools are suitable for complex parts but the cost is doubled.
Batch and order size
Batch effect: Single-piece processing requires sharing the initial programming and clamping costs, and batch production can reduce unit costs. For example, the unit price of 1,000 pieces may be 88% lower than that of a single piece.
Additional costs
Urgent orders: The expedited cost is twice the standard price.
Special tools and processes: such as EDM or Wire Cutting, an additional 100-200 yuan per hour.
3. Calculation method of CNC processing cost
Material cost estimation
Calculate the amount of raw materials based on the part volume and material density, combined with the market unit price (such as aluminum is about 30 yuan/kg, stainless steel is about 50 yuan/kg).
Processing time calculation
Formula: Total cost = material cost + (processing time × labor unit price) + surface treatment fee.
Example: The material cost of an aluminum alloy part is 100 yuan, the processing time is 30 minutes (unit price 100 yuan/minute), and the total cost is about 3,100 yuan.
Empirical ratio method
Large parts: The ratio of processing fee to material cost is about 1:1 (simple design) or 1.2-1.5:1 (complex design).
Small and medium parts: The ratio is 2-3:1 (simple) or 5-10:1 (complex).
Whenever a CNC machine produces a new product, engineers are required to debug the machine according to the product. Taking the turning machine debugging in the video as an example, excluding the programming time, it takes at least 4 hours to debug the machine.
4. Practical strategies to reduce CNC machining costs
Optimize design
Avoid thin walls (metal ≥ 0.8mm, plastic ≥ 1.5mm), deep cavities (depth ≤ 4 times the slot width) and inner sharp corners, and use rounded corner transitions instead.
Simplify the number of clamping times and reduce the need for flipping processing.
Rational material selection
Prioritize easy-to-process materials (such as aluminum 6061) and avoid high-cost materials such as titanium alloy unless performance is required.
Standardized process
Use standard apertures and threads to avoid customized tool costs.
Mass production
Expand orders after small-scale trial production to spread the initial costs.
5. Case reference
Simple parts: aluminum alloy housing (100×50×20mm), material cost 80 yuan, processing time 20 minutes, total cost about 2080 yuan.
Complex parts: stainless steel precision gear (tolerance ±0.02mm), material cost 200 yuan, processing time 60 minutes, additional polishing cost 500 yuan, total cost about 8300 yuan.
Conclusion
CNC machining costs are affected by many factors such as materials, design, and batch size. Costs can be significantly reduced through optimized design and reasonable planning. It is recommended to communicate with the processing plant about the feasibility of the design at the beginning of the project, and use online quotation tools (such as Mohou.com and Xometry) to quickly estimate the cost.
