sales@influxxlabs.com
386 South Abbott Avenue, Milpitas, CA 95035
+1 (408) 461-7185
CNC machining has revolutionized the manufacturing industry, allowing for precise and efficient production of complex parts. When it comes to acquiring CNC machined parts, understanding the quoting process is essential. This document aims to guide Mechanical Engineers through the key elements of how CNC machined parts are quoted by machine shops. This is based on my company’s standard practices for quoting jobs in the Bay Area, CA; other shops may have different methods.
1. How Many Setups?
Manufacturers examine the technical drawings and CAD files. The first thing considered is how many setups on the machine the part requires. Most shops with 3-axis machining centers require 2-3 setups per part. However, shops with 5-axis machining centers can typically reduce setups to just two due to the machine's ability to rotate the part.
- Machine the top holes and profile
- Face off the stock at the bottom held in the vise
- Machine the side hole
Setup costs are billed at an hourly rate that varies by machine type and shop certifications, ranging from $50 to $150/hour in the Bay Area, CA. Cheaper shops may bill less, while ISO-certified shops may charge a premium.
2. Programming
Programming the part in CAM software is another cost factor. This is billed at $70-$100/hour in the Bay Area and usually costs less than setup time, as it does not involve using the machine tool.
3. Tolerances, an Engineer's Best Friend
Tolerances influence the quoting process significantly. Achieving tight tolerances may add setup time and cost, depending on the difficulty of achieving the specified dimensions. For instance, a small bore with a +/- 0.0005” tolerance may be straightforward, while larger bores may require extra machining time.
4. Run-Time
Run-time refers to the time required to complete machining operations. This is billed at $80-$120/hour in the Bay Area. Material selection impacts run-time, with materials like aluminum and plastics being easier to machine than stainless steel.
5. Material
Material costs are billed directly to the customer, with shops typically ordering 20% more material to account for potential mistakes. Metal suppliers in the Bay Area include Industrial Metal Supply, San Jose Metal Supermarkets, and Metal-Werx.
6. Surface Finishes and Treatments
Anodizing, plating, or painting is often outsourced and billed per batch. For example, clear anodizing a batch might cost around $100.
7. Lead Times
Expedited jobs can increase costs by 20%-30% or more, depending on overtime and resource allocation. Some shops may double the original cost for rush jobs.
8. Quality Assurance and Inspection
Inspection costs are billed at $70-$100/hour and can take 1-2 hours, depending on part complexity. This ensures all features meet specifications.
Conclusion
Accurate quoting is essential for cost-effective manufacturing. Understanding the factors influencing quotes helps you select the right CNC machining partner. Compare quotes, capabilities, and quality standards before finalizing a partner.
Influx Labs provides competitive quotes and exceptional service. If parts aren't in specification, we will remake the order free of charge. Reach out with any questions or for a quote at sales@influxxlabs.com.