How to Reduce CNC Machining Costs Without Compromising Quality
CNC machining is a go-to manufacturing method for producing precise, high-quality parts across industries like automotive, aerospace, and medical devices. However, the complexity of CNC machining can also make it a costly process if designs and specifications are not optimized for manufacturing efficiency.
This guide will walk you through practical strategies to minimize CNC machining costs while ensuring your parts meet performance requirements.
1. Optimize Part Geometry
Complex geometries require longer machining times and specialized tooling, increasing costs. Simplify your design where possible to streamline manufacturing.
Tips to Optimize Geometry:
Avoid unnecessary tight tolerances: Apply tighter tolerances only to critical features. Standard tolerances (+/- 0.005”) are typically sufficient for most applications.
Design with machinable shapes: Incorporate fillets (rounded corners) instead of sharp internal corners to reduce tool wear and machining time.
Minimize deep cavities: Deep pockets or holes increase machining time and may require custom tools. Aim for a depth-to-width ratio of less than 4:1.
2. Choose Cost-Effective Materials
Material selection plays a significant role in CNC machining costs. Softer materials like aluminum are easier to machine than harder alloys like stainless steel, reducing tool wear and machining time.
Material Tips:
Match material to the application: Avoid over-specifying materials. If strength is not critical, consider less expensive options like plastic or lower-grade metals.
Stock sizes matter: Design parts to use standard material sizes to minimize waste and reduce the need for custom blanks.
3. Consolidate Features
Reducing the number of separate machining operations can lower costs significantly. Combining features into a single setup avoids repositioning the part and saves time.
Examples:
Combine drilled holes into arrays to minimize individual drill cycles.
Integrate multiple operations into a single setup using 5-axis machining if applicable.
4. Reduce Part Size and Weight
Larger or heavier parts require more material and longer machining cycles. Designing with size and weight reduction in mind can save on both materials and machining time.
Tips:
Hollow out thick sections where possible.
Use lightweight materials if part strength allows.
5. Leverage Standard Features
Custom threads, complex surface finishes, or unusual hole sizes can require specialized tooling and setups, increasing costs. Stick to standard features wherever possible.
Standardization Tips:
Use common thread sizes (e.g., UNC or metric threads).
Stick to standard hole sizes compatible with off-the-shelf fasteners.
6. Optimize Tool Access
Designing for better tool access reduces the complexity of setups and machining paths. Avoid features that require angled or hidden access.
Tool Access Best Practices:
Ensure all features are accessible from a single direction or with minimal tool changes.
Avoid undercuts unless absolutely necessary.
7. Minimize Secondary Operations
Secondary processes like deburring, polishing, or post-machining inspections add time and costs. Design parts to reduce or eliminate the need for these steps.
Strategies:
Use surface finishes that can be achieved directly through machining.
Avoid thin walls that might require additional reinforcement.
8. Order in Bulk When Possible
Setup costs for CNC machining are fixed, regardless of order size. Larger production runs allow you to spread these costs across more units, reducing per-part cost.
Pro Tip:
Work with your CNC shop to forecast long-term needs and negotiate bulk pricing.
9. Collaborate with Your Machining Partner
Involving your CNC machining supplier early in the design phase ensures that your parts are optimized for their specific capabilities and tooling.
Questions to Ask Your Supplier:
Can certain features be adjusted to reduce machining time?
Are there alternative materials or finishes that would lower costs?
What are the most cost-effective tolerances for my application?
Final Thoughts:
CNC machining is an incredibly versatile manufacturing process, but its costs can quickly escalate without thoughtful design and material choices. By implementing these strategies, you can reduce costs without sacrificing the quality or functionality of your parts.
Working closely with an experienced CNC machining partner ensures you get the best balance of cost, quality, and lead time. Reach out to your trusted supplier today to discuss how to optimize your next project for CNC machining!
