Designing CNC Parts That Cut Costs
CNC machining delivers the precision and durability engineers need. But design choices made early in the process can significantly affect cost, lead time, and manufacturability.
In this article, we cover seven proven design-for-manufacturing (DFM) rules, and show how instant quoting with MakerVerse helps you make better design decisions for both 3- and 5-axis parts.
Why DFM Matters More Than Ever in 2025
Design for manufacturability (DFM) ensures your parts are not only functional but also cost-effective and fast to produce. With shorter sourcing timelines and growing demand for custom components, good DFM can be the difference between an on-time launch and a costly delay.
7 Key Design Rules for CNC Parts
| Design Rule | Why It Matters | MakerVerse Tip |
|---|---|---|
| Avoid Deep Cavities | Deep pockets increase tool wear and cycle time. | Keep depth < 4x tool diameter. |
| Use Standard Holes | Non-standard sizes need custom tooling. | Stick to ISO drill sizes (5.0, 6.5, 8.0 mm). |
| Minimize Sharp Corners | Sharp 90° requires EDM, adding cost. | Add fillets ≥ tool radius. |
| Limit Thin Walls | Thin walls deform and vibrate. | ≥1.0 mm (metal), ≥1.5 mm (plastic). |
| Reduce Reorientation | Extra setups increase time and tolerance risk. | Design for fewer flips; use 5-axis if needed. |
| 3-Axis vs. 5-Axis | Wrong strategy raises cost and errors. | Use 5-axis for complex angles/undercuts. |
| Validate with Auto-Quoting | Instant feedback avoids rework and delays. | Upload to MakerVerse for instant pricing. |
1. Avoid Unnecessarily Deep Cavities
Deep pockets increase cycle time and tool wear.
Tip: Keep cavity depth below 4x the tool diameter. Example: a 3 mm end mill → max 12 mm cavity.
2. Use Standard Hole Sizes
Non-standard diameters often require custom tools.
Tip: Stick to ISO standard drill sizes like 5.0 mm, 6.5 mm, 8.0 mm.
3. Minimize Sharp Internal Corners
Milling tools are round; sharp corners mean extra EDM work.
Tip: Add internal radii equal to or larger than the tool radius.
4. Limit Thin Walls
Thin walls deform easily during machining and clamping.
Tip: Minimum wall thickness: 1.0 mm for metals, 1.5 mm for plastics.
Start Your Manufacturing Project with MakerVerse
MakerVerse is a platform for sourcing industrial parts. It provides instant access to a vetted supply chain and a full range of manufacturing technologies. With AI-powered quoting, order management, and fulfilment, MakerVerse helps with everything from initial prototypes to full-scale production.
5. Reduce Part Reorientation
Every repositioning adds setup time and tolerance risks.
Tip: Place features on as few faces as possible. For complex parts, consider a 5-axis.
6. Choose 3-Axis vs. 5-Axis Wisely
3-axis handles simpler geometries. Undercuts, compound angles, or multiple planes require a 5-axis.
Tip: If features can’t be reached from one direction, you’re in 5-axis territory.
7. Validate with Auto-Quoting Tools
Uploading to MakerVerse gives instant CNC pricing, factoring in material, tolerances, and geometry.
Example: Reducing a pocket depth from 12 mm to 6 mm in aluminum cuts the price by 28%.
3-Axis vs. 5-Axis: Which One Should You Choose?
Use a 3-axis when features lie on a single plane or are accessible from one direction.
Use 5-axis for complex curves, undercuts, and features across multiple angles, fewer setups, higher accuracy.
How Instant Quoting Improves Your Designs
Waiting days for a manual RFQ slows iteration. With MakerVerse, you can upload a file and instantly see how design changes affect cost and lead time. This works for both 3-axis and 5-axis parts, letting you optimize designs before production begins.
Smarter Designs, Faster Production
DFM isn’t just about tolerances, it’s about more innovative engineering. Apply these seven rules, validate designs instantly, and bring products to market faster.
👉 Upload your CAD file today and get an instant CNC quote
