Whether you’re making a one-off prototype or a batch of parts, keeping CNC machining costs down is important. Following design for manufacturing rules helps you make parts that are easier and faster to machine.
Add a Radius to Corners
CNC tools are round so they leave rounded corners inside pockets. Trying to make sharp corners means using smaller tools, slower speeds and more passes, which costs more. To save money, use a corner radius about one-third of the pocket depth and keep it the same on all edges. If you need sharp corners, try adding reliefs or undercuts instead of making the radius smaller.Always follow health and safety guidance when using CNC machines.
Keep Cavities Shallow
Deep cavities take longer to machine because more material needs removing, sometimes needing special tools. A good rule is to keep cavity depth no more than two to three times the tool diameter. For example, a 12 mm end mill works best in cavities up to 25 mm deep. Using manageable depths also helps if you’re working with Euromac bending machines, like the examples seen here https://www.cotswold-machinery-sales.co.uk/euromac-bending-machines/horizontal-bending-machines/.
Make Thin Walls Thicker
Thin walls can vibrate, bend or even break during machining, which slows everything down. Unless you need the part to be very light, make metal walls around 0.8 mm thick and plastic walls around 1.5 mm. Also, leave space around holes and edges to avoid weak spots.
By rounding corners, limiting cavity depth and making walls thicker, you can cut machining time and costs without affecting the part quality.