1. Internal Corner Radii
We have to keep in mind that most tools are 8 times deep which means if it’s 10 inches deep, you need a one and a half inch tool and therefore 3/4 inch radius. You can add in a radii that fits the bill of being 8 times the depth. However, if you don’t need a small radii for your form fit and function, the larger the radii, the faster this part can be machine.
2. Wall Thickness
Once you get to a certain thickness on each material, it gets much harder to machine. You have to start worrying about stuff like chatter or breakage, basically you have to start machining really slow, this can add the cost and lead time. So if it fits your form fit and function, we always suggest that you leave a wall as thick as you can get it.
3. Drilled & Tapped Holes
It’s common that people will drill a hole all the way through or drill it really deep and then they’ll tap it. The opportunity to reduce the cycle time and the cost of the part comes from the fact that 6 threads are just the strongest 23.
4. Tolerances
When sending a part to a professional manufacturer or rapid prototyping service, it is vital to provide the tolerance requirements for a given part so that the CNC Machine operator knows what degree of precision is required.
Though it might be appealing to ask for the tightest tolerances possible for the entirety of a part, it is important to remember that higher tolerances are accompanied by a higher price tag, as the rotations per minute must be decreased to meet tighter tolerances, incurring longer production times. You will also find it difficult to avoid wastage when tighter precisions are not met. Because of that, you may want to loosen the tolerance and notice the difference.
5. Materials
Choosing a CNC machining material that has better machinability is key to minimizing costs. If you’re prototyping but even for production, think about the aluminum, the cheapest material and it is a metal with good machinability, meaning it can be cut more efficiently than metals with a lower machinability rating, such as steel. Avoid choosing over engineered materials for your application.
6. Multiple Finishes
The lower the finish the higher the costs. If you ever seen this part and you want the outside anodized, then you want the inside powder-coated, that’s all manual labor, you have to mask all this anodized and after anodizing, mask all this powder cut the inside many times. So think about what you are using this part for, what costs you extra, what can you leave out, what can you add.
7. Quantity
The last way to save on CNC machining is to consider the quantity. The higher the volume the lower the costs. Small quantities require minimum buys on machine time, materials, and outside processing.m