End mill Materials

This section could deserve an entire article, so let’s keep it concise and talk about the two main materials used to make cutting tools: HSS and carbide.

High-Speed Steel (HSS) is the least expensive of the two, it provides good wear resistance and can be used to mill many materials, such as wood, metals,...

Coated Carbide end mills are more expensive than HSS ones, but they provide better rigidity and can be run 2 to 3 times faster than HSS. They’re also extremely heat resistant, making them suitable to mill tougher materials as well.

Are carbide end mills worth the extra money then? Yes, definitely.

Since they can run way faster than HSS, they will increase your machine productivity a lot. They are also more durable and have a longer tool life, making them worth the investment.

Another easy way to increase the performances of your end mills is to add a good coating. The most common one, TiAlN (Titanium aluminium nitride), will allow you to cut 25% faster on average without spending too much money.

If you don’t care too much about performance, then choose carbide end mills that are 8mm or less in diameter. Consider HSS for larger cutters to save some money, when the tool rigidity can be compensated by its larger diameter. Besides, if you are beginning with CNC milling, don’t forget that you might make mistakes and break a few end mills before getting it right, better HSS ones as well then.

To sum up

Let's answer our original questions with :

1. What kind of shapes do you want to mill?

2. This object will require to mill ...

3. What kind of material do you want to mill?

4. What are your goals in terms of performance and surface finish, while keeping an acceptable cost for you and staying within the capabilities of your CNC machine?

I want to make a small batch of 10 items, so I’m trying to optimize the machining time within reasonable limits.