How to Improve the CNC Turning

WMT CNC has some experienced engineers, they often give us some good application advice, in order to salesman can better communicate with customers. Now, we will introduce 7 tips to better CNC turning.

This really applies most when using carbide tools. When you increase the surface feet per minute speed (SFM), you will ensure that the material is in contact with the tool tip for a shorter amount of time and will also reduce edge buildup on the tool, which causes poor surface finishes.

Reducing the feed rate helps to improve surface finish. This will also help to reduce flank wear and prolong the insert’s longevity. In addition, doubling the nose radius will help to improve surface finish. For roughing applications, it’s best to use a tool capable of a high feed rate to remove material quickly. For finishing, it’s best to have a lower feed rate and shallower cut.

A poor surface finish can also be caused by improper chip breaking, downtime to remove chips and higher temperatures at the tool’s cutting edge. A chip breaker can produce smaller chips that are cleared from the cutting area quickly. And because there is no longer a need to clear chips by hand, safety is improved.

If the chip breaker can break the chips into adequate lengths, then vibration will be minimized; the chips will not wrap around the workpiece and tools will not be damaged. Chip breakers also reduce cutting resistance, which can avoid chipping or breaking the cutting edge. A lower cutting resistance can decrease heat and delay tool wear.

Creating a chip that is thick-to-thin is what you want. Your technique plays a vital role in getting smooth surface finishes. Choose a cutter that is smaller than the nose radius so you can program it for a smooth transition from line-to-line.

When you run your final cuts, don’t just limit yourself to checking your workpiece; you should also read your chips. The characteristics of your chips will indicate what machining set up or tooling adjustments are necessary.

Some may say that the same inserts can be used for both roughing and finishing. But it’s best to use separate inserts, one for roughing and one for finishing. For roughing, you can use a course-pitch cutter with a large nose radius, and a large rake angle with a rapid feed rate. For finishing, you can use a fine-pitch finishing tool with the proper lead angle and a wiper flat, which will give you a better surface finish.

There is a debate whether to use coolant in milling applications. But it all depends on the type of work you’re doing, such as deep cavity milling, the type of material and which insert you are using. Using coolant, in some cases, should be avoided. It may cause thermal cracking and shorten tool life and could affect the surface finish negatively. But with aluminum, low-carbon steel or nickel-based alloys, using coolant will prevent the tool from sticking to the workpiece.

It’s a good idea to check the condition of your toolholder. An old, worn-out toolholder may cause the insert to move. This will cause chatter and will negatively affect the surface finish of your part. You also want a rigid workholding that is stable, especially with a higher metal removal rate.