Why are cutting tools coated? Most would say it is to protect the tool. That answer is true as far as it goes, but the function of the coating is more varied and more specific than that. In this video, I get to talk about coatings with Julius Schoop, Ph.D., machining expert with the Cincinnati-based manufacturing consulting firm TechSolve. (Actually, he is now formerly with TechSolve—he accepted a university professor position while this video was in production.)
In particular, Dr. Schoop and I focus on the difference between physical vapor deposition (PVD) and chemical vapor deposition (CVD) coatings. PVD is a line-of-sight process allowing for a thinner coating and therefore a sharper edge. CVD produces a thicker coating more effective as a thermal barrier.
The machining footage in this video shows the difference as we experiment with different coatings in both roughing and finishing passes in 4140 steel. Choosing the right coating for the cut can have a dramatic effect on the performance of the process.
Consider these alternatives when conventional drilling can't do the job.
To make the transition to hard turning, you'll need to switch from carbide to CBN inserts, but that is easier (and more economical) than you might think. It's making the jump to much higher surface speeds that might scare you off. It needn't. Here's why.
Reducing cutting fluid use offers the chance for considerable cost savings. Tool life may even improve.