How to Select the Right Carbide Insert

The menu of available coatings for carbide inserts has expanded ten-fold in the past ten years. Selecting the one that can produce low cutting forces with smooth cutting action, good surface finish and long tool life becomes the user's dilemma.

What are Carbide Inserts?

Carbide inserts are tools used to accurately machine metals, including steels, carbon, cast iron, high-temperature alloys, and other non-ferrous metals. These are replaceable and come in various styles, grades, and sizes.

There are some primary considerations on how to choose the correct carbide inserts. One of those is the cutting operation, whether turning, Milling, or drilling. Carbide is more expensive per unit than other typical tool materials, and it is more brittle, making it susceptible to chipping and breaking. To offset these problems, the carbide cutting tip itself is often in the form of a small insert for a more enormous tipped tool whose shank is made of another material, usually carbon tool steel. This benefits from using carbide at the cutting interface without the high cost and brittleness of making the complete tool out of carbide. Most modern face mills use carbide inserts and many lathe tools and endmills.

Carbide inserts are used at high speeds that enable faster machining, ultimately resulting in better finishing. Choosing a correct carbide insert is vital because it can risk damaging the insets, machine, and cutting product.

Material of Inserts

Inserts are made of several different materials but commonly constructed of carbide, micro-grain carbide, ceramic, CBN, cermet, diamond PCD, cobalt, silicon nitride, and high-speed steel. The coating over the insert increases the wear resistance and life span of this cutting tool. These coatings include titanium nitride, titanium carbonitride, titanium aluminum nitride, aluminum titanium nitride, aluminum oxide, chromium nitride, zirconium nitride, and diamond DLC.

Manufacturing of Carbide Inserts

Let's discover the manufacturing process of carbide inserts to know better about its types and uses;

The suitable carbide insert for specific machining operations helps to stay ahead in competition among the cutting tools industry.

Carbide inserts, mainly tungsten and cobalt, start in powder form. Then in the mill, the dry raw material is mixed with a combination of ethanol and water. This mixture results in a gray slurry solution with a consistency like a yogurt drink. This mixture is dried and then sent to a laboratory for a quality check. This powder comprises agglomerates, small balls of 20 to 200 microns diameter, and then transported to pressing machines where inserts are made.

Primary considerations on how to choose the right carbide inserts

Metal cutting operation

Milling

Turning

Drilling

Material to be machined

Soft tool steel

Hardened tool steel

Aluminum

Brass or bronze

Any other alloy

Type of machine tool

5 Axis

High speed machining center

Conventional VMC

Manual milling machine

Horizontal milling machine

CNC lathe

Engine lathe

Swiss type

Other machine tools

Other considerations for choosing carbide inserts

Skill level of operator, machinist or toolmaker

Budget available for tool holders, vises and carbide inserts

Time schedule

Surface finish requirements

Capability of milling machine, lathe or other machine tool

Dimensional tolerance requirements

In most cases, there never will be one cutting tool insert solution that works for everyone. There are too many variables with respect to different machines, various coolants, speeds and feeds, and machining environments. What this article has attempted to show, in as brief a context as possible here, are basic starting points for insert selection for the various mold materials. The ultimate selection is left to you, hopefully now possessing a better knowledge.