Easily access valuable industry resources now with full access to the digital edition of Canadian Fabricating & Welding.

- TR6 TNCU/MU 0702 double-sided, ground inserts with six cutting edges, available with 0.5-, 1.0-, and 1.5-mm corner radii.

“Some machinists still view cermet as too brittle to use. That characteristic, however, has been dramatically changed. Today there are cermet grades that have the same traverse rupture strength as many carbide materials,” he said.

Easily access valuable industry resources now with full access to the digital edition of Canadian Metalworking.

“I think advances in carbides have pushed cermet a little to the side, but machining is not black and white. No carbide insert will give the best results 100 per cent of the time,” said Burton. “Cermet is a good alternate for those applications.”

“Depending on the material being cut, coatings can increase the wear resistance and extend the tool life,” Burton explained.

Using cermet does have a downside. Even though it can provide a long cutting life, Burton said there is no indication of when the edge is going to chip or become ineffective.

“With cermet there are so many variables that it is difficult to predict the exact length of tool life. So you set a timeframe for its use and leave it there. Based on our cutting data, we suggest using a 15- to 20-minute tool life as a rule of thumb. There are times when you can get a half-hour or an hour but it is difficult to pin down because of variances in the material being processed. You can order the same material from the same foundry and it might be one or two points different in hardness. That difference can make the interaction between the material and the cermet insert totally different and impact the insert cutting life,” said Burton.

Other applications, however, can benefit from cermet inserts. Mitchell said, “They can be used in many applications from finish to medium cutting applications where the depth of cut is 0.80 inch or less. In low-carbon steel and powdered material applications, they are usually a good first choice.”

Image

Iscar has released the Tor6Mill milling cutters and inserts, which are suitable for applications in the die and mould, turbine blade, and general engineering industries.

The inserts are produced from the company’s Sumotec carbide grades and are available in numerous cutting geometries, including:

Kevin Burton, product and industry specialist for turning products at Sandvik Coromant, said, “Many modern cermet inserts are nickel-free, which eliminates the environmental concerns. They have a core particle structure of titanium carbonitride which adds to the wear resistance. The second hard phase of a titanium-based carbonitride, with niobium and tungsten, gives it more plastic deformation resistance, so it holds its shape longer. The amount of cobalt controls the toughness to extend the tool life.

Unlike machining shops in North America, Japanese shops use cermet to cut chips about 20 per cent of the time. “Japan has been adding cermet to its everyday arsenal of cutting tool options so it has a larger piece of the insert market, but in North America that percentage drops to about 3 per cent,” said John Mitchell, general manager of Tungaloy Canada.

Sue Roberts, associate editor, contributes to both Canadian Metalworking and Canadian Fabricating & Welding. A metalworking industry veteran, she has contributed to marketing communications efforts and written B2B articles for the metal forming and fabricating, agriculture, food, financial, and regional tourism industries.

Keep up to date with the latest news, events, and technology for all things metal from our pair of monthly magazines written specifically for Canadian manufacturers!

The smooth finish of the cermet insert cutting edge prevents material build-up, making it a good choice for cutting gummy materials like low-carbon steel.

Image

Easily access valuable industry resources now with full access to the digital edition of Canadian Fabricating & Welding.

“Uncoated cermet is a good choice for finishing low-alloy and alloy steels. It’s also good for cast iron work where good surface quality, close tolerances, and/or low cutting forces are involved. A PVD [polyvinyl dichloride] coating helps when the job involves finishing and semifinishing of the low-alloy, alloy steels, or stainless.”

Cermet, a combination of ceramic particles held together by nickel or cobalt, is typically not the first choice when choosing an insert material.

Easily access valuable industry resources now with full access to the digital edition of Canadian Metalworking.

- TR6 TNMT 1004 single-sided insert with three cutting edges for 90-degree shoulder and face milling.

Keep up to date with the latest news, events, and technology for all things metal from our pair of monthly magazines written specifically for Canadian manufacturers!

ISCAR's New Products 2024 DO-GRIP - The NEW Narrowest Double-Ended Insert Sizes Range from 0.8mm to 1.2mm, Ideal for Small Widths in Parting and Grooving

“The smooth surface structure allows a much smoother flow of material during the cutting process. The edge stays sharper longer. It retains its original micro-geometry longer than carbide,” Burton said.

- TR6 TNCU/MU 1004 double-sided insert with six round cutting edges, available in 0.5- to 3.0-mm corner radii.

Take the time to check on advances in insert technologies for both carbide and cermet. Both types of inserts are incorporating advanced technologies to make difficult machining easier. It’s a bit like leapfrog. Carbide advances, cermet advances--repeat.

The cutting performance of cermet is about midway between that of ceramic and carbide. Cermet inserts are used most frequently in finishing applications. Their high heat- and wear-resistant properties allow machining at the high revolutions per minute and light feed rates that best produce high quality surface finishes.

- TR45 TNMT 1004 single-sided insert with three 45-degree cutting edges for general use and for face and chamfer milling.

“With carbide you can dial in the cutting parameters and get a gradual flank wear which is very predictable. You set the size just above nominal and wear down to just below. For example, you can say that after 500 parts, we change the edge.

The tool diameter does not change because all insert corner radii are designed to enable undercutting. They feature coolant holes directed to every cutting edge, and the cutter body includes a protective, polished coating for uninterrupted chip flow and protection from corrosion and wear.

The cutters are available in three configurations: TR6 ER endmills in a diameters of 16 to 32 mm; TR6 ER-M interchangeable milling heads with FlexFit adaptation in a diameters of 20 to 42 mm; and TR6 FR face mills in 52, 66, and 80 mm dia.

The smooth cutting edge of a cermet insert leaves a high-quality surface finish. Photo courtesy of Tungaloy Canada.

While technology has made cermet easier to use, cemented carbide has also advanced, gaining finer finishing capabilities in hard materials. In some cases, new carbide grades have nudged cermet out of jobs. But cermet’s thermal stability in high heat, resistance to oxidation, wear-resistant properties, and the recent reduction in brittleness is keeping it at the top of lists, particularly when a smooth surface is a crucial specification.

Image

The smooth surface structure of a cermet edge allows for a smoother flow of material during the cutting process. Photo courtesy of Sandvik Coromant.