Home Companies

Custom Carbide Tools company

Custom Carbide Tools company

About Us

Machining composites presents unique challenges compared to metals. Reinforcement fibers are abrasive, shortening tool life. The plastic matrix carries away little heat, unlike metal chips, and overheating can melt the matrix. Composites can delaminate, and burrs and fibers show on poorly drilled holes or poorly trimmed edges.
Other challenges include machining or drilling laminate stacks composed of composites combined with titanium or aluminum. Creating tools that drill such stacked holes in a single operation is particularly difficult. The common strategies for tool designs for cutting composites include uncoated carbide, tools with a diamond coating applied by chemical vapor deposition (CVD), and polycrystalline-diamond (PCD) edged or tipped tools. Traditional PCD is produced by sintering diamond crystals embedded in a metal matrix. The tool’s cutting section is cut to shape and brazed or sintered onto a carbide shank. Traditional PCD is limited in tool geometry, but some companies now offer PCD-veined tools that produce more-complex geometries.
Tool designs need to minimize cutting force pressures, especially in drilling. Avoiding delamination is paramount. Delamination typically occurs on the tool breakout, as the axial-thrust force puts pressure on the lower surface laminations. It also happens at the surface during entry,” explains Karthik Sampath, a senior engineer with Kennametal (Latrobe, PA). Although thrust correlates with breakout delamination, Kennametal also believes variations in fiber position and the presence of voids contribute. Unlike machining metals, where shearing and formation of consistent chips is desirable, machining composites means fracturing fibers, coupled with shearing the matrix material, according to Sampath.
To cut cleanly with the least amount of tool wear, Kennametal seeks to optimize tool geometry. Our tests prove that composite drills need a high helix angle, a severe clearance angle, and a high-rake gash angle for easier entry into the material,” states Sampath. He notes paying particular attention to the clearance angle behind the cutting edge. In one test that compared 10, 20, and 36° clearance angles, as clearance increased hole quality improved dramatically. Tool sharpness is also critical. Our findings conclude that having a sharp edge ≤10-m radius) before applying a coating material works best.”
As for materials, Kennametal recommends PCD-veined drills and diamond coating of low-cobalt steel drills. Diamond-coated drills deliver a 10:1 improvement in tool life over uncoated carbide and, in some cases, a 50% longevity increase over PCD-drill technology, according to Sampath. We recommend a diamond-coating thickness of 12 m for maximum wear resistance and good cutting properties. A thinner coating can lead to edge chipping, and a thicker coating does not improve the performance in proportion to its extra cost,” explains Sampath. Kennametal offers its B531 and B532-series drills for composite cutting.
A tool geometry designed to minimize cutting pressures is critical for cleanly cutting composites, agrees Stephen Jean, milling products manager of Emuge Corp. (West Boylston, MA). Our end mills are unconventional in appearance, and resemble a thread mill more than a typical carbide end mill. The tool incorporates two serrated cutting edges. One edge cuts in an upward direction, and the other cuts downward. In rotation, the effect is a scissors-like cutting action that efficiently mills the base material, while shearing the fibers and eliminating the fraying effect.” Emuge also offers PCD end mills and inserts, as well as a variety of CVD diamond-coated carbide inserts and end mills for machining composites.

Hot Products

Cutting Tools for Composites by Bruce Morey - Machining composites presents unique challenges ...
AMAMCO Tool has built a legacy as a custom solutions provider for more than four decades. A ...

Company info

Company Name: Custom Carbide Tools company
Country: China
Website: http://www.customcarbidetools.com/