Laser Line Ultra Simplifies Micro Cutting Tool Production

United Grinding North America Inc. (Miamisburg, OH) and EWAG developed the Laser Line Ultra for machining microtools required for the electronics, medical, and micromechanics industries. Specializing in the laser fabrication of cutting tools made of hard and ultrahard materials like tungsten carbide (WC), polycrystalline diamond (PCD), chemical vapor deposition diamond (CVD-D), and cubic boron nitride (CBN), the Laser Line Ultra uses an 8-axis configuration and picosecond lasers to machine complex micro geometries regardless of material hardness with negligible heat-affected zones.

To ensure homogenous hole quality with micro-sized drill bits, wear-resistance can only be achieved by micro-cutting tools made out of ultrahard materials. By using ultrashort laser pulses and the EWAG drill module, the machine enables diameter-to-length ratios up to 1 to 20. This allows manufacturers to produce tip thinning or chamfers and, unlike conventional techniques, the force-free process eliminates waste from tool breakage.

Laser processing ordinarily removes material according to thermal-based mechanisms. However, by using ultrashort laser pulses and correct laser parameters, the pulse is so short that heat doesn’t have time to be conducted into the cutting tool, creating little, if any, heat-affected zones. Carbide drill bits can accept the same processing chain and recipe for physical vapor deposition (PVD) coatings as ground cutting tools.

Applications of micro end mills include profiling printed circuit boards (PCB), milling of enclosures such as mobile phone cases, and fabrication of molds and dies. By using the EWAG mill module, the machine is able to fabricate 4-flute PCD end mills from cylindrical blanks with primary and secondary clearance faces fabricated both at the tip and circumference as well as a smooth, uninterrupted interface between PCD and WC, a crucial factor in the quality and chip evacuation performance of spiral tools. As a result, the surface quality of lasered WC surfaces is 20% better than the equivalent ground drill bit.

In general, lasered spiral tool surfaces, regardless of material, exhibit surface roughness values for Ra and Rz of less than 0.25 µm and less than 1.5 µm, respectively. Additionally, cutting edge radii are typically less than or equal to 5 µm and are symmetric with a k-factor typically equal to 1 plus-minus 0.2. In terms of diameter stability, a tolerance of plus-minus 0.005 mm can be achieved given a production run of 12 hours in a climate-controlled facility.

The EWAG drill and mill module are software options that enable users to fabricate spiral tools made of WC or PCD between 0.4 mm to 3 mm in diameter.

United Grinding North America Inc., 2100 United Grinding Blvd., Miamisburg, OH 45342, 937-859-1975, [email protected], www.grinding.com.