As products grow thinner and lighter to meet the needs of the electronics, medical, and micromechanics industries, United Grinding and Ewag have developed the Laser Line Ultra for machining the incredibly precise microtools required for these applications. Specializing in the laser fabrication of cutting tools made of hard and ultrahard materials such as 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 in cutting tools regardless of the material’s hardness and with negligible heat-affected zones.
To ensure homogenous hole quality with micro-sized drill bits, wear-resistance of the tools is of utmost importance and can only be achieved by micro-cutting tools made out of ultrahard materials. By using ultrashort laser pulses and the Ewag drill module, the Laser Line Ultra enables diameter-to-length ratios up to 1:20. This technology 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 significant heat has no time to be conducted into the cutting tool, creating little, if any, heat-affected zones. For example, carbide drill bits fabricated with the Laser Line Ultra 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 (PCBs), milling of enclosures such as mobile phone cases and for the fabrication of molds and dies. By using the Ewag mill module, the Laser Line Ultra 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 percent 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 <0.25 µm and <1.5 µm respectively. Additionally, cutting edge radii are typically ≤5 µm and are symmetric with a K-factor typically equal to 1±0.2. In terms of diameter stability, a tolerance of ±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 which enable users of the Laser Line Ultra to fabricate spiral tools made of WC or PCD between 0.4 mm to 3 mm in diameter. Like the Helitronic tool studio from Walter, parametric programming and automatic recommendations for laser processing parameters contribute to the module’s ease of use.