Installed following extensive production trials and product process approval, the improvement in gundrilling was based on the latest Botek Typ 113-HP gundrill development when producing 5.3 mm holes by 100 mm deep in the pins of crankshafts. The on-going provision of a re-grinding and coating service for the tools, which are used under around-the-clock production conditions, was negotiated by Mollart’s tooling director Chris Barker as part of an on-going supply contract.
Says Barker: “The change in gundrilling technology has generated massive savings, plus the added security and predictability in the process with known tool life and spindle up time. We are now working with the company’s engineers to extend the use of HP drills elsewhere.”
The Typ 113-HP drill has a special nose grind that takes in highly polished flutes and a kidney-shaped coolant channel to ensure maximum evacuation of chips from the cutting zone. The drill series is suitable for use over a wide range of materials, from aluminium to high strength steels.
The two-spindle special purpose gundrill machine is being run at 4,200 rpm and neat oil passes through the drill at 70 bar pressure.
