HGT PRECISION BILLET GEAR CASES
Our gearbox cases start out as 60kg blocks of Billet 7075-T6 aluminium alloy.
Whilst 7075-T6 is an expensive material, it's one of the strongest aluminium alloys available and is the industry standard for many aerospace and military applications. 7075-T6 alloy is as strong as many steels with a tensile strength of 78,000 PSI.
The strength and rigidity of a gearbox casing are crucial for gear performance, so we elected not to compromise performance by choosing a less costly material. We wanted the maximum strength and precision possible in our sequential gearbox casings and the best way to do that is to program CNC 4 and 5 axis milling machines to carve the exact shape that we need out of the 60 kg billets.
Not only does this provide the maximum strength and rigidity possible, but the robotic repeatability in the machining process allows us to reduce some of our tolerances down to just 7 microns.
The CNC mill creates a finish that you simply can't get by casting…there’s no rough sand cast marks, no ridges and valleys, no pinholes, just a mirror-smooth presentation. Although our gearcases look like they've been polished, they haven't. This is just the way they come off the CNC mills when you use high-speed tooling run at slow passes - a perfect finish.