Hard Broaching




The hard broaching process


Highly-loaded and high-quality bore parts need to be matched exactly with their related shafts after the heat treatment process. Especially speed gears, synchronous rings and many other parts have an inner spline bore for an optimal torque transfer to the related shaft. They require high accuracy to avoid load peaks in the assembled parts. In the most cases, the bores have too much geometrical distortion after the heat treatment process and the parts dont match with the spline of the related shaft. Unfortunately on such parts, the whole value added chain has already been exhausted. So, in this case it is recommended or necessary to salvage these parts to reduce costs and avoid scrapping these parts.


It is for this reason Fässler developed the hard broaching process with compact diamond plated broaching tools for broaching generally formed bores after heat treatment to eliminate distortions in an economical and rapid way. Distortions like concentricity, directional errors also pitch errors and ovality can be removed. Extensive burrs and other small damages can also be removed with this process. This generally results in decreased assembly time and in a much higher percentage of contact area, which leads to a longer useful product life - especially on heavily loaded gears.


HS-100-A Hard Broaching Machine




Bore forms and diamond plated broaching tools




We machine ...



Prismatic internal profiles






Internal splines






Multiple key ways












 Key ways


We correct ...



Helix errors










 Pitch errors








As just mentioned, the broaching tool is a diamond-coated tool designed according to the customers specifications. The broaching machine itself is very intelligent and very easy to operate. You have few possibilities to control the process with the graphical control for an optimal result and a minimal broaching time.


This Fässler hard broaching process is the easiest way to eliminate heat treatment distortions of bores and splines and salvage bad but valuable parts!