CBN Cutting Tools for Grooving

Hard part grooving can be a difficult process without the correct tools. CBN cutting tools for grooving can ease that process. During heat treatment, many features of machined components suffer distortion. If the position or dimensions of a groove are critical to the performance of a hardened component, David Richards can offer a simple solution to this problem - ‘Hard Grooving’. Based on the Top Notch system, David Richards supply grooving tools in a wide range of sizes from 0.5 mm width upwards. David Richards supply tools for circlip and ‘O’ring grooves with controlled corners or full radii, either full form for plunging or undersize for profiling.

Using such surface speeds typical for turning, grooves are machined at low feed rates (0.01 / 0.05 mm/rev). The low feed rate ensures that the swarf is very weak and brittle, decreasing the likelihood of it breaking the tool. Where there are no interruptions to the cutting path, coolant should be used to aid evacuation of the swarf and ensure that the component remains at a stable temperature for ease of measuring. If the cutting path is interrupted, an air blast will serve the same purpose without the risk of thermally shocking the PCBN tool.

If practical, it is better to finish a groove that has been pre-formed at the soft stage. This ensures uniform hardness around the groove and maintains the structural integrity of the component. However, if it is acceptable, satisfactory results are achieved grooving through a hardened layer into the core material. Successful applications include grooving case hardened (58 / 63 HRc) splined shafts and gear teeth, internal circlip grooving hardened EN31 (58 / 60 HRc)
bearing components, and producing profiles in the face of D2 tools steel tools using Full radii face grooving tools. All operations that would be time consuming and difficult to grind.

Whilst the Top Notch system offers an ideal base for most grooving tools, other systems have been employed with excellent results.

It naturally follows that, since David Richards can produce tools for ‘Hard Grooving’ full and partial form cbn threading tools, both external and internal, are available for ‘Hard Threading’. Where the pitch of the thread is large, or the diameter of the component is small, it must be remembered that the feed rate required, at the required surface speed for ‘Hard Turning’ will be relatively fast. But, producing a 90 mm diameter internal stub Acme thread 150 mm deep,
with a 6 mm pitch in 58 HRc Ni-Hard iron, at 120 m/min from blank bore, though somewhat exciting, proved a major cost saver.

To purchase CBN Grooving Inserts please visit

www.pgstools.com