Mollart Engineering Multi-surface roller burnishing tool eliminates secondary grinding processes
UK – A carbide roller tool for burnishing multiple surfaces of a component including internal and external diameters, radii, counterbores and end faces as part of a single CNC turning process is now available from UK-based, Mollart Engineering.
According to the company, the multi-surface boring bar style tool uses a conical, cup-style carbide roll that freely rotates on a precision bearing that accommodates both axial and radial forces generated from the pressure and direction of feed on the component.
The tool can even be used directly on pre-ground components that require a burnished texture level of finishing and very tight tolerances, Mollart says. An animation of the cycle of the tool showing ID, OD and face burnishing cycles is available on the company’s homepage, by clicking the photograph of the tool.
Mollart explains that an example is the transformation of the surface finishing of impeller motor shafts for a customer. With its application, development for in-cycle burnishing has been integrated into the turning process eliminating a sub-contract grinding process.
The 316 stainless steel motor shaft has two ground diameters: 50 mm for 100 mm lengths and 54 mm for 70 mm lengths – both produced within Ra 0.4 surface finish.
The tool has two sets of springs to accommodate bi-directional loading. One set is located within the tool shank which enables the entire head assembly to deflect when the carbide roll is pushed against the surface of the part and a second spring is located behind the carbide roll. The tools are available for most materials up to 40 HRC from a minimum bore diameter of 16 mm with different shank sizes to suit customer demands.