Green button process supported by novel workholding

Engineers from the aerospace supplier approached precision machining and workholding subcontractor Brown & Holmes for a purpose-built solution for manufacturing a series of components within a 'green button' cell. Reduced manual intervention was key, with the fixtures moving components through the mill-turn cell via robot handling, without any human interaction from when the fixtures entered the cell until they returned to storage, after the completion of the machining processes. Kevin Ward, joint director of Brown & Holmes, said: "This presented us with several challenges. We needed to ensure accurate and repeatable positioning of the components into the fixture, repeatable fixture location onto the machine tool and positive clamping and support of the component through the machining processes: alongside a number of size and weight constraints" In addition, all fixtures and clamping elements had to be of stainless steel construction, as a hot water wash within the cell would clean down fixtures and components between operations and at the end of the process. Stainless steel avoided likelihood of corrosion and, ultimately, failure of the fixtures. To help meet these challenges, Brown & Holmes worked with hydraulic workholding and handling technology supplier Roemheld (UK), which delivered the hydraulic cylinders and work supports for the final bespoke, fixturing solution. The total stainless construction raised several challenges for Brown & Holmes during manufacture, but also required Roemheld to re-design a number of clamping elements from its 'standard' product range and create one-off specials, due to the unusual material requirements. The finished application met all end user needs requirements and is in production today.