With a capability to grind gears up to 1,250mm diameter and cut gears up to 2,500mm, it has built a strong customer base across a diverse industry range that includes rail, energy, aerospace, steel processing, mining and quarrying. Its latest investment in a Robbi Omicron CNC6015 universal grinding machine from RK International Machine Tools is part of a drive for greater versatility and productivity, that will allow its growth to continue.
With its focus on one-off to low volume production (typically 50-off) DePe Gears requires its production facility to provide efficient and flexible capacity. When it came to internal and external grinding it had become reliant upon dedicated manual machines that didn’t provide the efficient flow of work required.
The challenge for DePe Gears and director Nigel Parker was to find a universal grinder that met all of the criteria: “We needed a machine with sufficient swing and weight carrying capacity for the work that we undertake, along with it having a single internal grinding head and two external heads,” he reveals. “Every supplier we contacted fell short, with the best meeting about 50% of our needs. At this point we hadn’t spoken to RK International, but one of the suppliers that had declined to quote suggested that they may be able to help.”
Discussions quickly progressed and using the Robbi Omicron CNC6015 universal grinder as the base machine for the project, RK International and Italy-based Robbi set about creating a bespoke machine that would fulfil DePe Gears’ requirements.
The basic specification of the Omicron 6015 includes a maximum grinding length of 1,600mm, capability to hold up to 1,200kg between centres and up to 300mm centre height. The changes made to suit DePe’s requirements included a purpose-built 500Nm workhead with a specific bearing configuration using Gamet bearings that gave a weight capacity of 300kg, 150mm from the spindle nose.
To handle the weight and size of DePe Gears’ components a special quill was also manufactured and centre height was increased to 350mm. “Most customers have a requirement for 90% external grinding and 10% internal,” says RK director, Dick Aldrich. “At DePe Gears that was closer to a 40/60 ratio and to meet the challenges posed by this, along with the wide variance in bore sizes to be ground, we used a direct drive 21kW, 30,000rpm internal grinding spindle. Added to this we installed power sensors as the spindle speeds and bore sizes meant that sound sensors alone wouldn’t be sufficient to monitor wheel contact.”
Other adaptions to the machine at DePe Gears included the fitting of linear scales and incremental linear encoders to all axes, adding a secondary, right-hand, external grinding wheel, automatic wheel balancing and gap control with in-cycle dressing, Renishaw probing, and a 2.5° index facility with Hirth coupling.
“The ease of which we could work with RK International made the whole process straightforward and we now have a machine that has replaced two older, dedicated machines and brought greater efficiency to our manufacturing process,” says Nigel Parker.
The physical attributes of the Robbi Omicron machine were not the only elements that were adapted for DePe Gears, as while CNC has played a major part in its production when it comes to turning, milling and gear form production, internal and external grinding has always been a manual process.
This has generated a large amount of human knowledge and experience over the years and the arrival of the Robbi machine created an opportunity to tap into this knowledge and generate further benefits for the company.
Once again working with RK, it has started a process of digitising that knowledge by undertaking an interactive and ongoing process of developing the control software used by the Siemens 840D sl control system. The standard parameters are being amended to suit DePe’s specific requirements, transferring the depth of knowledge of material types and grinding processes, all of which is being done remotely.
“Working with RK International in this way is allowing us to transfer our manual skills and knowledge to CNC,” Mr Parker explains. “The changes being made to the software will eliminate any potential problems that could arise from operators interpreting processes differently. In short, by negating manual input we will generate improved consistency in terms of product quality.”
RK International Machine Tools www.rk-int.com
DePe Gears www.depe.co.uk
