Stepping up a gear for wind power
The use of a linear actuator instead of a 'nodding' cam enables gear profile changeovers in minutes instead of hours
DePe has speeded up wind turbine gear production by upgrading a manual gear shaper to an advanced CNC specification.
The use of a linear actuator instead of a 'nodding' cam enables gear profile changeovers in minutes instead of hours.
Retrofit specialist Euro CNC used NUM gear shaping software and motion control hardware to bring the five-axis Stanko manually-controlled gear shaper machine up to modern day control standards. The machine is now controlled by a NUM Axium Power CNC system, using electronic gearbox techniques to synchronise the rotary cutter, gear blank and stroking axes. It also incorporates an innovative programmable replacement for the stroking axis, which reduces product changeover time from hours to minutes - significantly improving productivity.
DePe Gear Company specialises in the design, manufacture and refurbishment of gears and gearboxes for a diverse range of industrial and commercial applications, including the steel processing, rail, mining, quarrying and aeronautical industries. The company operates a considerable number of gear cutting, shaping and grinding machines at its Stoke-on-Trent manufacturing facility and has used NUM systems on three of its current gear cutting machines. In this particular case, DePe Gear Company purchased the Russian-built Stanko gear shaper initially for manufacturing large internal gears for the wind turbine industry, and subsequently commissioned machine tool engineering company Euro CNC to carry out the necessary refurbishment work.
Euro CNC specialises in retrofitting, rebuilding and upgrading machines. This often involves equipping manual machines with partial or full CNC systems. In recent years, Euro CNC has built up considerable knowledge of machine tools for gear production, and nowadays handles a wide variety of gear hobbing and shaping machines.
Nigel Parker, technical director of DePe Gear Company commented: "We are using the gear shaper for a variety of internally cut gears, including spur gears for wind turbine generator gearboxes and a variety of splined gears. Although it is too early to provide quantified data, we are definitely seeing a reduction in setup and operating times. Like our other CNC machines, the most significant benefit comes from the sheer versatility of this all-digital approach, which enables us to switch freely from manufacturing one type of gear to another under software control. Machine operators no longer need to laboriously count the number of teeth being cut, but simply push the appropriate button on the menu, which helps maximise throughput."
Traditionally, gear shaping machines employ a complex cam-driven 'nodding' axis arrangement to move the cutting tool up and down the gear blank as it is cut, the stroke of which needs to be synchronised to the rotation of the tool and the blank. This approach suffers from numerous disadvantages: it can involve up to three axes of movement, each subject to error, and is extremely difficult and time-consuming to set up, which does not sit well with the fast and flexible changeover requirements of modern manufacturing. Euro CNC consequently decided to develop an entirely new form of stroking axis, based on a fully programmable linear actuator. The end position, length and speed of the stroke can be freely changed under software control.
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