In today’s manufacturing industry, machine tools are of utmost importance. More important than those still, are the technologies behind them that enable manufacturers to ensure quality in their products, either in cutting, grinding, finish, and the like. These processes however, do require different technologies for optimum performance, even though they might require the same components, such as linear motors.
Linear motors in machine tools today are generally the flat bed type, which makes them work fine for laser cutters. This type of linear motor makes a poor compromise for CNC (computer numerical control) tool grinding, and so the team at ANCA have sought to adapt another type of linear motor – a cylindrical linear motor – for tool grinding instead.
The magnetic flux in flat bed linear motors are asymmetric and create tremendous downforces on the rails, making everything wear faster and further reduce efficiency in tool grinding, he noted.
To overcome this, they designed one with a magnetic flux such that the motor uses the entire symmetrical magnetic field, delivering more efficiency than a flatbed style linear motor. With this, they also developed a specialised servo drive software that would specially suit grinding applications.
The advantages of a cylindrical linear motor over the conventional flatbed one are many. For one, it eliminates cogging and improves surface finish on the tool when grinding. Also, being cylindrical, the linear motor is also more compact and would help minimise required floor space and contribute to a smaller footprint. This is also complemented by the fact that cylindrical linear motors have improved energy efficiency, and do not need a separate chiller unit for the motors; this further reduces required floor space and saves power.
In terms of wear, an IP67 rating evidences a long tool life for a cylindrical linear motor. With additional protection to protect magnets and winding, and no mechanical moving parts, these machines have a smoother axis motion and are precise and accurate even over time as wear is reduced.
The company has since used one such cylindrical linear motor in series of CNC tool grinders they produced to suit light manufacturing, regrinding, and even full production. To make an operator’s life easier, they also added a touchscreen that enables swipe and multi-touch, a handheld pendant for easier set-up, and an easy-to-access front loader door.
The cylindrical linear motor improves the CNC tool grinders in several ways. It caters for an accurate axis motion for a precise performance and enhanced surface finish, allows for unmanned operation—being a fully automated solution—and has the flexibility to different tools, spindle power and automation capacity while providing high levels of speed and productivity and a long machine tool life.
