|Robot automation on Compact Line grinders works in unison with Ewag’s Pin clamping system. |
The reasons for automating a grinding process are self-evident. Automation reduces auxiliary time, personnel costs and the risk of accidents, especially in high-volume-production grinding environments.
However, automating grinding operations, such as centerless grinding and cutting tool insert grinding for example, can present challenges to machine builders.
Studer Mikrosa GmbH (www.mikrosa.com) of Leipzig, Germany, and Ewag AG (www.ewag.com) in Etziken, Switzerland, are grinding machine companies that have successfully met the challenges of automation by designing innovative systems.
For Studer Mikrosa, the system is a high-speed loader designed for its centerless grinder.
Ewag zeroes in on automation with a robot that is paired with special clamping systems for the company’s insert-grinding machine.
Gerd Staadt, project engineer at Studer Mikrosa, said the easiest way to automate a through-feed grinding operation on a centerless machine is with a belt or bowltype system, or with roller loading that feeds parts through tubes to the grinder.
|Technically, Ewag built its Compact Line grinder around robotic automation. |
To automate in-feed grinding operations on a centerless machine, Staadt recommends gantry loaders that pull parts either from a conveyor or from a vibratorybowl system.
In addition, the company provides “combined” systems that automate both through-feed and in-feed operations on the same machine.
By far the most innovative automated loading system from Studer Mikrosa is its high-speed centerless loader for workpieces that are smaller than 8 mm (0.315 in.) in diameter and no longer than 80 mm (3.15 in.) in length, such as fuelinjection components.
Developed in cooperation with Wenger Automation & Engineering AG, the loader uses the machine’s flow of coolant to load and unload workpieces in less than one second and eliminates the need for external automation.
Compressed coolant, running through a patented system, pushes workpieces up from a rail within the grinder’s work zone to the overhead loader. The finished workpiece travels into one chute in the loader, while another chute in the loader releases a new part ready for grinding, and the coolant pressure from below lowers it to the work zone rail.
The loader is simple to operate and is integrated with the machine control. Because the loader is pneumatically driven – it has components that also are integrated into the machine – there is no need for additional power units.
|Studer Mikrosa’s integrated high-speed loader. |
When workpieces are blown off the rail they are resting on, they lose some of the coolant that adheres to them, but that amount is less than with conventional loading systems.
Made for Studer Mikrosa’s Kronos S (speed) centerless plunge-cut grinding machine, the high-speed loader operates on either oil or emulsions, making it available for a variety of applications, including single and dual production and sequential processing when two operations must be done.
In automating its 5-axis Compact Line grinding machine for manufacturing or for resharpening cutting tool indexable inserts, Ewag built its machine around a robot, Herbert Gruner a manager at Ewag said.
“As recently as 1999, the majority of our customers didn’t want a robot, now it is just the opposite. Everyone wants a robot,” Gruner said.
Instead of treating the robot as a separate unit, Ewag built the robot on the machine base of the Compact Line grinder. This integrated 6-axis Fanuc robot allows shops to use the machine in autonomous multi-shift operations.
Within the machine, the robot is positioned closely to the working B axis, so robot movement keeps to a minimum to reduce non-productive cycle times.
The robot automation is further enhanced by two special workpiece clamping systems.
|Studer Mikrosa’s integrated high-speed loader for centerless grinders uses coolant pressure to load/unload parts. |
One clamping system holds inserts as a vice would, while the other, called the Pin system, clamps inserts using their existing clamp-down holes. All clamping systems are mechanically – and identically – mounted on the machine’s B axis via a plug-andplay unit that provides maximum flexibility and reduced changeover times.
When loading an insert onto the Pin clamping system, the robot travels to a waiting insert and slides a tension pin through its clamp-down hole. The robot then picks up the insert with the pin, and carries it to the clamping unit.
At the clamping unit, the robot’s second set of grippers removes a finished insert and its tension pin, and loads the new insert.
It takes the finished insert back to the load/ unload station, removes the pin from the insert, and slides that pin into the next insert to be ground.
There are only two tension pins needed in the system. The clamping unit pulls pins downward and secures them in place in the same way a collet holds a rotating cutting tool.
Studer Mikrosa and Ewag grinders are available in North America through United Grinding Technologies Inc. (www.grinding.com).