Many job shops are considering automated machine loading and unloading systems in order to make more efficient use of their labor. To be effective in environments where short job runs and frequent change-overs are the norm, such automated systems must be flexible and intuitive to set up.
In the case of cylindrical grinding machines, Hans Ueltschi, national sales manager for United Grinding Technologies (Miamisburg, Ohio), says that job shops want an automated loading system that is simple, affordable and compact. Custom loading systems often do not provide the versatility for quick part change-over and require engineering time that can prolong the delivery of a new machine.
This drove Studer, a sister company of UGT, to develop off-the-shelf loading systems for a number of its internal, external and universal grinding machines. The automated systems do not require a dedicated control, but instead are programmed from a simple teach-in screen integrated into the grinding machine’s control software. In most cases, all that must be entered during setup is part size and load/unload locations.
External and universal grinding machines use a gantry-based picking system and loading station attached to the side of the machines. A parts picker travels horizontally between loading locations and workpiece clamping point, and is said to change parts in 7 seconds.
Parts can be presented to the picker via conveyor or pallet loading system. The conveyor version can be quickly adjusted by hand to accommodate different part widths and heights, and it accepts parts up to 300 mm long and 35 mm in diameter. The pallet version allows small parts to be loaded side by side for increased loading capacity. A statistical process control (SPC) chute is available for either loading version to deliver sample parts for SPC measurement purposes.
Internal grinding machines use integrated gravity-fed chutes that deliver parts directly through the machine enclosure. These systems do not require a separate loading station. Two pneumatic grippers are located inside the machine near the chuck and chutes. One gripper picks parts from the load chute and positions the parts in the chuck; the second gripper picks finished parts from the chuck and delivers them to the unload chute. Three-second part changes are possible, according to the company.
These loading systems are available as options on new Studer grinding machines, but they can also be retrofitted to installed machines. Mr. Ueltschi notes that similar systems are being developed for the Studer Mikrosa brand centerless grinders.