Step one: grinding the stem

The loading machines that feed the stems to the grinding machines comprise a two-pallet feeding system and a SCARA robot. Each pallet accommodates 100 components mounted vertically on pin fixtures. Both are automatically carried into the machine on two adjacent slide-ways using a pair of Joucomatic pneumatic cylinders. As one pallet of 100 work-pieces travels towards the robot, so a finished set is drawn away. They enter the machine via two automatic rise-and-fall safety doors, also actuated by two air cylinders.

The blanks are picked up, one at a time, by a gripper on the SCARA robot arm which transfers them to a second station which turns the component through 90i to enable it to be picked up by a second gripper that transfers the blanks correctly orientated to the grinding machine.

Each stem is re-orientated along its axes. A mounting plate used on the second station is turned through 90i axially by means of a Parker Pneumatic rotary actuator. The angle of rotation is controlled by a fibre-optic sensor that detects the position of two existing flats machined into the tang of the stem. A `pass’ signal is sent to stop the servo motor when the correct orientation has been achieved, at which point, the stems are fed to the grinder for machining scallops and chamfers.

When complete, the robot returns the stem to the second station where it is once again turned vertically. After this, the vertically operated gripper on the robot arm carries it back to the pallet and another blank part is picked up. The action is continuous so that as one blank is withdrawn from the pallet, a finished part is relocated in its original position. When filled with finished parts, the pallet is returned to the loading and unloading station while the second pallet is passed into the machine. The entire grinding cycle takes around 30s.