Mercury Marine LB200W

Mercury Marine was currently hard turning pinions and gears on several pieces of older equipment. These operations included several set-ups, slow cycle times (<30 pcs/hour) and very poor tool life, 25 pc per insert corner. They wanted to upgrade and streamline that equipment as well as implement auto gauging and automation. They also wanted to put different families of gears and pinions through the same cell on a single machine.

Assessment
The older machines Mercury were running had a lot of operation issues with breaking down a lot. Set-up time took too long and once they got running they were continually replacing inserts and trying to dial them in. The machine rapids were slow and tool changes took forever running up the cycle time. We knew we needed to eliminate the operator intervention where possible, to help speed up the process.

Solution
The solution provided by Ellison Technologies was a cell consisting of an CNC lathe, coupled to an Edmunds Gage and robotically loaded by a Fanuc LR Mate 200iB robot. The lathe had several required options which included, spindle orientation, X and Z axis abso scales, .1 micron control, robot loader interface, and post process gauging. A special pin chuck was designed and manufactured for the main spindle with several adapters to accommodate the different families of parts. A Kitagawa three jaw chuck was used on the subspindle. Both chucks equipped with air sense capability for proper part seat detection. The process of operation was such that the robot would use "FANUC VISION" System to pick up a part from the incoming conveyor and load it into the main spindle pin chuck. The lathe would machine the part. Use the torque skip option to transfer the part from the main spindle to the subspindle chuck. Machine the back side of the gear open the door and stop. The robot would then get a new gear from the incoming conveyor. Load it into the main spindle. Pick up the machined gear in the subspindle and load it into the Edmunds Gage. The Edmunds Gage would check the various features and send offsets to the CNC lathe via the RS-232 post process gauging interface. The robot would then place the part on the outgoing conveyor or put it in a scrap bin depending on the gage findings. The machine would automatically offset and machine the next part. The cycle would then continue on. On top of all of this, Mercury Marine required a 1.5Cpk on all machined features . Many features l had a .0005" tolerance. That doesn't leave a lot of variance at a 1.5Cpk. That is where the .1 micron control and the abso scales really shined. After dialing in the process, we were able to achieve the proper statistical capability (lowest feature being a 1.742 Cpk).

End Result
The end result of the installation of this cell was nothing but positive for Mercury Marine. They were able to have one operator machine multiple families of parts, where it took several previously. Tool life went from 25 parts per insert coner to 300 parts. They had one cabinet with all their different chuck adapters in one place near the machine which reduced set-up time to less than 45 minutes as opposed to the several hours previously seen on the older equipment. In process gauging kept their parts in spec and illiminted any scrap from getting to production. The operator of the cell is extremely happy with it, he says the machine holds size all day long and just runs and runs. He just loads up the infeed conveyor and watches it run. We were able to achieve a cycle time of under 39.5 seconds to machine the pinions and under 28.8 seconds for the gears, under the cycle time quoted by Ellison and achieving production rates of over 80 pieces/hour.