feature Honing On A Machining Center A specially designed tooling package for honing operations and along with live, on-board gaging allows critical honing operations to move to HMCs, thereby eliminating several separate steps on multiple dedicated machines. By Mark Albert 70 MMS December 2009 mmsonline.com

feature H oning is a particularly critical operation for Quincy Compressor in Quincy, Illinois. That’s because the quality of a compressor’s cylinder bores greatly affects its efficiency, and honing is the final and most critical step in the process of bringing cylinder bores to specification. A highquality bore finish ensures that the motion of the piston and the cylinder bore creates maximum air compression with minimum carryover. Carryover (sometimes called “blow-by”) refers to the minute quantity of oil particles that pass by the rings on the piston when a compressor is running. So honing...

feature On the outside, the most conspicuous addition to these otherwise “standard” machines is the gaging system’s control and readout unit mounted to the right of the operator’s door on the side of the machine. The inset shows a close-up of the unit. company moved to its current plant location. By then, the company had changed its name to Quincy Compressor. In 2005, the company became part of EnPro Industries, a family of manufacturing firms. It continues to specialize in compressors for industrial applications, especially those used i n re g u l ati n g c l i m ate c o ntro l sy s te m s a...

feature He says the project involved some essential modifications to a standard HMC. In this case, the team determined that a pair of Nexus 6800 II HMCs would be the best choice for Quincy’s needs. These 50-taper machines are equipped with 80-tool magazines and a two-station pallet changer. Modifications for honing included an additional compressed air line for the air gage on board the honing tool, a coolant inducer to deliver high pressure coolant to the body of the honing tool for activating the honing stones, and 10-micron coolant filter. Also, the machines’ controllers were modified so that...

feature size is reached, the gage unit signals the CNC to shut off coolant flow to retract the honing stones and begin the procedure for withdrawing the tool from the bore. Under programmed command, the honing tool completes one more stroke with coolant pressure re-activated. By precisely controlling RPM and the feed rate, a cross (Almost) Like Any Other Tool hatch pattern at the pre-determined angle can In The Magazine In operation, the typical honing process on the be imparted on the wall of the bore. (This crossHMCs works like this: After facing, milling, drilling, h atc h i s th e s i g n...