Flex-Hone in use at Copeland Corporation, a compressor manufacturer from Ohio, USA
Copeland Corporation in Sidney, OH, manufactures accessible and welded motor compressors and condensing units with capacities ranging from 1/4 hp to 100 hp. The company produces 750,000 compressors a year. The bodies of the compressors are cast by external suppliers and delivered to the Copeland plant.
According to Bruce Demers, the company’s production engineer, Copeland adheres to very strict standards when it comes to cleaning and deburring parts. This happens, he says, because contaminants such as cast iron dust, chips and burrs that are loose in an assembled compressor can cause the unit to fail.
The deburring operation at Copeland is particularly critical because each compressor head cover produces a burr on the cylinder at the time the cylinder is drilled. The compressors range from one cylinder to nine in tandem units.
To find an efficient solution to its deburring problem, Copeland used an innovative deburring and finishing tool called Flex-Hone. The manufacturer is Brush Research Manufacturing Co, Inc, Los Angeles, CA. The tool consists of an elastic hone with abrasive blades attached to the ends of high-density nylon filaments. At Copeland, the hone is inserted into a manual air tool and secured with a standard chuck.
The deburring of compressors at Copeland now works as follows: The castings arrive at the factory and are placed on one of three measuring stations where all the machine dimensions of the housing are created. The head cover is milled twice to the company’s micro requirement of 125rms. The part is then inserted into a finishing drill. During this process, a burr is created on the head surface where the drill bit crosses. If the burr were to remain there, it could cause the head to not fit properly, which would prevent the gasket from sealing. In both cases, the finished compressor could be leaking. At this point, after drilling, an operator places the casting on one of its machine surfaces so that the cylinder is in a horizontal position. He uses the pneumatic tool and removes the burr with the flex-hone. The hone rotates at around 100 rpm.
The hones vary in diameter from 1 inch to 3 inches, have a 180 grit and the abrasive is silicon carbide. Copeland manufactures compressors with 15-20 different bore sizes, so each flex hone covers a range of sizes, with the hone always being slightly larger than the bore. An operator can deburr a part with the tool in 0.25 seconds. According to Demers, the company has not experienced any problems with the deburring/finishing system. The total consumption of the Flex-Hone last year amounted to 2400 units, which corresponds to an average of 312 pieces per hone.
By using the Flex-Hone tool, Demers says Copeland has been able to maintain high quality standards at minimal cost. Without the tool, the company would be faced with two costly options. The first alternative would be to add a chamfering or deburring tool to the drill heads. This would require the purchase of new drill heads, which would cost between 1,000 and 2,000 dollars each. The company currently operates 30 drill heads.
The other alternative would be manual deburring, which would require 0.25 minutes of working time per part. The direct labor costs for this approach would exceed $50,000. This figure is not only unacceptably high but, as Demers points out, would also reduce the company’s overall capacity.