SLURRY IS NO WORRY

Weir Minerals North America (Madison, WI), a manufacturer of large pumps for mining slurry applications, needed large 108 in W x 108 in H pump housing Class 40 iron castings machined, including milling, drilling and boring. Each slurry pump housing consisted of a frame and cover section, each requiring an A and B load, which meant four set-ups for a complete housing assembly.

The manufacturer contacted Advanced Machine & Engineering Co. (AME; Rockford, IL) and several other contract manufacturers to do the machining on these parts, approximately two to three sets per week.

Each housing section weighed well over 5,000 lb, which presented substantial challenges for the fixturing. Rigidity was an absolute necessity, as well as controlling vibrational distortion from the enormous load and tooling masses involved.

?Although we began delivering the high-quality machined pump sets on time by using non-dedicated fixturing, setup was still taking far too long per part, resulting in much higher costs per pump set,? explains Steve Schubert, AME product manager. ?Changeover took as long as six to eight hours each time. Locating and clamping the pump housings was also quite tedious and the methods used raised safety concerns, both in materials handling, strapping and clamp positioning.?

Furthermore, clamping forces were less than optimal and created a negative effect on the manufacturing cycle time and the tool life. AME needed to significantly reduce the total set-up and machining time, plus improve operator safety.

The solution to this challenge was devised by the design of a single, dedicated Amrok® fixture, measuring 120 in W x 110 in H, to hold each pump section for both A and B loads that reduced setup times to less than 50 percent of the previous method. Additionally, due to improved locating and clamping methods, milling and drilling operations were optimized, resulting in a 45 percent reduction in the overall machining cycle time per pump set.

The keys to these substantial savings were the adjustable jacks built into the fixtures, which allowed proper support for the sections during the machining process on a horizontal milling machine. These savings were shared by AME with the customer. In addition, machining quality and surface finish improved by using only one fixture, instead of multiple, separate fixtures, thus allowing tighter tolerances to be repeated and maintained more easily. Machine operator safety was also enhanced due to the standardized lifting, locating and clamping methods that were employed with this fixture design.

In the end, Weir Mineral was so pleased with the results that they implemented a multiple vendor reduction process and awarded the entire project to AME. These slurry pumps are currently being used in the tar sand fields of Alberta, Canada, for oil extraction operations.

Advanced Machine & Engineering Co. is a global manufacturer and distributor of precision machine components, fluid power components, fixturing/workholding devices, power drawbar and spindle interface components, plus saw machines and blades. The company also designs and builds special machines for a variety of industries and provides machine rebuilding, retrofitting and contract manufacturing services.

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Advanced Machine & Engineering Co., 2500 Latham Street, Rockford, IL 61103, 815-962-6076, Fax: 815-963-4703, www.ame.com.