Industrial Engineering Case Studies Collection
https://www.macombgroup.com/4419/brand/delta
https://worldwide.deltafaucet.com/
9/1/2001
Productivity Engineering Boosting Multi-Spindle Productivity
Delta Faucet is taking advantage of off-the-shelf technology to improve multi-spindle screw machining productivity.
The real story here is the way that the plant has enhanced the machines with standard, readily available, off-the-shelf technology to fully exploit their productive potential.
A large component of that off-the-shelf technology is the machining attachments used on several of the multi-spindle screw machines. They were provided as parts of turnkey installations by the machine tool manufacturer, Gildemeister Italiana (GITAL), represented in the United States by DMG America Inc. (Schaumburg, Illinois). The machining attachments permit machining faucet components complete in one setup, eliminating the need for secondary machining.
Ken Myers, director of manufacturing services for Delta Faucet, explains that the 390,000-square-foot Jackson plant, built in 1994 and the newest of the firm's three U.S. manufacturing facilities.
The Jackson plant is not only expected to machine the components for faucet lines more efficiently and economically, hence the emphasis on machining parts complete in one setup, and hence the attachments to accomplish that goal.
For example, one of the plant's 35-mm-capacity multi-spindles is used to produce a slip-on tub adaptor (a universal mount for various tub spouts for bathtubs) that requires a drilled and tapped cross hole on the side of the part and a chamfer and counterbore on its back end. The part was previously produced as a multi-spindle part at the company's Greensburg plant. However, the cross-drilled and tapped hole and the back end chamfer and counterbore were machined in secondary operations. The part required extensive handling: “We'd machine the part on the multi-spindle, put it in a pan, take it to the degreaser, clean it, and then move it to a staging area for the secondary work. There was more handling of the parts through the secondary machining operations and then through cleaning again. The process not only created work-in-process inventory that took up space and had to be accounted for, but it also created increased opportunity for operators to make machining errors and for the parts to be nicked and scratched because of all the handling,”
At Jackson, the problem was solved by equipping a new six-spindle screw machine with two attachments, that permit the slip-on tub adaptor to be completely machined in a single setup. The first attachment is a cross-drilling and tapping attachment. When the carriage rotates the bar to the fourth station, the spindle slips out of gear, and the bar stops rotating. The attachment then drills and taps the cross hole in the part. The carriage then revolves the bar to the next station where it resumes rotating. After the front-end machining is complete and the part has been cut off, a second attachment picks off the part and presents it to a combination tool that chamfers and counterbores the back end.
Jobs are grouped into families of parts that may require a drilled and tapped hole on the side, a chamfered and counterbored back end, and so forth. The family of parts production methodology helps the machining department set up faster for the next job. Frequently, changing a tool or two is the only change needed to run the next part.
“When Jackson opened in 1994, changeovers averaged about two per week. Today our changeovers average about two per day. So it becomes imperative to run the parts in families to permit the changeovers to be made as quickly as possible.”
The machining attachments are just one arrow in Jackson's quiver of multi-spindle-productivity-enhancing tools. The Jackson plant typically assigns an operator to multiple machines to hold down labor costs. All machine operators gauge X number of parts per hour as indicated by the work instructions under ISO 9001. That becomes difficult when part cycle times are short. They cannot do loading bars into the machine manually and checking a number of features per part for a given job. To ensure that operators have enough time to adequately inspect the parts, the machining department has installed bar loaders on selected multi-spindle machines to save the operators the loading time.
The bar loaders increase the productivity of the machines on which they are installed because they permit continuous operation.
Accumulators Store Parts till Operator Attends.
Delta Faucet has also made the task of running multi-spindle screw machines easier by adding accumulators, which in this case are large rotating tables that receive the machined parts as they automatically exit the machines. The accumulators can hold from a few dozen to a few hundred parts at a time, depending on their size, allowing the operator to attend to additional machines and/or other duties away from the machine for extended periods.
With the accumulators, the Delta Faucet operators can perform the number of part inspections required, monitor the operations of the machines, keep the work area clean, even take a break, knowing that the machined parts are being safely stored.
A second advantage of the accumulators is that the parts are handled gently instead of being allowed to free-fall into a pan. The accumulators provide the gentle handling that such parts require. The improved handling of parts in the machining department permits less aggressive mechanical finishing.
Cutting Tools
No aspect of the Jackson plant's machining operation has been overlooked in the effort to boost productivity. In case of cutting tools, for parts on a near-continuous basis, and form tools continue to be the most efficient way to produce them. Insert-type tooling is used almost exclusively. Insert-type tooling is easier to set, saving time during setups.
Most of the technology that Delta Faucet has purchased is portable. That is, the bar loaders, accumulators and machining attachments can be removed from one multi-spindle machine and installed on another, enabling the plant to adjust easily to future changes in the company's product lines. Jackson's productivity engineering using readily available technology to get the most productivity from its machine tools, has served the plant so well in the 6 years it has been in operation.
35-45 Percent Savings
“By eliminating the need to run the part over another machine for secondary operations, we save the setup costs, operating costs and labor costs associated with that machine; we eliminate the scrap that can result from operator errors, and the additional part handling . . . the savings are substantial.”
Delta Faucet's executives inform that the savings realized by machining them complete in one setup ranged from 35 to 45 percent. The Jackson plant is completely machining the parts in less time than was required for either the primary or secondary machining operations previously used to produce the parts. The machining department is able to deliver parts to its customers, its assembly operations and its sister plants' assembly operations, much faster than ever before.
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