Cutting The Cost Of Casting With CAM System
About the time this company's products were getting more complex, they undertook a major re-engineering process directed at increasing productivity. CAM software played a big role in achieve their objectives.
Price Pfister, a Black & Decker Company based in Pacoima, California, is a leading supplier to the residential and commercial faucets market, producing lines of lavatory and kitchen faucets, bath accessories and lighting. The company has built its reputation and continued growth on the principle of providing customers with beautiful, high quality products at the best prices possible. Products are backed by the Pforever Warranty, one of the most comprehensive warranties in the industry. Price Pfister is also a leader in the industry-wide standard for reducing lead in residential faucets, meeting and exceeding the strictest national and California standards for lead levels, NSF-61 section 9. Price Pfister is one of the largest manufacturers of faucets, fittings and lighting in the North American market, with annual sales of $300 million.
Until fairly recently, most of Price Pfister’s faucets consisted of rectangular and circular elements. Because these shapes are simple, programming CNC milling machines to produce these faucets, or their castings, was all done by hand. Over the past few years, however, faucet shapes have become much more complex. “The trend in the industry is toward a more ergonomic look with graceful, curved surfaces,” says Alex Gabellieri, CNC programmer. “These are very difficult to program by hand. You really need to work directly with 3D CAD geometry in a CAM system to manufacture these parts accurately.”
About the time the products were getting more complex, Price Pfister undertook a major process re-engineering directed at increasing productivity. As part of this initiative, the company purchased six Traub seven-axis turning centers. These German machines feature twin spindles and twin turrets as well as live tooling. For example, a milling cycle could be running on the main spindle at the same time that a traditional turning cycle is being performed on the subspindle. The ability to perform both traditional lathe and live tooling cycles simultaneously makes it possible to cut the complex shapes of modem faucets and produce an entire faucet on one machine. Hoping to capitalize on this technology, Price Pfister connected each Traub machine to a bar feeding machine, attempting to create a fully automated, highly efficient faucet production system.
There was difficulty in making the system work, however, because of problems programming the Traub machines. It was a challenging task, as Mr. Gabellieri explains. “With all those axes, there are many things moving at once,” he says. “Everything must be perfectly orchestrated, and there is a lot of room for mistakes.” Price Pfister had purchased the machines as turnkey systems, with CAM software from a third party included in the price. Since Traub machines are somewhat rare, the software didn’t include an off-the-shelf postprocessor for these machines. It was up to the end user to develop one. But even after hiring the services of an outside programmer, Price Pfister was not able to produce a postprocessor that could operate the Traub machines without crashes. “This particular CAM software wasn’t architected to handle all those axes,” Mr. Gabellieri says.
The company decided to replace the CAM software. At the time, it was successfully using a program called ESPRIT from DP Technology (Camarillo, California) to program its wire EDM machines. “I was aware from reading trade journals that DP Technology also had software for multi-axis machining,” Mr. Gabellieri says. He asked the company to come to Pacoima to demonstrate its program. The DP Technology representative gave a presentation showing the software handling a seven-axis machining operation. “It was evident that this software had the architecture required to support the Traub,” says Mr. Gabellieri. “But the software vendor also agreed to demonstrate the effectiveness of this program on our machines before we would purchase it.” DP Technology sent an engineer to Price Pfister’s facility soon afterward. He spent five business days working with the in-house programmer, and by the end of that time, they had created a fully functional postprocessor. “In little over a week, we were up and running with real parts,” Mr. Gabellieri adds. “The ESPRIT program is very accurate and has operated 100 percent successfully ever since.”
Although Price Pfister originally purchased ESPRIT for programming the Traub machines, it is now used for programming all of the CNC machines. After a design for a new faucet has been released to manufacturing, a manufacturing engineer assigns it to either a Traub lathe or one of the CNC milling machines, depending on its production requirements. The CAD file is imported in any standard format into ESPRIT. Then, the engineer specifies the needed tools and the cutting speeds and feeds. These can be determined quickly by opening the appropriate technology page that defines the standard tools and the most common machining parameters for that particular machine. Standard tools are used whenever possible, but custom tools are also available as a menu selection, having been added by Price Pfister engineers to the software’s tooling library. Price Pfister has also optimized its technology pages to incorporate the company’s 90-year experience with brass cutting. “The vast majority of what we cut is brass, and we have mastered this operation,” says Mr. Gabellieri. “ DP Technology modified the technology pages to reflect our knowledge of the best speeds and feeds for brass.”
The ability to create NC programs by selecting operations and specifications from a menu has resulted in a 40-percent reduction in programming time on the milling machines, compared to when they were programmed by hand. Additional time savings result if the design is changed after the manufacturing operations have been programmed. “ESPRIT’s parameter-based architecture eliminates the need to re-program the part. We just change the geometry,” Mr. Gabellieri explains. “This has eliminated a lot of redundant programming.”
Price Pfister has reduced manufacturing testing time by 50 percent since installing the new CAM software. Part of this reduction is because the CAM program directly imports the CAD geometry, so there is no possibility of geometrical error. Another factor is the ability to simulate the manufacturing process in ESPRIT prior to producing any actual parts. Problems are found and fixed in the software so that when real parts are produced, the process is usually trouble-free.
Having the ability to program complex shapes is allowing Price Pfister to do things that were impossible before, resulting in some impressive cost savings. Usually, faucet spouts are cast and polished; that is the traditional, cost-effective method of production. But sometimes the company wants to do a short production run to get a new design into the market to gauge consumer reaction. Previously, it wasn’t possible to use milling machines to produce these short runs because it wasn’t possible to generate the machine code by hand. With ESPRIT handling the programming, these parts can be machined instead of cast, saving $150,000 in the die costs for each casting. The company has manufactured three short runs this way so far, for a savings of $450,000. Similarly, short runs of valve handles are now run on the Traub turning centers. Previously they were produced on screw machines, which require form tools to generate the shapes. Creating one form tool cost $10,000. After having produced five short runs of valve handles on the Traub machines, Price Pfister has avoided $50,000 in unnecessary costs. The total savings from just these few production runs is $500,000.
Price Pfister has found an additional efficiency related to its use of DP Technology CAM software. Because the ESPRIT module for wire EDM shares the same user interface with its machining center and lathe modules, it is necessary to teach only one interface. The common GUI also gives the company more flexibility in assigning programmers. “A wire EDM programmer can help us with the CNC jobs and vice versa,” says Mr. Gabellieri. “Programmers can easily help each other regardless of which machine tool they usually work with.”
Having software that can generate tool paths for the seven-axis Traub turning centers is helping Price Pfister meet its productivity goals. The company now has an automated system that can produce complex faucets in a single machining operation. Price Pfister has also gained the ability to manufacture short runs on its CNC machines, eliminating the expense and delay of having them cast. This is all that the company hoped to achieve when it purchased new CAM software. But as an additional bonus, Price Pfister is now saving significant amounts of time on programming and testing. “Buying ESPRIT software has been a very positive experience,” says Mr. Gabellieri. “It does exactly what the company says it does.”
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