Production Technology News

Software Opens Doors for Faster and More Efficient Part Production

July/August 2005

Preci-Manufacturing, Inc. has taken their machine tool operators and turned them into highly-skilled programmers with excellent results. But it took CAM software to make it happen.

As Senior Programmer Peter Martin said, “Not everyone out on our shop floor is able to program. In fact, very few of the people on the floor who set up and run machines have well-developed programming skills. We have quite a number of machine tools, so the number of programs that are written every day would really prohibit on-the-floor programming. We also have a fair amount of relatively difficult programs to do. They’re involved with a lot of machined features to program. Programming on the floor would be feasible in some cases, but not very often. For our mills, we have multiple jobs set up on the machine at the same time, and programming one would mean stopping production. That is something we don’t want to do.”

Preci-Manufacturing, Inc. (Winooski, VT) found that the solution to greater machining productivity for their mills and lathes was off-line programming using Mastercam CAD/CAM software (CNC Software, Inc., Tolland, CT).\

With over 30 years of experience, Preci-Manufacturing has developed a history of innovative engineering, efficient production, and uncompromising quality. Their success has been driven by accepting and meeting the varied manufacturing challenges that their large customer base demands. Their highly trained staff uses the most advanced measuring equipment and instrumentation, both during and after production, to assure accuracy and production dependability.

In Preci’s 38,000 sq. ft. facility, they have 58 machine tools (8 milling machines, 11 machining centers, and 38 turning centers) and 100 employees. In business since 1950, they do high-precision machining work for the defense, aerospace, medical, and injection molding industries, producing medical and surgical instruments along with hip replacements, knees, suturing devices, implants, fine-pitch gears, prototype components, parts for injection molding machines, auto engine rotating components, and QSLM class-3 fasteners. But they are always willing to take on just about any type of part from a customer. Customer lot sizes vary from one to 50,000 pieces. They can also do cylindrical surface ID creep-form grinding, creep grinding for threads, EDM work, gear cutting, broaching, honing, and lapping.

Preci uses the latest CNC machine tools for manufacturing precision components. All types of materials, including high temperature alloys, can be machined to tolerances of up to ±50 millionths. They have three programmers, two for their turning centers and one for their milling department, who produce as many as 15 programs a day. Programs are transferred with a disk, but the company plans to add an Ethernet system to the facility.

Mastercam has helped the company immensely in four-axis machining and using live tools in mill/turn applications. Mastercam allows their programmers to easily see and verify their tool movements in four-axis machining and quickly program live tooling moves compared to programming on the machine tool.

For surface work, Preci relies on Mastercam to program the complex surfaces of blisks for jet engines. Machining is so accurate that the machine tool even does the final finishing, which is often reserved for manual hand finishing.

As far as parts go, Martin added, “If you can envision it, we machine it. We don’t do mold work, so we don’t generally get into complex surfacing, and we don’t really use the mill/turn capabilities of our machines that much. But other than that, any combination of grooves, threads, recesses on turned parts, including parts with drilled off-center holes, we’ll do.”

Martin also mentioned that many of their parts would be very impractical to program at the machine tool because of their complexity. By programming offline, they keep their spindle usage high, which adds to their productivity. Martin explains, “It’s one thing if you have cycle times that can take many hours. The operator can go into the CNC control’s background and program it, and you’re not losing any productivity. You’re actually benefiting, because you’re giving the operator something else to do while he’s standing there. But our cycle times are never measured in hours. Our parts are machined within two to three minutes. This just doesn’t give you enough time to do anything else at the machine except tend to the parts.”

Martin added that Mastercam has a number of features he likes. “I would say on the turning side, the more recent versions of Mastercam have greatly enhanced grooving toolpaths and given us greater control over tool entry and exit points.”

Program verification for crash avoidance is another feature that Martin likes. “I verify all the time,” added Martin. “Although nothing is completely bulletproof, verification is great. If you have a complex part and you’re doing things like edge breaks on it, it’s easier to get the most out of those edge breaks without actually nicking other surfaces.”

He remarks, “Mastercam is laid out in a very rational manner. I actually taught myself how to use it without any assistance from anyone way back in 1993. I found it was fairly easy to teach myself how to use the software and how to edit the post well enough to get myself a program that I could use. I was using it on the shop floor for several years. We did evaluate other software at one time, but nothing seemed to give us what we wanted as well as Mastercam did. It’s even more useful now. It has layers of complexity and usability that offer a lot of capabilities, making it a very, very powerful program. You’re generally able to do almost anything that you want to do, without having to resort to old-fashioned programming techniques, like whipping out the calculator or pulling data off the CAD files so that you can write something manually. That’s important, not having to do a lot of manual editing to programs or having your operators out there on pins and needles because they don’t know if there is a crash built into the program or not.”

Vice President Lloyd Grunvald said, “We like Mastercam because technical assistance is very good, updates are really good, and it’s a program that’s continuously being worked on for enhancement. We heard they’re coming out with a new version that’s fully Windows® compatible. The posts are fairly easy to create and there are a lot of generic posts that are on the Web that we can get our hands on and modify accordingly.”

Grunvald said that they take existing post processors and change them to suit their equipment, or their programming style. Their local Mastercam Reseller does this for them also.

In all, Mastercam has given Preci an easier and more productive way to make complex parts quickly, which keeps their customers happy.