Automation in Electrode Milling

Excell Machine and Tool saw significant benefits by automating its graphite machining center.

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When Robert Berg founded Excell Machine & Tool (Hudson, WI) back in 1981, he had no idea of the technology advances that would change his shop. Berg always held a strong belief in reinvesting in the business, and when automation began to prove itself as a practical solution for improving the productivity and profit-ability of small to mid-sized shops, he wasted no time in jumping on board.

An Excell-ent Niche

Ron Tarczon, sales manager for Excell sees its niche as "a mid-sized shop specializing in fast turnaround with changes as needed. We do a lot of prototyping as well as production tooling - 300-ton press range and smaller. We work with a lot of custom molders as well as captive shops. We specialize in close tolerance molds for a range of industries including automotive, electronics and medical. Constant change of jobs makes us search for new ways to do new things. Excell specializes in cutting multiple parts where the accuracy of a machine can be determined very quickly. Tolerances vary, so do materials and finishes, but the biggest challenge is keeping up with all the different types of parts our customers ask us to make. We can maintain zero tolerance if the customer requests, but the normal range is .0001 to .0002 of an inch."

Graphite Milling Meets the Robot

The technology that sets Excell apart from other mold shops is the extent to which they use automation in electrode milling. Since March 1999 Excell has made extensive use of its new Roku-Roku GR435N CNC graphite machining center equipped with a 3R WorkPal robot. The 435 is used primarily for milling graphite and occasionally copper electrodes. By automating the GR435 with a 3R WorkPal, a single machine operator can load 32 blanks at a time. The robot automatically changes out each blank with a finished part. The operator has enough time to complete several operations on other machines.

Greater Accuracy and Repeatability

The Roku-Roku GR435 is built to jig-borer standards of quality and accuracy. It features bridge construction with Meehanite GC for excellent shock and vibration dampening as well as minimal thermal distortion in normal working environments. The machine's bridge construction reduces the distance from spindle center to the Z-axis guide ways, minimizing the opportunity for thermal distortion and simultaneously producing extreme rigidity. Bridge construction also eliminates the X-axis table overhang commonly associated with C-frame construction. The GR435 also takes full advantage of the Fanuc 16iM controller and its advanced capabilities, including Digital Intelligent Servo System, for unsurpassed speed and accuracy in even the most complex 3-D contours.

Excell's lead programmer Brad Struemke says, "Our Roku-Roku is far more accurate and more efficient and at least one-third faster than our other machines, because of much easier setups. The repeatability is what we've come to expect from a quality machine - it's excellent. The hard drive in the 435 allows us to store a tremendous amount of information - multiple files for multiple operations."

Automation Benefits

Excell recognized several significant benefits by automating its GR435. It relieves the operator of several tricky and tiring alignment operations; it allows the machine to work with greater accuracy; and there is a significant reduction in rejects, with far less material tied up in stock. But most importantly, automating increases Excell's profitability. Shorter runs mean more frequent setups, which increasingly impact on the bottom line. Every minute of setup time converted to active machining time means lower costs. Automating the GR435 with a 3R WorkPal has helped Excell minimize their setup times, leading to higher productivity, greater flexibility and increased profitability.

Team Approach to Success

Among the practices that set Excell apart from their competition is their ability to focus and set goals as a team. According to Ron Tarczon, "It's one of the major contributing factors to our very low turnover. Each member of the team has a say in setting short- and long-term goals. We believe in and practice teamwork, employee commitment, and excellent communication." This even extends to the "wish list" that's posted on the bulletin board. This list basically answers the question, "What machines, inspection and measuring equipment and tooling will we need next month or next year in order to stay competitive?" "We've always maintained a strong belief in having top line, leading edge technology equipment to produce quality work and stay competitive," Tarczon states. "Our Roku-Roku/WorkPal automated graphite milling system not only gives us the quality we need, it keeps us competitive and profitable."

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