April 24, 2003
At its factory in Vonore, Tenn., MasterCraft builds boats and trailers in adjacent bays. It offers the option of a trailer with every ski boat it sells.
Recently the company wanted to increase the efficiency of its trailer-building operation. Specifically, this entailed replacing a 20-year-old sawing machine plagued by performance that was no longer satisfactory, broken blades, and poor tolerances.
"We were looking for a saw that was faster, safer, and that produced a better finished part," said Ryan Lewis, a process engineer with MasterCraft.
In the search for a replacement machine, MasterCraft's criteria included lower cost of operation, improved accuracy, and greater ease of operation, as well as enhanced blade life, reduced setup time, and the ability to handle a compound miter cut on one of the trailer's cross members. The challenge was to complete the compound miter cut with the correct angular and length dimensions straight from the saw, without subsequent operations.
The company looked at several options, including band saws and circular cold saws. The majority of the work was cutting 2- by 2-inch and 2- by 3-in., 1/8-in.-wall steel tubing, and circular saws were able to cut the materials twice as fast as band saws, while producing parts with less burr and better surface finish.
After reviewing many options, the company chose the Kaltenbach KKS 400 H, a universal, semiautomatic circular cold saw. This general-purpose miter-cutting saw has an upstroking blade and a standard 180-degree miter range with hard stops at 45, 90, and 45 degrees. According to the company, changeover time from 45 degrees left to 45 degrees right takes a few seconds, eliminating the guesswork and time spent on this common cut pattern. The upstroking blade principle helps with coolant and chip management.
The saw manufacturer demonstrated the cold saw's compound miter cutting capability at its technical center during a visit from MasterCraft representatives. The compound angle was achieved by a combination of rotating the table and tilting the tube to specified degrees. The company used the information taken from the demonstration to construct a simple fixture for use in production-an arrangement that improved on the old method of multiple cuts and labor-intensive setup.
Previously producing trailer cross members with compound angles involved four steps:
With the new saw and the custom fixture, the process now has two steps:
The machine also met the company's need to reduce setup time. The saw uses a vertical clamp with a 6-in. stroke, which reduces setup time between tube sizes. It also comes standard with a push-button blade height setting that can be set in-cycle.
The previous equipment required the operator to use a measuring tape to set the correct location of the length stop, which was bulky and awkward to move. After setting the length stop, he had to measure the first processed part of each batch with the measuring tape to confirm an accurate setting.
The length stop measuring system purchased with the new saw allows the operator to change the length stop between setups by moving it to the correct location using the steel ruler that is integrated with the system. Because of the accuracy of the equipment and its integrated length stop measuring system, the operator now checks the parts only occasionally to confirm the calibration of the length measuring system.
According to MasterCraft, the new saw has made processing easier.
"We have implemented a new process for a compound cut that has improved the fit of a particular piece on the trailer," said Lewis. "The saw is more user-friendly-no bending over to load the steel."
As a result of the custom fixture used on the new saw, the company was able to simplify the compound miter cut process and reduce the cycle time by about two minutes per cross member. It also takes half as much time to install the custom fixture on the new saw as it did to set up the fixtures for the previous saw.
For more information, contact David McCorry, president, Kaltenbach USA, 6775 Inwood Drive, Columbus, IN 47201, 800-825-5729, fax 812-342-2336, sales@kaltenbach usa.com, www.kalten bachusa.com. Kaltenbach offers a range of metal cutting, circular sawing, and band sawing machinery and ancillary equipment.
MasterCraft Boat Co., 100 Cherokee Cove Drive, Vonore, TN 37885, 423-884-2221, fax 423-884-2295, www. mastercraft.com. MasterCraft is the world's largest producer of inboard and V-drive water ski, wakeboard, and powerboats.
TPJ - The Tube & Pipe Journal® became the first magazine dedicated to serving the metal tube and pipe industry in 1990. Today, it remains the only North American publication devoted to this industry and it has become the most trusted source of information for tube and pipe professionals. Subscriptions are free to qualified tube and pipe professionals in North America.