Moldmaking Report: Hooked on Speed
There's more to the picture than brute speed when measuring the performance and benefits of today's high-speed machines. How you use this technology is just as important as what you use. A number of e...
There’s more to the picture than brute speed when measuring the performance and benefits of today’s high-speed machines. How you use this technology is just as important as what you use. A number of equipment suppliers are doing more to help moldmakers capture those benefits and stay competitive with off-shore companies.
One traditional definition of high-speed machining is a cutting speed that is five to 10 times faster than conventional cutting methods. The problem with this definition is that new machines and technology are changing the meaning of “conventional”. As well, the definition somewhat inaccurately emphasizes speed at the expense of all other capabilities in current generation of high-speed CNC milling machines.
“Ideally you want a machine that’s not only high-speed, but high performance,” says Vince D’Alessio, vice president sales and marketing at Elliott Matsura Canada Inc. “There’s more to high speed than just spindle speed.”
D’Alessio says the company recently sold a Matsuura MAM.72 five-axis vertical machining center to a company in Mississauga. The machine comes with a standard 12,000 rpm spindle speed, but can be ordered with optional spindle speed of 20,000 or 30,000 rpm.
“The ability to do 5-axis machining is where the North American market is going,” says D’Alessio. “It allows you to orientate the part in all directions, so you can get a complete part in one setup. This reduces setup time, but it also eliminates risk of something going wrong by having to set up again.”
Depending on the version, the MAM.72 can store up to several hundred tools, a feature which allows a moldmaker to have different mold set-ups programmed and stored on different pallets. The machine purchased by the company in Mississauga is being run unattended around the clock, including on weekends, with a spindle utilization in the range of 90%, reports D’Alessio. By contrast, a stand-alone CNC machine typically has spindle utilization of about 30%.
For a company to reach such high level of utilization with a machine like the MAM.72, it has to make an up-front investment in engineering. “Once you have the fixtures set up, the tooling set up, the programming done, you don’t have to tear down like you do with a stand-alone machine,” says D’Alessio. “That’s important because some customers are now refusing to pay for set-up time.”
Moldmakers climb learning curve
Technique and accuracy are as important as a machine’s speed in maximizing efficiency. A moldmaker in Detroit is using four Makino machining centers to manufacture the core, cavity and lifters of larger tools more efficiently, says Tony Facione, process engineer at Single Source Technologies, Inc (SST), a Windsor-based Canadian distributor of Makino products. The machines are 3- and 4-axis MCC 2013, a 3-axis vertical S56 and 4-axis horizontal A55E with pallet changer. The S56 comes with a standard spindle speed range of 130 to 13,000 rpm and a linear positioning accuracy of +/-0.000120 in.
Facione reports that the company uses the MCC 2013s to concurrently machine the core and cavity and the S56 and A55E to machine the lifters.
“The high accuracy of these machines allows them to eliminate the benchwork on the pocket and lifter,” says Facione. “They can produce a lifter in under two hours, which is a significant reduction from the eight to 10 hours typically needed before handwork. A larger tool typically would have 15 lifters and slides, but could have as many as 50, depending of the design.”
Ultra fast, ultra stable
The Mori Seiki NVD5000 vertical machining center is especially designed for mold and die manufacturing. Tests conducted under various tests cutting conditions show that machine stability, measured in roundness of a cut, is unaffected by the amount of table load. Spindle acceleration up to 20,000 rpm is accomplished in 2.68 sec, a 50% improvement over the company’s comparable previous model.
Haas Automation Inc.’s VF-2SS vertical machining center comes with a standard 12,000 rpm, inline direct spindle, an ultra-fast tool changer and 1400 ipm rapid transverse. The direct-drive spindle is coupled directly to the spindle, resulting in less vibration, less heat and better surface finishes. Haas says the machine’s tool changer is the fastest it has ever built, taking less than 1.6 seconds to change tools.
Deckel Maho Guildmeister will be introducing the new DMC 75V Linear vertical precision machining center to the Canadian market in the near future. The machine comes in 3-axis or 5-axis models and is equipped with Seimens’ linear drives in all axes. The linear drives generate 2G acceleration and deliver 3,542 ipm of rapid transverse. The company, which has been in Canada for three years, also sells a lower cost machine, the 64V, with linear drive in only the X-axis, the axis which carries majority of the tool’s motion. The 64V comes with 2755 ipm rapid transverse.
“Linear drive is the wave of the future,” says Neil Teague, DMG regional sales manager. “It is very precise.”