CULTURAL differences should be appreciated and celebrated. Differences of opinion should be respected and explored. Variety is the spice of life. Viva la difference! Salute variability in injection molding? Not so much.
Slight differences in mass produced products can cause huge headaches for manufacturers by hurting quality, requiring more inspections, generating added scrap, and otherwise increasing labor and costs. Many manufacturers have had to live with these problems as a natural consequence of operating their equipment, and none more so than those who use injection molding machines. Until now.
Cincinatti-based Milacrons acquisition a few years ago of former Indiana-based Autojectors recently produced a machine that combines their technologies and expertise, proving that some mergers really do mix synergies beneficially, and create new organizations that truly are more than the sum of their initial parts. Magna V vertical-insert injection molding machine blends the former, smaller firms vertical-molding technology with Milacrons digital hydraulics, PC-based controls and software, and other capabilities to achieve levels of accuracy and repeatability that reportedly hadnt been possible for vertical molders before now.
|FIGURE 1: MOLDING CHARACTER|
Milacrons Magna V vertical-insert injection molding machine uses digital hydraulics, PC-based controls, and a large, low table to reduce cycle time and increase repeatability.
Turning the Tables
Just over a year old, Magna V joined digital positioning and overlapping functions with an open-access C-frame design that increases production flexibility, speed and precision. It includes Milacrons Xtreem PC-based controls, digital hydraulics, and fast cycling features in a tie-barless C-frame that provides more mold space to allow molding of more and larger products. The machine also reportedly has the widest range of clamp forces, including 30, 50, 80, 130, 200, and 280 tons with stationary, shuttle, or rotary tables. Injection unit sizes range from 0.7 to 54 oz.
Multi-component configurations are available, including vertical/vertical. Process-specific packages are available for Magna V that allow it to perform/produce wire and cable molding, golf balls, reel-to-reel terminals, stamping encapsulation, needles, tube and hose connections, coil encapsulation, and high-speed molding.
Magna V includes several design improvements that shorten cycle time and changeover. Tony Marchelletta, Milacrons vertical product technology director, says the low, large-diameter, wide-open table meets the needs of North American molders. Also, the rotary table is performance tuned for faster rotation with higher-torque motors, improved gearing, and closed-loop control. The tiebar-less C-frame is ideal for use with quick mold-change systems, and allows molds and core cylinders to extend outside the platens. This increases Magna Vs mold capacity up to 30% over toggle and tie-bar machines, says Marchelletta. This lets processors use larger tooling on a smaller tonnage insert machine. It also streamlines mold handling, and improves access to mold cooling and electrical connections.
In addition, Magna V uses digital transducers, immune to EMIRFI electrical noise, to provide positioning accuracy of ±0.001 in. for each critical axis. This allows precise, profiled control of injection, sled, clamp, ejector, and table motions. These transducers also reduce setup time by eliminating the need to manually set up position sensors around the machine, and work with a closed-loop hydraulic clamp to minimize changeover time.
Because very few companies build vertical injection-molding machines, many were traditionally almost completely hand constructed. This also could lead to some inherent, subtle production variability, even by two of the same machines making the same product.
Autojectors had been putting Milacrons controls in its machine before, but the big push after the merger was to switch the vertical machines linear-positioning devices to digital to increase repeatability for users, says Mike Litten, Milacrons controls development manager. Going to more extreme control makes molding processes easier for users later on because they dont have to weigh as many parts, take as many samples, or do as many visual inspections as they did with lower-tech machines in the past. These new controls also help users comply with FDA regulations or SPC rules in automotive applications because the controls monitor and document the molding process, and extract required data as needed.
Strickley adds that adding Milacrons smart hydraulics technologies to the Autojectors vertical press reduced the historical vertical injection-molding variability, increased repeatability, and consequently improved the quality of many of its end-users molded products. Combining these technologies has really been a godsend for us, he says.