CASTING INNOVATIONS
Control Upgrade of 1,200-Ton Cold Chamber Diecasting Machine A great way to boost both overall
equipment effectiveness and machine utilization is to increase injection performance. On the range of indus- trial machinery, diecasting machines require a higher scale of size and complexity–this is a function of the great forces and high speeds associ- ated with injecting large quantities of molten aluminum into a near-net shape. Considering the size and complexity of the hydraulic circuits of diecasting machines, there are no quick fixes. However, many options are possible when the overall machine is in good condition, but injection performance is lacking. Many diecasting machines in use
today were developed when servo hydraulic technology was not ready for the demanding casting environ- ment. Visi-Trak worked with customer MPG (Twinsburg, Ohio) to do a control upgrade of a 1,200-ton cold chamber diecasting machine that was retro-fitted in August 2014. At the end of 2013, MPG was
investigating ways to improve per- formance across all machines and identified a single machine that was due for an upgrade. By analyzing the data gathered by its original monitor- ing system, it found the plant was not getting consistent performance across
several critical parameters. In particu- lar, management considered measures that would improve the consistency of the following four parameters: • Intermediate shot velocity. • Calculated start of fast shot. • Fast shot velocity. • End of shot position. In addition, onsite quality checks
through visual and X-ray inspection indicated that parts manufactured on this machine had variations for acceptable levels of porosity. Of the above parameters, the most challeng- ing to control with the existing factory supplied hydraulic circuit was the consistency of the fast shot velocity and the end of shot position. When considering the upgrade, a number of objectives were defined. Te first factor considered was the overall condition of the machine. Te second consideration was to look at ways to decrease operating costs. Tird was to improve the capability of the machine in order to keep up with market demands. After reviewing these objectives,
Visi-Trak recommended an upgrade package that included the Sure-Trak2 Shot Control System, 80-mm Olm- sted SV Cartridge Valve piloted with a Woodward HRT R-DDV servo- valve, a conversion manifold, Total-
Trak2 HMI, Visi-Trak 20-Pitch Tail Rod and transducer assembly and an option for proportional control of intensification pressure. A turn-key solution was requested,
incorporating all phases of the upgrade from tear down and installation to start-up and sign-off. When manu- facturing and pre-assembly work was finished, disassembly began on a Fri- day. By the following Friday, hydraulic and electrical installation was com- plete. Start-up and tuning required an additional two days, which meant that in just over one week, the machine was producing castings. During the first few months, MPG witnessed dramatic decreases in machine downtime, at which point several capability studies commenced. First, the trend chart for the four
parameters comprising the objectives of the project was reviewed. A marked improvement for slow, intermediate, and fast shot velocities was observed. As well as showing an improvement, end of shot position became more reli- able and adjustable. Calculated start of fast shot showed moderate improve- ment. Te data showed significant improvement in the parameters most critical to the project. Die flashing occurrences were reduced drastically, resulting in the almost complete elimi- nation of the problem. MPG also experienced an increase
in machine uptime, improved ef- ficiency, less maintenance time spent on the machine and improved part quality. Altogether, this accounted for an eight-month ROI. Machine utilization also was
measured in comparison to other machines. Tree machines running the same part at the same time were studied. Over the period of the study, the upgraded machine performed with 20% better machine utilization as compared to the two other ma- chines running the original supplied control configuration. After installation, two unantici-
Over the period of the study, the upgraded machine performed with 20% better machine utilization as compared to the two other machines running the original supplied control configuration.
42 | MODERN CASTING January 2017
pated results were found after one year of machine operation: there were no downtime instances for hydraulic leaks on the shot end and there were no spare part replacements.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60