WHERE TOUGHNESS REALLY COUNTS

MIGHTY VMCS AT PEERLESS INJECTION MOLDING, INC.

By: Tom Walsh

in addition to accuracy, tool and die makers want toughness in their machines. These machines have to be tough in order to stand up to the constant beating they take from cutting tool steel and a variety of other die and mold materials. Cuts have to be deep, fast and accurate in order to satisfy customers and of course the 'bottom line'.

Unlike two of the better-known makes of VMCs, the Mighty VMCs at Peerless Injection Molding, Inc., Torrance, California, are much heavier, tougher and more rigid. 'Cuts are deeper, faster and more accurate,' stated Scott Taylor, Peerless Injection Molding's President, 'In addition to tool steel, we cut a variety of other materials including aluminum, copper and graphite. Therefore we need machines that are at the forefront of the NC marketplace. That is why we selected Mighty.'

The machining area at Peerless was expanded over a year ago so that the company could build larger and more complicated tooling for its own injection molding operation. The company had found that it was difficult to meet injection molding schedules, due to the availability and reliability of its tool and die suppliers. Now, because of its excellent tool and die capability, the company is also providing machining cervices to other injection molding companies.

Peerless' main workhorse is a Mighty VIPER V-1500. Recently, Peerless added another VMC-850 with the latest in controller technology. Both machines are built on a heavy duty Meehanite casting to ensure maximum rigidity and feature large box ways that have been hardened with Turcite B and precision grounded, making them ideal for the stability required for precision machining of die molds.

VMC-850

As mentioned, the VIPER VMC-850 is the latest addition to Peerless' machine shop. It features the newest in control technology from Mitsubishi, the PC-NC based Meldas MAGIC 64 open architecture controller. Transforming the personal computer into a high performance controller capable of high speed and high accuracy cutting, the MAGIC 64 supports Windows. Extremely user friendly, the operator can easily and quickly develop his own customized screens using commercially available application software and the customized application interface library available from Mitsubishi.

According to Taylor, 'We have 4 technicians in our machine shop who can program a CNC machine. Having a controller that can take any PC-NC software allows the technician to program right at the machine, thus saving valuable production time, especially in a mold shop where part runs are so limited. Software used to be an issue, but we are comfortable with most PC-NC based software and now look at the machine as a means for productivity increases. In addition to the latest controller technology, this machine is also capable of 10,000rpm. This means that it can handle 99% plus of all our high speed machining needs. To get a machine with higher rpm capabilities just wouldn't be practical.'

The VMC-850 is, pound for pound, one of the toughest and most productive VMCs on the market. The travel is 34" x 20" x 24.5" and it has a 40" x 18" table that supports 1,100 lbs.

VIPER VMC-1500

The first machine acquired was the VIPER VMC-1500. With its 67" x 30" table, this machine filled a niche that other manufacturers did not offer. This unit is a heavy duty VMC that has a heavy duty Meehanite casting, which makes it really solid. The column, bed and saddle are oversized, fully ribbed and can easily support heavy loads without table deflection. The VMC-1500 is ideal for machining molds and features large box ways. In addition to its solid frame, the V-1500 uses large ballscrew assemblies for maximum rigidity and precision. The ballscrews are located in the exact center of each axis, which effectively eliminates heat and lost motion. High torque AC digital servo units are directly coupled to the ballscrews, moving the axes faster and with more precision. Equipped with Mitsubishi AC digital motors, cutting time is minimized with the high reliability and precision movement. Likewise, its arm type automatic tool changer is one of the fastest in the industry.

Taylor stated, 'This rigidity shows up in the surface finish. Many lighter weight VMCs allow a waviness or ripple in the surface that is completely unacceptable in this industry. The VIPERs are extremely rigid and avoid this problem. Cutting thin deep ribs is easy with the VIPER, because of its rigidity. As I have stated, the VIPERs are really tough!

'Another example is the spindle loading. We don't exceed more than 60% not because the spindle won't take it, it's the tooling that won't take it. We have found that it is often more productive to take two shallower cuts than one deep one. For example, two cuts at .200" deep / 300 ipm are more efficient than one at .400" deep / 160 ipm. This is easier on the tools as well.'

The V-1500 features the Mitsubishi Meldas 530 CNC 3D graphic controller with a 32-bit CPU. Featuring multi-window capability, the controller utilizes user-friendly interfacing and is a leader in establishing operator ease and performance.

The arm type automatic tool changer is random and bidirectional to minimize tool change time. The magazine for V-1500 holds 30 tools, accepting tools with a maximum length of 12" and weighing up to 33 pounds.

The Mighty CNC machines are equipped with high-speed tapping. Tapping time is reduced by as much as 50% over conventional tapping eliminating the need for costly, floating-type tap holders. A direct synchronous sensor is built into the spindle motor. The digital control achieves a perfectly synchronous rotation of the spindle and Z axis servo motor.

FULL SERVICE CAPABILITIES

Taylor commented, 'Offering our tooling services to outsiders allows our customers full service capabilities. Because we are an injection molding shop, we can fully test the dies under a production environment. Likewise we have a strategic partnership with a rapid prototyping shop that has a stereolithography unit, allowing us to develop prototypes for our customers as well.'

Taylor concluded by saying, 'The VIPERs have served us well as we literally run them around the clock. The mold and die shop is an excellent addition to our injection molding operations and has the added capability of generating additional income for the company.'