High-Performance Gantry-Style Machining Center Builds In Accuracy

With a long-standing reputation for manufacturing quality screen graphics equipment, M & R Printing Equipment (Glen Ellyn, Illinois) was not content to continue trusting its complex machining requirements to outside machine shops. M & R Printing first welded and then outsourced various textile press parts. But farming out parts took too much time and resulted in quality control problems. To gain control of the manufacturing process and tighten up production times, the company purchased the UMB 6 from Unisign, produced and sold by Monarch Machine Tool (formerly Genesis Worldwide, Cortland, New York). The UMB 6 is a novel gantry-type machining center that features an integrated rotary table and a powerful right-angle head.

Capitalizing on the versatility of the UMB 6, M & R Printing now does all its complex machining work in-house, maintaining the requirements necessary to produce its broad line of screen printing equipment, including carousel textile presses, flatbeds, belt printers, dryers and adhesive application equipment—everything necessary to reproduce colorful graphics on a range of materials from tiny decals to XXL sweatshirts and large banners.

Registration accuracy is the primary concern of M & R’s customers. In a typical silkscreen carousel configuration, pallets are rotated to various stations where the exposed garment surface is contacted by each print head, and a pattern of color is applied. For proper registration, both upper and lower elements of the carousels, which are up to 23 feet (7 meters) in diameter, need to correspond closely with each other. When colors aren’t applied precisely, overlaps and bleeding occur, resulting in fuzzy lines and blended colors. Meticulous registration and high-quality impressions require precision equipment that often entails complex, precise machining requirements. High-production, bi-directional textile presses also need to operate smoothly and at high speeds with minimum downtime. According to Jacek Wojcik, chief manufacturing engineer at M & R, the UMB 6 has responded to all these concerns.

Equipped with a right-angle 50-taper head, automatic rotary table, coolant-through-spindle, and traveling tool storage with tool pre-selection, the UMB 6 is used by M & R for milling, drilling, and tapping surfaces of different carousel press models, rotating pallet arms and machine heads. A custom-designed fixture is utilized that permits operators to quickly change the setup from one style of carousel to another. To produce carousel pallet arms and heads, other custom-designed fixtures are employed for multi-part machining.

Mr. Wojcik says that the most important features of the UMB 6 are the rotary table and the right-angle head. Integrated into the fixed machine bed at one end of the X axis, the CNC rotary table is used to machine the many surfaces of the carousel’s components. The powerful 35-hp, 50-taper right-angle head enables the faces of the carousel, the pallet arms, and the printing heads to be milled, drilled and tapped in one operation. A pick-up station attached to a column of the gantry accommodates both the angular head and the cover ring for the spindle nose. Coupling the angular head to the main spindle is fully automatic for fast tool changes. With the UMB 6, each of these parts is now machined in-plant in a single setup. Productivity gains, according to Mr. Wojcik, have been substantial. “The product is more accurate now,” he states.

With its rigid, stationary machine bed and essentially unlimited X axis (to 472.4 inches), the UMB 6 accommodates long parts such as the carousel arms for the M & R presses. Its open design and large, accessible work zone make loading and unloading an easy task for M & R operators. With a milling capacity of 31 inch3/min. (St 60), spindle torque to 119 foot-pounds, and positioning accuracy of 0.0006 inch per 39.3 inches, the UMB 6 provides M & R Printing with both the power and precision in a production environment. Mr. Wojcik says that the UMB 6 gives M & R the capacity for “fast machining of a volume of complex parts.” Mr. Wojcik is impressed with the machine’s accuracy, universality and versatility. “We’re finding even more uses for this machine. We like the wide range of possibilities created by the many features of the UMB 6,” he says. MMS