Increased flexibility and higher productivity are constant goals in the manufacturing industry. The “productivity braking” effect of frequent retooling is a particular problem where series length and the shape, dimensions and materials of components vary widely, e.g. subcontract production. Here, pallet systems and automatic production cells have proved highly effective in the hunt for greater flexibility and productivity.
Bilfit AG in Diepoldsau, Switzerland, focuses primarily on steel and aluminium milling for series of 1 – 1,000 pieces. The medical technology, machine, packing and telecoms industries provide most of the company’s customers. Varying technical requirements in respect of components and assembly work demand great flexibility. Roman Müller, MD, explains one of the key factors in the company’s strategy: “Earning money on low-price products in a high-cost country such as Switzerland necessitates a high degree of machine utilisation and an optimum workflow.”
The milling cell, a five-axis Mikron UCP 600 Vario 5 and a WorkMaster, is intended for small series and one-off production.
Ever since they took over the company in 2001, Roman Müller and his business partner, Daniel Ritz, have worked purposefully towards the goal of improving the company’s position. Around two years ago, to optimise the production flow and increase capacity, the company moved to a new building with 650 m2 of climate-controlled premises.
At the same time, because Bilfit’s vision is to be a development and production partner for its customers, the range of offered services was expanded. This expansion included raw materials. Thanks to several supply contracts, materials can now be obtained quickly and at a lower price. Increased collaboration with companies specialising in heat and surface treatment has led, even though the quality requirements are high, to faster deliveries.
Since October 2007, Bilfit has had a flexible, automatic production cell (a 5-axis Mikron UCP 600 Vario with a WorkMaster) in which the milling machine’s working range covers most of the company’s output.
Pallets of various sizes are loaded “chaotically” into the magazine.
Talking of the step into automated production, Roman Müller says: “Geographic closeness was one of the reasons we chose System 3R.” He continues pragmatically: “The product quality, professional advice and support provided by System 3R led us to assume that Mikron, which is part of the same company group, would offer the same. We thus chose the machine that matched our requirement specifications.”
The assumption proved right when the cell was installed. There were no interface problems and, after some fine tuning during the running-in period, the cell was integrated into continuous production. All within a week!
“As early as running-in, we were impressed by the cell’s capacity. A rotating machine table, 170 tools in the machine and 42 positions for GPS240 and GPS120 pallets in the robot magazine,” recounts Roman Müller.
Workpiece in a vice on a GPS240 pallet.
WorkMaster’s modular concept gives the flexibility that subcontractors find essential. The machine can be configured for each user’s needs. Two different pallet systems? No problem! The number of racks can be adapted to the volume of work, e.g. start with a few and then increase the number of magazine positions as the orders increase.
A WorkMaster can serve up to 3 machines of different makes and providing different machining functions. The open system architecture offers practically unlimited possibilities.
When machining rectangular or rotationally symmetric parts, the GPS pallet systems are a further guarantee of versatility. Whether handled manually or automatically, the GPS240 system ensures a repetition accuracy of 0.002 mm.
Roman Müller: “As early as running-in, we were impressed by the cell’s capacity.
In rotary machining, the workpiece can be secured to round pallets with dimensions of 70, 120 or 240 mm. Machine-adapted chucks ensure precise mounting of the pallet to the machine table or spindle. Furthermore, chuck adapters allow several pallet sizes to be handled automatically.
At Bilfit, GPS240 is used for large (up to 300 x 300 x 300 mm) workpieces, jigs and fixtures. Smaller items, jigs and fixtures are mounted to the cheaper GPS120 pallet. This presents an even more attractive investment picture and ensures optimum use of magazine capacity.
Whether it is 1 or 1,000 parts and the machining time per part is 4 or 50 minutes, customers expect punctual deliveries and the stipulated quality. Tolerances of 0.01 mm and tighter are commonplace at Bilfit. Roman Müller emphasises the milling cell’s properties: “Five-axis machining in a single set-up in the Mikron and the precision of GPS pallets provide exactly what is required.”
Workpiece in a vice on a GPS240 pallet.
Thanks to the investment in automation, Bilfit has increased its spindle hours. The milling cell is currently used 2 shifts a day. Roman Müller concludes: “We are still gathering experience. However, given the already noticed benefits in the form of shorter set-up times, increased precision and faster throughput, we are aiming at a utilisation of 22 hours a day. We are not there yet, but soon...”
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