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21/05/2012

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18/05/2012

The Samsung’s Weight and Tool Size Won it for Dugard

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18/05/2012

Medical device manufacturer invests in new Doosan high-performance turning centre

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17/05/2012

Dugard ECOs ideal for Steel, U Drilling, Hogging and Profiling

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Productivity boost with Lehmann Rotary Tables and Brother Machine centres

Story added 02 November 2011.

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Productivity boost with Lehmann Rotary Tables and Brother Machine centres. Contact Avon CNC UK Lehmann agents for further information.

Vertical 3-axis centres with rotary axis on top impress with high precision and efficiency.

The EA-510 gear unit rotary table by pL LEHMANN turns the Brother TC-S2D-0 three-axis drilling and milling centre into a highly productive 4-axis machining centre. Fully automatic, this combination guarantees the efficient production of mass production parts for the automotive industry at Klingel GmbH.

Klingel GmbH is a manufacturing service provider with two key business areas: the production of safety-related hydraulic cylinders predominantly as a customised production in small numbers and the manufacture of supplier parts for the automotive industry in mass production from 50,000 units upwards. The company founded by the brothers Dieter and Volker Klingel in 1978 employs roughly 270 staff today and is managed by the next generation. Bernd Klingel, responsible for commercial aspects including sales, explains the philosophy of the family company: "We place great importance on producing the best quality in an environmentally-conscious way using state-of-the-art technology and highly automated processes. Our most important factors also include strict adherence to schedules and outstanding customer focus." Mainly aluminium in the form of pressure or gravity die casting and sintered metals and steel parts are machined. Klingel is also open to new materials. For example, the most recent projects have seen zinc or magnesium being machined.

W&R – professional partner for machines and automation

The market for metal machining is highly competitive, however. As a result, offers must be calculated with tight margins, yet realistically. "For example, we received an order from TRW, one of the world's largest automotive suppliers, to machine zinc housing parts for a belt tensioner", reports Bernd Klingel happily. "The order volume is 3.2 million units." It was up to his cousin Ulrich Klingel, managing director for technical aspects, to determine the most cost-effective process and most productive machine concept to be able to economically manufacture the belt tensioner parts. For this, he put different machines from different manufacturers to the test and reports: "Whereas some offers were too expensive and the x-axis was measured too short, cheaper offers were also ruled out because they were too slow. We found the perfect solution at W&R-Industrievertretungen in Mainz, who act as the exclusive partner for the Japanese mechanical engineering company Brother in Germany."

W&R is much more than just a machine dealer. The company develops, manages and realises complete solutions together with its customers and suppliers, including Klingel GmbH, for whom Andreas Zugck acted as the central W&R contact person. Ulrich Klingel confirms: "With him, W&R provided us with a very competent contact partner for support with machines, control, automation and service. His experience in automation and great ideas were a decisive factor why we have a system in operation today that fully meets all requirements regarding quality, precision and costs and that has been running fault-free in a three-shift operation for over a year now."

Simple reliable machining in the shortest cycle time

As the person responsible for the Klingel company, the project manager Jörg Gastl grappled with the task of economically machining belt tensioner housing parts . This meant inserting three bore holes into one side of the zinc casting pieces that are roughly the size of the palm of your hand and one bore hole on the opposite side. The aim was to achieve a daily batch of roughly 6000 units. Businessman Bernd Klingel notes: "The net value added per part is very low with this order. This means we also don't have a large profit margin and definitely cannot afford any faulty production. If the system produces faulty goods for half an hour, we can no longer hit our daily production targets." This resulted in more requirements, for example integrating quality assurance and achieving the greatest possible system availability.

At the start there was the idea of solving the problem with a shuttle table system. However, to produce the required numbers, two shuttle table systems would have been necessary each with two devices, one under the spindle and one on the loading side. That would have clearly blown the preset budget.

Fully automated system with two 3+1-axis machines

Finally, a manufacturing cell designed by Klingel and W&R, which mainly consists of the two TC-S2D-0 and TC-S2C-0 tapping centres from Brother, proved to be the most cost-effective alternative. They offer short tool change times (chip-to-chip) of 1.7 seconds, each has a 14-tool magazine and x, y and z traversing axes of 700 x 400 x 300 mm. The x-axis of 700 mm is particularly advantageous as it makes it possible to clamp eight pieces at the same time. The machines are interlinked via a robot, which is equipped with a 16-compartment gripper. As the part distance in the charge carrier is equal to the one in the device, it can accept eight blanks and eight finished pieces in parallel. In this way it supplies both machines and places the machined parts back in the charge carrier. They are transported to the testing and washing station and finally transferred via the conveyor belt.

The core of the system is the device on the machines, which Andreas Zugck from W&R has developed together with Jörg Gastl. Its basis is an EA-510 rotary axis from pL Lehmann. It includes the clamping device and takes over the swivelling of components by 180 degrees.

Long-standing partnership between W&R and pL Lehmann

The W&R company uses rotary axes by pL Lehmann from Bärau in Switzerland on their machines as standard. Andreas Zugck is firmly convinced of the quality and precision of these components. His opinion: "The Lehmann rotary tables provide the highest positioning accuracy, outstanding stability and admissible load, which we fully exploited in this case. Our Swiss partner's service, which is one of the most important factors in this kind of automation, is superb, in our experience." Jörg Gastl agrees: "As the housing parts are relevant to safety, the required quality is particularly high. With these components, we must comply with certain angular positions, radial and axial runouts that are not just influenced by the machining centre's three axes but also the Lehmann table. For this, we trusted Swiss accuracy and established that the positioning accuracy meets all requirements. Even when we needed clarification from one of the jig builders we commissioned, a professional Lehmann representative was always available within a few hours, or one day at the most."

The collaboration with Peter Lehmann AG was of huge importance for the installation of supply and control cables above all else. Jörg Gastl explains: "We very quickly recognised that we need lots of supply and monitoring media for this complex clamping device. For example, we could not guarantee high quality machining without air control. However, we were able to lay all the hydraulic lines for clamping as well as pneumatic lines for air sensor technology through the axes' rotary union. In this respect, the support and project management by W&R, combined with the performance by Lehmann, was excellent." The aligning of the casting parts also demanded a smart solution, whose design Jörg Gastl calls a small work of art, but one which he would rather not describe in more detail.

Everyone involved is delighted with the complete system. The cycle time, one of the most important criteria for economical production, is roughly ten seconds per workpiece for machining, including loading and unloading time. And the system availability is almost 90 percent, "slightly higher than we had calculated" the company bosses conclude with satisfaction. They call it an all-round coherent concept.

Other systems for machining magnesium parts

As a result of these positive experiences, Klingel has ordered another system from W&R in the meantime with Brother machines and a Lehmann gear unit rotary table on top. In future, magnesium chain case covers, which will be used to cover camshafts, are to be manufactured here. According to the project manager Jörg Gastl, automation is slightly more complex as an additional leak test of the parts and automated washing process is integrated in this case. Two Brother TC-S2D-0 three-axis drilling and milling centres are being used again, each of which is fitted with an EA-510 gear unit rotary table from pL Lehmann. They are loaded and unloaded by one robot; another takes over the feeding of parts to the washing station and leak test.

To a large extent, the device makes use of the full potential of the rotary axis in terms of its size and weight . Jörg Gastl explains: "We have managed to place six components, meaning we generate an advantage over our competitors in terms of cycle time and cost. This is, among other things, to the credit of W&R and Mr Zugck, who was completely responsible for automation."

The workpiece is a relatively thin magnesium part that can easily start to vibrate. That is why six clamps are used per component that are also supported by hydraulic counterholders underneath. For safety, two air sensor lines, kinds of air jets, scan the component. The Lehmann axis has made it possible to accommodate all the required lines and feed them through the relatively small counter bearing. Jörg Gastl considers the combination of a Brother machine with a Lehmann axis to be a huge success: "They go perfectly together, because in this way we can even machine relatively large components in a small machine interior. It is particularly ideal for magnesium machining that requires a fire protection device, because the smaller the machine interior is, the less argon has to be injected in case of fire."

The system is currently still under construction. At the moment, there is only one of the two Brother TC-S2D-0 models in the hall. It will run in manual operation until Christmas. Then the second machine will be assembled and full automation will be installed.

Box 1

Basic advantages of a 3+1-axis solution

Vertical 3-axis centres with a rotary table on top present a sound alternative to four-axis machining centres in many cases. They are convincing in terms of acquisition costs, accessibility, space requirements, energy consumption and much more. There are highly powerful arguments in its favour. Among other things, with this kind of 3+1-axis solution, multi-part/multi-side machining can be done much more easily, as clamping towers or yokes can be integrated into the extra axis, whereas with 4-axis machines there is always a greater risk of collision with the structure swivelling or rotating with the table. A significant plus point of the 3+1-axis solution can also be found in the quantities to be moved: while a 4-axis machine has to accelerate and decelerate the whole machine table plus workpiece, with a rotary axis on top it only moves together with the workpiece, resulting in significantly lower quantities. Additionally, axes on top have the basic advantage that you can disassemble them. If three-axis machining is sufficient, the whole machine space can be freed up for large bulky workpieces.

Box 2

Innovative Swiss rotary table technology

pL LEHMANN, a family-owned company from Bärau (Emmental) in Switzerland, has launched a generation of gear unit rotary tables on the market as the 500 product line, whose elegant design successfully packages its top quality inner worth. The rotary tables are consistently modular in design and leanly manufactured. As a result, the 500 product line is not just up to 30 percent more cost-effective than its predecessor but also extremely efficient and flexible. For example, the spindle speed is up to 110 min-1 with the 507 model. This enables cycle times of up to 0.34 sec/90° including spindle clamping, supported by additional electronics. All rotary tables are designed in IP 67 and are rustproof.

The 500 product line's CNC rotary axis is available in four sizes - 507, 510, 520 and 530 - with centre heights of 110 mm to 240 mm, suitable for face plates from 100 to 500 mm. This means that over 170 different varieties and combinations can be created, from the simple single-spindle fourth axis to a four-spindle swivelling table structure with fourth and fifth axes. The modular design makes it possible to reconstruct or extend the rotary table at anytime to perform new machining tasks. The 500 product line three-axis machines thus offer the ideal conditions for machining many parts, as required in e.g. the automotive, aviation and watch industries and for medical and dental technology.

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