TPT November 2010

T echnology U pdate

Clamping unit for laser fixtures IN a laser welding fixture all welding seams should be clamped with a zero gap. AWL, The Netherlands, often uses a hydraulic pusher to achieve this. Although this solution works well, the fact that it uses a hydraulic principle is a disadvantage in a laser welding fixture, as oil spills and the risk of fire due to sparks emitted during the welding process are always present. Therefore, AWL has developed an alternative solution. AWL’s pneumatic pusher has a maximum pressure of 16 bar, achieving a maximum pressure force of 785N. This is more than sufficient for the pressing of sheet metal parts in laser welding applications within the automotive market. The cylinder is single-acting and, unlike a hydraulic cylinder, does not use a return spring. The return stroke is achieved through

vacuum. There is no loss of power and the stroke can be increased, enabling a greater release stroke. This release provides the ability to auto eject the product from the fixture, making removal of the product easier. The greatest challenge in developing the cylinder was building the unit as compactly as possible, as a lot of pushers need to be placed close together in a laser fixture. The solution to this problem was found by seaming both the outer and inner cylinder. This way, the outer size is similar to that of the hydro cylinders. Additionally, special mounting blocks for the hydro cylinders are no longer needed as the pneumatic unit can be easily connected with a tube. Although the pneumatic pusher has the same outer size as the hydraulic one, a larger piston diameter can be applied, which increases the surface and the pressure force. With a load of 16 bar a special system with a compressor or booster is required. The hoses, fittings, valves and air supply are adjusted for the workload. However, for most applications 10-12 bar is more than sufficient. Use of the AWL-developed cylinder is specifically intended for applications where there is little space, but a need for many pressure points. This solution offers great perspective for welding thin plates in the automotive industry. Besides laser welding, AWL also expects to use the pneumatic cylinders for gluing solutions. LESSMANN is a leading company in producing technical brushes. Among them are wheel brushes, roller brushes, hand brushes and others. Depending on the application and the customers’ requests different wires, abrasive nylon or diamond filament is used. For the treatment of weld seams in the tube and pipeline industry special knotted wheel brushes were developed. They are ideal for the treatment of U- and V- weld seams. Due to the narrow construction with a brush width of 5-6mm also low lying weld seams in U- and V- welds can be reached. Cinder, scales and other contaminations are removed fast and efficient. Especially after multi-layered welding processes and to recognise asperities on the seam the cleaning is necessary. High tensile wires in combination with Pipeline brushes

To ensure that parts of a product, within a given tolerance, are well clamped, AWL developed a variant with a magnetic piston. In cases were pressure points need to be even closer than the 30mm that is normal with a pneumatic pusher, an attachment can be placed with a U-shaped fork anti- twist feature, enabling clamping even closer together. The pneumatic pushers will be the new AWL standard, and will replace the hydraulic pushers from now on. The company states that customers have already shown interest in replacing existing hydraulic fixtures with the AWL pneumatic principle. AWL-Techniek BV – The Netherlands Fax: +31 341 411822 Email: info@awl.nl Website: www.awl.nl

AWL’s pneumatic pusher

different construction characteristics used by Lessmann guarantee a long product life. The spreading of the filling material in the brush is 100% steady which helps to create a quiet product run and an unproblematic operation even over a long periiod of time. Depending on the field of application brushes with high tensile steel wires or high tensile stainless steel wires in different wire sizes are deliverable. The types with stainless steel wire have green side plates. Different standard bores or threads adapted to the national and international technical requirements are deliverable ex stock. The standard brushes are available in the diameters 100mm, 115mm, 125mm, 150mmand 178mm. Custom-made products are available on demand. The brushes have a high durability due to the high quality of the wire and they cause an eminent brushing result. Lessmann GmbH – Germany Fax: +49 9082 70778 Email: p.lessmann@lessmann.com Website: www.lessmann.com

TUBETECH CORPORATION LIMITED TUBETECH WUHU MANUFACTURING CO.,LTD

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N ovember 2010

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