AWL develops new clamping unit for laser fixtures

In a laser welding fixture all welding seams should be clamped with a zero gap. To realize this, AWL often uses a hydraulic pusher. Although this solution works well, the fact that it is a hydraulic principle is a huge disadvantage in a laser welding fixture. 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, the pneumatic pusher.


AWL’s pneumatic pusher has a maximum pressure of 16 bar, hereby achieving a pressure force of max. 785 N. 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 the hydraulic cylinder, doesn’t 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.

Limited space
The biggest challenge in developing the cylinder was building the unit as compact 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 easily be 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.

Applications
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. But the application does not stop there. Besides laser welding, AWL also expects to use the pneumatic cylinders for gluing solutions.

Special version
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, a 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 shall replace the hydraulic pushers from now on. Customers have already shown interest to replace their existing hydraulic fixtures with the AWL pneumatic principle.

More information
If you would like to know more about AWL’s pneumatic pushers, please contact Gerrit Bikker, Head of Engineering on 31 (0) 341 411 811 or send an email to: g.bikker@awl.nl.

Benefits at a glance

• No hydraulics are used in the fixture, so no risk of oil leakage/fire
• No need for a hydraulic power unit
• Cost effective, as the piping of the pneumatic cylinders is much simpler in comparison with the hydraulic ones and the replacement of parts is much easier
• Possibility to eject products from the fixture via the extra release stroke
• Possibility of position detection by using a magnetic piston.
• Quick and easy to replace as the cylinders are placed individually and not in a manifold like the hydraulic cylinders
• Existing hydraulic pushers are easy to replace with pneumatic ones