The cost-effective unit can be specified in a number of sizes and formats, although the two-stage Lapp Blaster 6040 Duo fitted to the company’s demonstration vehicle is predicted to be the most popular, along with the slightly larger 7050 Duo.  

Unlike existing sand and bead blasting cabinets that simply abrade the surface; the Lapp Baster has been designed to remove the recast layer created by the EDM process, and to effectively shot peen the annealed Heat Affected Zone (HAZ) located just below. By cleaning and peening it efficiently removes the re-deposited molten metal particles from the surface of the workpiece, and peens the remaining surface. 

Peening a surface spreads it plastically, causing changes in the mechanical properties of the surface. It helps negate the propagation of surface micro-cracks. These cracks do not form in a material that is under a compressive stress, so the Lapp Blaster compresses the surface to increase crack resistance and improve surface finish, with a 0.3 micron Ra achieved within a few seconds of processing.

While the Lapp Blaster can be applied to an automated process, Erodex expects most of the cabinets to be manually operated. Subsequently, the ergonomics of loading and unloading workpieces, working at a comfortable operation height without fatigue and visibility through the large viewing windows with high grade internal lighting, will be positive considerations. Low running costs are also a factor, with just a single phase 240V electrical supply and shopfloor compressed air at 4 bar required.

As a respected EDM consumables supplier, the company is all too aware of the constraints put on the application of both the wire and die-sink EDM process, especially in the aerospace industry. As Sales Director, Steve Rolinson, explains: “The aerospace industry recognises EDM as a valuable process for component production. However, EDM machines can compromise the surface integrity of these components. Therefore, secondary machining operations, including grinding, milling, or chemical etching, were required to remove the recast layer and HAZ to avoid micro-cracks. 

“Tests have indicated that the Lapp Blaster will allow aerospace manufacturers to use the EDM process to manufacture even more components. With this cost-effective technology manufacturers could possibly eliminate secondary machining operations, reducing costs and decreasing delivery times.”  

As well as providing pre- and post-sales support with demonstrations held at customers’ premises, Erodex will offer the Lapp Blaster 6040 Duo on a subcontract hourly basis at a competitive rate. This service can be accessed either at the company’s facility in Halesowen, or at the customer’s premises.

With a twin working volume of 590 x 400 x 250 mm, the Lapp Blaster 6040 Duo will be able to accommodate the majority of parts that have been produced by the EDM process. Two nozzle sizes are fitted, a 2.5 mm diameter for peening and a 5 mm diameter for preparation and cleaning. The long-life spherical media is available in a variety of diameters, to suit the workpiece and the finish required. 

Typically, it ranges from 20 to 30 micron for finishing and 50 to 70 micron for preparation. A vortex separator system fitted to each chamber ensures that only the media is recycled and returned to the nozzle, with all the removed debris falling away into a capture vessel below. So, the running cost of the cleaning and peening chambers is very low with grit consumption at just a few grams per component.

Built in Germany, each Lapp Blaster will come with a two-year warranty, and a stock of consumable frontline spare parts and media will be held by Erodex. “Any operator will quickly become adept at using the Lapp Blaster and will gain a feel for the process. Typically, parts are processed in a matter of seconds,” Steve Rolinson concludes.