Light-Metal Shot Blasting

August 27, 2015

Ryan Gehm

Walther Trowal’s new continuous feed tumblast machines have been specially adapted for gentle shot blasting of light metals like die-cast and forged aluminum and magnesium components. (Pictured is a forged undercarriage component—raw and finished—made from aluminum.) The German company’s re-engineered THM troughed belt shot blast machines also are suitable for steel, zinc, and brass components. Highlights of the new THM range are the electric media dosing system and redesigned blast turbines with smoothed throwing blades; the result is drastically reduced media consumption, lower dust emissions, and a significantly higher uptime of the turbines, the company claims. The continuous troughed belt machines can handle large quantities of bulk produced small parts as well as large, thin-walled single work pieces with complex shapes. Contrary to batch tumblast machines, where the parts are continuously tumbling over each other with a high risk of nicking, in the THM machines the work pieces are spread out throughout the length of the trough, ensuring nick-free processing by rolling over the polyurethane coating of the transport rods. As a result, the work pieces are exposed to the blast stream from all sides and always at the same distance from the turbines, ensuring even shot blasting results. The machines can be equipped with a different number of turbines; for example, for forged aluminum components the THM 700/4/E with four turbines with 15 kW each offers optimum performance.