Torq Thrust – an automotive wheel model developed in the 1960s by American Racing – is the most famous and most copied wheel design of all times. And it has not lost any of its attractive appeal. In 2008 Wheel Pros, a leading manufacturer and distributor of top brand wheels took over the brand and in 2020 decided to “reshore” the production from China back into the United States. For this purpose an entirely new production line was set up in Auburn, Alabama. During his time as owner of the competitive brand MHT, now also a part of the Wheel Pros group, the vice president for marketing at Wheel Pros had a highly positive experience with Rösler. Therefore, he recommended this surface refinement specialist as partner for the surface finishing of around 50,000 wheels per year. A major requirement was that the cast aluminum wheels with diameters from 15 to 20 inches and widths between 7 and 9 inches are finished fully automatically. Another demand was that the mechanical process achieved an absolutely repeatable high luster finish comparable to the previous manual polishing operation within relatively short cycle times.
41 Rösler special wheel finishing machines and one Rösler wet blast system
In close cooperation with the mass finishing experts at the Rösler headquarters in Untermerzbach, Germany, Rösler USA developed a suitable multi-stage finishing solution. In a first step the surface of the cast and partially machined automotive wheels is homogenized with a wet shot blast process. For this purpose a standard wet blast machine was specially adapted to the specific task at hand. The machine is equipped with a rotary table and six blast guns mounted to adjustable mounting brackets in the blast chamber. Loading and unloading of the work pieces takes place manually, whereas the actual finishing process runs automatically.
The wet blast process is followed by a 3-step mass finishing operation in the compact FBA 24/2 Turbo vibratory systems that were specially developed for wheel finishing. These machines, equipped with 2 vibratory motors mounted to the outside of the processing bowl, allow the finishing of automotive wheels with diameters of up to 24 inches within exceptionally short cycle times. The infinitely adjustable speed of the vibratory motors and the flexible motor position permit the perfect adaptation to different processing tasks. For the finishing process the wheels are mounted to a specially developed fixture that can be pneumatically raised. This ensures not only that the wheels can be loaded and unloaded ergonomically but also that the processing media can remain in the processing bowl during the work piece load/unload operation.
The first finishing step consists of a pre-grinding operation. Since it lasts around 2 hours, 19 of the 41 finishing machines are dedicated to this first process step. The required processing time for each of the subsequent pre-polishing and polishing stages amounts to one hour. Therefore, only 11 machines are needed for each of these two stages. Since Rösler also develops and supplies the processing media, these are perfectly adapted to the various process stages.
To allow an environmentally sustainable operation, the contaminated process water is cleaned by centrifuges and can, therefore, be recycled back to the mass finishing process. For this purpose Wheel Pros purchased two fully automatic Rösler centrifuges, model Z 1000.
Virtual pre-commissioning of the machines
The new wheel manufacturing line at Wheels Pros is scheduled to start operation in April 2022. The pre-commissioning of the first 11 wheel finishing machines took place virtually in September 2021. The 3-step finishing process in the FBA 24/2 Turbo machines was broadcast by live stream from Germany to the United States. Beforehand, the wheels used for the pre-commissioning had undergone a wet blast process at Rösler USA. On this occasion the colleagues at Wheels Pros, connected online with Rösler Germany, noticed that the automatic mechanical finishing process produced significantly better results than the manual finishing operation used to-date.