Recently Western Coating contacted Wheelabrator for a blasting solution at its Auburn, WA plant. The company provides epoxy-coated rebar for projects ranging from private residences to salt water piers to miles of ramps and bridges. Because coated rebar is less likely to cause concrete spalling and fracturing, it is often specified for the construction of longer-lasting structures.
Western Coating''s two existing machines were worn out, leaking abrasive, and constantly in need of maintenance, causing a lot of downtime on the line. Two new Wheelabrator® skew roll machines, installed in January 2004, provided the answer.
Skew roll machines provide an excellent solution for blasting round cylindrical objects 12 in. in diameter or less. Capable of handling large production runs, these machines are often used for scale and rust removal prior to coating, profiling, descaling, and shot peening on any number of objects including tubing, rods, bar stock, billet, and more.
The machines are designed to rotate a part in the blast zone for 100% exterior surface cleaning while conveying the part through the machine. The V-shaped conveyor rolls are turned at a 45-60 deg angle to the horizontal axis of the machine to control the number of part rotations in the blast zone and the speed of travel through the machine.
Designed with the latest technology in mind, the new skew roll machines measure 12 ft long x 8 ft wide x 16 ft high, including the elevator. Running side by side, Western Coating''s two identical machines are used to blast ¼ to 2 in. rebar. The rebar is loaded 90 deg to the conveyor travel, and each machine has one blast wheel that blasts grit onto the rebar, putting a deep profile on it. After blasting, the rebar goes through a process known as fusion bond coating, in which the bar is heated in an induction machine to a specified temperature, then coated with a fusion bond powder epoxy and cooled with water. Finally, the rebar is holiday tested for voids in the coating.
"Our new Wheelabrator machines run up to two shifts per day," says Tom Whitish, branch manager for the Auburn plant. "We have had almost no maintenance on them, and they have very little cleanup. We are very pleased with the profile they provide on the rebar, as well as with their production."