Wheels & Brakes are manufactured in plant 7 of AEL. Presently we manufacture the entire wheel rim assembly along with the brake drum (completely assembled with brake panel,brake shoe, spring etc), spokes and nipples. The wheel rim is manufactured by cold forming, TIG welding and electroplating surface treatment (nickel chrome plating)..
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We start the process CRCA (Cold rolled cold annealed) coils with decoiler to match the speed of the rolling mill.
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The ends of the coils are joined by Tig (Tungsten Inert Gas) welding.
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The sheet is formed by cold rolling with 14 stations, 28 rollers and 4 bending rollers. After stamping, knurling is undertaken which gives gripping to the tier.
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We use CRCA as per IS 513-1994grade D/DD. We use a 10 station forming process to reach the final profile from the knurling sheet.
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Seam welding is done as per customer specification. It is a continuous welding process to join 2 layers of sheet. It is an automatic welding process for different thickness and speed of the machines.
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The seam welded rim profile is passed through forming rollers to achieve the final rim profile as per customer requirement.
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The process incorporates auto cutting controlled by specialized dedicated PLC system to define the rim diameter.
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We use butt welding to join cut ends of the rim. It is a heavy voltage friction welding process. The two ends of the rim are brought close together in a gradual manner. Due to heavy heat generation at the end of the rims, rims get fused. After welding is completed the two ends are forged to form a firm joint. We use a stretching/sizing process after the rolling mill. Till now the rim is not perfectly round and by using the stretching machine, the rim is stretched by a few mm's (2 to 3 mm). The wheel is perfectly round now.
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The butt welded rim joint has the appearance of a rough grid. We first use a manual grinding process with proper care to avoid chilling of the joint and then automatic polishing operations are undertaken. The rim is not only important for safety but aesthetically important too. To enhance the surface fineness without compromising the joint (leakage area) we polish using a 7 levelled-daisy and side polishing machine.
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The final polishing is automatic, where we achieve a 0.4 Ra value. The wheels used for this process are 180 to 600 grits.
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The spoke holes are punched (punch and die) and dimples are formed by profile blocks. The wheel rim needs to face the abuse of a harsh environment and demands resistance to corrosion for its intended life. This is achieved by tri nickel chrome plating. We use a state of the art nickel chrome plating process with ETP treatment.
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