Innovative solution help minimise mistakes at the assembly line
27 AUGUST 2020
Assembling rear axles can be tricky. The designated operator must quickly determine which screw is to be tightened in which hole. When presented with this dilemma, Scania’s Smart Factory Lab found an innovative solution.
Some rear axles are for disc brakes, others for drum brakes. To complicate matters further, there are rear axles for trucks with air suspension while others have leaf springs. Distinguishing between them is challenging since when attaching the central gear to the rear axle housing different screws are used in different patterns depending on the rear axle variant while all the central gears are drilled with 14 holes. All of these variants randomly pass by the designated operator.
This task has been made simpler by placing a projector attached to a computer over the operator. The computer identifies which central gear variant is up for assembly and projects green beams to the correct screw required and the right hole. Conversely, a red beam is shown if the operator inadvertently picks the wrong screw or hole.
Quality assuring and mininising waste
“We assemble up to 400 rear axles per day and although an experienced operator might be able to distinguish between the variants, it’s very difficult for newcomers,” says Production Engineer Zebastian Hallsten at Scania’s axle and gearbox assembly plant in Södertälje. “Regardless, this is demanding for all and you must be on your toes.”
Mistakes are always discovered later in the assembly process, but the faulty central gear must then be removed and assembled again from scratch. “It’s essential that the two components are tightly joined together to avoid leakage.”
“This system can guide the operator step-by-step while monitoring that each step is correctly performed, making it impossible to assemble wrongly and thereby assure quality,” says Project Engineer José Maria Sabater Iglesias, Smart Factory Lab. “The solution might easily be scalable to other assembly stations and could also be applied in logistics for order picking.”