The manufacturing of automobile disc brakes can be a physically demanding and challenging process that has sophisticated tracking requirements. Alber Gussbearbeitungs-GmbH, developed a fully automated disc brake finishing and testing process that assures the highest quality product and relieves employees of physically heavy work. Integrated machine vision gives the handling process eyesight with a modern vision system and reliably reads alphanumeric characters (Optical Character Recognition).
Car parts manufacturers today are no longer satisfied manufacturing first-rate precision components only. Many manufactured components must be tracked in order to ensure complete reliability in the traceability process; to meet this challenge Alber acquired two In-Sight® smart vision systems from Cognex to read alphanumeric codes on rotating discs brakes. Not only does this increase the safety of the process, but it also relieves employees of performing the strenuous task.
Disc brakes for cars weigh between 12 and 20 kg (26.5 and 44 lbs). Before Alber implemented Cognex machine vision technology, employees had to repeatedly lift the heavy discs out of a stainless steel box and place them on different stations. Performing this heavy work posed health risks to people on the production line. Today this is no longer an issue because the turning and milling process of downstream finishing and inspection work has been fully automated.
To automate this process, automation specialist CNC Automation Würfel GmbH, in collaboration with image processing experts from i-mation GmbH, taught a Yaskawa Motoman MH50-35 robot how to see.
A keen eye
An In-Sight vision system was installed directly on the gripper's head. With its automatic focus, quick image acquisition and built-in lighting, the fully-integrated smart camera recognizes the location of disc brakes delivered onto a conveyor belt. The camera aligns itself to the inside diameter then image data is transmitted to the robot control within fractions of a second, allowing high-performing magnets to quickly grip the discs.
After picking up the disc brake, the first step is reading the alphanumeric characters. To perform this step, the robot puts the disc brake on a rotary disc. A second In-Sight system reads the alphanumeric characters, helped by its integrated red LED lights to put the characters into focus. The high-speed 1K In-Sight line scan imager captures the pixelated embossed characters as the disc brake makes two rotations.
Reliable reading of different embossed characters was one of the most challenging tasks for the machine vision experts at i-mation, because the type of embossing can differ from one product lot to the next. i-mation overcame the challenge using a step-by-step teach-in procedure of all possible variants. This was made easier by the high-performance OCRMax™ image processing tool for OCR applications from Cognex and with user-friendly In-Sight Explorer software.
After reading the alphanumeric characters, the finishing and inspection steps take place, including balancing and sound testing. Finally, the robot creates stacks of six discs each in a stainless steel box and then placed a wood cover on top. The robot's In-Sight camera locates the exact position thanks to a simple black cross.
For Alber the fully automated disc brake handling system and both machine vision systems by Cognex are the first of their kind and they are playing critical roles in automating the production line and relieving employees' stress.