Hydraulic Valve Braze Detection System
HydraForce, the world’s largest supplier of hydraulic cartridge valves, electro-hydraulic valves, custom manifolds and electrohydraulic controls, approached us looking for a suitable solution to enhance their in-house inspection process by defect detection and automatic rejection for production on site in Birmingham, UK.
The main objective for the system is to detect the presence of a braze on various sized valves from production. The braze can be a copper paste or sometimes a ring, which is melted to fuse the separate parts of the assembly together. The presence of a complete braze ring is critical to safety compliance, as the valves are pressured in excess of 3000 PSI. If the joint is not fully brazed, it could fail under pressure causing damage and risk of injury.
HydraForce required a system that offered detection and rejection functions in order to separate parts with absent or partial braze application, ideally with minimal operator input. HydraForce have 80 different components of varying sizes to inspect, therefore the need for a system storing multiple recipes that could be changed with ease is a must. ID marking is a key feature required for parts passing inspection, providing HydraForce with a clear indication that they have successfully been processed and the braze is present.
The following standalone detection and rejection system with minimum operator input was proposed to HydraForce. The main shell consists of a mild steel frame, with sliding magnetic lock cell doors to allow ease of access for pallet placement and removal. An SD card within the processor holds the software, recipe database and reject images. Other main components of the system include an Epson T6 SCARA robot, sensors, pneumatic actuators, cameras, lenses and lighting. To meet HydraForce’s production/inspection demands, two of these systems were manufactured.
Pallets of parts are manually loaded via the sliding front doors, then the inspection process can start from the push of a button on the HMI panel. For safety precautions, Sick UK Ltd miniature photoelectric sensors are in place to detect potential collisions with the Epson T6 SCARA robot. A collision could happen should the incorrect parts (as per the set recipe) be loaded, causing the robot to try to pick a part at the incorrect height. The built-in sensors will stop all movement if they are out of tolerance, triggering an alarm to check for a correct recipe or pallet change.
Each part is inspected individually. The robot positions each of them in turn in front of the Sick 2D vision PICO cameras. They are then spun 360° as the camera takes an image at every 60°. Six different photos are taken by each camera to inspect the braze to decipher if it is a good or bad part. The top camera is mounted to a linear slide that allows the inspection area to adapt to the size of the part being inspected. The cycle time for this sequence takes approximately 9 seconds per part to complete, from pick up from the palette through to release into the appropriate exit chute. This should allow HydraForce to inspect approximately 400 parts per hour, per machine.
Upon inspection, if the part is deemed good and the braze is detected & complete, the robot will stop the part in rotation to enable insertion into the stamper, providing a clear indication that it has passed successfully. Once stamped, the arm will pick up and move the part across and release it into the exit chute specifically for good parts.
If there is no evidence of a braze on the part, or it is incomplete or partially missing, it is rejected immediately. The robot arm will move the part to the other exit chute specifically for bad parts. A confirmation sensor is positioned above the reject chute. If this does not detect a failed part released, the system will stop and an alarm will sound to alert the operator.
Prior to the delivery and installation of the two systems, thorough in-house testing was completed by our engineers at Adbro Controls. As a result of this, the installation and commissioning time could be reduced upon delivery, thus allowing HydraForce to commence inspection using the new process as quickly as possible.
The new standalone system provided by Adbro Controls has proven to be a valuable addition to HydraForces’ inspection process. It has been agreed that Implementing the detection and rejection system has had a positive impact to the companies quality process.
The time taken to inspect pallets has improved greatly and as a result not only do they successfully inspect at least 800 parts per hour, but the new levels of efficiency has enabled operators to clear all pallets awaiting inspection quicker than before.