Walsall Pressings is a well established manufacturing company based in the West Midlands. The company specialises in technical metal presswork and is very active in the automotive industry, supplying tier one manufacturers with pressings, robotic welding and mechanical assemblies.
The company has a long term contract to supply engine components to a global automotive manufacturer. One such component is a clamp retainer that is formed from a single piece of steel into a U shaped
Walsall Pressings has a commitment to produce well in excess of 500,0000 clamps in a 12 month period, such a high volume of components requires an automated visual inspection is critical in order to maintain quality both in the cosmetic appearance, as well as for verification of correct forming ensuring zero flaws.
The clamp retainers are manufactured from a single piece of steel and are pressed in one action into the required shape which consists of two shoulders on each side of the clamp. It is in this area that the forming process can cause the surface of the metal to blister or split. As up to 2000 clamps might be manufactured in a 12 hour period, it is impractical for a human to reliably inspect each clamp.
The vision system uses two industrial cameras located each side of the conveyor at a 45 degree angle, so that the shoulder on each side of the clamp would be imaged as it passed through the inspection machine. Optical sensors detect the presence of the clamp on its arrival and triggers both cameras simultaneously along with a pair of white Scorpion LEDbars which are synchronised from the cameras, ensuring even illumination along the length of the clamp, with no motion blurring due to fast exposure, made possible by the use of the LED strobe.
The images are processed by Scorpion Vision Software, on a compact PC located inside the inspection system. Image processing is carried out before inspection takes place, using software filters to normalise the light level across the image. The second stage of this image conditioning is the conversion of the images using a propriety filter within Scorpion Vision Software that 'flattens' the surface area to be inspected. The vision system then scans the structure and locates any marks or deviations in the surface of the metal.
The system operates in a semi automatic manner in that it is 'fed' new clamps from a rotating bowl feeder singularly, with each inspection taking 8 seconds, the longest process being the time the clamp takes to travel along the conveyor before it arrives at the other end of the machine.
A pass will let the clamp continue on to the end of the conveyor and into a pallet ready for packaging. If a clamp fails inspection, a pneumatic device will open a trapdoor so that the clamp falls into a reject bin.
Walsall Pressings can be confident that the machine will inspect 100% of parts and that any flaws in the surface of the metal will be detected.
Vision System Components:
- Industrial cameras
- Optical Sensors
- LED bars and strobe
- Scorpion Vision Software
- Compact Vision PC