Dinalot SA, a Spanish company, manufactures five different styles of small metallic machine parts for the motor industry. When the motor industry subcontractor needed an inspection solution to check the production quality of its precision mechanical injection components, it turned to Cognex integrator partner Ikusmen Vision Artificial, also a Spanish company.
Ikusmen installed a visual inspection system that offers high speed and accuracy to considerably improve production output quality by providing 100% inline inspection of parts. The parts are machined metal disks that feature 6 tapped and countersunk holes. The visual inspection system measures hole position for each hole with respect to each other, and relative to a central positioning notch. In addition, the system measures the diameter of these holes.
Previously Dinalot required an operator to manually take the measurements and carry out all of the checks. Because of the high degree of precision required, the measurements used to take a long time and the checking itself, which involved selective sampling, had the disadvantage of letting through many non-compliant parts.
After studying the production conditions, Ikusmen put in place a solution that was capable of carrying out the necessary measurements and checks on all manufactured parts while simultaneously satisfying the key precision, production speed, and cost requirements.
The system comprises two Cognex In-Sight 1000 vision sensors, an XY Cartesian robot, and a rack-mounted industrial PC. The PC is used to control the vision sensors and the robot, and to display the current vision inspection image and the measurement results. It is also used at the application tuning stage to configure the two sensors and to indicate which version of the product is to be checked.
The In-Sight sensors are mounted on a robot arm as shown in the figure. The first In-Sight sensor, mounted vertically above the parts to be inspected, is used to check the position and diameter of the holes. The second In-Sight sensor, mounted at a specific angle, looks inside the holes to check the threading. The horizontal control surface is fitted with LED backlighting manufactured by Cognex.
The parts arrive at the inspection station after passing through a cleaning bath. The robot picks up the part to be inspected and places it on the control surface. The first In-Sight sensor initially locates the central notch on the part and then calculates its position.
Next, the robot moves the camera so that it is above the nominal position of each hole. The vision sensor then calculates the angle of each hole relative to the central notch and measures their diameters. All these measurements are carried out to a level of precision of +/- 0.02 mm for the diameters and +/- 0.1° for the angles.
The robot positions the second In-Sight sensor so that it can inspect the inside of each hole. It inspects the quality of the threading by measuring the number of threads and the width of the grooves. Once these checks are complete, the robot places good parts on a stacking device and the failed parts in a discard container.
The entire operation takes only 9 seconds, which means that every part produced by Dinalot can be inspected, for all five of its production models. It also ensures that no faulty parts will ever find their way to the end customer.
Thanks to the Ikusmen solution, it has also been possible to automate the "palletization" of the manufactured parts. The vision system data obtained during the control process has also allowed Dinalot to refine its machining process.