Cognex Vision System Helping Shorten Component Production Cycle Times
28 September 2011
Manufacturers usually produce small components in large volumes. In order to shorten cycle times and save on production costs, THEILINGER Automation & Papiertechnik GmbH, a robotics and automation specialist based in Nuremberg, Germany, uses a new mulitfeeder, along with an intelligent vision system to speed up the production of high-volume small components.
THEILINGER’s system incorporates a delta robot, an intelligent imaging device, and a very user-friendly interface, in addition to classic automation components such as a conveyor pusher, belt, and wheel. THEILINGER’s multifeeder demonstrates what state-of-the-art mechatronics can do in the tightest of spaces. It is fast, precise, and above all easy to operate thanks to the integration of an intelligent state-of-the-art Cognex vision system.
THEILINGER has developed a high-performance pick-and-place system for use in the automotive component industry. The system feeds small parts, such as punched flanges that attach exhaust manifolds to engine blocks, to a double surface grinder. In the process, it also checks the quality of the parts, their orientation, and their positioning.
A pusher singles out the small parts from a bulk magazine and feeds them onto a conveyor belt. Once the parts are on the belt, the Cognex In-Sight® 5401 high-resolution vision system detects their position. The In-Sight 5401 identifies their preferential position based on an infrared light system. The position of the parts is the key identifying characteristic, as burring present on only one side after punching needs to be removed in the subsequent grinding process. The system also has to detect unwanted material residues in through-holes and bolt-fixing holes, using an orientation point applied during punching as its guide.
The In-Sight 5401 detects ten workpieces as one data packet in each five-second cycle and transmits the data to the robot controller. The average cycle time per workpiece in practical operations is up to 0.7 seconds.
The seeing robot
The In-Sight 5401 acts as the intelligent eye of the delta robot. This compact standalone vision system is highly robust and easy to use. It requires no special image processing or programming skills, so it can be quickly and easily configured for the wide variety of parts handled in production operations.
With its delta kinematics system and its low moved mass, the parallel robot enables high operation speeds. The delta robot is regarded as a model mechatronics product. It incorporates mechanical components such as joints and axles, electronic components such as servomotors and control boards and a robot controller that ensures precise positioning of the gripper arm. THEILINGER has over ten years' experience in deploying its tested and proven robot controller in industrial applications, picking components from the moving conveyor belt and placing them with absolute precision.
The intelligent system
Depending on the workpiece being handled, the flange feeder examines the inner or outer contours of the part to detect whether it can be picked. A major argument in favour of picking workpieces by the inside contours is that when workpieces are positioned close together and require picking on their outer contours, it is possible that some of them cannot be picked up. . To respond to this challenge, the system can optionally be fitted with an automatic picker changer.
The In-Sight 5401 communicates continuously with the robot program, which ultimately controls the entire THEILINGER multifeeder system. This means that no additional PLC (programmable logic controller) is needed. This simplification of the process helped to cut both capital investment and maintenance costs.
The system was designed to enable the operator to change product jobs independently, with no need for programming skills and with minimal effort. The machine can be reconfigured for new components in just a few minutes, with just a few clicks.
To make operation of the multifeeder as easy as possible, the THEILINGER engineers automated the robot calibration process. At the press of a button, the delta robot places the component at various positions and synchronizes the exact positioning with the In-Sight 5401. The intelligent vision system is referenced to the coordinates system of the robot, ensuring that the exact position on the conveyor belt is ascertained at high speed.
The operator can calibrate the system independently at any time. THEILINGER incorporated In-Sight Explorer as an add-on component and uses In-Sight Explorer for in-process adjustment of key parameters, such as the gray-scale value, is used to assess the quality of the centre hole. The acquisition rate and the number of components to be detected can also be adapted to changing requirements.
In selecting the system components, THEILINGER focused foremost on reliability. It ultimately chose the Cognex In-Sight 5401 based on the tens of thousands of prior applications through which the product was able to demonstrate its performance capabilities. The Cognex vision system is especially suited to applications in the automotive industry and has delivered highly "visible" benefits in the truest sense of the word in manufacturing plants around the world.
For details, visit Cognex on-line at http://www.cognex.com