To automate production lines for motor plugs IWM Automation relies on a vision solution and the automation expertise of Balluff. Ten cameras in a multi-stage assembly and punch process monitor for correctness, completeness and quality. The result is a highly efficient system which reliably detects errors and removes NOK parts early in the process. Balluff assisted in the entire conception and implementation phase with consulting and engineering contributions.
In just a few days the branched assembly line at a renowned automobile supplier will be producing motor plugs in various configurations. Around the clock and with a virtually zero defect rate. The approximately ten meter long system is waiting to ship from IWM Automation GmbH with headquarters in Porta Westfalica. It is the result of a close cooperation with the sensor and manufacturing specialists at Balluff. IWM Automation is a manufacturer of specialty machines with an emphasis on individual solutions for assembly and inspection systems. Their customers are primarily automobile companies and their suppliers.
Focus on over 100 individual inspections
The special challenge in the assembly plant for motor plugs lies in reliable monitoring of various assembly, stamping and inspection processes. Before, during and after individual work steps a total of over 100 individual inspections are performed and their results made available to the central machine controller. The basic housings are moved along on one- or two-track conveyors. After passing through multiple stations they arrive at the end of the system a five differently configured connector types.
The multi-stage and complex production process takes place in several steps through essentially six stations. The plug components are assembled fully automatically, punched out depending on the type with up to 64 pins, checked and at the end individually labeled by laser. The individual components are fed using conveyors or via bulk containers and vibratory bowls. Gripping and assembly applicators pickup the components and position them at a predetermined location on the plug housings brought in on workpiece carriers. This presumes the components were already correctly recognized and are free from defects. All workpiece carriers are equipped with RFID tags which are read by BIS M read/write heads along the assembly line at the individual stations.
Balluff vision solutions for efficient manufacturing processes
"The challenge is to design the construction and multi-stage assembly process for differently configured plugs intelligently, in a coordinated way and in the final analysis efficiently," says Torsten Meyer, Head of Project Management for Steering and Drivetrain Systems. "In managing this task Balluff was always at our side in word and deed and with a high level of expertise." A broad set of various tasks needed to be handled along the automated production line. The goal was to minimize defect rates over the entire process. Parts with defects needed to be recognized at such at the respective stations and immediately removed from the line.
A key topic in the assembly line is the checking of location, alignment or distances of objects, checking for completeness, and monitoring previously performed work steps. This is precisely what industrial image processing systems have been designed for: The BVS SC SmartCameras from Balluff read not only machine codes, text or serial numbers. The associated software supports robots in positioning, detects orientation, make-up and detail features of components. "We decided on Balluff vision solutions even in the early conception phase: The system offers an easy to integrate, versatile and high-performance range of uses for visual quality inspections, identification and positioning. It detects process errors early to prevent bad lots and resulting costs," emphasizes Torsten Meyer.
Wit the Balluff solution the user receives a complete package: Software, library, manuals and online help are already integrated into the SmartCamera. The offering is aimed especially at users who do not deal with image processing on a daily basis. "Turn it on and go" is the slogan: Simple and intuitive operation, flexible adaptation to the respective automation environment as well as the use of industry standards help users of all levels of expertise.
Results in fractions of a second
At the first two assembly line stations three SmartCameras check for presence of plug housings and their location in the detected space. They use two tracks and contour checking to see whether a 64-, 32- or 24-pin connector is in view. Using Balluff spot and flood lighting systems the cameras detect whether a white or black insert is installed on the side. The integrated CMOS sensor chip makes the images available for processing quickly and reliably, with a typical processing time of 200 to 300 ms. Alternately the user can also access other stored images. The SmartCamera stores up to 100 inspection programs, and comprehensive importing and exporting functionalities with training images represent valuable features.
Three SmartCameras are responsible for checking pins on the connector inserts at the third station: A flood light illuminates the plug, and the tips of the pins are sensed individually using brightness tools in the software. Only if all the pins are present and correctly fitted do the plugs remain in the production process.
Another SmartCamera checks the punch patterns of the connector inserts and the latches for presence. At the end of the process two SmartCameras handle a final latching check of the plugs and verify the distance of the detents from the plug housing. If the requirements are not met, the image processing system causes the component to be immediately removed from the line. This ensures that only OK parts leave the plant.
Simple operation, custom configuration
The SmartCameras are easily and intuitively operated using common web browsers and the Balluff Vision Solutions user interface. Equally simple is generating the desired inspection programs and sending the inspection results to the controller or file servers. The SmartCameras are incorporated into any system environment using digital in-/outputs, standard LAN or Ethernet/IP. Additional sensors are simple to integrate using the IO-Link master interface.
The SmartCameras can be configured so that only the data essential for the controller have to pass through the process network. This minimizes data load and secures the process network. Not only all the important functions, but also monitor, configuration and statistics modes are shown in a clear and organized way. In Monitor mode the inspection program runs continuously, with results made available on selected outputs or sent to the PLC or a host computer in the form of so-called results packets. In Statistics mode the user can have the global yield rate and statistics values for individual result parameters represented. Only setting-relevant parameters are visible for any of the tools, and each SmartCamera can be specifically and conveniently adapted to the individual requirements.
With Balluff Vision Solutions IWM Automation has stabilized their entire production process. Intelligent analysis algorithms output the results over the interface and in the desired format. Thanks to the great flexibility of image processing value creation relevant information can be derived from the data at any time. Since the system can be operated using a common web browser without any special software, remote maintenance and service concepts can be implemented easily and without any special expertise. "Our long years of partnership has proven itself one more: Again in this project Balluff have demonstrated their automation expertise and supported us immensely from the engineering phase to the final startup," summarizes Torsten Meyer.
Fig. 1: Modular production line for motor plugs by IWM Automation
Fig. 2: 64-, 32- or 24-pin connector? The Balluff SmartCamera detects whether the correct plug type is present
Fig. 3: Balluff SmartCameras carry out the final latching inspection and check the distances between the detents and the connector body
Fig. 4: Depending on the model up to 64 pins are punched out. A Balluff SmartCamera then checks the punch results