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A Cognex In-Sight 5100C vision system is helping an automotive supplier to improve its inspection capabilities.

The automotive supplier has to perform 100 per cent inspection of a transmission control module (TCM) to verify the mechanical integrity of the unit.

Manual inspection, which was used in the past, was expensive and left the possibility of bad parts reaching the customer due to human error.

Universal Instruments worked with the automotive supplier to devise a solution.

A gantry now moves a Cognex In-Sight 5100C vision system into position to read a 2D Data Matrix code and verify, through optical character recognition, markings on top of the part.

The gantry then picks up the part and positions it so two more In-Sight 5100C vision systems can inspect system connectors on the side and bottom of the part.

This automated inspection system has provided perfect quality to date, while also delivering substantial labour savings and part traceability for the company.

The TCM controls an automatic transmission, using sensors from the vehicle as well as data provided by the engine control unit (ECU) to calculate how and when to change gears for optimum performance, efficiency and shift quality.

The result is better fuel economy, reduced engine emissions, greater shift-system reliability, improved shift feel, improved shift speed and improved vehicle handling.

The immense range of programmability offered by the TCM also makes it easy to adjust the performance characteristics of the transmission for different applications.

Information is delivered to the TCM via controller area network bus (CANbus) communications and the TCM in turn provides information to the ECU and generates error codes if a problem is detected.

This TCM is critical to vehicle performance so 100 per cent inspection is required to verify the mechanical integrity of each unit that comes off the assembly line.

For example, if the customer was to receive a TCM with a defective connector, the supplier would be subject to substantial penalties, including 100 per cent containment and inspection of all products until root cause corrective action had been approved by the customer and implemented by the supplier, not to mention the blemish on the supplier’s quality scores.

The supplier was not satisfied with manual inspection because it is never completely accurate.

Human error is inevitable and completely unacceptable in this case.

The supplier aims to eliminate all bad parts.

The supplier also wanted to provide documentary proof that individual parts had passed inspection in case any questions arose.

The automotive supplier worked with Universal Instruments to develop an automated solution that provides 100 per cent quality at an economical cost.

Universal offers a broad range of manufacturing solutions, including component and die processing, odd form and final assembly, transport systems, flexible process cells and peripherals.

The customer had already decided to use a laser-marking system to provide traceability at the individual component level.

Universal’s challenge in this application was to read a 1D barcode on the pallet, a 2D Data Matrix code and text on the product, and inspect the power and signal ports on the product for mechanical integrity.

These operations all had to be carried out in a short period of time and within in a limited amount of space.

Francois Caudrillier, director of product management and solution integration for Universal Instruments, said: ‘This application involves an extremely wide range of challenging vision tasks.

‘It would not be that difficult to find three different vision systems that could meet these three very difficult challenges.

‘But using three different systems would dramatically increase the complexity and cost of the solution.

‘It would also most likely be impossible to physically fit three conventional vision systems in the cramped confines of a single cell.

‘The Cognex In-Sight 5100C provided the answer to these challenges.

‘It reads 2D Data Matrix codes and performs optical character recognition as well as dimensional inspection.

‘The ability to use a single vision system to meet all of the requirements of the application saved time and money because we were able to work in a single programming environment and with a single interface throughout the project,’ Caudrillier added.

In-Sight vision systems include a camera, lens and all required hardware in a single, compact self-contained package.

The 84 x 124.7 x 61.6mm vision system (3.34 x 4.91 x 2.43in) easily fits within the tight confines of the cell.

The compact size allows for placing multiple vision systems inside the cell to capture multiple sides of the product in order to meet the tight cycle-time restrictions.

The self-contained inspection algorithms made it easy to provide the 360-degree inspection required to meet the customer’s requirements.

Cognex Easybuilder software walks the user step-by-step through the process of setting up a vision application.

Users can drop in tools simply by clicking on features of interest.

Caudrillier continued by saying: ‘Cognex provided excellent support in this application.

‘We sent it samples of the product and it helped to define the lensing and lighting solution for the application.

‘This assistance freed up our engineers to work on other aspects of the project,’ he added.

The solution developed by Universal Instruments utilises a 1500mm-wide Polaris Junior assembly cell.

The Polaris Junior cell features a three-axis gantry driven by lead screws and controlled by a Galil motion card with repeatability of 0.0004in.

An Omron programmable logic controller (PLC) defines the location and sequence of the inspection operations.

A pallet carrying the product is transferred by a conveyor to the input station of the assembly cell.

Here, a 1D barcode on the pallet is read by a barcode reader.

The barcode reader sends the part identification number to the PLC.

The PLC in turn sends the number to the factory host and obtains authorisation to process the product.

The product is then transferred to the work-in-process stop in the station.

The gantry carrying an In-Sight 5100C vision system moves into position above the product.

This vision system, as well as the others in the cell, uses an integrated spectrum ring light.

The vision system reads the 2D Data Matrix code on top of the product.

It also performs optical character verification of the text on the product.

The results are sent to the PLC and the PLC verifies that the code and characters match the information provided by the host based on the 1D barcode.

In the case of a mismatch the part is rejected.

Next, a gripper on the robot arm that is offset from the camera picks up the part and holds it in position so that another 5100C vision system can inspect the signal port on the side of the product and yet another 5100C below the product can read the power port on the bottom of the product.

Each port is a custom over-moulded connector with pins contained with a shroud.

The two vision systems each use line-finder tools to find the end of the connector that serves as a reference point for subsequent operations.

Then the vision system verifies that pins and leads are present in the connector and that the pins are not bent.

The results of each inspection are sent to the PLC, which makes the decision on whether to pass or fail the part.

Based on this decision, the gantry sets the product on either a pass conveyor or a reject conveyor.

In addition, a sampling of parts that pass inspection is placed on a quality audit conveyor for manual inspection.

The results from all of the inspection operations are sent to the PLC.

The PLC then sends the information to the factory host where it is stored and can be recalled in case a question arises in the future.

The new inspection system provides a substantial improvement in accuracy relative to manual inspection.

Every automotive supplier knows the danger of shipping even one bad part to a customer and also knows that manual inspection runs the continual risk of errors.

This automotive supplier has taken action to ensure 100 per cent automated inspection of every component, virtually eliminating the possibility of errors.

In addition, machine vision provides substantial cost savings by eliminating the need for manual inspection.

The supplier plans to expand its use of machine vision in the future to ensure that it continues to exceed its customers’ expectations.

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