Vision system ensures speed and accuracy of automation solution
September 23, 2013 by Steve Geraghty
As amazing as the human eye is, just about everyone knows that it’s unreliable in repetitive work, especially when the work involves judging slight differences in size. To avoid the mistakes that workers are bound to make from time to time, most manufacturers rely on automation for their quality checks these days.
Established in 1942 and headquartered in Lisle, Ill., Altman Manufacturing is a family-owned manufacturer of automation, fabrication, and tool and die cutting machinery that specializes in developing equipment and processes to mechanize and finish hard-to-automate products, including rubber and plastic goods without a defined geometry.
About three years ago, a customer that manufactures Elastomer rubber components for use in the medical industry approached Altman Manufacturing to develop a machine that it could use to automate its process to inspect finished products.
“To illustrate their challenge, our customer brought us three different products they produced: a seal, an item similar to an ‘O’ ring, and a filter,” explains Paul Altman, Jr., who leads engineering at Altman Manufacturing. “While they were made of the same silicone material, the three products were of different sizes, shapes and colours, and the screen, in particular, had holes that could easily be filled during the manufacturing process. The customer wanted an inspection system that would inspect these different parts and could also scale to inspect any new parts they manufactured in the future.”
The time and labour required to inspect products using the customer’s current manual system were costly. Inspections were completed by workers who sat at inspection tables and manually checked the small parts — some of which were less than an inch in diameter — as they moved down a conveyor. Even the most efficient operator was only 87 per cent effective, and because the manual inspection process was time consuming and tedious, effectiveness often diminished in the last hours of each shift.
Seeing the proof
Altman Manufacturing has worked with providers of virtually all vision inspection systems and knew that a vision system from Teledyne Dalsa would be effective for this application. However, before any system is put into production, Altman must evaluate the parts using a sample system for pre-production inspection he developed with Teledyne Dalsa. Using the sample inspection system allows him to view different parts and design appropriate lighting to ensure the camera delivers the optimum results.
“We use this pre-production process to create a customer presentation that illustrates how a product could be inspected. In production it points to the defect, describes how it was found and the algorithm we used, and explains how a defective part would be sorted,” Altman says. “We can show a customer how effective a solution will be before they order the machine, similar to a proof of concept. This ability is especially important when developing a vision system — until we have a lighting scheme and know which lens will be used, we can’t be sure if a solution will function as we expect.”
The right light and the right camera equals the right view
The machine Altman Manufacturing built for the medical component manufacturer uses Teledyne Dalsa’s GEVA Vision Appliance, eight Genie high-resolution, 1600 cameras, and iNspect vision application software. The system is set in advance based on which parts are to be inspected. Specific lighting schemes and camera zones have been developed for each unique part. For example, one part may require inspection using an overhead light, while another may need an under light, and a third may require a dark-field inspection. Each part and lighting scheme is also associated with a particular field of view, so one part will be inspected with cameras one, two and three, but a second part will be inspected with cameras one, four and six. To simplify an otherwise complex process, cameras are set so that no elaborate focus techniques are required. As a part moves down the conveyor, it crosses on to a glass disk and is viewed under the appropriate lighting scheme and with the designated camera regime. Images are then inspected using Teledyne Dalsa’s iNspect software. If a part doesn’t meet the pre-set requirements, it is discarded.
“With this automated inspection system, our customer inspects more than 100,000 of the same type of part in each run and transitions seamlessly from part to part, inspecting as many as 20 different parts in a day,” Altman notes. “Thanks to the efficacy of the Teledyne Dalsa vision system, the machine can inspect three parts per second with 99.97 per cent accuracy, a rate of speed and accuracy that was unimaginable before.”
Altman credits Teledyne Dalsa’s GEVA Vision Appliance with ensuring the scalability of the solution.
“The GEVA Vision Appliance enables the solution to be completely adaptable,” he says. “We can incorporate eight different cameras for eight unique fields of view, but then choose which ones will turn on when for a completely flexible implementation.”
Even given the complexity of the solution overall, Altman notes that Teledyne Dalsa’s iNspect vision application software has simplified the design and deployment of the automated inspection process.
“Customers do not have to be technically skilled to use iNspect. The software works with real-world dimensions and drag-and-drop algorithms for an easy-to-use operator interface,” comments Altman. “There is no need for an operator to have the expertise to write code, and a user can easily switch from part to part or create a scheme to inspect a new part.”
In fact, Altman says that while training for other types of programs may take weeks, the training for iNspect was completed in just over a day, and he was able to deliver a level of training that ensured that the operator he trained could train someone else.
Flexibility for the future
Altman never had any doubt that the Teledyne Dalsa solution was ideal for this application, but his confidence was proven again after the equipment had been in operation for more than two years.
“The Teledyne Dalsa vision system was ideal in that it allowed us to incorporate multiple cameras and gave us the ability to control them with easy-to-use software,” he notes. “Recently, the customer needed to inspect a completely different and unique part — a slit in a Duckbill — and they were able to set up the appropriate lighting scheme and fields of view on their own without any help from me. They’re highly satisfied with the solution, and the results are proven. Eliminating manual inspections alone has led to a significant return on investment, and the speed and accuracy of the new equipment has increased productivity rates overall. Plus, they’ve demonstrated that the solution can scale to meet all their future demands.”
Steve Geraghty is the director of Teledyne DALSA Industrial Products.