Omron Dedicated F200 Vision Systems Factory Automation RF ID Programmable Logic Controller

DEDICATED VISION SYSTEMS HELP REDUCE ELECTRONICS MANUFACTURER'S QUANTITY OF DEFECTIVE PARTS SHIPPED TO LESS THAN 25 PER MILLION

Although great emphasis is placed on networking plant floor applications these days, there is still a strong case to be made for dedicated systems in some instances. BI Technologies (Fullerton, CA), a worldwide supplier of electronic components for over 50 years, realized that moving from a networked machine vision system to four dedicated vision systems in one production area actually decreased quantity of defective parts shipped and lowered labor costs.

BI manufactures a variety of electronics products, including passive, magnetic and hybrid microcircuits. A pioneer in potentiometers, these products continue to be a key factor in BI's ongoing success. In order to maintain their market leadership in this area and to continue supplying their customers with high-quality products, BI has always championed automation to reduce the quantity of "out the door" defects and to enhance overall product quality. They were an early proponent of using machine vision systems to inspect their tiny components and have installed many vision systems throughout their facility.

"Vision systems are critical to us for inspecting things that the human eye could possibly see but not consistently, particularly with parts this small," says Leon St. Hilaire, BI's Equipment Development Manager. "The 100% quality assurance that we strive for can only be ensured by using automated vision systems."

Being an early proponent of vision systems has its downsides, however. In their RSA (Rotor Sub-Assembly area), BI was using one vision system from the late 1980s to inspect the subassemblies that are placed in finished potentiometers. The vision system was networked into four machines to inspect the 2 million subassemblies BI manufactures each week. Any time there was a problem with a camera on one system, says Mr. St. Hilaire, technicians had to shut down all of the machines to make repairs and adjustments, which include camera alignment, focus and lighting. This happened at least once or twice every week, with each repair requiring anywhere from 15 minutes to several hours, resulting in reduced productivity.

"Since the vision systems in the RSA area are installed strictly to monitor whether the machines are running properly and not to gather trending and other historical information, networking really wasn't necessary," Mr. St. Hilaire points out. "So, when we started looking at new vision systems for this area, we knew we wanted a dedicated system so that we wouldn't have to shut the entire line down if one camera went down." Another problem BI encountered was that the company from whom they purchased the machine was sold several years ago so that having their equipment serviced was becoming more and more difficult.

After evaluating several manufacturers' systems, BI decided to purchase four dedicated F200 machine vision systems from Omron Electronics, Inc. They chose the Omron F200 for several reasons:

• substantial cost savings over some of the comparable systems they reviewed;
• the level of technology provided by the F200 is perfect for the application. The F200 is a binary system that features simple menu-driven programming and can perform up to 1800 inspections per minute;
• Omron's good reputation and over 50 years in business was important to BI for product quality and service reasons;
• the F200's compact design. The system fits in an area less than 10 inches square, saving panel space in control cabinets and making it ideal for machine installation. "We have also discovered that the F200 can be used around solenoid valves, other inductive loads and motors without causing any disruptions to the vision system," comments Mr. St. Hilaire.

Each vision system consists of a camera and lens, a video monitor, a processor and a light source. Each system is controlled by either an Omron C40K or C200H PLC.

The majority of the installation time was spent setting up lighting. "We tried out many lighting configurations and, after a couple of weeks, we decided that a backlighting system was most effective for this application," Mr. St. Hilaire says. "Once we determined this, implementing the system was very easy."

In the RSA area, metal contacts are inserted into rotors, which are built into all trimming potentiometers. Each vision system inspects the position of the contact as it relates to the rotor, the height of the contact, the condition of the wires and whether there are any gaps between the metal contacts and the rotors.

As a result of installing the F200 dedicated systems in this area, BI has reduced rejection rates from 1,000 ppm (parts per million) to less than 25. And, when a part is rejected, the entire lot must be manually segregated and sorted Since the parts rejection rate is down, BI has also saved on the labor required to sort rejected parts. Downtime on each of the four machines as a result of the vision systems has been minimal.

Using what they learned about lighting in the RSA area, BI Engineers combined backlighting with top lighting when installing two F200 vision systems on their new Model 23 Synchronous Automatic Assembly and Test Machine. This machine manufactures BI's new Model 23 potentiometer from start to finish, including quality testing and inspection. Using a top-lighting method, the first camera verifies that an O-ring is properly fed into a sub-assembly. The second camera uses backlighting to determine whether the O-ring and the sub-assembly are properly joined. The system inspects 72 parts per minute, far below its 1800 inspections per minute capabilities, but all BI currently needs for the job. "There was no need for us to install a higher-end system on the Model 23 machine," says Mr. St. Hilaire. "The F200 provides all the capabilities we need, consistently and accurately."

The heart of the system is an Omron CVM1 PLC. If any defects are spotted, the PLC communicates this information via RS232 communications to a control panel. A message alerting the machine operator to the defect is displayed on a screen at the centralized message area. A bell alerts the operator when a new message is displayed. If one part is rejected, the part is automatically removed from the production line. If more than one part in a row is rejected, the system shuts down and a trending report is generated, allowing rapid identification of problems.

BI has realized many benefits as a result of using Omron's F200 vision systems, the main ones being reliability and the quality of product that leaves their facility, says Mr. St. Hilaire. The vision systems are helping BI achieve their goal of less than 25 defective ppm in this area as well.

BI's future plans for vision include installing F200s both in existing equipment and in new equipment design. They plan to replace their ancient wire brush contact manufacturing system with several F200s and they are also considering installing vision systems on screening equipment for the first time.

"The reason, quite simply, that we use vision systems throughout our manufacturing facility, and the reason we will continue to invest in vision, is so that our customers will receive products of the highest possible quality," concludes Mr. St. Hilaire.