Paint shops evaluate their practices to meet automobile manufacturers' demand for quality. Could a robot be the best man for the job?
At a time when most automobile manufacturers are aggressively trimming operational costs, the paint room managers are faced with a difficult task: how to maintain or even lower the defect rates on parts moving through the paint room.
Combine this with the industry's tightened purse strings and the challenge of getting cleaner has also gotten tougher. With no breakthrough technology on the horizon, automotive manufacturers can't expect quantum leaps in reducing first run defect rates. As a result, many are turning to the lower-cost and lower-tech alternatives of process improvement and employee training as a means to prevent contaminants from entering their clean spaces in the first place.
“Auto manufacturers' main concern is the amount of contamination carried in by the people,” says Paul Malloch, sales director of U.K.-based Countdown Clean Systems Ltd, a provider of cleanroom garments and supplies. “There is a major drive toward the education process of the individuals because the auto makers are aware that they can get the most sophisticated equipment in the paint booth and have an expensive process to clean it. But if the people abuse it, the whole thing goes out the window.”
At Daimler-Chrysler's Belvedere, IL, plant, the workers are reminded regularly of what may cause defects in the paint and are drilled in the commitment to continually improve the operations. “As we go along, we continue to learn more and more about different types of defects, meaning we are stricter on ourselves on the quality of what we do,” says Mark Ackerman, process reliability manager in the Belvedere paint shop.
Daimler-Chrysler is also tightening performance requirements of the consumables used with the paint shops, such as tack wipes, filters and garment materials as a part of its commitment to continuous improvement.
Finding cost savings
With cleanrooms that typically average a relatively “dirty” ISO Class 8, companies that serve the cleanroom industry see ample opportunity to clean up the air and parts that run through automotive paint shops. But the trick or these suppliers is to prove that new products or services add real improvements to quality, and as a result, operational cost-savings.
“We do have the budget concerns,” says Gary George, paint specialist with Daimler-Chrysler's paint and energy management group. “Suppliers should understand that we are trying to get the products in that are providing the best price at the best performance.” In real terms, that means auto makers are interested in the cost per unit, not of the consumable supplies, but of the cost of those consumables spread out over the number of cars that move through the facility.
“So it's not just about the best price,” George notes. “We might spend an extra five dollars on a filter, but only if we know for that extra money we can get an extra month's life out of it.”
Some savings are easy for mangers to squeeze out of their paint shops. In one instance a manufacturer noticed its workers were not using the entire surface of the tack cloths—wipers used to clean dirt off cars before they enter the paint booth. Because the 17-inch square cloths were so large, workers were folding them to better fit their hands, then disposing of them without refolding to use the inner sides. The simple solution: switch to an 11-inch square at a lower cost. The size fits the activities of the workers better, is not folded and all sides of the cloth are used.
While some savings are achieved simply and inexpensively, other efficiencies are not so cheap. Robots have steadily made inroads as the painting method of choice in most paint shops, especially at newer factories. The reason is simple: more robots in the paint booths mean fewer humans working in the clean areas, and hence, a decreased chance for human source contamination in the paint.
In addition, the robots deliver not only a high-quality finish, but one that uses and wastes less paint. “We are seeing improvement in the robots where they have the rotary atomizers, the bell versus the spray gun,” says Ackerman. “You can get a much better transfer efficiency with the bell and that eliminates waste.”
At Fanuc Robotics of Rochester Hills, MI, company officials hear the industry's need to cut costs out of the system and are squarely focused on making its paint robots and the paint delivery mechanism as accurate and efficient as possible. “We try to do things with applicators and applicator cleaners that maximize the efficiency to determine how we can eliminate paint overspray,” says Jon Karr, vice president of paint shop automation with Fanuc. “The more efficient we can be with those applicators, the more we can get the paint on the parts. That means less contamination, less paint waste, and fewer particles going into the flush system of the booth that needs to be brought out as waste. There are all sorts of by products to higher transfer efficiency and if the booths run more efficiently, it cuts down on both expense and the potential for paint defects.”
The people equation: training and garments
Keeping a handle on or even reducing costs within the paint operation doesn't necessarily mean automakers are forsaking attempts to reduce product defects. Instead, they are finding cheaper ways to get better results, which means a focus on employee education and training.
But manufacturers aren't blind to the challenges of getting workers to embrace and adopt the kinds of changes needed to make an operation cleaner. At Swedish auto part supplier Plastal AB's Ghent, Belgium, plant, worker training preceded the opening of its state-of-the art plant by more than two years, says Herman Vandevoorde, central services coordinator.
“We prepared with slow changes in the old paint shop, which did not have a cleanroom,” says Vandevoorde. “We slowly brought everyone along about how to behave in a cleanroom for two years before we built this installation.”
To be effective, the training needs to be continuing and consistent. “It's really a continuous improvement issue,” says Ackerman. “We will take operators out of the booth at the end of their shift, show them what the dirt defects look like and help them understand how that defect is directly related to their actions in the booth.”
Some dirt defects are also the result of activities of workers before the car or part even enters the cleanroom for spraying. “It is common to take a tack cloth or a tack wiper to wipe down a car before it goes to the paint booth,” says Rob Nightingale, president of Toronto-based Cleanroom Garments and a member of the Institute of Environmental Sciences and Technology (IEST; Rolling Meadows, IL) Working Group 29. “But the workers need to know how to effectively wipe the area they are working on and wipe in a unidirectional fashion. I see people not following that procedure quite often. This is easy to correct with good standard operating procedures and training.”
Garment suppliers have also stepped up to fill a void in the past 15 years in paint shops. Yet, garment programs using fabric and laundering technologies from other industries using cleanrooms can be an added expense some paint shop managers might feel they could do without.
For potential clients that are “on the fence” of committing to a new garment program, Malloch likes to let the garments prove themselves in a two-week trial. “It's not like the electronics industry where it might be a couple of months before they can measure the impact of a change,” says Malloch. “In automotive it is quick, and if we can get it in a cell and run it for a couple of weeks, it is easy to see what effect it has on the defects of the vehicles going through.”
Further, garment suppliers have learned the need to tone down their technology to better fit the needs of automakers. “We simply don't have to supply the level of service to our automotive customers as we do to the electronics or pharmaceutical industries,” says Robert Verlinde, managing director of Countdown Clean Systems' Belgian office. “We provide better garments and service so that they are getting something in between what they would get from an industrial laundry and a cleanrooom laundry.”
Improvement down the line
Expanding the controls further and further outside the cleanroom could be the next wave in paint lines. “Most of the focus tends to be on the wet areas, where the paint is applied,” says Malloch. “There needs to be improvement farther down the line for the product used to clean the car or how the car is cleaned. Once you clean up where the paint is actually applied, you need to then move it farther down the process to make sure the car is clean before it gets there.”
Could significant changes be afoot in the coming years? Perhaps, if one major manufacturer has a successful breakthrough (see “Plastal pushes the envelope”). “Talk to anyone about car production and everyone is looking at everyone else to see what they are doing,” Malloch adds. “If one makes a stride ahead in any one area, all the others will look at it and say it's where they should be headed.”
Plastal pushes the envelope
Plastal whose installation in Ghent, Belgium, supplies bumpers and fascia to the nearby Volvo plant has created a system that relies heavily on automation and robotics throughout the production process. The reason is clear: Humans are a primary source of contamination in paint shops, so the less humans involved, the better the paint will be.
To limit human contact to the bumpers, the injection molding and removal from the molds is handled entirely by robots. Workers in the plant's cleaning or masking areas who might handle the bumpers wear rubber gloves, cleanrooom coveralls and caps. Once cleaned, the parts move through a flaming room to quickly burn off any “hairs” left over from the molding process.
Inside the cleanroom, Plastal's workers are covered from head to toe with cleanroom garments and hoods. The painting of each set of bumpers is executed solely by robots. “These people are not directly in the paint shop, and only enter if it breaks down or there is a problem,” says Herman Vandevoorde, central services coordinator. “The three workers inside the cleanroom monitor and operate the robots.”
The plant currently has first run rates of 82 percent and 92 percent after polishing. “We know we can do better and we will be doing much better by next year,” says Robert Verlinde, managing director of Countdown Clean Systems' Belgian office. “Everyone of the 250 workers here has a particular job to do and they are responsible for being as clean as they can be, even if they are not working in the cleanroom. By next year, we should hit 89 percent on the first run.”
A closer look at recommended paintshop practices
It's been more than three years since the release of Recommend Practice 29.1 (RP 29.1) “Contamination Control Considerations for Paint-Spray Applications” was released by the Institute of Environmental Sciences and Technology (IEST; Rolling Meadows, IL). The result of nearly six years of work, RP 29.1 brought together the best thinking of both paint-spray operators and suppliers to the industry.
“At the height of work, we had roughly 45 active members of the working group from across all areas of interest, representatives from two of the “Big Three” paint companies and cleanroom garment companies all taking a piece in their area of expertise to get it published,” says Rob Nightingale, president of Cleanroom Garments and a member of IEST's Working Group 29 (WG29).
Covering topics ranging from the selection of garments and cleaning aids to filtration of air and paints, RP 29.1 has filled the information void and become the primer for paint-spray operations. “When we started work, we knew that spray facilities were facing similar issues but did not have the depth of knowledge or solutions for many of the contamination problems they encountered,” Nightingale notes. “RP 29.1helped fill that information void.”
At press time, IEST WG29 was preparing the final drafts of the first major update to RP 29.1 with the intention of publishing the updated version RP 29.2 in 2003.
More of an addendum than a re-writing of the recommended practice, RP 29.2 will provide guidance on three additional topics. These include: paint application, the manner and whether to apply liquid or powder paints; dirt and defection detection and analysis, methods for determining the source of dirt in the paint process; and process environment management, methods for measuring air quality and air velocity within the paintshop.
“We've kept working on these topics since the release of 29.1,” Nightingale says. “It wasn't that these are new concerns, we just had such a big job writing 29.1 from scratch that we wanted to get the major parts published. We knew we would eventually update it.”
For more information on IEST's RP 29.1 or WG29, visit the IEST website at www.iest.org.
