Collins & Aikman, a leading Tier One automotive supplier, provides carpet sets to several major automotive manufacturers. These sets, manufactured at locations in Greenville, SC, and Old Fort and Farmville, NC, are made up of high quality carpet material and as many as four vinyl wear pads, added to increase durability. Each set is available in carefully selected colors with all elements, carpet and padding, matching detailed customer specifications.
As part of its continuing quality improvement program, Collins & Aikman recently resolved to migrate the color matching process from a manual to a fully automated process. The process enhancement would assure color match quality from sample to sample, and eliminate mistakes in color matching due to human error.
After evaluating candidate solutions from other sensor companies, C & A Greenville came to Balluff. C & A had determined that color sensors using fiber optic technology would fail, due to inadequate separation of sensor lenses. Contrast sensors would also fail because of their inability to read colors off the carpet texture. One of the major problems in reading true carpet color is that, due to handling, the nap or pile can lie differently from one piece of carpet to the next, changing its perceived color.
Balluff, a leader in photoelectric color recognition, went to work on the problem under the direction of C & A''s process engineer, Ted Manning. Roger Altendorf, Balluff''s photoelectric sensor specialist, went on site to analyze the situation. "The trick in this application was to accurately read and match color from two completely different materials. Different textures, materials, and nap angles dramatically complicated the problem, with the carpet material tending to display variable hue."
After evaluating a number of possible sensors and process solutions, the Balluff team came up with the answer -- using the Balluff BFS 26K color sensor as a basis for the final color matching process. Up to four Balluff sensors read the vinyl pads and two more read the carpet. The BFS 26K carpet sensors were programmed to recognize the carpet color regardless of nap/pile orientation. The full-color Balluff sensor, with three programmable outputs, is sufficiently flexible to be set up for go/no-go for all the color variations Collins & Aikman requires.
Solid fixturing is key for any color matching application. The carpet must be read at precisely the right angle and precisely the right distance. Setup distance was not as critical on the vinyl wear pad color match, but a specific sensing angle was still needed to correctly read all the colors. The other key solution factor was that all elements in the process -- sensors, carpet, and pads -- had to be absolutely still for a split second. The Collins & Aikman team recognized this and devoted considerable effort to provide solid, protective fixtures for the Balluff sensors.
Collins & Aikman''s Ted Manning comments, "Our automotive customers have absolute standards when it comes to color match on these carpet pieces. Balluff has helped us substantially increase our yields of perfect carpet sets, while simultaneously raising our productivity and lowering our scrap rate."
The success of Balluff''s accurate color matching solution led to a second application for its BFS 26K sensors. Collins & Aikman uses a water jet cutter to prepare the finished carpet assemblies for correct installation in specific vehicles. Two Balluff BFS 26K sensors are now used in a final process check to ensure efficient production by verifying that only carpet sets that meet C & A''s total quality parts criteria are cut for final installation.
"Quality and productivity is the name of the game when it comes to the automotive industry," says Manning. "Balluff gave us the means of simultaneously increasing our quality and our productivity to more than meet the requirements of our automotive customers when it came to this particular production process."