The present invention relates generally to assembly processes and, more particularly, to a method for paint repair in a reduced retooling cost assembly process.
In order to remain successful, many industries that produce consumer goods must produce these goods in approximately the sequence in which they were ordered. If the actual or perceived time to receive a product is higher than customer expectations, then the customer will find alternative, faster producers of a similar product. Therefore, it is in the best interests of producers of consumer goods to constantly strive to produce these goods in approximately the sequence in which they were ordered.
Unfortunately, producing goods in ordered sequence usually results in increased retooling costs. Most producers of large consumer goods have a limited amount of assembly lines available for each product. Generally, there are more versions of a product than there are assembly lines to produce that product. The result is that each time a different version of a product is required, the assembly line tooling must be changed.
One example of this is the painting process in an assembly plant where the process is capable of producing a multitude of different colored vehicles on one assembly line. As different customers order these vehicles, the probability of having multiple vehicles that need to be painted the same color is low. Unfortunately, each time a new color is required, the system needs to be retooled, i.e., the current colored paint in the paint guns needs to be drained and each gun needs to be flushed with paint solvent before the new color can be used. This results in increased material costs because of paint and solvent lost during the purge cycle. Hazardous material cost for disposal of paint and solvent is increased.
Additionally, because of the sensitivity of the painting process to defects caused by contaminants, the presence of some colors of paint will cause defects in subsequently used paint of different colors due to over spray carried onto the next color. Obviously, the more often a new color is required, the more paint and solvent needs to be purged from the spray guns and the more defects occur. This can result in an increase in repairs and the associated waste of solvent and paint to correct the defects. The increase of repairs results in higher costs and can have an impact on the emission of volatile organic compounds (VOC""s) to the environment.
One known technique to improve the paint mix is to prioritize the vehicle colors as they were ordered. As each vehicle was ordered, it would be given a special priority in order to increase the number of vehicles built together with the same color. Unfortunately, this xe2x80x9cnational mixxe2x80x9d resulted in negligible success because of small block sizes (i.e. less than 2).
Additionally, when a vehicle needs to be repaired in the paint shop, it is pulled out of sequence and introduced in the beginning the paint shop line where a new color may already be in use. This act of paint repair requires that the current colored paint in the paint guns be drained and flushed with paint solvent before the repair color can be used.
The disadvantages associated with conventional paint repair techniques have made it apparent that a new technique for paint repair in a reduced retooling cost system is needed. The new technique should be able to repair paint defects without requiring paint gun purging and reduce VOC""s released into the atmosphere.
It is an object of the invention to provide an improved and reliable means for paint repair in a reduced retooling cost system, particularly in the painting process for consumer products. Another object of the invention is to repair paint defects without requiring paint gun purging and reduce volatile organic compounds (VOC) released into the atmosphere.
In accordance with the objects of this invention, a method for paint repair in a reduced retooling cost system is provided. In one aspect of the invention, a method for paint repair in a reduced retooling costs system begins by analyzing vehicle orders in a product order sequence to determine the number of different colored vehicles present. The vehicle orders are sorted by color to generate an optimized product order sequence having all like-colored vehicles grouped together. Each group of vehicles is then painted in the order determined by the optimized product sequence. Each vehicle is then inspected for paint defects. If a paint defect occurs on a vehicle, then it is removed from the optimized product order sequence and repaired. Upon completion of the repair, the repaired vehicle is reinserted back into the optimized product sequence to be repainted. Only between each different color group does a paint purging process occur. After the vehicles are painted, they are resorted back into the original product order sequence so that they may be produced in approximately the sequence in which they were ordered.
The present invention achieves an improved and reliable means for paint repair in a reduced retooling cost system. Also, the present invention is advantageous in that it reduces the number of defects caused by changing paint colors. In addition, reduces the VOC""s released into the atmosphere and lowers hazardous material disposal costs.
Additional advantages and features of the present invention will become apparent from the description that follows, and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.