Excavator Coating Process Optimization Research

With the rapid growth of excavator’s production, the market competition isbecoming increasingly fierce. Competition exists not only in quality, but also on price.Energy saving and cost reducing have become an urgent problem for excavatormanufacturers. The motive is to optimize the painting process of excavator structuralparts by parallel experiments, and the scope of the study included surfacepretreatment process, primer painting, puttying and polishing, topcoat painting. In thispaper, the optimized painting process parameter to obtain high-quality and highperformance coating films was selected by comparing with the coating films ondifferent structure parts using the traditional coating process and the modified process,respectively. The experimental results from pilot production showed that the qualityof the composite coating had reached the level of the industry benchmark byoptimizing the painting process, as well the goals was achieved to reduce productioncosts and improve market competition due to improvement of the painting efficiencyand the utilization rate of raw materials, and decrease of the energy consumption.Surface pretreatment process: Using saturated steam oil removal instead ofhigh-efficiency detergent oil removal; make the workpiece surface without oil beforepretreating.80wt%1.0mm steel shot and20wt%1.0mm steel wire cut shots weredetermined by optimizing choice. Through experiments, the blasting parameters wereoptimized as follows: blasting time for20min, shot blasting machine current for25to30A. The clean rank of workpieces outside surface reached the Sa2.5, some groovesor inconspicuous site reached Sa2, the surface roughness was controled between40to70μm after shot blasting treatment.Primer and topcoat painting: Improved the painting quality, efficiency and theutilization rate of paint by choosing appropriate paint, retrofitting the sprayingchamber, analyzing the structure, also optimizing the spraying sequence and sprayingparameters. The average utilization rate of primer and topcoat increased by10.6%-23.1%and10.2%-22.7%, the average spreading rate of primer and topcoat increased by1.34m2/L and0.64m2/L and the uniformity of film thickness conformedto the principle of80-20after optimizing the painting process.