The Research And Application Of High-pressure Waterjet Cleaning Based On Remanufacturing

With the gradual development of society, it becomes harder and harder to develop economy relying on the resource consumption. The natural resources will be exhausted one day. However, remanufacturing is a kind of effective mean to reduce the resource consumption accepted by the worldwide nations. It could greatly increase the reutilization ratio of resources, reduce waste production and weaken the pressure to the environment.Remanufacturing cleaning is the precondition of the remanufacturing process. The quality of remanufacturing cleaning directly restricts the following process including flaw detection, testing, restoration, assembly, etc. So it deserves enough attention. Traditional remanufacturing cleaning usually use manual cleaning, chemical cleaning, high-temperature incineration, shot blasting, etc. These cleaning methods are of severe pollution, high cost, high labor intensity, etc. Therefore, this thesis proposed that high-pressure waterjet technology is applied to remanufacturing cleaning. High-pressure waterjet is a technology that the water is pressurized to several MPa and even a few hundred MPa by the pump, and then converted to high speed waterjet through a nozzle with small-diameter outlet. The waterjet contains huge impact energy for accomplishing certain tasks. High-pressure waterjet cleaning is a physical cleaning method, which cleans the dirt via the impact energy of high-pressure waterjet. The dirty water can be filtered for recycling to reduce the cost. The majority problems of above cleaning methods could be solved.This subject simulated the flow field distribution in the nozzle with COMSOL Multiphysics. The influences to the flow field with different nozzles were researched. The velocity distribution along the axis and outlet radius was compared for optimizing the nozzle structure and giving advices to nozzle selection.The high-pressure waterjet testing equipment was developed. It could perform component clamping, standoff distance adjusting, traverse speed adjusting, pressure adjusting, etc. The surface coating of cast iron was selected as research target. The decoating law with different standoff distances, pressures and traverse speeds was analyzed through experiments. The problem of quantifying the decoating rate was solved by the introduction of picture processing. The tested materials were taken pictures and then distinguished between the original coating and the exposed matrix by different colors. The actual cleaning area was then counted. The cleaning effect of each single factor was analyzed. At the same time response surface methodology was used for getting the combined cleaning effect of multi-factors. The law was analyzed for optimizing the cleaning process.When remanufacturing parts were cleaning by high-pressure waterjet, the strong impact force would influence the surface quality. For researching the intensity of the influence, the white light interferometer was used to observe the change of the steel surface roughness and damage after cleaning. A specific shape of hole was found and its morphology was analyzed. The research results could be used to provide projects selection and theoretical and technical support for high-pressure waterjet applying in remanufacturing cleaning.