Research on baking soda media blasting technology for achieving the cleaner production for stripping PTFE coatings in food utensils remanufacturing process: FEM analysis and economic appraisal

Abstract

The efficient and environment-friendly stripping of damaged Polytetrafluoroethylene (PTFE) coatings is a committed procedure in the remanufacturing process of food utensils. A green and economically valuable baking soda media blasting technology that could meet remanufacturing roughness standards was proposed in this paper, aiming for avoiding the fluorine-containing solid waste disposal challenges and roughness mismatch of existing stripping methods. The compatibility between baking soda media blasting technology (2.0–3.4 μm) and remanufacturing process roughness standards (2.5–4 μm) was confirmed by comparing the stripping ability with other media (alumina, glass bead and walnut shell) at different blasting angles and pressures, and its efficient stripping process parameters (30° and 0.7 MPa), stripping rate (6.81 mm2/s) and cleanliness (The weight percentage of element F was 0.68%) were determined. Based on finite element model (FEM) analysis, the LSTC-dynamics (LS-DYNA) explicit dynamic solver was used to track the process of single particle eroding the coating to explore the extruding-plowing composite stripping mechanism of the stripping coating using the baking soda media blasting technology at the micro level. The discrete phase model (DPM) was used to track the process of particle beam impacting the coating to verify the variation law between the stripping area and blasting process parameters at the macro level. The PXRD and FT-IR test results of the recovered baking soda media and PTFE coatings showed no impurity peaks, confirming the feasibility of the baking soda media recovery project. Based on the economic appraisal by management accounting evaluation method, the introduction of the baking soda media recovery project could significantly reduce the process chain cost by 136852.62 ¥ per year. As a PTFE coating stripping technology that can completely solve the fluorine-containing solid waste disposal problem, the baking soda media blasting technology owns the advantages of non-pollution and low technical cost, which is expected to realize cleaner production of food utensils remanufacturing process in the future.