The Use of a High-Pressure Water-Ice Jet for Removing Worn Paint Coating in Renovation Process

Abstract

The paper presents the results of investigations into the possibility of using ahigh-pressure water-ice jet as a new method for removing a worn-out paint coating from the surface of metal parts (including those found in means of transportation) and for preparing the base surface for the application of renovation paint coating. Experimental investigations were carried out in four stages, on flat specimens, sized S × H = 75 × 115 mm, cut from sheet metal made of various materials such as steel X5CrNi18-10, PA2 aluminium alloy and PMMA polymethyl methacrylate (plastic). In the first stage, the surfaces of the samples were subjected to observation of surface morphology under a scanning electron microscope, and surface topography (ST) measurements were made on a profilographometer. Two ST parameters were analysed in detail: the maximum height of surface roughness Sz and the arithmetic mean surface roughness Sa. Next, paint coatings were applied to the specimens as a base. In the third stage, the paint coating applied was removed by means of a high-pressure water-ice jet (HPWIJ) by changing the values of the technological parameters, i.e., water jet pressure pw, dry ice mass flow rate m˙L, distance between the sprinkler head outlet and the surface being treated (the so-called working jet length) l2 and spray angle κ for the following constants: the number of TS = 4 holes, water hole diameter φ = 1.2 mm and sprinkler head length Lk = 200 mm. Afterwards, the surface morphology was observed again and the surface topography of the specimen was investigated by measuring selected 3D parameters of the ST structure, Sz and Sa. The results of investigations into the influence of selected HPWIJ treatment parameters on the surface QF removal efficiency obtained are also presented. Univariate regression functions were developed for the mean stripping efficiency based on the following: dry ice mass flow rate m˙L, working jet length l2 and spray angle κ. Based on these functions, the values of optimal parameters were determined that allow the maximum efficiency of the process to be obtained. A 95% confidence region for the regression function was also developed. The results demonstrated that HPWIJ treatment does not interfere with the geometric structure of the base material, and they confirmed the possibility of using this treatment as an efficient method of removing a worn paint layer from bases made of various metal and plastic materials, and preparing it for applying a new layer during renovation.

Possibilities of Rock Processing with a High-Pressure Abrasive Waterjet with an Aspect Terms to Minimizing Energy Consumption

“…Threefold repeatability of the tests was used. This task required the following steps to be conducted [ 17 , 60 ]: Determination of variability range of the studied parameters. Choice of the class of the mathematical model.…”

“…Ice particles are added to the high-pressure waterjet [ 7 , 8 , 9 , 10 ], along with solidified carbon dioxide particles CO 2 [ 11 , 12 ], or garnet, corundum or olivine [ 13 , 14 , 15 , 16 ]. High-pressure waterjets with dry ice admixtures CO 2 are mostly used for cleaning surfaces [ 17 ]. On the other hand, high-pressure waterjets with harder admixtures are used to cut and separate mainly flat titanium materials [ 18 , 19 , 20 ], heat-resistant steels [ 21 , 22 , 23 ], austenitic steels [ 24 , 25 , 26 , 27 , 28 ], aluminum alloys [ 29 , 30 , 31 , 32 , 33 ], copper alloys [ 34 , 35 ], plastics reinforced with different types of fibers [ 36 , 37 , 38 , 39 ] and glass or ceramics [ 40 , 41 , 42 ].…”

Possibilities of Rock Processing with a High-pressure Abrasive Water Jet with an Aspect Terms to Minimising Energy Consumption

“…Three fold repeatability of the tests was used. This task required following steps to be conducted [17,60] The average values of the outputs of the object E were approximated with a a polynomial of the second degree, obtaining the regression equation as two-parameter functions: ]. Using matrix calculus, the column vector {b} of the unknown coefficients in Equation ( 12) was calculated from the matrix formula:…”

“…(y = E ), y − average values of experimental results. The test results after statistical processing according to the algorithm presented in the study [17,60] were used to develop regression equations ( 15) and (16).…”

“…Ice particles are added to the high-pressure water jet [7  10], solidified carbon dioxide particles CO2 [11,12], or garnet, corundum or olivine [13  16]. High-pressure water jet with dry ice admixtures CO2 is mostly used for cleaning surfaces [17]. On the other hand, high-pressure waterjet with harder admixtures is used to cut and separate mainly flat titanium materials [18  20], heat-resistant steels [21  23], austenitic steels [24  28], aluminum alloys [29  33], copper alloys [34,35], plastics reinforced with different types of fibers [36  39] and glass or ceramics [40  42].…”