Abstract
Exterior car-body parts are made of steel or aluminum sheets. Their formability and appearance after painting depends not only on the mechanical properties but also on their surface texture. The surface roughness characteristics, the roughness average Ra and the peak count Pc per centimeter depend on the texture of rolling mill’s finishing rollers, their wear and the degree of removal by the rolling mill. The research was carried out on heat-treated finishing rollers on the surface of which a controlled texture was created by changing the electro-discharge texturing (EDT) parameters. Parameters and the number of electro-discharge texturing experiments were optimized using full four-factor experiment techniques at the upper and lower levels of the parameters in the form of 24. The significance of the impact of individual EDT parameters and their interactions was identified based on the variance results. The ANOVA variance analysis results confirmed that the roughness Ra and the peak count Pc depend primarily on peak current (Ip), discharge peak voltage (Up), pulse on time (Pont) and pulse off time (Pofft). Optimization of the effect of the above parameters on the target roughness RaT,FR values and the peak count PcT,FR of finishing rollers was performed by the response surface methodology (RSM). Obtained regression models describe relationships between the input parameters of the electro-discharge texturing of finishing rollers and the output characteristics of the RaT,FR and the PcT,FR texture to a very high degree. The reliability of the electro-discharge texturing process of working rollers was assessed using the process capability index Cpk.
Highlights
When presented with a choice of similar products sold at a similar price on the market, the customer often makes a choice based on their quality
The main aim of this paper was to obtain optimized electro-discharge texturing parameters of rolling mill finishing rollers for surface texture finish values ranging from RaT,FR = 1.539 to RaT,FR
The research involved a sample of 48 pieces of finishing rollers (i.e., 16 for each level of parameters), the surface of which was subjected to texturing by the EDT 2100/4500 device in a BP250 oil dielectric with eight copper electrodes at varying levels of input parameters of electro-discharge texturing (EDT), creating textures with the target roughness values RaT,FR1 = 1.538 μm, RaT,FR2 = 2.5 μm and RaT,FR3 = 3.8 μm and the peak count PcFR1 = 158 cm−1, PcFR2 = 99 cm−1 and PcFR3 = 68 cm−1
Summary
When presented with a choice of similar products sold at a similar price on the market, the customer often makes a choice based on their quality. Mechanical blasting of working rollers results in a stochastic texture creation, which cannot be controlled For these reasons, use of stochastic systems of texturing finishing rollers by the method of shot blast texturing has been abandoned in favor of deterministic texturing systems: electric discharge texturing (EDT), laser beam texturing (LBT), electron beam texturing (EBT) or the Topocrom method [4,5,6,7]. Electro-discharge texturing (EDT) can produce a wide range of RaFR roughness from 0.5 to 10 μm with a PcFR peak count up to cm−1 , with a uniform microrelief surface, good reproducibility of the surface texture of the finishing roller and its transfer to the sheet surface [7]—Table 1. By optimizing the input parameters of these processes, it is possible to control the process of texturing the finishing rollers to meet the ever-increasing surface quality requirements of sheets intended for bodywork parts
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
