Jozef Mihok

Experimental Study of Surface Roughness of Wood Plastic Composites after Turning

In this study, surface characteristics of the samples of experimentally manufactured woodplastic composites (WPC) were determined. Turning process was used to produce surfaces by removing material from a rotating workpiece. For turning, the rotation speed, feed, and depth of cut determine the rate of material removal and resulting surface quality. The surface roughness is one of the most important factor affecting coating performance of the WPCs. Parameters of surface roughness (final micro-geometric characteristics Ra, Rz) of the samples was determined using a stylus-type profilometer Surftest SJ 401. This information will provide baseline data on the quality of WPC samples after turning.

The Use of SMED in Engineering Manufacturing

To survive in such an increasingly competitive world, there is a need of continuous improvement in every type of industry. An answer to these challenges for manufacturing companies is the implementation of lean concepts. The importance of short changeover times, SMED, has always been critical for manufacturing companies. It is one of the many lean production methods for reducing waste in the manufacturing process. Its a quick and effective way adjustment process of the actual product to another product. The practical part is focused on usage of SMED in manufacturing. Project was realized in engineering company oriented on machining heavy products. Separating time to external and internal we saved about 10% of total production time. The result is proposal timetable of standard changeover process. Also timetable of two pieces in batch, because insertion two pieces in the batch reduced the total time of production. Total time was reduced of two changeovers.

Non-Destructive Testing of Inhomogeneity of Wood Plastic Composite

The purpose of this study is to investigate of Non-Destructive Testing of Wood Plastic Composite (WPC), where the axis errors are mainly cracks caused by not change of cutting conditions (cutting speed and feed rate), respectively geometry of he cutting tool, but their imperfect encapsulation of wood with plastic (HDPE). Detection of surface defects was used visual inspection, colour penetrate test and fluorescent penetrate method. To detect internal defects was used X-ray. Pictures taken with a digital microscope camera does not provide sufficient information about internal defects, captures only the surface and as a result it is postulated that the cracks are spreading along the length of the profile extrusion axis (it is not possible to state their course in different layers – cross section along the thickness). Solution is use of the new technology – connection of metrology and tomography – metrotomography (X-ray scanning).

The Chip in the Up and Down Milling Process

The milling is the most used technology in engineering. The shape of chip is important for its transport and for economical aspect of this technology. The volumetric coefficient of chip represents the shape of chip. The small chip has a lower volumetric coefficient, but the very small chip is not very desired in the machining, because it can damage the machine. The main aim of this contribution was monitoring of chip in the milling process by high-speed camera and consequently the evaluation of this chip by the volumetric coefficient of chip. This coefficient was monitoring in the peripheral up and down milling with the different radial cutting depth.