Pingxiang Cao

Tribological Properties of Ceramics Tool Materials in Contact with Wood-Based Materials

Tribological properties of ceramic cutting tool materials in contact with wood based materials were studied in this paper by examining how Al2O3-ceramics and Si3N4-ceramics behave in dry sliding experiment in contact with wood-based materials and by comparing their behavior with tungsten carbide material at the same time. It had been found that the ceramics exhibited much better tribological properties than tungsten carbide material, and Si3N4-ceramic performed better than Al2O3-ceramics. The Al2O3-ceramics with an addition of ZrO2 had better tribological performance than the common Al2O3-ceramics in contact with wood-based materials. The tungsten carbide had better tribological performance than ceramics in tribological contact with wood flour/PE material. A well-marked difference occurred in various cutting materials/MDF frictional pair, but the differences in various cutting materials/PB frictional pair were insignificant. An increase of the normal force didn’t result in any significant decrease of the friction coefficient. An addition of ZrO2 in the Al2O3-ceramics could inhabit corrosive wear.

The cutting performance of Al2O3 and Si3N4 ceramic cutting tools in the milling plywood

ABSTRACT This research focuses on the cutting performance of Al2O3 and Si3N4 ceramic cutting tools in up-milling plywood, the results of which are as follows. First, whether the tool material is Al2O3 or Si3N4 ceramic, the cutting forces at low-speed cutting were less than those at high-speed cutting, and the machining quality at low-speed cutting was greater than that at high-speed cutting. Then, whether at low- or high-speed cutting, the cutting forces of Al2O3 cutting tools were higher than those of Si3N4 cutting tools, and the machining quality of plywood milled by Al2O3 ceramic cutting tools was poorer than that milled by Si3N4 ceramic cutting tools. Finally, Si3N4 ceramic cutting tools were more suitable to machine the wooden productions with much glue content than Al2O3 ceramic cutting tools for the better machined quality.

Machinability investigation in turning of high density fiberboard

A series of experiments were conducted to assess the machinability of high density fiberboard using cemented carbide cutting tools. The objective of this work was to investigate the influence of two cutting parameters, spindle speed and feed per turn, on cutting forces, chip formation and cutting quality. The results are as follows: cutting forces and chip-breaking length decrease with increasing spindle speed and decreasing feed per turn. In contrast, surface roughness increases with decrease of spindle speed and increase in feed per turn. Chips were divided into four categories based on their shape: dust, particle, splinter, and semicontinuous chips. Chip-breaking length had a similar tendency to the variance of cutting forces with respect to average roughness and mean peak-to-valley height: an increase in the variance of cutting forces resulted in increased average roughness and mean peak-to-valley height. Thus, high cutting speed and low feed rate are parameters suitable for high-quality HDF processing and will improve not only machining quality, but production efficiency.

Cutting forces and chip formation revisited based on orthogonal cutting of Scots pine

Abstract The objective of this study was to understand better the cutting forces and chip formation of Scots pine (Pinus sylvestris L.) with different moisture contents (MCs) and machined in different cutting directions. To that end, an orthogonal cutting experiment was designed, in which Scots pine was intermittently machined using a tungsten carbide tool to produce chips. The cutting forces were measured and the chip shapes were quantitatively described. Four conclusions can be drawn: (1) with increasing MC, the average cutting forces initially decreased and then stabilized, while the angle between the direction of the main and the resultant force continuously decreased. (2) The average cutting forces in the 90°–0° cutting direction were lower than the same forces in the 90°–90° cutting direction. (3) During machining, the dynamic cutting forces fluctuated less in the 90°–0° case. However, the dynamic feeding forces showed a decreasing trend in both the 90°–0° and the 90°–90° cases. (4) The process applied produced granule chips and flow chips, while less curly flow chips with a higher radius of curvature were more easily produced from samples with high MCs in the 90°–0° cutting direction.

Architectural (decorative) natural fiber composites for construction

Natural fiber composites, such as fiberboards, have been frequently used in construction due to their good physical and mechanical properties, as well as their dimensional stability. However, the industrial applications are restricted to a certain extent due to the raw surface or quality of surfaces. Surface decoration/treatments, as a secondary processing for fiberboard, which is essential to avoid these original self-defects, have been researched and developed for many years. With surface decoration, the value and applications can be significantly increased. This chapter presents the technology of surface laminating and finishing, including the flat lamination, roll flat laminating with polyurethane reactive hot melt (PUR), thermal forming, wrapping and surface finishing, and printing, discussing their principles, technological processes, technological parameters, and typical production lines. A possible industrial application of the decorated composites is also investigated.