Experimental tests of PVD AlCrN-coated planer knives on planing Scots pine (Pinus sylvestris L.) under industrial conditions

Abstract

Raw pine wood processing and especially its mechanical processing constitute a significant share among technological operations leading to obtaining a finished product. Stable implementation of machining operations, ensuring long-term repeatable processing results depends on many factors, such as quality and invariability of raw material, technical condition of technological equipment, adopted parameters of work, qualifications and experience of operators, as well as preparation and properties of the machining tools used. It seems that the greatest potential in the search for opportunities to increase the efficiency of machining operations has the modification of machining tools used in it. This paper presents the results of research work aimed at determining how the life of cutting tools used in planing operations of wet pine wood is affected by the application of chromium aluminum nitride (AlCrN) coating to planar industrial planing knives in the process of physical vapour deposition. For this purpose operational tests were carried out under production conditions in a medium-sized wood processing company. The study compares the effective working time, rounding radius, the profile along the knife (size of worn edge displacement, wear area of the cutting edge), selected texture parameters of the planar industrial planing knife rake face and visual analyses of cutting edge condition of AlCrN-coated planar knives and unmodified ones. The obtained experimental results showed the possibility of increasing the life of AlCrN-coated knives up to 154% compared to the results obtained with uncoated ones. The proposed modification of the operational features of the knives does not involve any changes in the technological process of planing, does not require any interference with the machining station nor its parameters, therefore enabling rapid and easy implementation into industrial practice.

Influence of regeneration process parameters on geometry and defects of clearance surface of planer knives used in wood planing process

“…It was observed in the tests, however, that flattening (kurtosis, G2) is negative in most cases, which means that the distribution of the surface topography feature values is less concentrated than in a normal distribution. Only in the case 15 Selected topographic features of the tested surfaces in the form of contour maps, unevenness height distribution and the material ratio curve for the grinding process carried out with a CBN grinding wheel with B151 grains: a equivalent chip thickness h eq = 0.03 μm (Z' = 0.32 mm 3 /(m s)); b equivalent chip thickness h eq = 0.08 μm (Z' = 2.4 mm 3 /(m s)) ◂ of the parameter describing the surface total height of waviness (Wt), was a distribution obtained with a concentration very close to a normal distribution (for which excess kurtosis is equal to 0). However, considering that the calculated statistical test values for asymmetry (Z g1 ) and kurtosis (Z g2 ) mostly range between − 1.96 and + 1.96 (critical value of a normal distribution), the results can be considered acceptable evidence The following graphs (Figs.…”

“…This issue is the subject of numerous studies and scientific works. For example, the long-term use of planer knives leads to significant wear of the working edge, which can be described by cutting wear parameters, as worn edge displacement, nose width, rake face wear or the radius of the cutting edge [10,14,15]. Selected forms of wear, such as initial lapping, abrasive wear, cracking or chipping can be observed on the rake surface of the planer industrial planing knives with the use of microscopic observation and visual analysis.…”

“…Selected forms of wear, such as initial lapping, abrasive wear, cracking or chipping can be observed on the rake surface of the planer industrial planing knives with the use of microscopic observation and visual analysis. In some cases, wear in the form of cracks and material loss or abrasive wear may be so great that it requires an appropriate knife sharpening strategy [10,15], especially in the case of CrCN/CrN or AlCrN-coated planing blades. Those layers, formed by cathodic arc evaporation, have the critical force in the scratch test above 77 N and show HF1 class (according to Daimler-Benz test), which means they possess proper adhesion properties and are characterized by good wear resistance, as proved by an international team in [16,17].…”

“…Fig 15. Selected topographic features of the tested surfaces in the form of contour maps, unevenness height distribution and the material ratio curve for the grinding process carried out with a CBN grinding wheel with B151 grains: a equivalent chip thickness h eq = 0.03 μm (Z' = 0.32 mm 3 /(m s)); b equivalent chip thickness h eq = 0.08 μm (Z' = 2.4 mm 3 /(m s))…”

Effect of Pro-Ecological Cooling and Lubrication Methods on the Sharpening Process of Planar Blades Used in Food Processing

“… Test and measurement stands used in the described research: ( a ) five-axis CNC special grinder for sharpening technical blades; ( b ) special device for removing rewind from the blade after grinding; ( c ) position for contact measurements of surface texture equipped with a stylus profilometer Hommel-Tester T8000 by Hommelwerke GmbH, Villingen-Schwenningen, Germany [ 38 ]; ( d ) digital measuring microscope Dino-Lite Edge AM7515MT8A, AnMo Electronics Corporation, New Taipei City, Taiwan, China [ 39 , 40 , 41 ]; ( e ) special test stand for cutting force measurement. …”