Comparison of measured and calculated values of cutting forces in oak wood peripheral milling

The aim of investigations was to determine whether the tested models for calculating forces in wood cutting, set up under strictly controlled laboratory conditions, can yield sufficiently accurate results for predicting wood behavior in real cutting conditions. Tests were carried out on oak wood (Quercus robur). On the basis of measured values for the required cutting power, cutting forces were calculated and used for comparison by applying the method of coefficient (Kršljak’s model) and Axelsson’s model. The analysis indicated that there is not a result, but there is similarity in the curve shape, i.e. changes in measured values are followed by corresponding changes in calculated values. It can be inferred that analyzed models are not suitable for the cutting forces quantification, but could serve for comparing different cutting modes. More accurate modeling of the cutting process requires, besides physical, wood mechanical properties as well.

Research on cutting performance of ceramic cutting tools in milling high density fiberboard

The effect of cutting parameters and tool parameters on cutting forces and tool wear were investigated in high density fiberboard (HDF) peripheral up-milling using toughened ceramic cutting tools. The results showed that whether at low speed cutting or high speed cutting, the tangential forces Ft and normal forces Fr increased slowly with the increase of cutting length. The tangential forces Ft and normal forces Fr at low speed cutting were higher than that at high speed cutting. The tangential forces Ft and normal forces Fr decreased with the decrease of wedge angle in the same rake angle. Then, the effect of high cutting speed on the flank wear was greater than that at low cutting speed. The bigger wedge angle tools led to the serious flank wear. The main wear pattern in milling HDF consisted of pull-out of the grain, flaking, chipping and cracking, the main wear mechanism were adhesive and abrasive wear.

Analysis of cutting performance in high density fiberboard milling by ceramic cutting tools

In order to study the cutting performance of TiC reinforced Al2O3 ceramic cutting tools in milling high density fiberboard, the effects of cutting parameter on the cutting forces, tool wear and cutting quality were investigated. Under the condition of same average chip thickness, feed per tooth and geometry angles, firstly, the change rate of maximum cutting forces were higher than that of average cutting forces at two different cutting speeds, and the cutting forces at high speed cutting was less than that at low speed cutting. Secondly, the flank wear at high speed cutting was more pronounced than that at low speed cutting, whose abnormal wear were pull-out of grain, cracking, chipping and flanking. Thirdly, the machining quality at high speed cutting was better than that at low speed cutting. Fourthly, the tendencies of cutting forces, tool wear and surface roughness relative to cutting length were similar, but the change rates were different, especially at the initial stage. Finally, high speed cuttingare plausible to use in HDF processing, which not only improves machining quality, but also promotes production efficiency.

Cutting forces in quasi-orthogonal CNC milling

The paper is focused on the analysis of cutting forces in milling of MDF on the CNC machine (SCM Tech 99 L, SCM Group, Italy). The measurement of the forces was realized by a three-axis piezoelectric dynamometer Kistler 9257B (Kistler Holding AG, Switzerland). The forces were examined and analysed during quasi-orthogonal milling with a single-edged blade. The resulting forces were compared to each other depending on the conventional and climb milling of the edge of the MDF at changing feed speeds from 1.5 to 4.5 m∙min-1 with steps of 0.75 m∙min-1. The experimental values of cutting forces were also used for the first assessment of the fracture toughness and shear yield strength, main parameters of computational model based on Ernst-Merchant theory and on fracture mechanics. These values were input data for the calculation of the specific cutting resistance for CNC machining. The experimental data confirmed that the cutting force increases and the specific cutting resistance decreases with the increasing chip thickness.

Determination of maximum torque during carpentry waste comminution

In order to elaborate design guidelines for developing efficient and possibly most energy saving mills for comminuting carpentry, OSB and MDF waste, there have been performed some tests aimed at torque demand on the working unit of the machinery participating in that process. The tests were carried out on a cylindrical wood chipper. There were indicated the maximum, minimum and average values of the torque, indispensable for the comminution of boards with defined geometric sizes (5 – 50 mm wide ) and thickness (3 – 28 mm). The value of torque required in the comminution of carpentry waste increases with growing cross section, and the torque vs. cross section relation is approximately linear. The presented values may constitute not only a set of input data indispensable for modeling the power which is necessary for the comminution process, but they can also enable the validation of the existing cutting models with a single cylinder cutter.