Examination of wood adhesive bonds via MicroCT: The influence of pre-gluing surface machining treatments for southern pine, spotted gum, and Darwin stringybark timbers

The successful manufacturing of glulam from several important Australian commercial timbers is quite challenging due to difficulties in gluing. Improvements in adhesive bond performance of spotted gum, Darwin stringybark, and southern pine timber have been achieved using alternative pre-gluing surface machining methods, e.g., face milling and sanding-post planing, when compared to conventional planing methods. In order to improve the understanding of the effects that different surface machining methods have on adhesive bond performance, this study used micro X-ray computed tomography and microscopy to assess key adhesive bond criteria. There was a considerable loss in the amount of adhesive after the wet and dry test cycles for all species. There was also an extremely high frequency of voids in the glue lines for all species, which would negatively impact bond strength and durability. Face mill prepared timber boards resulted in thicker glue lines and greater resistance to adhesion loss, compared to boards prepared via planing. For the two hardwood species, face milling also resulted in greater adhesive penetration; however, for southern pine, there were no significant differences in adhesive penetration between the three surface machining treatments. Adhesive penetration was much deeper in southern pine compared to spotted gum and Darwin stringybark.

Structural improvement of face mills designs based on systems approach

The article is devoted to the designs improvement of face mills with round inserts on the basis of a systems approach. The increasing a cutting efficiency with face mills is provided by improving their designs in the following aspects: increasing the tool life, accuracy and productivity, improving the quality of the machined parts surface. Analysis of the operating conditions of the milling cutters is carried out element by element (body, shank, inserts and their location, etc.), these components are considered as one system. The technological system (machine, holder, workpiece, tool) is presented as a supersystem, which is under the influence of active, intermediate acting, reactive and derivative factors. The article decomposes into elements (cutting, body, base and fastening parts) of a standard face mill with round inserts and performs their system analysis relatively the occurrence of adverse cutting conditions. On the basis of this the scheme of structural improvement aspects of face mills designs is developed. As a result of structural improvement and variants synthesis, the authors propose concepts of face mills designs for different machining conditions.

Processing the Working Parts of Tools Used in Construction Industry Using High Energy Methods

This paper considers the effect of hardening of throwaway cutting inserts made of hard alloy T15K6 using continuous laser impact at various modes. Tests were carried outon inserts made of hard alloy T15K6. The cutting properties of the inserts were determined by cutting on a T612 vertical milling machine. A face mill with a diameter of 100 mm with mechanical mounting of tested inserts was used as a tool.Dry milling was performed using two inserts. At that, cutting mode was of impact natureas the mill diameter was larger than the width of machined workpiece. Number of passes – 5. Cutting modes:v = 197 m/min, h = 1 mm, S = 160 mm/min, b = 90 mm. Machiningwasperformedonworkpieces made of 40X grade steel (GOST 4543-71). Workpiecedimensions– 160x60x90 mm. During the machining, hard alloy inserts moved beyond the workpiece edge and cut into it from the other side. One of the main performance characteristics of hard alloys is material rigidity (modulus of elasticity, Е). Tests were carried out after various types of laser impact at bending and material rigidity was determined by strain gauging. Decreasein the slopeofstraight-lineportionofrelativestrain-versus-stress curve at bending indicates the decrease in hard alloys’ modulus of elasticity after laser processing. Small defect structure is being formed.

A Survey on the Effects of Cutting Parameters on Surface Roughness When Milling 40Cr Steel Using End Mill Cutter

In this paper, the empirical research on the effects of cutting parameters on surface roughness when milling 40Cr steel with face mill is conducted. The cutting parameters in this study include the cutting speed, feed rate and depth of cut. The tests are conducted in the form of Central Composite Design. The analysis shows that, for both Ra and Rz: (1) the feed rate has the greatest effect on surface roughness, followed by the degree of influence of the depth of cut, cutting speed with insignificant effects on surface roughness. (2) only the interaction between the feed rate and depth of cut have a significant effect on both Ra and Rz; the interaction between the cutting speed and feed rate, the interaction between the cutting speed and depth of cut have negligible effects on the surface roughness. In addition, the regression equations showing the relationship between Ra, Rz and cutting parameters is developed in this study.

Effect of the Relative Position of the Face Milling Tool towards the Workpiece on Machined Surface Roughness and Milling Dynamics

In face milling one of the most important parameters of the process quality is the roughness of the machined surface. In many articles, the influence of cutting regimes on the roughness and cutting forces of face milling is considered. However, during flat face milling with the milling width B lower than the cutter’s diameter D, the influence of such an important parameter as the relative position of the face mill towards the workpiece and the milling kinematics (Up or Down milling) on the cutting force components and the roughness of the machined surface has not been sufficiently studied. At the same time, the values of the cutting force components can vary significantly depending on the relative position of the face mill towards the workpiece, and thus have a different effect on the power expended on the milling process. Having studied this influence, it is possible to formulate useful recommendations for a technologist who creates a technological process using face milling operations. It is possible to choose such a relative position of the face mill and workpiece that will provide the smallest value of the surface roughness obtained by face milling. This paper shows the influence of the relative position of the face mill towards the workpiece and milling kinematics on the components of the cutting forces, the acceleration of the machine spindle in the process of face milling (considering the rotation of the mill for a full revolution), and on the surface roughness obtained by face milling. Practical recommendations on the assignment of the relative position of the face mill towards the workpiece and the milling kinematics are given.