The effect of alternative cutter paths on flatness deviations in the face milling of aluminum plate parts

In this paper the relationships between the alternative machining paths and flatness deviations of the aluminum plate part, were presented. The flatness tolerance of the main surface of the plate part has crucial meaning due to the assembly requirement of piezoelectric elements on the radiator. The aluminum bodies under investigation are the base part of the radiators with crimped feathers for the train industry. The surface of the aluminum plate part was milled using three different milling strategies: along of longer or shorter side of workpiece and at an angle of 45°. The aluminum bodies were machined on milling centre ecoMILL 70 DMG MORI. The flatness deviation measurements were carried out on the Coordinated Measuring Machine Altera 7.5.5 Nikon Metrology NV. These measurements were made during the manufacturing process of the radiator, namely after machining, however, before the process crimping of feathers. The results that were obtained enables the validation of assumed milling path strategies in connection of the subsequent machining and assembly processes

Coupling of Local Wood Properties Extracted from X-ray Computed Tomography with Cutting Force

While X-ray computed tomography (CT) is used extensively in sawmills, its primary applications are improving value-yield and process automation. Three-dimensional CT scanners have also been extensively used for log sorting and sawing optimisation. However, there is hardly any resent research utilising CT from a cutting process perspective. This study addresses this gap by adopting CT to investigate the correlation between local wood properties — namely density, knots and annual rings — and cutting forces. Cutting forces for clear-wood and knotty-wood specimens of Scots pine (Pinus sylvestris L.) followed the expected trend corresponding to the density profile: dense regions led to high cutting force while other regions caused low cutting forces. However, it was found that in addition to density, knot orientation relative to cutting direction, annual ring width along the cutting path, and annual ring angle in relation to the cutting direction were critical factors that influence the cutting process. This study illustrates the feasibility of coupling local wood properties obtained from CT data with cutting force, potentially inspiring further research on a variety of wood property/cutting force relationships.No fulltext license, permission to publish fulltext recieved separately.</p

Cutting Forces for Clear and Knotty Pine Wood

Sawmill managers are interested in carrying out the sawmilling process in an efficient manner with minimal waste of raw material. In primary processing, an increase in productivity can be achieved if the process can be controlled. This can be achieved by developing a macro-mechanic model of the cutting power determination considered from a point of view of modern fracture mechanics has been developed. For the model knowledge about fracture toughness and shear yield stresses is vital. Pine wood (Pinus sylvestris L.) is a popular species which is widely used in wood industry in Poland and Sweden. Test samples with a cross section of 70 × 70 mm were originated from the both countries. Before sawing, all wood samples were scanned on X-ray Computed Tomography in laboratory conditions in Skellefteå (Sweden). These CT scans were helpful in indicating where clear and knotty samples were obtained from beams. Cutting tests were carried out on the custom-made laboratory stand in Skellefteå. The rotating arm held the wood sample, and the cutting speed equaled 15.5 ms−1. A stellite tipped tooth was fed into the wood sample with uncut chip thicknesses for clear wood 0.5; 0.7 and 1.1 mm, and for knotty wood 0.3; 0.5 and 0.7 mm. The tooth data: overall set equal to 2.9 mm, rake angle 27°, and clearance angle 12°. A piezoelectric sensor on the tooth holder measured the cutting forces. On the basis of the experimental findings it is possible to create mathematical models cutting forces for clear and knotty pine wood. For knotty wood the intercept is almost twice than for clear wood.No fulltext license, permission to publish fulltext recieved separately.</p