Investigation of the Effect of the Front Angle on the Strength of the Cutting Wedge by Photomecanics

Stress-strain state of cutting wedge models is evaluated by photomechanics method in the work. Models are made of optically sensitive organic glass of ED-6 grade. The aim of the study is to improve the method of selecting geometric parameters of the cutting wedge based on experimental data from photomechanics. The effect of the face angle on the strength of the cutting wedge was considered.

Kinematic analysis of involute hob cutter with rotary hard-alloy rods

A design of a hob cutter for cylindrical cog-wheel finishing is considered. In view of that the values of geometrical parameters specified by a designer are not preserved during hobbing (gear milling) there was carried out a kinematic analysis, which has shown that the values of geometric parameters change in the course of motion, but they do not transgress the bounds of acceptable ones. There is presented the analysis of the value impact of a static front angle upon angles of cutting. The technical solution offered allows increasing the accuracy of cog-wheel machining and decreasing hard alloy consumption.

Freckle formation and prevention in high strength low alloy steel ingots

Freckles considerably limit the development of larger electro-slag remelting (ESR) ingots. To simulate the freckling conditions in ESR ingots, high-strength low alloy (HSLA) steel was solidified with varying solidification front angles. Note that the freckling potential is enhanced and the orientation of freckle channel tends to be in the vertical direction with increase in solidification front angle. This is because the tilted solidification front contributes the available buoyancy and transports light (Si, Mn, Cr)-enriched liquid flows upwards toward the mush zone and then accumulates in the open segregation channel. For freckle formation in experimental HSLA steel ingots, a modified Rayleigh number (Ra) that considers the anisotropy of permeability and solidification front angle was evaluated and a threshold value of Ra that separates the freckled and freckle-free area was determined to be 0.79.

TECHNOLOGICAL PROCESS OF PROCESSING COMPOSITES USING THE DEVELOPED DESIGN OF THE CUTTER FOR ROUGH TURNING

The article considers the technological process of mechanical processing of composite materials. The characteristic of composite materials and their physical and mechanical properties is given. The rationale for the need to improve the design of the cutting tool is given. The design of the cutting head has been developed for the cutting process. It consists of a rough and finishing incisors. To determine the optimal geometry of these incisors, 20 incisors of each type were manufactured with a modified geometry. Experiments with changing the values of the back and front corners were carried out. Recommended minimum front angle values for soft and hard materials. The radius of rounding of the roughing tool is recommended. The technological process of processing composite materials is given. The design of the roughing tool is described in detail, which largely eliminates the disadvantages of processing, increases productivity, improves quality, and increases durability.

Interrelation between Shearing Angles of External and Internal Friction during Chip Formation

The aim of this work is to develop a methodology for graphically analytical calculation of angles of chip formation process for the case when the initial data are reliable empirical dependencies for the cutting forces’ components and value of shearing angle are obtained experimentally. The research method is based on the application of the elements of cutting theory with respect to flow chip formation scheme and the model of plastic deformation of metal with one slip surface with free cutting without a build-up on the front surface of the blade. Academic novelty is characterized by the developed algorithmic model which is based on the interrelation of shearing angles, external friction-slip chips on the front surface of the blade, internal friction-shear in the plane of shear and the front angle of the blade. The algorithmic model is implemented programmatically in the NI LabVIEW environment and graphically analytical in the KOMPAS-3D program. There were carried out computer experiments and identified the dependencies of chip formation angles on cutting speed and the front angle of the blade. The practical significance consists in the possibility to carry out an engineering analysis of the metal cutting mechanics without carrying out some valuable complex experiments.

Postural and Load Distribution Asymmetries in Preschoolers

<p>The aim of the study was to investigate the postural and load distribution symmetries in preschool children. The sample consisted of 67 preschool children with a median age of 54.00 ± 5.06 months. Postural parameters such as the horizontal alignment of the head, the acromion and Antero Superior Iliac Spines (ASIS), the angles between the acromial and ASIS, frontal, Q, knee and ankle and horizontal asymmetry of the scapula in relation to T3 were evaluated by photogrammetry. The baropodometry was used to identify the distribution of plantar pressure, while the medial arch of the foot was analyzed by photographic image. The median, standard deviation and the symmetry ratio were calculated for each parameter considered symmetry values greater than 90%. The Pearson’s or Spearman’s correlation were used between the parameters analyzed. There was asymmetric for postural and load distribution parameters for both genders and a null correlation between the symmetry of the surface and foot morphology and negative weak correlation significant between of the load foot and the front angle of the lower limb symmetries. The presence of asymmetries, postural and/or of load distribution, observed in early childhood suggest the importance of monitoring the postural and foot load parameters in the long term, preventing future postural and biomechanical alterations.</p>