Increasing the Efficiency of Food Material Cutting during Inclined and Shear Movements of Knife

Mathematical models for predicting the resistance forces that are developed during the inclined and sliding cutting of food materials have been developed. The dependence of the actual cutting angle on the angle of inclination and sliding speed of the cutting edge at various sharpening angles have been investigated. For the inclined cutting mode, the dependence of the useful resistance force on the cutting speed has been determined at various angles of inclination of the cutting edge and designed sharpening angles. For the sliding cutting mode, the dependence of the useful resistance force on the feeding speed has been demonstrated at various sliding speed values and designed knife sharpening angles. The dependence of the transformed dimensionless sharpness of the knife on the angle of inclination of the cutting edge and the sliding speed has been established for different constructional sharpness values of the knife. The results of the study indicate that the useful resistance force is significantly reduced during the inclined and sliding cutting processes when compared with the normal cutting process, and a change in the pattern of fiber destruction, which significantly increases the cutting efficiency of cutting tools, is obtained.

A Critical Review on Optimization of WEDM Process Using Taguchi Array

Wire electrical release machining (WEDM) innovation has developed at special case rate since it was first applied over long term prior.WEDM is a widely recognized unconventional material cutting process used to manufacture components with complex shapes and profiles of hard materials. In this thermal erosion process, there is no physical contact between the wire tool and work materials. Wire Electrical Discharge Machining (WEDM) is getting more tasks in fields like dies, punches, aero and many more. It is the very difficult task to get optimum process parameters for higher cutting efficiency. In WEDM process rough machining gives lesser accuracy and finish machining gives fine surface finish, but it reduces the machining speed. This review involves process, principle, literature and applications of WEDM using Taguchi array. Keywords: WEDM; Materials; Machine; Cutting efficiency; Optimization process.

DEVELOPMENT OF A MACHINE FOR CHOPPING WOOD RESIDUES

CAD software and FEM analysis were used to modify the drum of threshing machine into machine for chopping wood residues. The operating parameters that affecting the performance of the chopping machine are drum speed (450, 1000 and 1200 rpm), three stages of serrated disk arrangement clearance between drum flail knives (0.7, 1.5 and 3 cm) and three levels of feeding capacity (W1 􀵌 300, W2 = 360 and W3 = 420 kg.h-1). The developed machine was operated by the addition of two types of knives (sharp free knives + serrated discs) to the original knife existing already in the machine. The machine was evaluated in terms of production capacity, cutting efficiency, power requirements and energy consumption. Using the modified (serrated) saw disk mill and flail knives reduced the energy requirement for chopping and raised fine degree of the chopped materials and solve the clogging problem. The cutting productivity and cutting efficiency raised with reducing the clearance between flail knives (0.7, 1.5 and 3 cm) while the power requirements and energy consumption reduced.

An investigation into the cutting efficiency of a novel degradable glass as an alternative to alumina powder in air abrasion cutting of enamel

Objectives To develop and test the cutting efficiency of a novel degradable glass as an alternative media to alumina powder for air abrasion. Materials and methods A zinc-based glass (QMZK2) was designed, produced, and evaluated with a multi-modality imaging analysis. The glass dissolution study was carried out in three acids, using ICP-OES (inductively coupled plasma optical emission spectroscopy) at 5 different time points: 2.5, 5, 10, 60, and 240 min. The cutting efficiency of both materials was tested under the same parameters on slabs of elephant enamel. A stained fissure of a molar tooth was air abraded with the glass and evaluated with X-ray micro-tomography before and after air abrasion. Results The particle size distribution of the glass was similar to that of alumina 53 µm but with a slightly greater dispersion of particle size. The shape of the particles was angular, appropriate for cutting purposes. The dissolution study showed that the glass dissolved rapidly in acidic conditions at all time points. Between the two variables, pressure and powder flow, pressure was found to influence the cutting speed to a greater extent than powder flow. Conclusions Alumina powder was found to perform significantly better in 4 of the 9 conditions tested on elephant enamel, QMZK2 in one, and no significant differences were found for the rest of the 4 conditions. The QMZK2 seems to offer promising results as an alternative material to alumina. Clinical relevance. QMZK2 glass has the potential for replacing aluminum oxide as a degradable material in air abrasion technology.

EFFECT OF VARIOUS STERILIZATION AND DISINFECTION PROTOCOLS OF TOOTH PREPARATION BURS ON THEIR CUTTING EFFICIENCY AND THEIR RELATION TO THE SURFACE ROUGHNESS OF TOOTH PREPARATION – AN INVITRO STUDY

AIM: This study aims to evaluate the effect of sterilization and disinfection of rotary diamond burs on their cutting efciency and their relation to their surface roughness. A total of 12 (n=12) burs and acrylic typodont teeth of (n=36) were taken MATERIALS AND METHODS: which consists of Diamond TF-13 (MANI) (n=6) and Tungsten carbide bur 169L bur (Prima Dental, Prima Classic) (n=6). These burs were divided into 6 groups. Each group consists of Sub Groups A & B. Sub Group A in each Group Contains Diamond TF-13 (n=1) and Sub Group B in each group contains Tungsten carbide bur 169L bur (n=1). Each single Group is subjected to different methods of sterilization and disinfection with Autoclave, Hot air oven, Ultrasonic, Glass bead, Chemical Disinfection (KORSOLEX) after the tooth preparation. Samples of crown preparation were prepared by placing the mounted tooth on a Modied Milling Machine. After each use, these diamonds and burs were sterilized for 3 cycles of tooth preparation simultaneously and the tooth were evaluated for the surface roughness with a surface prolometer and the resultant values were noted and statistically analyzed. The burs were evaluated for the surface quality under Stereomicroscope and scores were given from 0 to 5 according to the grits and wear present on the surface of the burs. Diamond rotary burs CLINICAL SIGNIFICANCE: should be sterilized and disinfected as it has become a mandatory protocol for the dental professionals to prevent cross-contamination and cross infection between the dentist and dental personnel. However, different sterilization and disinfection methods can have undesirable effects on the ability of the burs to effectively reduce the tooth structure. Irrespective of the type of bur and sterilization process used, the cutting efciency decreases after multiple usage of the burs.

Digital Generating Method for Cylindrical Helical Gear based on Indexable Disk Milling Cutter

To solve the problem of low efficiency in digital generating machining for producing small or medium batches of helical gears, a method to improve the machining efficiency with an indexable disc milling cutter is presented in this paper. First, the mathematical model of the tooth profile and the indexable disc milling cutter are established. Second, according to the spatial free-form envelope theory, the overall planning scheme of the tool path is given; the relative position and the relative transformation matrix of the tool and tooth profile during digital generating machining using the indexable disc milling cutter are solved, the simulation cutting and actual cutting experiments are conducted, and the cutting efficiency per unit time and cutting simulation time of the two tools under the same deformation conditions is obtained through a finite element analysis experiment. The results show that the cutting efficiency of the indexable disc milling tool was 2–3 times higher than that of the end mill cutter.