Pei Qi Ge

Study on Removal Mechanism of Fixed-Abrasive Diamond Wire Saw Slicing Monocrystalline Silicon

The physical model of fixed-abrasive diamond wire-sawing monocrystalline silicon was founded to analyze the elastic deformation of the wire, supposing that every grit was connected to the surface of the wire by a spring. Ignoring lateral vibration of the wire, the geometrical model of wire-sawing was founded; the average cut depth of single grit was calculated theoretically. Based the indentation fracture mechanics and investigations on brittle-ductile transition of machining monocrystalline silicon, the removal mechanism and surface formation was studied theoretically. It shows that in the case of wire-sawing velocity of 10m/s or higher, infeed velocity of 0.20mm/s and diamond grain size of 64μm or smaller, the chip formation and material removal is in a brittle regime mainly, but the silicon wafer surface formation is sawed in a ductile regime. The size of the abrasives, the wire-saw velocity and infeed velocity can influence the sawing process obviously.

Relationship between the Grit Cut Depth and Process Parameters in Electroplated Diamond Wire Sawing KDP Crystal

A wire-saw cut KDP crystal geometrical model was founded and a mathematical model was established to calculate the grit average cut depth, based on indentation fracture mechanics theory(IFMT). The relationship between the grit cut depth and wire saw process parameter was analyzed theoretically. The research results indicate that there exists an approximate monotone increasing non-linear correlation between grit average cut depth and the ratio i value of crystal feed speed and wire speed. By increasing the wire speed and crystal feed speed accordantly, the value of i can be maintained invariable, however, this way can simultaneously bring higher machined surface quality and machining efficiency.

Research on Endless Wire Saw Cutting of Al2O3/TiC Ceramics

This article investigates the cutting of Al2O3/TiC ceramics using a fixed abrasive diamond endless wire. The effect of wire speed and feed rate on material removal rate, cutting force, surface roughness and wire wear is investigated. The cut surface of Al2O3 /TiC ceramics is studied. This study demonstrates the advantage of fixed abrasive diamond endless wire cutting of Al2O3/TiC ceramics.

Analysis of Grit Cut Depth in Fixed-Abrasive Diamond Wire Saw Slicing Single Crystal Silicon

A mathematical model to calculate the grit average cut depth in wire sawing single crystal silicon was founded. So the grit average cut depths were calculated theoretically by choosing different process parameters, and influences of process parameters on grit cut depths of slicing silicon crystal were analyzed. Analysis results indicate that the grit average cut depth relates to the silicon mechanical properties, grit shape and size, wire speed and ingot feed speed, etc. And there is a monotone increasing non-linear correlation between grit average cut depth and the ratio i value of ingot feed speed and wire speed, when the i value is lower, the average grit cut depth is lower.

Experimental Investigation on Brittle-Ductile Transition in Electroplated Diamond Wire Saw Machining Single Crystal Silicon

Based on reciprocating electroplated diamond wire saw (REDWS) slicing experiments, a study on REDWS machining brittle-ductile transition of single crystal silicon was introduced. The machined surfaces and chips were observed by using Scanning Electron Microscope (SEM), and some experimental evidences of the change of material removal mode had been obtained. The experimental results indicate there is a close relationship between material removal mode and the ratio r value of ingot feed speed and wire speed, through controlling and adjusting the r value, the material removal mode can be complete brittle, partial ductile and near-ductile removal.

Investigation of Subsurface Damage Depth of Single Crystal Silicon in Electroplated Wire Saw Slicing

Based on reciprocating electroplated diamond wire saw slicing single crystal silicon experiments, a bonded interface sectioning technique was used to measure the silicon subsurface damage (SSD) depth, and the influences of wire saw speed and feed speed on silicon SSD were studied. Moreover, based on the indentation fracture mechanics (IFM) theory, a theoretical model of relationship between SSD and surface roughness (SR) was established for predicting the SSD depth by measuring the SR. The results indicate that SSD depth decreases with the wire saw speed increase and feed speed decrease, within the range of experimental technical parameters. There exists monotone increasing non-linear correlation between SSD depth and SR (Rz) in wire saw slicing single crystal silicon, that is, SSD－SR+χSR3/4. And the experimental measure values coincide with the theoretical prediction values comparatively, therefore, the theoretical model can be used for predicting SSD depth rapidly, expediently and accurately.

Performance Evaluation & Action Mechanism Analysis of Extreme Pressure Additives Used for Oil-Based Cutting Fluids

Although it is unexpected, pure mineral oils or machinery oils are still widely used as cutting fluids in many cases and areas. In this paper, the performanc e of extreme pressure (EP) additives, including Chlorinated Paraffin, Acid phosphate, and ZnDDP, was eva luated with the index of material removal ability and specimen hardness drop by the use of grinding test method. A micro-structure model of specimen surface layer under wet grinding c onditions was proposed, which could be used for explaining the boundary lubrication mechanism of cutting f luids. The characteristic was revealed that organizational structure and shearing strength of specimen surface layer at wet grinding conditions descended along the out normal line direction of the specimen surface. Ba sed on experimental research, high-performance oil-based cutting fluids we re d veloped and tested in several machine-building factories. The fluids one also expected to be appli d in the processing of natural rock materials, during which the friction between diamond tools and rock is the main barrier to increase processing efficiency.

The Numerical Simulation for Thermal Deformation in Grinding Hardening Thin Workpiece

The high temperature in grinding hardening induces workpiece thermal deformation. The thermal deformation causes a concavity on the ground profile and affects the grinding hardening depth. The paper uses ANSYS thermo-mechanical coupling module to simulate the thermal deformation in grinding hardening. The workpiece profile by simulated is compared with the test result.

Study on the Conical Spiral Tube Bundle Heat Exchangers with Pulsation Flow Generator Structure

Elastic tube bundles are universally used in heat transfer enhancement by flow-induced vibration in heat exchangers, and the study of the heat transfer performance is of importance. The structure of conical spiral tube bundle heat exchanger was introduced first, and the structure of pulsation flow generator was also introduced. The frequency of pulsation flow was discussed. Finally, in condition of same shell side diameter, the heat transfer and natural frequency of the conical spiral tube bundle were compared with the planar elastic tube bundle. The results show that the natural frequency of conical spiral tube bundle was smaller, the heat transfer performance of conical spiral tube bundle was better than the planar elastic tube bundle.

Study on Service Performance Evaluation of Grinding Coolants

Grinding coolants have the functions of cooling, lubrication, cleaning and rust prevention in grinding process. To avoid the environment pollution, we should develop environmental protection grinding coolants. So it is important to research the performance evaluation for grinding coolants. In this paper, three different test methods for grinding performance evaluation of grinding coolants are used to investigate the influence of three coolants on grinding process. The three test methods are four balls test, tapping torque test and real grinding test. The test results showed that the mechanism of four balls test is simple, and the test results have good repeatability, but there is a large divagation with real grinding test results. The tapping torque test has a good relativity with cutting process. The real grinding test is the best test method for grinding performance evaluation.