109511221
Automated process planning for the manufacture of sliders
FCAPP for the manufacture of injection moulded components, which will facilitate the standardisation of process planning and significantly reduce lead-time. The main components of the mould such as the slider, the lifter and the mould base are considered in this system. In this paper, the automated process planning for the manufacture of a lifter is described. A combination of the generative and variant approach (hybrid approach) is used for the development of the system. The input to the system is a 3D lifter model. First, the system classifies the lifter types and extracts the feature parameters from the model. Each lifter type refers to a standard process plan template, in which a set of processes is presented in sequence. Secondly, the system selects the machines, cutters, fixtures, and cutting parameters for each process in the plan template, based on the actual dimensions of the features and constraints and rules defined in the system and the available machining resources. The process plan execution is then simulated on the screen step by step.
28342459
Process planning optimization for the manufacture of injection moulds using a genetic algorithm
This paper reports a real application of a computer-aided process planning (CAPP) system, IMOLD_CAPP, for the manufacture of injection moulds. A combination of a template and a generative approach is used for the development of this CAPP system. The input to the system is the three-dimensional mould components developed by IMOLD. Here, the process-types and their sequences for a particular type of mould component are defined in the plan template based on company practice, while selection of machine tools, cutting tools, and cutting conditions for different processes in the plan template are optimized by a method based on genetic algorithms (GAs). The objective function of optimization is to minimize overall processing time. The performance of the optimization is compared with an algorithm based on simulated annealing (SA), and the GA-method is found to be appropriate for the optimization. This approach is expected to be applicable in most mould shops based on their available machining resources.
97577218
A study on the grinding of glass using electrolytic in-process dressing
Grinding of brittle materials such as glass is gaining importance due to the rapid developments in the areas of machining of storage devices, microlenses, and optical communication devices. Grinding of such glasses is difficult because grinding wheels wear out easily due to the hard and brittle nature of the materials being machined. Grinding wheels with fine abrasive size are required in order to achieve ductile mode grinding. Problems such as wheel loading and glazing can be encountered while grinding with fine abrasive wheels. Electrolytic in-process dressing (ELID) is an efficient method to dress the grinding wheel while performing grinding. In this paper, a fundamental study on the mechanism of the ELID grinding technique is discussed in detail. Several sets of experiments have been performed to determine the optimal grinding conditions. From the experiments, it has been established that surface roughness could be further improved if the current duty ratio to dress the grinding wheel were increased. The force patterns and the changes in the profile of the grinding wheel during machining are also presented and discussed in detail.
26262056
Molecular dynamics simulation of the effect of tool edge radius on cutting forces and cutting region in nanoscale ductile cutting of silicon
Unlike in conventional cutting processes, where the undeformed chip thickness is significant compared to the cutting tool edge radius, in nanoscale cutting processes, the undeformed chip thickness is very small, on the nanoscales. Therefore, the tool edge radius can not been ignored. It has been found that there is a brittle-ductile transition in cutting of brittle materials when the cutting tool edge radius is reduced to nanoscale and the undeformed chip thickness is smaller than the tool edge radius. In order to better understand the mechanism of the transition, a molecular dynamics (MD) method, which is different from continuous linear mechanics, is employed to model and simulate the nanoscale ductile mode cutting process of monocrystalline silicon wafer. The simulated variation of the cutting forces with the tool cutting edge radius is compared with the results of the cutting force from experimental cutting tests and they show a good agreement. In the simulated results, it can be seen that the thrust force is much larger than the cutting force in cutting. The simulated results also denote that the resultant force in the cutting process is not uniformly distributed along the cutting tool edge. In the simulation, the elastic springback of small thickness is observed on the machined workpiece surface.
135911643
Method of dry-etching evaluation using quantum dots
Abstract New dry-etch processes, such as low-power reactive-ion etching (RIE) and electron cyclotron resonance, offer very low levels of residual lattice damage. These levels are below the resolution limits of traditional characterisation methods like Raman, photoluminescence, Schottky diode, etc. We show that the single-electron charging of a quantum dot fabricated using dry etching offers a very sensitive method of damage detection. For SiCl 4 SiF 4 RIE of GaAs we find a defect density of around 1015 cm−3, which is at the level of the background impurity concentration in the as-grown material.
45952050
Fourier-transform solution to the problem of steady-state transonic motion of a line load across the surface of an elastic half-space (the corrected Cole-Huth solution)
Abstract Considered in the present article is the problem of a line load load moving at a constant transonic speed across the surface of an elastic half-space. Solution of the problem is derived here using the method of Fourier transforms.
15632777
Numerical solution of a Fredholm integro-differential equation modelling Theta-neural networks
We propose several approaches to the numerical solution of a new Fredholm integro-differential equations modelling neural networks. A solution strategy based on expansions onto standard cardinal basis functions and collocation is presented. Comparative numerical experiments illustrate specific advantages and drawbacks of the different approaches and are used to motivate alternate strategies.
137236624
Quantum electron beam probe of sidewall dry-etch damage
Damage as a result of ion bombardment may occur both at top surfaces and at sidewalls. We propose a method of probing sidewall damage using coherent electron focusing. A collimated electron beam is reflected off an internal boundary formed by dry etching. Spectra measured in an applied magnetic field are influenced strongly by increased levels of etch damage. Monte Carlo simulations combined with experiments on multiple beams reveal the separate contributions of boundary roughness and inelastic electron scattering. Electrostatic calculations reveal a damage shadow beneath the sidewall.
11875786
A cost-efficient high-performance bit-serial architecture for robot inverse dynamics computation
A novel cost-efficient parallel and pipelined bit-serial array architecture is proposed for the computation of robot inverse dynamics. It achieves a certain bit-serial execution-time lower bound. The core of the system consists of two arrays of multifunctional bit-serial cells. One of the arrays computes the forward iterations, and the other one evaluates the backward recursions, of the Newton-Euler dynamics algorithm. At the current state of technology, the resulting high-performance system may be realized in only two custom VLSI chips and a minimum number of first-in-first-out register files. The organization, operation, and performance of the proposed array structure is discussed. The architecture and functionality of an individual multifunctional bit-serial cell used as the building block of the array structure is described.