This paper describes a simple but effective method for partitioning free-form surfaces. Here, based on the surface curvatures, a free-form surface can be successfully partitioned into convex, concave and saddle regions. The chain code technique in the image processing field is applied to determine the boundaries of each region. These regions can be separately machined by different kinds and sizes of cutting tool. Therefore, the machining time can be reduced significantly. A B-spline surface is given as an example to demonstrate the proposed method including partitioning and machining. A Matlab 1 program was developed to perform the surface partitioning task and to get the coordinates of all points on the boundaries. Pro/Engineer 1 Wildfire 2.0 was used to create the computer-aided design (CAD) model of the free-form surface and generate the tool path for each region for illustration purposes.
This paper describes a computer-aided design for design of the concave globoidal cam with cylindrical rollers and indexing turret follower. Three models with different modeling methods are made from the same input data. The input data include some basic dimensions of the globoidal cam system and a table of angular input and output displacements of the cam and the follower. The cam model must have no interference with the rollers when their motions are simulated in assembly conditions. In this study, Pro/ENGINEER® Wildfire 2.0 is used for modeling the cam, simulating motions and checking interference and errors of the system.
Monthly counts of industrial machine part errors are modeled using a two-state Hidden Markov Model (HMM) in order to describe the effect of machine part error correction and the amount of time spent on the error correction on the likelihood of the machine part to be in a "defective" or "non-defective" state. The number of machine parts errors were collected from a thermo plastic injection molding machine in a car bumper auto parts manufacturer in Liberec city, Czech Republic from January 2012 to November 2012. A Bayesian method is used for parameter estimation. The results of this study indicate that the machine part error correction and the amount of time spent on the error correction do not improve the machine part status of the individual part, but there is a very strong month-to-month dependence of the machine part states. Using the Mean Absolute Error (MAE) criterion, the performance of the proposed model (MAE = 1.62) and the HMM including machine part error correction only (MAE = 1.68), from our previous study, is not significantly different. However, the proposed model has more advantage in the fact that the machine part state can be explained by both the machine part error correction and the amount of time spent on the error correction.
Abstract. This work aims at the utilization of an orthotropic damper in demolition and forming machines. FEM model and quasi-dynamical calculations are used for the solution. After that the resulting force affecting the underlying bed is analysed. The research traces the dependence of the mass of orthotropic material on the time of force process. Based on the measured data it is possible to design a new orthotropic damper for the machines.
The research activities of the Department of Manufacturing Systems at TU of Liberec are related to projecting, designing and construction of prototype CNC machines for laser cutting. The result is a prototype device assembled of standard aluminium profiles using the motion control linear actuator with ball screw.The paper presents the design and construction of the prototype machine. The components and their assembly are described below. The implementation of technical parameters and other options outlined the continued development and application of the equipment is also listed below.
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