Algorithm for workcells design

The paper presents a methodology for the design of the manufacturing cells, covering all the necessary steps, from the analysis of the customers’ needs, to part families for group technologies, process engineering, control procedures, production rate, production planning (push or pull workflow), supply in the manufacturing cell, workcell configuration, work standardisation. The necessary tools through each stage are presented. Also, there are presented links to major company systems. For each design stage, deliverables are specified. this design approach is not linear. At each stage it is possible (and indicated) to go back and analyse the previously established parameters. The methodology is a complex one, and in a wider space the detailed parameters will be presented in extenso

Kanban Systems in the Context of the Enterprise Systems

Companies are under increasing pressure from customers, competitors, limited resources, etc. These conditions oblige companies to permanently improve their organizational structure and the activities of all system’s flows. The paper analyses the types of Kanban systems, in the broader context of the enterprise systems. The most important reference architectures were analysed (with the emphasis on the modules dedicated to flow description) and the standards that allow the activity modelling of a manufacturing enterprises. Starting from this context, the paper describes three models of Kanban systems that are specific to companies with different information systems development. Models are: Push production with withdrawal Kanban; Pull production with withdrawal Kanban and production Kanban triggered by Kanban board; Pull production with withdrawal Kanban and production Kanban triggered by the dispatch to the customers. The models are graphically described using Value Stream Map (VMS) symbols. These models are useful in the development and improvement of production flows

BORING HEADS DESIGN - A GENERALIZED APPROACH

The paper presents the representative model of the boring heads obtained from the generalized model of the cutting tool. The model contains axle and hole type surfaces, some of the edges having adjustment facilities. By particularization of the representative model of the boring heads, a large range of constructive solutions could be obtained. The best boring head for a specific need can be designed after studies and simulations done in conjunction with different optimization criteria. Studies on stress analysis of boring heads, clamping system analysis (done by the elasticity of the tool body) and cutting forces (in order to design a dynamic balanced boring head) are presented in the paper

Systemic analysis of the caulking assembly process

The present paper highlights the importance of a caulking process which is nowadays less studied in comparison with the growing of its usage in the automotive industry. Due to the fact that the caulking operation is used in domains with high importance such as shock absorbers and brake systems there comes the demand of this paper to detail the parameters which characterize the process, viewed as input data and output data, and the requirements asked for the final product. The paper presents the actual measurement methods used for analysis the performance of the caulking assembly. All this parameters leads to an analysis algorithm of performance established for the caulking process which it is used later in the paper for an experimental research. The study is a basis from which it will be able to go to further researches in order to optimize the following processing

The Usage of the Johnson-Cook Constitutive Model in the Finite Element Analysis of the Caulking Process

The present paper highlights the importance of generating a model for analysing the caulking process. The caulking operation is a fast, cost-efficient, cost-effective way of assembling, which is currently less studied in world-wide papers. The operation is at the border between plastic deformation and cutting process. It is therefore necessary to create a model to describe the process. In the paper are presented the main examples of applications, the main parameters that characterize the process, the current state of the cutting and plastic deformation models. After the analysis we concluded that the most valuable model for describing plastic deformations is the Johnson-Cook model. This information is the basis for developing a model for describing the caulking process

A study of thermo-elastic characteristics of the machine tool spindle

In order to avoid the failure of machine tools spindles in the real machining process due to an increase in temperature, it is essential to predict its thermal behavior in the designing phase. The characteristics of machine tools significantly depend on the thermal-elastic behavior of the spindle. These parameters directly affect the productivity and quality of machining operations. This paper presents a thermal - elastic model of the machine tool spindle which was based on the quasi-static model of bearings and the finite element (FE) model of the spindle shaft. Based on quasi-static model of bearings with angular contact, heat generated and thermal contact resistances (TCR) are determined for each position of the balls. The aforementioned constraints have been applied to the 3D FE model of the spindle which allowed for establishing non-stationary change of temperature and thermal deformation. In order to prove the efficacy of the proposed model, experimental measurements of spindle and bearing temperatures were done using thermocouples and thermal imager