DEVELOPMENT OF A PROTOTYPE OF A SPECIAL PURPOSE MACHINE

摘要

The manufacturing sector is under severe pressure to reduce costs in order to be globally competitive. Capital cost is the major factor contributing to the production cost. Hence, reducing the cost of manufacturing equipment, without compromising quality, is an ultimate target for equipment manufacturers. This research focuses on the development of a low-cost special purpose machine, which would be especially suitable for the tooling industry. The machine consists of a base, a moving gantry, which carries various interchangeable attachments, such as: a conventional milling spindle, a high speed spindle and an Electric-Discharge Machining (EDM) unit. The design was verified and optimised through modelling using Finite Element Analysis and Dynamic Analysis. The developed PC-based machine controller has an open-architecture, which provides the required control and communication functions. The machine was calibrated with the aid of a laser interferometer in order to eliminate the geometric errors of the axes. The calibration process was followed by a compensation methodology to improve the machine accuracy. The machine technological capabilities were tested by means of machining of cores and cavities of a rubber injection mould using milling and EDM. The developed machine prototype can be used as a platform for a full-scale special purpose machine for manufacturing small to medium size moulds and dies.