An Automated Press Working System

Abstract

The paper describes the design and development of a computer controlled, press working system which includes a power press and first operation feeding station. The work forms part of a project to develop an integrated manufacturing system for power presses which is funded by the ACME Directorate of SERC and Lerche Engineering Limited.

The control system is based on a Z80 microprocessor and consists of a single board computer and suitable interfaces to drive a stepping motor and solenoid operated pneumatic spool valves. A program has been developed which initialises the feed, positions the end-stop, controls the feed sequences and synchronises the press operation with the feed. The end-stop is positioned by a stepping motor in an open-loop control system. The feed synchronises the press with reference to top dead centre. The feed sequencing has been achieved via solenoid valves and the feed-back signals from sensors which detect the presence of the carriage at each end of the stroke.

The system is very versatile and has many advantages. It adapts to any stroke length and positions the end-stop accordingly. Multi-feeding would be selected automatically if the stroke length is beyond the physical capability of the feed. Additionally because the feed controls and synchronises the press a more efficient control of press speed has been achieved. The system can easily be installed and synchronised with other press shop elements.