Control system for Astracast PLC

Mould temperature control system for asterite moulding plant

Ellison's were approached with a design brief for a mould temperature control system for asterite moulding plant.
The brief was a detailed description of the process characteristics; it contained information on the behaviour of the main process materials during all stages of manufacture. This information was the basis for ascertaining the design parameters that would form the performance specification.

Performance specification,-

Heating:
Flow water temperature had to be maintained at any desired temperature between 50°C and 110°C within a tolerance of ± 5°C, on the heating and cooling circuit. Then at the point of contact between the pattern and the product a desired temperature was to be maintained within an allowable deviation of MAX ± 2°C, a tolerance that was later refined at clients request to control within ± 1°C.

This spec applied to both halves of each mould and needed to be controlled independently as the show face and back face needed to deviate by 20-30°C to achieve quality product.

Also during polymerisation of the methyl-metha-acrylate monomer/silica mix (asterite) a specific temperature of 95-100°C had to be maintained onto the back face for curing.

Cooling:
Based on 64 moulding stations 2000kW cooling had to be provided after curing to stabilise the material for de-moulding during the final stage, a diversity factor of .6 and fully modulating controls allowed for variations in production.