Plastic Dish Cover Mould

Producing condition of transparent PP

1. Barrel temperature range: 200 – 250°C

2. Mould shrinkage: 1.2 – 2.5% depending on wall thickness and Processing conditions

3. Mould temperature: normally 15 – 40°C, up to 65°C for thick parts

Storage and handling of transparent PP material

Polypropylene resin should be stored in a manner to prevent direct exposure to sunlight and/or heat. The storage area should also be dry and preferably do not exceed 50°C. 

Maintenance of cooling waterways

The function of the cooling water channel is to cool plastic parts in the cavity by cooling water, which has a great influence on the molding process of plastic parts.

1. Hazards of cooling water channel blockage

During long-term work, the surface of the cooling water channel is prone to deposit scale, dirt, rust, etc., which will reduce the flow area of the cooling water flow channel and greatly reduce heat exchange between cooling water and mold, so that the cooling effect is greatly reduced.

2. Inspection of cooling water channel blockage

The increase of sediment on the surface of the cooling water channel causes partial blockage of the water channel, which can be determined by measuring the flow rate of the cooling water in the internal condition of the cooling water channel. When measuring, a pressure control valve can be installed between the mold and cooling water channel to measure the pressure drop of cooling water through the mold under the same conditions. Thereby, clogging of the cooling water channel can be discriminated against. If it is blocked to a certain extent, it must be cleaned up in time.

3. Cleaning of the cooling channel

Since the design of the cooling channel is related to the shape of the cavity on plastic molding design in mold making, its shape is twisted and inconvenient to disassemble. Therefore, it cannot be cleaned by mechanical means. While it can only be washed with a cleaning agent, and adhered dirt is removed under the strong force of the cleaning agent. There are a variety of cleaning agents that can be used.