Wet Pressing Process

Shown below is a basic pressing process common to most single and three stage presses. Machinery and equipment can vary from semi-automatic to fully automatic dependant on customer needs and can be designed to suit your specific requirements.

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The Pressing Process

Whether you are using a single stage or a three stage press the pressing process is basically the same; the filling of a mould with wet concrete, pressing the concrete until hard, ejecting and stacking the finished product.

A concrete mix design for the product is required using local aggregates if available.

These aggregates are precisely weighed and batched according to the mix design and dispensed into the mixer. A controlled amount of water is added producing a workable wet concrete allowing suitable flow from the wet mix hopper and into the mould.

To assist with water extraction during the pressing process and to help with the release of the pressed product from the mould a paper or a filter cloth is used.

Before pouring concrete into the mould a filter paper or cloth is placed into the bottom of the mould. Once the paper or cloth is in place a measured volume of concrete from the wet mix hopper is dispensed into the mould, if the water content of the concrete is correct the concrete should flow equally around the mould without any further assistance. Finally a paper or cloth is then placed on top of the wet concrete.

With all the above in place and the press start conditions have been met, the mould can be sent round to the pressing position under the main ram. Once the table has located, the pressing ram will automatically start to press onto the wet concrete for the time duration set by the press operator. This can vary between 5 - 60 seconds dependant on the quality of the materials and the depth and shape of the product being made.

During this time water is extracted from the wet concrete using a vacuum through the die head producing a wet but hard product.

As soon as the pressing process is complete the ram is withdrawn from the mould, the table and mould will turn automatically to the next position over the ejector ram.

When the table and mould have reached the correct position, the ejector ram automatically pushes the now pressed concrete out of the mould.

At this point the take off machine takes over, lowering the vacuum head plate down onto the ejected concrete product creating a vacuum and picks up the product. The carrier then travels over to the waiting pallet where the products are neatly stacked along with previously made products and will continue until the pallet is full.

The pallet when full travels along a roller conveyor to a point where it can be lifted off by a fork lift truck and put into a curing area for 24 hours, less if curing systems are installed. They are then quality checked, banded into packs and placed onto the stock ground.