The operation of a block-making machine is based on the vibration and compression of the concrete. They have a hopper in which to receive and store the fresh cement for the production of the blocks. After this, the material is dosed in to fill the mould with the right amounts. To make it easier to fill each mould, the tray and the mould are vibrated, and the shaker is too. Once this step is done, the piece is compressed to the exact size and the air that appears between the sand grains and the gravel is removed. Finally, it is vibrated again to help its compression (harder than when the mould was filled).