Mechanical Functions

Mechanical Functions

Extrusion pressing is principally pushing the billet with a hydraulic stem and enough power along the container through the extrusion die. The pushing power range of the presses in tons start by 300 and increase up to 20,000 tons.

Thermal Regulation.

The importance of the mechanical centering of the press is a process known by everybody and is performed periodically. But thermal regulation is used by very less extruders to increase the production, die lifetime and the quality.

The observation and control of the thermal status of the container, billet, die and profile can be defined as a thermal arrangement. Principally is the success of the isothermal heating only possible by a good control of these factors.The measurement of the net billet temperature with single cell die oven, multi regional container heating, a successful conical heating of the billet, and thermocouples before pres loading or contact-free pyrometers is important for the thermal regulation.

The exit temperature effects the extrusion speed directly; any changes to any of the factors above will decrease the extrusion speed and the isothermal extrusion advantage will be lost.

Routine control of the main parts of the press

  1. Check the tightness of the column parts and be sure that they don’t move unintentionally under load at least once a month. The most important is that the nuts have the same tightness since the columns will bear unequal loads.
  2. An ultrasound testing of the columns every 12 months is recommended in order to be sure that there are no internal problems developing.  Particular attention needs to be paid on the toothed region at the end of the column. We recommend to perform the ultrasound testing when load is applied on the columns. In this way, sensitive changes can be observed.

Ultrasound testing will reveal any existing damaged regions. The testing frequency needs to be increase in order to track the status of such damage. We recommend to change the column after the determination of any cracks. If the replacement should be performed immediately or not can be determined according to the size of the crack. Another point, what is to be remembered here, is that the expansion coefficient will be different even if the replacement tie rod should be of the same material and at the same stiffness as the old tie rod. As a result can non-homogenous loads cause pre-mature breakages and cracks. The most appropriate is to replace all tie rods at the same time.