Dec 4, 2014 in Industrial Surveying by
  • Metal Extrusion press – Laser tracker measurement of components and analysis for increased productivity through improved alignment
  • Metal Extrusion press – Laser tracker measurement of components and analysis for increased productivity through improved alignment

We have just completed the 3D measurement of a 25000 ton Copper extrusion press. Our task was to provide an accurate “picture“ of the press components and the range of movement the press exhibited during operational loads.

Specifically we measured :

  • The bed plates /press base level with respect to gravity.
  • Where the front and back ( resistance ) platens parallel and was there any twist in their relationship.
  • The centreline coincidence of the Ram, Container and Die.
  • The tooling stack relationship to machine centreline and if this relationship alters under extrusion loads.
  • Does the billet loader position billet in centre of container?
  • The dynamic movement of the components and if the front platen “moved” under pressure.

During a scheduled maintenance shut we measured the various components with our laser tracker. Repeatability measurements showed we were achieving accuracies of 25 micron.

One of the great things about Poly works software is the ability to collect a series of individual point measurements on a component and then generate the best fit mathematical model of that components whilst analysing a statistical report of the deviations of individual measurements.

Due to the nature of the press it is complex to establish the machine centreline when all one has is a number of cylindrical rams and open cylindrical containers for billet and tooling stack.

To determine the “best fit machine centre we measure a number of circular slices around ram etc and the circumferences of the open cylinders.

From these circles we calculated a best fit vector through them and could analyse the vector both in a gravity defined coordinate system and in a best fit machine coordinate system. Polyworks allows for continual switching between coordinate systems and reporting is recalculated dependant on coordinate system chosen.

Once a best fit machine centre line was established we could then measure individual components. For example on the ram piston we measured some 20 points on it cylindrical surface from which the software could provide us with both the cylindrical dimensions but also report on the variation of the cylinder vector from the machine centre line.

Once we had established relationship of the various components to the machine centreline we could then measure their how their alignment varied as the press was put under load utilising the dynamic measuring capabilities of the laser tracker.

Whilst these measurements where being taken we built up a detailed evaluation of the presses behaviour which could be illustrated in a 3d model.

The complete survey took  11 hours with immediate reporting to the client allowing for some simple remedial work before the end of the maintenance shut.