Wednesday, May 20, 2009

CRE Machines Launched By Holton Crest

Holton Crest has announced the launch of its continuous rotary extrusion machines, which it says are ideal for turning metal feedstocks into profitable bar, tube and complex profile products. The Holton Crest's continuous rotary extrusion (CRE) lines are capable of producing shapes and profiles across a large range of product cross-sectional areas from reductions to expansions. The machines are ideal for the continuous high-volume production of application-ready copper and aluminium electrical busbars and conductors requiring optimum surface quality and straightness.

Production scope includes transformer winding strips and motor commutators. The current application growth areas for Holton machines lie in the production of advanced materials, with their capability of processing material at a high rate. For example, in continuous high-volume production of application-ready copper, production rates of 4,000kg/h are achievable with the HC4000. The Holton Crest design ensures the product continually maintains a number of advantageous properties, namely high surface quality and cleanliness, and high dimensional accuracy and straightness.

The key machine feature enabling both high quality and productivity is DSPx2 (Dynamic Shoe Positioning Dual Axis). The DSPx2 system is a vital element of the real-time production control system as it maximises productivity and extends tooling and extrusion wheel life by continually optimising the gap between them in both the horizontal and vertical axis. Fine control of this multi-dimensional parameter is essential for high-pressure hollow and profile extrusions and when frequently changing between varying sized products.

A range of feedstock materials have been processed into high-value products using Holton Crest CRE technology. Feedstock handling and conditioning varies according to the material to be processed. Granules are usually fed by hopper into a specially designed compactor before entering the rotary extruder. Provided the feedstock is of sufficiently high purity and is in the form of solid particulate shapes, it may be suited to CRE. Clean in-house scrap or aluminium dross can be processed.

In some instances, quality issues may be overcome by a pre-cleaning step. Aluminium feedstocks are also readily made by Holton Crest machines into micro multi-port extrusions for cooling and vehicular applications. In another application, commercially available zinc granules are used with a rotary extruder to clad steel wire.

Rotary extrusion is a continuous process requiring no external heating where the product is usually coiled but can be cut to length. Put in its simplest terms, the material to be processed is fed into a groove on a rotating extrusion wheel and becomes compressed between the wheel, special tooling and an abutment. Once it becomes extrudable, it can be processed continuously through a suitable die.

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