Heavy-duty tie-rod hydraulic cylinders have been specified for the electro-hydraulic control system of a 'dynamic shoe' version of continuous extrusion machines.

Parker Hannifin series 2H heavy-duty tie-rod hydraulic cylinders have been specified for the electro-hydraulic control system for the 'dynamic shoe' version of Holton Machinery's new range of Conform“ 2000 continuous extrusion machines. For more than 20 years, the Conform machine has stood at the forefront of continuous extrusion. In addition to the traditional feedstock materials such as rod or continuously cast bar, the Conform process is capable of accepting a wide range of alternative feedstock materials.

These include granules, scalper/sawing chips, powders, needles, rapidly solidified materials and chopped wire.

The machines are used for both low cost, high volume activities such as profiles for electrical conductors and very high value, low volume processes associated with space technology and high energy physics.

Before the introduction of the new Conform 2000, the machines had manual, static set-up procedures that were unalterable once running.

The new Conform 2000 is fast to set up and adjusts to optimum operating parameters automatically and dynamically during running.

One of the most critical aspects of Conform operation is the control of the size and shape of the gap between the tooling (held in a so-called extrusion shoe) and the extrusion wheel.

This gap has traditionally been set at a best compromise to accommodate the particular product both in the cold start-up mode and in the normal running temperature mode.

With the new Conform 2000, both absolute gap and gap shape can be adjusted dynamically during normal running under load.

This allows optimum start-up and optimum running positions to be achieved.

It also means that any slight wearing of the tooling or wheel during a production run can be compensated.

User benefits resulting from this dynamic shoe feature include reduction in set-up time, quicker achievement of production speed, reduction in start-up and production scrap, and reduction in required skill levels.

The Conform 2000 extrusion shoe is moved in both horizontal and vertical axes by the Parker Hannifin hydraulic actuators.

The shoe is moved closer or further from the grooved wheel as the extrusion process takes place.

Direction and scale of movement are controlled by an intelligent PLC, using readings relayed back from gap, pressure and temperature sensors located near the dynamic shoe.

Should the PLC calculate that the feedstock is under too much stress, then it will shorten the cylinder's stroke and draw the shoe away from the rotating wheel.

thus allowing the material to cool.

If the feedstock needs heating, then the shoe and wheel are brought closer together.

'The efficiency and reliability of the Parker hydraulic cylinders has been an integral part of the success of the new Conform 2000', said Matthew Lawrence, Holton's Marketing Executive.

'Since the launch of the machine we have already taken four orders for the Conform 2000.

Two of the machines will produce multiport tube for the European and Far Eastern car industries, a third will produce copper in the Far East, whilst a fourth has been supplied in Central Europe.' Parker's Series 2H cylinders are available in bore sizes from 1/1/2in to 12in and in 17 standard mounting styles.

Any practical stroke length can be supplied and standard operating pressure is up to 210 bar.

Deceleration devices (cushions) can be built in if required.

A number of piston seal options are available, including cast iron piston rings for extreme durability, Lipseal pistons for applications where load holding is critical and Hi-Load pistons which resist side loading and are recommended for long stroke cylinders.