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Functional Principles of Corrugator

Technology

Functional principle of die heads in corrugated pipe production with oneextruder

This method of production for double wall pipes,whose inner and outer layers are beingextruded from the same material supplied fromone extruder, is an especially economicaldesign. The below die head has material flowdivided by the spider into material for inner andouter layer.

This die head was especially manufactured forpipes made of polyolefin such as PE and PP. Theextruded material is split up here in the materialdistributor box and is controlled via bolts.

Therefore an individual adjustment of thematerial supply for the inner and outer wall ofthe pipe is enabled.

Functional principle of die heads in the production with two extruderOne extruder for the pipe external wall, oneextruder for the pipe internal wall. Thereby, youhave the possibility to use different materials foreach pipe layer, to use different colors and to

produce flexible pipes.

Immediately after the forming process of theprofiles outer layer, the smooth inner layer ofthe pipe is extruded. Thereby, the high staticloading capacity is achieved by means of thehomogeneous welding.

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Disc die head for pipes with an outer diameterof up to 2000 mm. This construction unites thefollowing advantages due to the relatively shortdie head:

lower weight of the die head shorter flow channels lower energy consumption simple control of the material

temperature

higher output easier handling

This technology of die head can also be utilizedtogether with a material distributor box usingone extruder.

Functional principle of die heads in the production of triple wall pipes

An additional smooth outer layer is put on thecorrugated pipe using a cross die head. Oftenthis will then be run through a traditionalvacuum sizing tank with a puller and cutoffdownstream from the tank. In applications notrequiring a smooth outer wall the pipe can berun without a sizing tank.

The use of a cross head die is not limited tomaking triple wall pipes, but could also be used

in the production of technical parts with varyinginsert sections.

Corrugator with a closed mold block channel

Corrugators with a pipe diameter of up to 65mm are built in closed construction, this allowsfor very high production speed at a highsmoothness of running and continuouslubrication.

They are typically water cooled using a waterjacketing method to enclose the mold blocks.

This style of corrugator has been a work horsein the automotive wiring harness industry.

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Corrugator with an open mold block channelDue to the open horizontal construction, the

mold blocks are installed on a chain of mold

block carriers.They do not run in closedchannels but on a horizontal plate, equippedwith guiding rails. The guiding rails combinedwith a synchronized upper and lower mold blockdrive, guarantee an exact positioning of themold blocks in the middle channel and therebyassuring a high pipe quality Due to the openconstruction and to the mold block design, themold block change-over has become mucheasier and faster as only one screw has to beloosened.

Shuttle corrugator principal

In the UNICOR shuttle system, the mold blocksin the return channel are not sent back to themiddle channel in a closed chain at the samespeed. They are sent back individually withincreased return speed. This reduces thenumber of required mold blocks and thus thecost of investment.The reversing of the mold blocks at the inlet andoutlet of the middle channel does not take placein guiding curves. The mold blocks are carriedto the inlet and the outlet of the middle channelin a right angle, hereby the width of themachine is reduced. The entire movement ofthe mold blocks is carried out by servo-motorsand is SPS-controlled. This guarantees the

highest smoothness of running and an excellentproduct quality.

Mold Blocks for pipe corrugator machines

Vacuum mold blocks are recommended for amajority of the products:

uniform distribution of the wallthickness

unlimited possibilities of the pipe profileor part geometry

better production tolerances excellent finished part surface increases the production speeds with

better plastic to mold contact

allows higher use of recycled materialsin polymer.

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Mold Block styles for pipe corrugators

On the inside, the mold blocks show thenegative of the profile of the produced pipe asper the profile drawing and upon request withengravings for marking. For making certaindiameters, we are also able to put more profilesin one mold block. Thus you save change-overtime as well as the costs of additional moldblock sets.

The cooling system of closed channel pipe corrugators

The walls of the middle channel and ofthe return line of the mold blocks areuniformly drizzled with cooling waterdealing with the spray cooling.The more efficient the cooling of themold blocks is, the higher is theproduction speed and/or the shorter

the mold block chains can be.

Mold block cooling for the corrugator range of 500 mm to 2000 mm outer

diameter

Direct cooling is required for larger pipe sizesand higher outputs as the heat can be extractedmore efficiently.In shuttle corrugators the cooling water iscontrolled by a temperature loop that keeps themold surfaces at a tightly controlledtemperature. Water cooled molds are known forvery good temperature control especially inclimates with highly variable planttemperatures.