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Extrusion
- Pin-Type extruders
- Transfermix extruders (MCTD)
- Extruder gear pump systems
- Multiplex extrusion systems
- Extrusion heads
- Planetruder
Pin-Type extruders
Pin-Barrel extruders are designed to generate additional shear flow in the extruder screw channel for achievement of a homogeneous temperature heat-up of the rubber and plasticization. Due to the pins the rubber flow is divided when passing a pin and re-united. If higher energy input is required for the extruded compound the maximum number of pins can be successively increased to a total of 36 pins. Therefore Pin-Barrel Extruders offer a high flexibility for optimization of the cold feed extrusion process for each individual compound.
The picture shows a PIN70 x 14D extruder equipped with rapid die change extrusion head as used for apex extrusion.
Transfermix extruders (MCTD)
The Multicut Transfermix (MCT) extruder is a concept of mixing by flow division and rearrangement of flow elements was introduced. The heart of the MCTD system is a concentric double screw which, by means of reducing and increasing flight depths respectively in screw and barrel, the compound is mechanically sheared and longitudinally mixed in order to produce a homogeneous compound.
The picture shows a MCTD200 x 13D extruder equipped with an adjustable wide extrusion head as used for tread extrusion.
Extruder gearpump systems
For applications in the tire industry
By combining the highly effective plasticizing properties of PIN or MCTD screw and barrel configuration with the volumetric feeding properties of a gear pump, many disadvantages of single screw extruders can be eliminated. In the Shark® configuration the excellent plasticizing properties of the extruder are used to effectively masticate the compound and feed the gear pump, whilst the pump is used to generate the high die pressures without generating excessive temperatures.
The picture shows a Shark® 70 with cross head for breaker production in VMI Baldwin line.
By using the gear pump for pressure build-up, less demand is placed on the extruder which leads to an increase in throughput for comparative extruder sizes. The extruder is used only to achieve effective mastication and to ensure sufficient feed to the gear pump. Consequently the feed to the gear pump and therefore the throughput of the entire system is increased as less work energy is wasted for pressure build-up.
The picture shows a Shark® 90 with cross head for breaker production in VMI Baldwin line.
Multiplex extrusion systems
VMI-AZ has developped a wide range of duplex triplex and quadruplex extruders.
Duplex system
The picture shows the MCTD150 underpack duplex extruder with an adjustable duplex head.
Triplex system
The picture shows the Mini triplex system for laboratories and bicycle tire production.
The drawing shows the Quadruplex system.
Extrusion heads
Mainly for the tire industry VMI-AZ has developed a large range of cross heads, wide extrusion heads and multiplex heads to accommodate their extruders, or manufactured by others. Also changing the die rapidly belongs to the possibilities. In our range you will find: Rapid die change extrusion head
VMI-AZ has developed a rapid die change extrusion head that is particularly suited for tire profile production. Pre-heating of the new die cassette is accomplished by placing the new cassette in the pre-heating position of the extruder head while the extruder is still in operation. Using AZ's unique technology the required time for a die-change can be reduced to only a few seconds.
Above pictures showing the functionality of the rapid die-change extrusion head.
Cross heads for wire and fabric coating
Cross heads are designed for production of breaker or body ply for tire reinforcement. The main task for the head is to keep the reinforcement material in place by using special designed guides and to cover the material with rubber. In most applications the head is used in combination with a gear pump so that constant flow and pressure is provided. The pressure inside the head is important to ensure sufficient contact between the reinforcement material and the rubber. VMI-AZ cross heads offer the possibility to control the pressure by tailor made die design for each application.
The picture shows a cross head for tire breaker production in open position.
Wide extrusion heads
The VMI-AZ wide extrusion head is designed for tire tread production and rubber sheets. These extrusion heads are designed for optimum efficiency at high relative throughputs and controlled temperatures. This is achieved by very short screw-die distances, carefully designed temperature control zones as well as novel compound flow channel construction. The wide extrusion head with simple die-change system is available from 300 mm (12“) up to 800 mm (32“).
Above pictures showing a fully automatic adjustable wide extrusion head with an open and closed die holder.
Multiplex Heads (MFK Sandwich System)
VMI- AZ multiplex extrusion heads are based on a common modular design allowing the vertical retraction of the upper half of the extrusion head so that flow channels may be quickly exchanged. All systems are hydraulically operated and controlled by a central hydraulic power pack. The upper part of the head can be opened by vertically positioned hydraulic cylinders to enable cleaning and changing the flow channels. The lower flow channels are integrated into the lower part of the head body (single head), or placed into the lower part of the head body and pressed down from the upper part and moved upwards by hydraulic cylinders for cleaning and changing (duplex, triplex, quadroplex etc.).
The die package is bolted together and used as one set that can be prearranged before use. Preheating of the die package is possible for quick die package exchange. The entire package is pressed backwards against the flow channel by the die locking system and pressed down by the clamping wedges in which the electrical die heating rods are located.
Above pictures showing front view of a VMI-AZ multiplex extrusion head in closed and open position.
Planetruder®
- S Single drive system
- M Single drive system
- L double drive system
- XL double drive system
The Planetruder® is the perfect combination of a drag flow conveyor and a volumetric operating pump. On the one hand this enables efficient plasticisation of the compound by the extruder and on the other hand efficient pressure build up by the planetary gear pump. Therefore the system offers all the process advantages like high pressure build up, improved temperature output behavior and extremely precise output as already knowing from standard extruder gear pump systems.
Caused by the unique design, the Planetruder® features a very compact layout which is more similar to standard extruders. A Planetruder® can be supplied with a single drive system or with two drives, the models for the single single drive systems are: Planetruder® S and Planetruder® M. The double drive system comes with the models: Planetruder® L and Planetruder® XL.
The picture shows a Planetruder® M process section with pin-type screw.
The picture shows a Planetruder® XL process section.
- Rapid die change extrusion head
- Cross heads for wire and fabric coating
- Wide extrusion heads
- Multiplex heads (MFK Sandwich System)
For more information please see our brochures or contact us sales@vmi-group.com.