Our company is proud of being the owner of the 100% of its technology.
This is possible thanks to the fact that all essential components are internally produced through high-level production and quality processes.
Proof of this is the production of the screw elements that compose the extruder screws in their entirety, the barrel and – above all – the manufacturing of the gearboxes.
Particular attention is paid to the search for new construction materials to be used to improve our extruders performances.
The result is an extruder whose strength lies in its versatility and that allows it to be fit for a wide range of production layouts typical of the most varied compounding production types.
Production flexibility is our motto to provide our customers with tailor-made solutions.
Our die is defined as a ‘quick-change’ die, as disassembly takes place by loosening – but not removing –
the fixing screws.
In this way, there will be no hot parts to handle and it will be possible to change the final part by lifting it from the special handles and by replacing it according to cleaning needs or the necessity to change the strands number or size to be obtained.
In case of extraction of the extruder screws, a hinged system is present and it can be opened in order to allow – only by extracting some of them – a quick access to the tips.
Therefore, only four screws will require handling and there will be neither hot parts nor a certain weight to support.
Another significant aspect is the side heating of the die. In many cases –and above all with the new high-productivity machines – the supply chain is very wide and implies the possibility to reach different temperatures according to the various areas, which – in turn – generate irregular flows with consequent strands of different diameters. There are also heating elements places laterally to allow to vary the heating and to compensate for this phenomenon.
The barrel – which represents the process area – is set up by using different modules with different functionalities.
From a construction point of view, they are available in two geometric shapes: round or square.
Different shapes also determine the use of various types of electrical heating elements. In the case of a round shape, ceramic or cast (aluminium, steel or bronze) heating elements can be used, while candle or cast heating elements (aluminium, steel or bronze) can be used for the square barrels.
With regards to the construction materials – according to the applications – there are more options: from the nitrided barrel to the barrels with removable inserts in special anti-wear, anti-corrosion steels or even the combination of the two properties. These steels range from fully-hardened materials to HIP and bimetallic materials: we are always at the forefront in the research for new materials to improve our extruders performance.
Inside the barrels, you can find the screws, consisting of two shafts and modular screw elements. These elements are made with the same steels used for the barrels and can have multiple geometries and functions: transport, kneading and special elements.
Our gearboxes are manufactured and designed in-house.
Co-rotating twin screw extruders require special gearboxes able to transmit the high torque density required by this type of machines.
The gearbox is designed using drawing and calculation programs, which allow to obtain the expected results and withstand the stresses to which it is usually subjected. The design is carried out by calculating the parts in real dimensions and on three-dimensional models.
These are special gearboxes where the motion is divided among various power branches and re-joined to be able to transmit the power to the two screw shafts. This gives life to a very complex gearbox with special devices and adjustments to ensure that each screw shaft receives exactly half of the power.
The high torque density requires the use of advanced materials and treatments that must be monitored.
By producing the parts entirely – manufacturing and processing them in-house – we can evaluate all aspects of the manufacturing process.
In the same way, all the gearboxes are dimensionally inspected by our internal testing.
The lubrication system – which carries the oil to each part – is placed outside the gearbox and it is provided with sensors to prevent any malfunction from damaging the gearbox.
Our company always places extreme care in choosing the motor to install on its machines.
The motor supplied can be of different type, such as:
DC motor with various degrees of protection according to its application
The motor is equipped with temperature sensors, encoders for more accurate speed control and –
in the case of water-cooled motors –
a system that checks temperature and flow. In addition, the system is equipped with a solenoid valve and a filter to prevent foreign particles to enter the motor.
A torque limiter is inserted between the motor and the gearbox to eliminate overloads, which can be arising from possible screws locking while preserving the gearbox. These devices – purchased externally – are however analysed together with the supplier and customized according to their use. The uncoupling of the limiter, which completely zeroes the torque, is signalled by a microswitch that stops the motor to prevent the torque generated by the motor due to inertia from discharging on the gearbox.
The side degassing system is a device used to optimize atmospheric degassing /venting throughout the extrusion process. Some processed materials, in fact – due to their specific rheological features – can cause clogging of the standard degassing chimney, thus preventing the correct devolatilization of the gases. In these cases, it is necessary to use the side degassing system, where the degassing chimney is assembled on a twin-screw device, which guarantees high volumes of devolatilization, while avoiding any clogging, material stagnation or pollution due to the degraded polymer.
The side degassing device is therefore composed of a housing and a pair of co-rotating transport screws very similar to the side feeding machines, but the standard hopper has been replaced by a chimney. The hermetic seal guarantees a correct seal during operation with vacuum levels commonly used in compounding processes.
The twin-screw side feeder is a device that allows the feeding of materials through the extrusion process. Materials introduced can be additives, polymers, resins or fillers, either in form of powders, granules or fibers.
Its use – according to formulations –
is recommended when it is necessary to increase the percentage of a filler, the production capacity and – in some cases – the quality of the compound produced. The number of side feeders used varies according to the formulation and the process, from one in case of standard compounds up to three for highly filled compounds (e.g. polyolefins with 86% CaCO3).
The deaeration system is a piece of equipment patented by Maris that allows to improve the feeding capacity of some types of powders in the extrusion process.
The goal is to increase the material bulk density by removing the air contained in the powders (fillers).
Its function lies in the use of a vacuum action on a porous filtering surface that allows the removal of the air contained in the fillers to be fed into the extruder.
Resorting to this technology –
if compared to a standard side feeder – can increase the screws filling and, consequently, the production capacity, while reducing the specific energy and –
therefore – the energy consumption or, more generally, obtain a reduction in the production costs.
