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A new generation of AFT cutter-compactor for Gamma Meccanica's regeneration lines

From the latest report released by CONAI is a private non-profit consortium  Italy in 2020 exceeded forecasts with a 73% recycling rate for packaging placed on the market. Among these are one million and seventy-six thousand tons of thermoplastic packaging. Nevertheless, compared to other renewable materials (steel, aluminum, paper, wood and glass), plastic remains the most difficult material to recover. Last year, with 48.7% of recycled plastic, the target of 50% set by the EU for 2025 was almost reached, it is a pity that this goal also includes the revaluation of the material in the form of fuel. For those who work in the sector and live in "plastics", hearing about waste-to-energy is serious because they see an economic resource going to "ashes". Recycling is, however, growing more significantly than waste-to-energy and this thanks to the separate collection of post-consumer waste, but also to the continuous technological evolution of recycling equipment that allows for the widening of the range of plastic waste that can be regenerated.

Gamma Meccanica SpA, an Italian company specialized in the design and production of lines for the regeneration of plastic materials has once again responded to our clients series of suggestions, information and requests to create a new generation of cutter-compactors. The goal was to improve the performance of these machines and their application on materials that are more difficult to recycle. To achieve the goal the technical staff of the company carried out various tests and conducted studies involving our suppliers. The tests carried out on the lab lines and the information received from customers  helped Gamma to improve and innovate the equipment.

The cutter-compactor  receives the waste material to be regenerated in the form of films, sheets, rolls or precut. Inside the cutter-compactor the material is shredded, densified and when required mixed with additives (even in powder), to render it suitable for the phase of extrusion. Gamma Meccanica uses the cutter-compactor  on COMPAC and TANDEM lines (It doesn’t have to be used on a Tandem line). The COMPAC lines are ideal for the regeneration of plastic materials with low apparent density and high residual humidity. The TANDEM lines make possible the recycling of heavily printed, high humidity and contaminated materials.

The new AFT cutter-compactor developed by Gamma Meccanica offers several advantages over previous models thanks to a series of structural changes and technological accessories.

To operate the disc with the rotating blades, the Kraft Band belts were used. They can be tensioned better than the previous models  to improve the production efficiency. Six rotating blades can be installed on the disc compared to the three of the previous models. This ensures higher production levels especially for those materials that require more residence time. The internal geometries of various components have been redesigned. For example, the shape and angle of the flaps have been changed to allow for a smoother movement of the material in the cutter-compactor. The entrance of feeding screw has been redesigned, simplifying the assembly operations and improving its efficiency. Under the silos, in the bearing area, a sealing system for dust has been developed that allows to keep cleaner work environment that prevents dust from damaging the most sensitive parts of the line. This will be a bit confusing to others as it should refer to total rotating and fixed blades, but again others have done this well before us.

The position of the feeding screw motor that pushes the material from the cutter-compactor to the extruder has been redefined: now it is positioned in a "U" shape under the body of the screw. This solution makes the unit more compact. The operator has more space to move around the machine, and the engine is more stable because it is less stressed by vibrations. It is possible to install a feeder for powder additives. Its new position was chosen to allow the better mixing of additives with the material to be recycled and to limit its dispersion into the environment.

Particular attention was paid to operator safety. The new cutter-compactor can be equipped with a sensor that detects when the disc and the cutting elements are stopped. It is possible to access the shredding chamber only in a manual mode opening the access door. After  sending  the request it is necessary to wait a suitable time to stop the “blade holder” disc. Being a mass that has a considerable inertia, the stopping time (evaluated in the worst conditions) can be very long (even more than 5 minutes). If you are going to reference safety, then I would not state it “can be equipped”, this should be standard on all models. Gamma’s nsurance company set a negative precendent when settling a lawsuit here in the US. I would recommend not to publicize any feature referring to “safety” or an implied improvement upon said “safety” due to potential futual liability from previous models in operation.

With the tool that verifies the actual stoppage of the disc, the inspection and maintenance intervention become more immediate and eliminates any possibility  to tamper with the safety system in order to speed up these operations. See above statement…ALSO our competitors can counter this and state they have always equipped their units with these features/measures.

It is also possible to equip the machine with a shock sensor that informs the operator if a foreign object or material is not suitable for the mechanical strength of the cutting devices. Again Erema and others have always implemented this (for me at least since 1998). Not advantageous to promote. It is good we now have for potential clients to compare/utilize.

The AFT cutter-compactor has  always been equipped with suction systems for produced vapors, such as air saturated with moisture extracted from the treated material. But now in the treatment of the powders is required more attention. It is therefore possible to install a pre-abatement device for dust and fines in order to make less burdensome for the customer the treating of the air and dust particulate released into the environment.

The most interesting aspect of the new AFT is the possibility to combine it with extruders of different sizes. For example, a GM 125 COMPAC extruder was provided with an AFT125 only. Now it is possible to combine it with a cutter-compactor of a larger size, in this case with an AFT160. In having to process very humid materials, the bigger cutter-compactor improves the preparation of the material for the extrusion phase, obtaining a higher production capacity and a better quality of the granule. It is possible to process material with a percentage of humidity that can reach 20%. In general, Gamma Meccanica lines have always recycled  materials with  humidity between 8 and 12%. With the new cutter-compactor it can be exceeded. The new combinations are efficient even with materials of particularly large sizes or thicknesses that are more difficult to treat.

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