Plastic Recycling Machines: Regeneration

Plastic Recycling Machines: Regeneration

Washing and crushing of plastic objects is the main part of creating recycled plastic that is suitable for further use. Still, it is not the end. Many production processes have higher requirements to the recycled plastic. To create again the original virgin plastic material further processing is necessary for which we have a few solutions available.

Agglomerator


This machine can be an economical solution for creating hard plastic raw material out of plastic foil and film. The rotating blades of the agglomerator squeeze the film scraps together. During this process, heat is created and the thin film melts together to small chunks that are better suitable to use in further production processes than the light and fugitive film scraps.

Packing Silo


After all processes are finished and the desired final recycled product is produced, the product has to be packed. Mostly this is done in big-bags. With the packing silo this packing process is convenient and when the bag is full, the bag can be changed by closing the silo for a while and changing the bag. Like this the recycling process doesn’t have to be interrupted while changing the bag.

Granulation Extruder


The most professional way of regenerating virgin material is a granulation extruder. The extruder melts the plastic completely and squeezes it through a mold with defined holes. After cooling down the plastic strings can be cut into pellets with defined dimensions looking the same as the original virgin pellets. Granulation extruders are available with water and air cutters.

Extrusion Lines: How do They Work?

Extrusion Lines: How do They Work?

Extrusion lines are used for a continuous production of plastic or wood plastic composite (WPC) pellets, pipes, profiles or sheets. Thickness and diameter can vary depending on the specific needs of a company.

The process of extrusion starts when plastic flakes or powder are fed into a hopper. Different types of plastics can be used as a raw material, for example PE, PP, PS, PET, ABS, WPC and PVC.

Immediately after going into the hopper, the raw material comes in contact with a rotating screw. The screw forces the material through a barrel in which temperature is gradually rising. Heating zones are necessary to prevent overheating of the polymer and its degradation. The heat is generated by an electric motor, as well as by friction and pressure inside the barrel. In some cases the electric motor can be even shut off, as the temperature generated by friction and pressure is high enough to melt the plastic flakes. Extruders also have cooling fans that keep the temperature under control. However, it is important to always keep an eye on the temperature control meter. The machine operator should be present to make sure the extruder functions within established parameters.

At the end of the barrel one can find a screen pack, which is designed to remove any contaminants, and a breaker plate. The latter represents a metal puck with holes. It reinforces the screen pack.
When melted plastic goes through the screen pack and the breaker plate, it reaches a die. The die is made from steel and gives the plastic its final form. In order to ensure a smooth process, the flow of the molten plastic should be even.

The next step is cooling. It can be done with water or air depending on the properties of the profile. Then the final products can be cut and packaged. Another option is to connect the extruder to a thermoforming or a blow molding line. In this case, you can continue the process and produce various plastic consumer goods (e.g. containers, cups, bags, bottles, plates, cutlery etc.)

Single- and Twin-Screw Extruders

Single screw extruder is a basic machine for plastic processing. It works best when there is one type of a polymer involved.

Twin-screw extruders have higher production rate. They are also much more suited for mixing polymeric materials. There are several types of twin-screw extruders: co-rotating intermeshing, counter rotating intermeshing and non-intermeshing. The first type is the most commonly used one.

Energy and maintenance costs are comparable for single- and twin-screw extruders. However, the latter have larger functionality and cost more. Twin-screw extruders are more flexible, productive and offer higher output quality. With them it is easier to control the temperature of materials, and their transportation is very stable. As a result, little residual is left, and you can change production material without interrupting the machine for cleaning.

Extruder Maintenance

Extrusion lines can serve a long time with a high productivity and a minimum downtime if the right maintenance is performed. Regular inspections of the equipment is a must. They will help you to prevent any problems and schedule downtime if necessary, so you won’t find yourself in a situation when the line has to be stopped in the middle of the process.

Regular inspections mean that extrusion lines should be checked on a weekly, quarterly and annual basis. Weekly checks are performed while the extrusion line is running and imply verification of pressure and temperature indications, oil flow, condition of plugs and guards. Quarterly and annual checks are performed both while the extruder is running and while the scheduled downtime is taking place. Usually the machine operator visually inspects the lines, records noise levels, searches for oil leaks, changes filters and other parts if needed. A detailed description of the maintenance recommendations and requirements can be found in the extruder manuals.

 

BOMAC Industries strives to provide innovative solutions for recycling plastics and offers a wide range of plastic recycling lines and machines for most common plastics and rubber, for example PET bottles, plastic film, car tires, PVC profiles etc.

How to Choose Plastic Recycling Machines

How to Choose Plastic Recycling Machines

Choosing high quality recycling equipment that suits your needs is an important step in setting up your recycling operations. In this article we will guide you through the main types of plastic recycling machines.

If you collect or buy mixed plastic waste, you first need sorting and washing equipment. For example, polyethylene terephthalate (PET) should be recycled apart from polyvinyl chloride (PVC). Good sorting machines will have sensors that are able to detect specific polymers. NIR detectors can recognize a large variety of plastics (e.g. PVC, PS, PA) and guarantee about 96 percent separation. X-ray detector can recognize only PVC with a bit higher guarantee level – 99 percent. You may want to use a combination of detectors and add manual sorting at the end of the line to minimize risk of automation failure.

Another important step in recycling process is size reduction. Here you can choose between crushers and shredders. They have basically the same function: to cut plastic items into small pieces. Crushers are usually very compact and are more suitable for smaller items like bottles, bags, buckets etc. BOMAC Industries offers industrial crushers that, while remaining compact, are designed for continuous operation, and are capable of cutting heavy and bulky objects.

Shredders take more space than crushers. They are perfectly suitable for quick and continuous crumbling of heavy and dense materials. Some single-shaft shredders perform more of a tearing motion. They are relatively slow and do not guarantee the same output (size of pieces can vary). This is the reason why BOMAC Industries offers both single-shaft and double-shaft shredders with durable hard-metal knives and optimized knife geometry: they guarantee consistent results. These machines are also very energy-efficient and produce little noise. Generally, shredders require good maintenance: you want to make sure that no foreign materials (e.g. a piece of blade) get inside the machines, otherwise they can be damaged. It is also important to keep the knives sharpened.

You need pulverizers in order to grind the plastic into powder or tiny granules. They are especially useful for recycling heat-sensitivity plastic (PE, PVC) as these machines have automatic temperature control. Pulverizers are easy to maintain, guarantee accurate output size and offer a possibility to vary input speed. BOMAC Industries also provies pulverizers with hard-metal friction discs and long-life drive belts.

Extrusion lines are usually the last ones in the recycling process. Extruders melt raw plastic and form a continuous profile (e.g. plastic or WPC pellets, pipes, sheets). Thickness and diameter can be varied depending on your needs and types of resin. You may choose between single- and twin-screw extruders. Energy and maintenance costs are comparable, however twin-screw extruders are more expensive and offer more benefits. For instance, they are more flexible, productive and offer higher output quality. With twin-screw extruders it is also easier to control the temperature of materials, and their transportation is very stable. As a result, little residual is left, and you have a possibility to change production material without interrupting the machine for cleaning.

You may want to go one step further and use the plastic you recycled for manufacturing new goods (e.g. plastic bags, cups, bottles or cutlery). For that you will need thermoforming lines. This equipment is suitable for different types of plastic films and sheets (PE, PP, PS, PET): it heats the raw material, forms a specific shape and advances it to the trim station. The main advantages of thermoforming lines are high automation, ergonomic controls and variety of output speed. When the equipment is installed, you only need manual checking of the products for defects and packing. Employees aren’t exposed to the hazardous areas.

If you consider procuring recycling machines and have questions, do not hesitate to contact BOMAC Industries. We are happy to help!

BOMAC Industries strives to provide innovative solutions for recycling plastics and offers a wide range of plastic recycling lines and machines for most common plastics and rubber, for example PET bottles, plastic film, car tires, PVC profiles etc.