Soft plastic waste is one of the hardest materials to recycle profitably. PP woven sacks, jumbo bags and film have very low bulk density, they trap air and moisture, and they usually carry printing ink. Feed that material straight into a screw extruder and the machine starves, surges, and produces pellets full of bubbles.
A compacting strand cooling cutting plastic granulator is built specifically to solve that problem. It combines a cutter-compactor, a screw extruder, melt filtration, water strand cooling and cold cutting into one continuous line. The result is a uniform cylindrical pellet that can go straight back into weaving, film blowing or injection moulding.
MOOGE (Jiangsu Mooge Machine Co., Ltd) manufactures this line in two configurations: the RDL single stage series and the RSL double stage series, with input capacity from 100 to 1000 kg/h. This guide explains how the line works station by station, how to choose between single and double stage, and what information to prepare before you request a quotation.

What Is a Compacting Strand Cooling Cutting Plastic Granulator?

 
A compacting strand cooling cutting plastic granulator is a complete plastic pelletizing line that processes flexible plastic waste in four linked stages:

• Compacting - rotating and fixed blades cut the loose material and compress it into dense agglomerates
• Extrusion - a single screw extruder melts, plasticizes and degasses the compacted material
• Strand cooling - the melt is extruded through a die head into round strands and cooled in a water tank
• Cutting - the dried strands are chopped into uniform cylindrical pellets by a pelletizing cutter

The words in the machine name describe the process itself. "Compacting" refers to the force feeder. "Strand cooling" refers to water bath cooling instead of water-ring or underwater cutting. "Cutting" refers to cold strand cutting, where the plastic is already solid before the blade touches it.
This is the traditional and most mature pelletizing process in the industry. It is not the newest method, and that is precisely why buyers choose it: the mechanism is simple, spare parts are widely available, and operators can be trained quickly. MOOGE builds the machine as part of a wider Plastic Pelletizing Line range.

How the Compacting Strand Cooling Cutting Process Works, Step by Step

The complete line contains eighteen working stations. Material moves through them in this order:

• Feeding conveyor belt feeds loose film or bags into the compactor
• Semi-auto metal detector removes ferrous and non-ferrous contamination
• Compacting force feeder cuts and compresses the material
• Single screw extruder, first stage, melts and plasticizes
• Vacuum degassing system pulls out moisture, air and volatiles
• Laser filter, self cleaning type, removes solid contamination
• Degassing die head performs final venting and divides the melt
• Single screw extruder, second stage, on RSL double stage models only
• Hydraulic screen changer, piston type, gives secondary filtration
• Die head forms continuous round strands
• Water cooling tank solidifies the strands
• Shaking and air drying machine removes surface water
• Air blower dryer performs deep secondary drying
• Pelletizing cutter cuts the strands to a set length
• Vibration screen separates oversize and fines
• Air feeding system and silo convey and homogenise the pellets
• Electric control cabinet manages the whole line
• Water chiller machine supplies low temperature cooling water

Each station is described in more detail in the sections below.

RDL Single Stage vs RSL Double Stage Strand Cooling Granulator: Which to Choose

This is the first decision every buyer has to make, and it depends almost entirely on how clean and how printed your input material is.
The RDL single stage line uses one extruder. It is shorter, cheaper and simpler. It works well when the material is reasonably clean and lightly printed.
The RSL double stage line adds a second extruder after the first. Compared with a single stage granulator, the double stage strand cooling pelletizer offers better degassing, finer filtration and more stable running, which helps prevent material degradation. It is the safer choice for heavily printed woven sacks, mixed post-consumer film, or any application where the customer buying your pellets specifies low gel content.

Consideration	RDL Single Stage	RSL Double Stage
Extruder configuration	One single screw extruder	Two single screw extruders in series
Degassing	Vacuum degassing	Vacuum degassing plus degassing die head
Filtration	One filtration stage	Two filtration stages
Best suited material	Cleaner, lightly printed scrap	Printed sacks, mixed post-consumer film
Melt stability	Good	More stable, less degradation
Floor space needed	Smaller	Larger, L or U layout possible
Relative investment	Lower	Higher

If you are unsure, send a material sample description to our engineers. Choosing a single stage line for dirty material is the most common and most expensive mistake in this product category.

Materials This Strand Cooling Pelletizing Line Can Recycle

The compacting strand cooling cutting plastic granulator is designed for soft, flexible thermoplastics. Typical input materials include:

• PP woven sacks and raffia
• PP jumbo bags and FIBC
• PP film and PP sheet
• BOPP labels and printed film
• Nylon yarn and nylon fibre

The process suits most thermoplastics, and it converts flexible PP film or bags into uniform cylindrical pellets that can be sold or reused directly.
Input material should be washed and dried before pelletizing if it comes from post-consumer sources. For that step MOOGE supplies a matching Waste PP Film/Bags Plastic Washing Line. If your feedstock is rigid rather than flexible, the Waste PE/PP/PS/ABS Rigid Plastic Recycling Line is the correct starting point instead.

Capacity and Motor Power: 100-1000 kg/h Models Compared

All models use a screw L/D ratio of 28-33:1 on the main extruder. On RSL double stage models the second screw runs at 10-12:1.

Model	Screw Dia.	RDL Motor	RSL Motor	Capacity
SJ100	100 mm	55 KW	55+22 KW	150-200 kg/hr
SJ120	120 mm	75 KW	75+30 KW	200-300 kg/hr
SJ150	150 mm	110 KW	110+37 KW	400-500 kg/hr
SJ160	160 mm	132 KW	132+37 KW	500-600 kg/hr
SJ180	180 mm	160 KW	160+45 KW	600-800 kg/hr
SJ200	200 mm	200 KW	200+55 KW	800-1000 kg/hr

Output varies with material type, moisture content and bulk density. The figures above are for reference and should be confirmed against your specific feedstock.

Feeding Conveyor Belt and Semi-Auto Metal Detector: Protecting the Screw from Scrap Metal

 
The feeding conveyor belt feeds loose soft PP film or bags smoothly and continuously into the compacting force feeder. An anti-slip surface stops material sliding back during feeding. The belt is interlocked with the compactor behind it, so feeding speed adjusts automatically to keep material flow uniform and prevent blockages.
The semi-auto metal detector sits in this section and detects incoming metal contaminants such as iron, copper and stainless steel before they reach the compactor. This protects the screws and die heads, which are the two most expensive wear items on the line. Sensitivity is adjustable. For buyers processing baled or heavily contaminated scrap, a VH-Series High Duty Industrial Plastic Shredder Machine placed before the conveyor is worth considering.

Compacting Force Feeder: How Bulk Density Affects Extruder Output

The compacting force feeder is the component that makes the whole line viable. Multiple rotary and fixed blades cut the flexible material at high speed and force it into high density agglomerates, which are then fed directly into the screw extruder.
Why this matters commercially: loose PP film has a bulk density of roughly 0.03-0.05 g/cm3. A screw extruder cannot maintain output on material that light. The compactor raises bulk density before extrusion, which increases throughput, prevents bridging in the feed throat, and keeps feeding stable. Without it, the same extruder would run at a fraction of its rated capacity.

Single Screw Extruder First Stage: Screw L/D Ratio and Plasticizing Quality

The first stage single screw extruder uses a 28-33:1 length to diameter ratio and a high performance screw design. It plasticizes, melts and mixes PE and PP material under high temperature.
L/D ratio is worth understanding before you compare suppliers. A longer screw gives the polymer more residence time, which means more even melting and better mixing. A short screw is cheaper to build but produces inconsistent melt, and inconsistent melt shows up later as uneven strand diameter and variable pellet size. The optimized screw geometry on this line delivers consistent melt and high output, and its stability directly determines the stability of the whole pelletizing line.

Vacuum Degassing System: Removing Moisture, Ink and Volatiles from the Melt

The vacuum degassing system sits at the middle section of the main extruder. A vacuum pump removes residual moisture, trapped air and low molecular weight volatiles from the melt.
The practical effect is fewer bubbles and less odour in the finished pellets, plus higher density and better transparency. This is the station that decides whether your pellets can be sold to a quality-conscious buyer or only to the commodity market. It is especially important for printed material, where ink solvents have to be driven off.

Laser Filter (Self-Cleaning Type) vs Hydraulic Piston Screen Changer: Two Stages of Filtration

The line filters the melt twice, and the two filters work on different principles.

Laser filter, self cleaning type

Installed at the first stage extruder outlet, the laser filter replaces traditional wire mesh with a solid filter plate containing precision laser-drilled holes. Because the plate is solid it does not deform under high pressure. An automatic scraper system cleans the plate continuously during operation, which eliminates manual screen changes and minimises melt loss. Melt pressure stays stable and pellet quality stays consistent.

Hydraulic screen changer, piston type

Positioned at the second stage extruder outlet, this unit provides secondary filtration of fine impurities and gel particles. The dual filtration design raises final pellet purity significantly, which matters for high-end applications with strict impurity limits. Both plate type and piston type filters are available as options.
For buyers: if your customers test for gel count or black specks, specify the two-stage filtration. If you are producing pellets for low-grade applications, single filtration may be sufficient and will reduce your capital cost.

Degassing Die Head and Die Head: Forming Uniform Strands for Cooling

The degassing die head is mounted at the end of the first extruder. It removes remaining gas and moisture as the melt passes through, and at the same time divides the melt evenly into multiple strands. It combines venting and shaping in one unit.
The main die head extrudes the fully plasticized and filtered melt into multiple continuous round strands, similar in appearance to noodles. Flow channels are designed for stable and uniform output, which guarantees consistent strand diameter. Consistent diameter is not cosmetic: if strands vary in thickness, they cool at different rates and the pelletizing cutter produces pellets of different lengths.

Water Cooling Tank and Water Chiller Machine: Why Cooling Length Controls Pellet Quality

A circulating cooling water system rapidly lowers the temperature of the hot strands so they solidify into their final shape. Both cooling length and water temperature are adjustable, which ensures the strand cools evenly from the outside to the core. Uneven cooling causes yellowing and internal stress in the pellet.
The water chiller machine supplies consistently low temperature coolant. That coolant does three jobs: it cools the extruder barrel to prevent material degradation, it solidifies the molten strands in the water bath to avoid deformation, and it hardens freshly cut pellets so they do not clump or tail.
Buyers in hot climates such as the Middle East, India and North Africa should confirm chiller sizing at the quotation stage. A chiller rated for a temperate climate will underperform at 45 degrees ambient.

Shaking Air Drying Machine and Air Blower Dryer: Preventing Yellowing and Porous Pellets

The shaking and air drying machine removes most surface water from the strands using high frequency vibration combined with strong airflow. The vibration also aligns the strands so they enter the next stage smoothly.
The air blower dryer then uses a high pressure blower for secondary deep drying, ensuring the strands are completely dry before cutting. Skipping or undersizing this stage causes two visible defects in the finished pellet: yellow discoloration and a porous surface. Both are immediate grounds for rejection by pellet buyers, so drying capacity is not a place to save money.

Pelletizing Cutter and Vibration Screen: Producing Uniform Cylindrical Pellets

The pelletizing cutter cuts the dried strands into uniform cylindrical pellets at a set length. High precision wear-resistant blades produce clean cuts with minimal dust and consistent size.
The cut pellets then pass through a double layer vibration screen, which separates oversized particles and fine powder from the product stream. Only uniform, well-shaped pellets continue to the silo. This improves yield and, more importantly for traders and distributors, improves batch-to-batch consistency, which is what repeat customers actually pay for.

Air Feeding System, Silo and Electric Control Cabinet: Automating the Finished Line

The air feeding system conveys qualified pellets into the storage silo using compressed air. The pipeline is fully enclosed, which prevents secondary contamination and saves labour. Inside the silo, pellets are mixed and homogenised so that each batch is consistent.
The electric control cabinet integrates electrical control, variable frequency drives, temperature regulation and fault alarms for every connected machine. It uses a centralized interface for parameter adjustment, and includes overload protection and interlock functions to protect both equipment and operators. For buyers with limited technical staff, this centralization is the difference between a line that needs a specialist and a line an ordinary operator can run.

Customization, Quality Control and Export Support

 
The compacting strand cooling cutting plastic granulator can be designed around your factory space and your final product requirements. Common customization points include:

• Line layout in L shape or U shape to fit an existing building
• Single stage or double stage extrusion
• Filter type, plate or piston
• Chiller capacity matched to local ambient temperature
• Voltage and frequency for your country
• Silo capacity and conveying distance

On quality control, MOOGE has over 15 years of experience designing and manufacturing plastic recycling and granulator machines. Machines are built to detailed drawings, and each line is connected and test run in the workshop before shipment. Our facility includes metal shearing, bending, milling and lathe machines, supporting a capacity of around 100 sets of plastic recycling line per year.
For support, a technical team is available 24 hours for pre-sale and after-sale questions, and engineers can design the full recycling line and prepare drawings to your requirements.

How to Prepare Your Inquiry

You will get an accurate quotation much faster if your first message includes:

• Material type - PP woven sack, jumbo bag, film, sheet or nylon
• Whether the material is printed, and how heavily
• Whether it is washed, and approximate moisture content
• Target output in kg/h
• Available floor space, length and width
• Local voltage and frequency
• Destination port

Photographs or a short video of your material are more useful than a written description, because bulk density and contamination level are easier to judge visually.

Frequently Asked Questions

What is the difference between strand cooling cutting and die-face cutting?

Strand cooling cutting extrudes the melt into strands, cools them fully in a water tank, dries them, and then cuts solid plastic. Die-face cutting cuts the melt at the die while it is still soft. Strand cutting is simpler to operate and maintain, and it produces a clean cylindrical pellet. Die-face cutting suits higher output and certain material types.

What capacity range is available?

Input capacity is 100 to 1000 kg/h across six screw sizes, from SJ100 with a 100 mm screw up to SJ200 with a 200 mm screw. Both RDL single stage and RSL double stage models cover this range.

Can the line handle printed PP woven bags?

Yes. Heavily printed material is the main reason to choose the RSL double stage configuration, because the extra degassing and second filtration stage handle ink residue and volatiles more effectively than a single stage line.

Does the material need to be washed first?

Post-consumer material should be washed and dried before pelletizing. Clean in-house production scrap can often go directly into the compactor. If you need a washing stage, it can be quoted together with the pelletizing line.

What pellet shape and size does the machine produce?

The line produces uniform cylindrical pellets. Pellet length is set by the pelletizing cutter and can be adjusted. Diameter is determined by the die head hole size, typically in the 3 mm range for recycled PP and PE.

Can you supply the complete line including the chiller and silo?

Yes. The quotation can cover the full process from feeding conveyor through to air feeding system, silo, electric control cabinet and water chiller machine, or individual sections if you already own part of the equipment.

Conclusion

A compacting strand cooling cutting plastic granulator remains the most practical and cost-effective way to turn flexible PP and PE waste into saleable pellets. The process is mature, the components are proven, and the operating knowledge required is well within reach of a normal production team.
The decisions that actually affect your return are choosing correctly between the RDL single stage and RSL double stage configuration, sizing the chiller and drying stages for your climate, and matching capacity honestly to your real feedstock rather than to a headline figure.
If you would like model recommendations, a detailed specification, layout drawings or a quotation for your material, our engineering team is ready to help. Send us your material details and target output through the contact page, or message us directly on WhatsApp at +86 13584489215. We are happy to review your feedstock and advise on the right configuration before you commit to anything.