Packaging factories, brick makers, metal processors and logistics companies all need strong, low-cost strapping. A PET strap production line lets you make that strapping in your own plant. It runs recycled PET bottle flakes, virgin PET, or a mix of both.
This guide explains how the line works, step by step. It follows the real machine order, from the Honeycomb Crystallizer Dryer to the Automatic Winder Machine. You will also find model specifications, supplier selection tips and answers to common buyer questions. The information matches the SJ-series PET packing strap production line from Jiangsu Mooge Machine Co., Ltd. (MOOGE).

What Is a PET Strap Production Line and How Does It Work?

 
A PET strap production line is a complete set of machines that turns PET raw material into high-strength packing strap. The line dries the material, melts it, filters the melt, forms a thick strap, stretches it, embosses it and winds it into coils.
The process has four main stages:

• Preparation: crystallizing, drying and feeding the PET.
• Melting and shaping: extrusion, filtration, metering and die forming.
• Strengthening: cooling, heating, stretching, embossing and heat setting.
• Finishing: winding and electrical control.

Stretching is the key step. It improves the toughness and strength of the strap. A well-run line delivers stable quality, with good straightness and equal width and thickness control.

Raw Materials for PET Strap Making

The line accepts 100% recycled PET flakes from waste bottles, virgin material, or a mix of the two. Recycled flakes reduce material cost. If you also need to produce your own flakes, our PET Bottle Washing Line removes labels, caps, glue and contaminants to give you clean PET flakes. Clean flakes make the strap line easier to run.
Strap offcuts and start-up scrap can be crushed into small pieces for reuse. A Plastic Crusher/Grinder Machine handles that job.

Where PET Strap Is Used

PET strap is widely used in logistics, warehousing and manufacturing for heavy-duty bundling, palletizing and unitizing. Common loads include:

• Bricks and building materials
• Metal coils
• Timber
• Cotton bales and packaging materials

Step 1: Drying PET Bottle Flakes with the Honeycomb Crystallizer Dryer

Crystallization comes first. The Honeycomb Crystallizer Dryer heats and stirs the PET flakes so they do not stick or clump at high temperature. It also removes surface moisture. The interior and the stirrer are made of stainless steel. This system is optional, so check with your supplier whether your material needs it.

Step 2: Removing Moisture with the Dehumidify Machine

PET absorbs moisture, and moisture causes hydrolysis during melting. Hydrolysis weakens the material and lowers strap strength. The Dehumidify Machine removes this moisture before extrusion, so the melt stays stable and the strap keeps its strength. Parts that contact the material are stainless steel. Even drying across the whole batch is one of the main reasons a line produces consistent strap.

Step 3: Feeding Material Automatically with the Screw Loader

The Screw Loader moves recycled PET bottle flakes, PET granules and other raw materials to the next machine. Screws, barrels and grooves that touch the material are stainless steel. Automatic feeding reduces manual handling and gives the extruder a steady supply.

Step 4: Melting PET in the Single Screw Extruder

The Single Screw Extruder melts the PET at high temperature. Its specially designed screw gives a high plasticizing rate and a uniform melt, which supports continuous, stable production. Key features include:

• Inverter control of motor speed
• A stable additive feeding system
• Screw and barrel made of 38CrMnAlA steel with nitriding treatment, which extends service life

Step 5: Filtering Impurities with the CPF Filter Machine

Recycled material can carry small impurities into the melt. The CPF Filter Machine filters them out before the melt reaches the die. Its large filter area means operators change the filter screen mesh less often, so the line runs longer between stops.

Step 6: Controlling Melt Flow with the Metering Pump

The Metering Pump delivers the melt to the die head at a constant flow rate and pressure, without pulsation. This steady flow keeps strap thickness uniform and supports continuous production. Buyers who care about tight thickness control should look closely at this component.

Step 7: Shaping the Strap Through the Die Mold

The Die Mold forms the melt into the strap shape. Size and thickness are adjustable. The die is made of 38CrMnAlA steel with polishing, heating and quenching treatment. Depending on the model and your output target, the line can extrude 1 to 4 straps at one time.

Step 8: Cooling and Solidifying in the Water Cooling Tank

After the strap leaves the die, it enters the Water Cooling Tank. Cold water cools the strap and fixes its shape. The tank body is stainless steel, and the frame is welded profile steel with precision-treated fixing surfaces. A liquid level controller keeps the water level constant.

Step 9: Pulling the Strap Forward with the Haul-off Machine

The Haul-off Machine pulls the strap forward, stabilizes its shape and controls conveying speed. A Delta inverter (Taiwan) adjusts the motor speed. Steady pulling speed helps keep width and thickness equal along the whole length of the strap.

Step 10: Heating the Strap in the Hot Air Circulation Oven Machine

Before stretching, the strap passes through the Hot Air Circulation Oven Machine. An air blower circulates hot air so the strap heats fully and evenly. The oven has a double-layer body with an insulation layer inside, which helps hold the temperature steady.

Step 11: Boosting Tensile Strength with the Stretching Machine (2 or 3 Sets in Series)

The Stretching Machine (2 or 3 sets in series) stretches the heated strap under precise control. This step improves the toughness and strength of the finished strap. Motor speed is adjusted by a Delta inverter, and the machine is fitted with a clamp subassembly. Two or three sets work in series, so the strap is stretched in more than one pass.

Step 12: Adding Grip Patterns with the Embossing Machine and Setting Shape in the Heating Forming Tank

The Embossing Machine presses a pattern into the strap. The pattern increases friction, improves strapping security and gives the strap a better appearance. The embossing roller has a hardening treatment for long service life.
The strap then enters the Heating Forming Tank. Heat setting removes internal stress and stabilizes the strap dimensions. After that, the strap is cooled and formed in a water tank.

Step 13: Coiling the Finished Strap with the Automatic Winder Machine

The Automatic Winder Machine winds the strap neatly and tightly into rolls of the specified size. A torque motor controls winding speed. An automatic weighing system sounds an alarm and stops the machine when the roll is full, which saves operator time.

How the Electric Control Panel Keeps the Whole PET Strap Production Line Running

The Electric Control Panel switches the whole line on and off. You can choose a PLC touch screen, which lets operators monitor, control and optimize the process in real time. The panel uses Schneider contactors and thermal relays that protect the motors. PLC-based automation keeps the line efficient and stable from the first machine to the last.

PET Strap Production Line Models and Specifications

The table below lists the SJ-series models. The line can be designed to match your factory area and final product requirements. For photos, videos and the full process flow, see our PET Strap Production Line page.

Model	Capacity (kg/h)	Strap Size (mm)	Installed Power (kW)	Area Required (m)
SJ65/33 Single Strap	50-60	9-19	85	35 x 4 x 5
SJ75/33 Single Strap	80-100	9-19	100	38 x 4 x 6
SJ75/33 Double Strap	80-120	9-19	110	40 x 4 x 6
SJ90/33 Double Strap	150-200	9-19 / 25	150	45 x 5 x 7
SJ120/33 Triple Strap	200-250	9-19 / 25	220	50 x 5 x 7
SJ130/33 Four Strap	400-450	9-19 / 25	300	55 x 6 x 7

 
Output depends on the material and the strap size you choose. Always confirm the final configuration with the supplier before you order.

How to Choose a Reliable PET Strap Production Line Supplier

 
A good decision starts with clear requirements. Use this checklist when you compare quotations:

• Target output: choose a model that fits your daily volume, not just your current orders.
• Strap size and number of straps: confirm width, thickness and whether you need 1, 2, 3 or 4 straps at once.
• Raw material condition: tell the supplier whether you use recycled flakes, virgin PET or a mix, and how clean the flakes are.
• Key components: ask about the screw and barrel material, die material, drying system, melt filter, inverter brand and contactor brand.
• Space and power: check the area and installed power against your plant layout and local supply.
• Support: ask about installation, operator training, spare parts and technical support after delivery.
• Documents: request a clear quotation, a machine list and videos of the line running.

Common Buyer Concerns

Overseas buyers often ask the same questions before they send an inquiry:

• Will recycled flakes weaken the strap? Strap strength depends on drying, melt filtration and stretching. A proper drying system, a large-area filter and controlled stretching all reduce the risk of weak spots.
• Can the line be customized? Yes. The line can be designed around your factory area and your final strap requirements, including the number of straps.
• How can we check quality before ordering? Ask for running videos, a full component list and a clear technical agreement. Discuss your own material and strap standards at the same time.

MOOGE offers customized turnkey solutions for plastic recycling lines. If you plan to build a complete flow, from bottle washing to strap making, one supplier can make planning and coordination easier.

Frequently Asked Questions

Can a PET strap production line run 100% recycled PET bottle flakes?

Yes. The SJ-series line runs 100% recycled PET flakes from waste bottles, virgin PET, or a mix of both. Clean, well-washed flakes give the most stable results. Good drying and melt filtration also matter when you use recycled material.

What output capacity can I choose?

Input capacity ranges from 50 to 450 kg/h, depending on the model. Smaller single-strap models suit startups and regional strap makers. Larger triple-strap and four-strap models suit high-volume factories.

What strap sizes can the line produce?

Strap width is 9-19 mm on all models. The larger models, from SJ90/33 upward, also cover 25 mm. Tell us your required width and thickness so we can confirm the right die and configuration.

How many straps can the line extrude at one time?

The line can extrude 1 to 4 straps at one time, depending on the model and your production target.

Do I need the Honeycomb Crystallizer Dryer?

The crystallization system is optional. It heats and stirs the flakes so they do not clump, and it removes surface moisture. The Dehumidify Machine then dries the material further. Send us your material condition, and we will advise whether you need both.

How much factory space does the line need?

The required area runs from about 35 x 4 x 5 m for the SJ65/33 to 55 x 6 x 7 m for the SJ130/33. The line can be designed to suit your factory area, so share your layout when you request a quotation.

Conclusion

A PET strap production line turns recycled bottle flakes into strong, practical packing strap through a clear sequence of machines. Each stage matters: drying, melting, filtering, shaping, cooling, stretching, embossing, heat setting and winding. When these machines work together under stable PLC control, you get consistent strap quality and steady output.
If you are planning a new strap plant or upgrading an existing one, tell us your material condition, target capacity and strap size. Contact our team for product details, a quotation, customization options or technical support.