Plastic Blown Film Machines: Output Capacity and Resin Compatibility

A Plastic Blown Film Machine https://www.jldplastic.com/plastic-film-blowing-machine/plastic-blown-film-machinemelts polyethylene resin, shapes it into a thin bubble, and cools it into continuous film. Output capacity depends mainly on screw diameter, motor power, temperature control, and cooling. Resin compatibility depends on how well the machine settings match the polymer's melt behavior. The SJ-series high-pressure film blowing machine described here is designed for LDPE, LLDPE, and PE. It offers screw diameters from 45 mm to 90 mm and listed lay-flat widths from 600 mm to 2000 mm. This guide helps procurement managers and packaging engineers match machine size and resin choice to real production needs.

Overview of Plastic Blown Film Machines and Their Working Principles

Main Components and Materials

A blown film line has a screw and barrel, a circular die, an air ring, nip rollers, a winder, and a frame that can snap back into place. Screw and barrel carry the most weight since they feed, melt, and mix the resin. Sizes of the screws in the SJ series are 45, 50, 55, 65, 75, 85, and 90 mm, and the L/D ratios are 28:1 or 30:1. A longer screw gives the plastic more time to melt and mix, which helps the melt be more even. There are 4 to 6 heat bands that go around the barrel, so the resin doesn't get too hot all at once.

Step-by-Step Blown Film Extrusion Process

There are five steps to the process. To begin, resin pellets fall from the hopper into the barrel. Second, the screw moves the melt forward at 150–180°C and 20–120 r/min. Third, the melt makes a tube as it runs through the round die. Fourth, air makes a bubble in the tube, and the air ring cools it down. Fifth, the bubble is flattened by nip rollers, and the film is put into the winder. Bubble size and pull speed decide how wide and thick the film is. This Plastic Blown Film Machine makes films that are 15 to 100 μm thick. When I size a line, I look at all five steps because they all change the output and film quality.

Machine Types: Single-Layer, Multi-Layer, Automatic, and Manual

There are two main ways that buyers sort Plastic Blown Film Machines. A single-layer line squirts out a single resin stream, while a multi-layer line mixes several streams into one die to make a hybrid film. A manual machine needs the user to change the speed, temperature, and thickness. An automatic line, on the other hand, has controls that keep those settings fixed. It works well for PE film jobs like high-pressure clear film, vest-style bags, flat bags, and food packing bags. If you need to protect your product from oxygen or moisture, ask about multi-layer options before you pick a size.

Output Capacity: Key Dimensions and Performance Factors

How Output Capacity Is Measured

Output capacity is usually shown in kilograms of film per hour. Three things make that number work. What the extruder does is set by the screw size and speed. The film width tells you how much material one meter of film needs. How heavy each meter gets is based on how thick the film is. It takes more melt per minute to make a wide, thick film than a narrow, thin one. The ceiling is set by the motor power. The SJ series has a 7.5 kW motor that goes with a 45 mm screw and a 55–75 kW motor that goes with 85 mm or bigger screws. People who want to buy something should ask for the rated output for the specific glue and thickness they have, since one rated number doesn't always work for all jobs.

How LDPE, LLDPE, and Other Resins Change Speed and Quality

LDPE is easy to melt and forms a clear, soft film, so it works well in the 150–180°C temperature range for this Plastic Blown Film Machine. LLDPE makes film that is less likely to tear or cut. But its melt is tougher to push, which means the screw and motor have to work harder. It is common to mix the two: LDPE makes things clear and easy to work with, while LLDPE makes things tough. Check with the supplier first because HDPE film is stiffer and clearer, but it needs to be heated and cooled in a different way. When the melt index changes, both speed and film strength change. This means that resin grade is just as important as resin family.

Tuning Temperature, Screw Speed, and Cooling

Three settings let you choose the right speed for the film. With a total heating power of 10–40 kW, the 4–6 heating zones let operators set a gentle temperature range of 150–180°C. The bubble can't stay in place if the melt gets too hot. If it runs too cool, bits that haven't melted can show up in the picture. The output goes up when the screw speed is raised between 20 and 120 r/min, but the melt heat and motor load go up too. Stronger air cooling sets the bubble faster and lets you pull faster, but uneven cooling makes the width change and creates wrinkles. I only make small changes to the settings at a time and check the thickness after each one.

Comparison of Plastic Blown Film Machines by Output Capacity and Resin Compatibility

Comparing the SJ Series by Screw Size

I'm not ranking brands here; instead, I'm comparing configurations because the right size depends on your film width and resin. The table shows the SJ-series numbers that I can confirm:

Series	Max Lay-Flat Width	Main Motor Power
45 mm	600 mm	7.5 kW
50 mm	800–1000 mm	11–15 kW
55 mm	1200 mm	18.5 kW
65 mm	1500 mm	22–30 kW
75 mm	1800–2000 mm	37–45 kW
85 mm and above	Check with SYM	55–75 kW

The 45 and 50 models are made for bags and narrow film runs. When it comes to wide film for big bags and industrial soft packaging, the 75 series works well.

Automatic vs. Manual Operation

Buying manual lines is usually cheaper, but it depends on how skilled the person running them is. Changes in resin, thickness, or width have to be made by hand, which slows down the process and can lead to more scrap at the beginning. With automatic lines, you can control the temperature, thickness, and wrapping, which makes sure that the film stays the same over long orders and with different resin blends. People who buy mixed LDPE and LLDPE recipes get more out of steady control than people who buy just one resin all year. Different sellers use different words to describe what functions are automatic on the model they are offering, so make sure you ask each one.

Single-Layer vs. Multi-Layer Trade-Offs

A single-layer line is easier to set up and keep up. This Plastic Blown Film Machine is meant to work with high-pressure clear film, flat bags, and food bags. When you use multi-layer co-extrusion, you can add layers like barrier resins that keep oxygen and moisture out of food, seeds, and pharmaceutical goods. This means the die has to be more complicated, there are more extruders, and control over each layer has to be tighter. We at SYM use multi-layer co-extrusion to make our finished bags, so we know how the structure of the layers affects the closing and barrier effects. Pick the structure based on how well it protects the product, not how many layers you want.

Maintenance and Troubleshooting Tips to Sustain Output Efficiency

Common Faults and Their Causes

There is a short list of things that can cause output losses. Uneven film thickness is often caused by an air ring or die gap that isn't level. Gels, which are sometimes called "fisheyes," usually mean that the resin didn't melt well or broke down. If the melt temperature is too high or there are drafts near the line, the bubbles may not stay stable. The output goes down slowly as the gap between the screws and barrels gets bigger. This makes the melt less even. By comparing the hourly output to the rated value, I can find signs of wear before they cause the Plastic Blown Film Machine to shut down.

Routine Maintenance and Parameter Calibration

A simple schedule keeps a lot of problems from happening. Every shift, I think the operators should check the heater bands, thermocouples, and air ring openings. It's possible for them to clean the die lip and look for dirt on the nip rollers once a week. You should check the motor power, shaft oil, and screw-to-barrel clearance every three months. If you change the resin, you need to re-adjust the temperature profile and screw speed to work with the new grade. After that, write down the choices that made the thickness stable. The next shift can quickly repeat a good run thanks to written records.

Spare Parts and After-Sales Support

It costs more to have downtime than to buy parts. Keep extra heater bands, thermocouples, belts, and filter screens on hand in case they run out. Before you place your order, ask the seller for a list of suggested extra parts and how long it will take to get each one. Support is just as important as tools because when something goes wrong, you need to be able to get help quickly. More than 40 expert staff work at our plant, and our customer service is open 24 hours a day. A fault report and a fix can happen faster when people can talk to each other clearly.

Procurement Guide: Selecting the Right Plastic Blown Film Machine

Define Volume, Width, and Resin First

These are the first three numbers you need to work with: the monthly film tonnage, the target lay-flat width, and the thickness range. Then, write down the name of each resin you want to use, along with its grade and any blends. Pick the machine with these numbers. A 50-series machine can be 800–1000 mm wide, and a 65-series machine can be 1500 mm wide. Leave room for seasonal highs, which are important for people who pack food and agricultural goods. Don't just buy for peak demand, though. An oversized machine that isn't being used at all wastes energy and floor space. Tell the seller what you want to make, like food bags or soft packaging for factories, so the team can make sure it fits.

Budget, Financing, and Total Cost of Ownership

The budget only has one line for the order price. Add up the cost of energy, extra parts, starting waste, training for operators, shipping, and installation. This Plastic Blown Film Machine has an energy-efficient motor and a 4–6 stage temperature control system that makes sure the film thickness is the same and the yield stays stable. I suggest that you compare quotes based on how much each kilogram of film costs over a number of years, not on the price tag. You should ask each seller if they offer financing or leasing, as terms vary by seller and country. Ask for written quotes that cover the same ground; that way you can compare like with like.

Supplier Checks: Certification, Delivery, and Warranty

Check out the factory that's behind the Plastic Blown Film Machine. More than 100 people work at SYM's workplace, which is 8,600 m². We are certified to ISO 9002 for our quality management system and by China's QS. We ship to more than 40 countries. Your QA team will also look at the plastic grade for food-contact film. In 21 CFR 177.1520, the U.S. Food and Drug Administration (FDA) states the olefin polymers that are allowed. Write down the shipping time, guarantee length, fitting help, and availability of spare parts. Before you sign, also ask if you can see a sample film made from your own plastic.

Conclusion

This section talks about the output of a Plastic Blown Film Machine, which is based on the screw diameter, motor power, temperature control, cooling, film width, and film thickness. How the settings are changed by the resin: Grades like HDPE need separate proofing, while LDPE makes the film clear and easy to run. LLDPE also makes it stronger against tears and punctures and has a higher motor load. The screw sizes in the SJ series range from 45 to 90 mm, and the processing temperature ranges from 150 to 180°C. The stated lay-flat lengths range from 600 to 2000 mm. For mixed recipes and long orders, automatic control works best. Lines with one layer work well for simple PE film, and lines with more than one layer work well for gaps. Output stays steady thanks to regular calibration, spare parts, and careful checks by the supplier. Setting the volume, width, and resin before comparing prices helps buyers find the best match.

FAQ

Which resins can the SJ series film blowing machine process?

The SJ series is made for PE, LDPE, and LLDPE. High-pressure clear film, vest-style bags, flat bags, food packaging bags, and general packaging film are all made from these resins. Ask our team to make sure it will work with another material, like HDPE or PP, before you place your order.

How can I raise output without lowering film quality?

One setting at a time. The screw speed should be raised to between 20 and 120 r/min. Next, check the thickness, melt temperature, and bubble stability. Increase the speed and make the cooling stronger. It is important to make sure that the motor power is right for the resin, especially if you are using LLDPE, which puts more strain on the motor.

What maintenance keeps a film blowing machine running well?

Every shift, check the heater bands and thermocouples, and clean the die lip once a week. Check the wear on the screws and barrels regularly. After changing the resin, make sure the speed and temperature are set correctly again, and keep important spare parts on hand to avoid long stops.

Request Your Plastic Blown Film Machine Quote from SYM

Want to buy a Plastic Blown Film Machine from a company that responds quickly to questions? SYM has been making products for more than 20 years and has customer service available 24 hours a day, 7 days a week. Send your plastic type, film width, and thickness range to jinlidasuliao@zohomail.cn, and our team will give you a price for a good SJ-series model. For more information on the goods, go to jinlida.aixdb.cn.

References

1. Blown Film Extrusion, 2011

2. Film Extrusion Manual: Process, Materials, Properties, 2005

3. Extrusion: The Definitive Processing Guide and Handbook, 2005

4. Plastics Extrusion Technology, 1997

5. Applied Plastics Engineering Handbook, 2011

6. Code of Federal Regulations Title 21, Section 177.1520 (Olefin Polymers), 2023