Are you looking to produce beverage bottles but not sure what type of PET blow molding machine will best meet your needs?
Perhaps you have been asked to supply polyethylene terephthalate (PET) beverage bottles instead of polypropylene (PP) and want to know how to adapt your business?
First, we need to acknowledge what options there are for machines, with three main types on the market:
Single-stage PET blow moulding machine
Two-stage PET blow moulding machine
The exact type of PET blow molding machine your bottle production needs depends on output, available space, bottle contents, and desired shape/size.
What is PET blow moulding machine
This is a manufacturing process commonly used to create plastic bottles. However, it can also be used to produce oil gallons and larger plastic containers.
plastic is also used in the mass production of plastic bottles.
In this article, we will focus on the PET blow moulding machine
PET starts by entering the machines through a preform or parison. These can be made in the same factory or purchased separately.
PET plastic, if made inside, must be heated and made into the desired size, shape and weight.
These are pre-calculated so you get the exact bottle you need.
Your preforms or parisons are then heated to become moldable before being blown to the desired size and shape.
Hot air is blown under pressure into the plastic preform or parison to produce the bottles.
If you have a stretch blow molding machine, there will be another step here to form the bottle, after which the formed bottles are allowed to cool and then removed so they can move on to the next step in your setup.
According to waste statistics, “481.6 billion plastic bottles are used worldwide in one year. This amount is 40 billion per month.
With numbers like these, the plastic bottle industry will continue to grow in the coming years as uptake increases in countries that still rely on glass over plastic.
As most beverage bottles are produced from PET plastic, the demand for a reliable and efficient PET blow molding machine will also increase.
What are the processes of blowing and producing bottles?
As with all manufacturing processes, some steps must be systematically followed to ensure a consistent product and quality for your customers.
Whether you use a single-stage or two-stage PET blow molding machine to produce bottles, the following steps must be performed:
Complete drying of PET materials and dehumidification
Heating PET material for temperature correction
Injection of liquid PET into a preform mold for the shape and size of the bottle
Preform cooling, so it retains its shape
Cooling of the finished product
Remove the dried, shaped and cooled bottle from the equipment
Of course, there are variations in the steps depending on whether you are running a single-stage or two-stage production line.
The key differences here are:
If you need parison or preform, for PET bottle plastic, you need preform.
Whether the preform is allowed to cool after injection, reheated to that temperature when ready for molding, or whether the preform is kept warm enough that reheating is not required.
The difference between preform and parison
Nominally, these may look very similar and are easily confused with each other. Of course, we will explain some key differences below.
PET plastic can be used in both forms. Choosing the best option for you depends on the used pet blowing machine and the desired bottle products.
Preforms are produced using a plastic injection machine. PET plastic raw materials and heating them to the right temperature can flow like a viscous liquid.
The preforms are placed inside the PET blow molding machine where the plastic is injected under pressure and accommodates the opening and threading as specified.
Once sufficiently cooled, these PET preforms can be stored until needed, when they are reheated and molded into their final shape and size.
Working this way means you can generate the preforms yourself in-house and then store them until you need them. It may be more economical to buy preforms from another manufacturer.
Modern advances in preform manufacturing methods have improved accuracy, and their transportation is relatively efficient due to their compactness and lightness.
Filling sites tend to do things this way because they don’t have to purchase the injection molding machine itself or have skilled operators run it and check tolerances.
If your bottling plant relies on injection blow molding or injection stretch molding, you need PET preforms.
This style of plastic molding relies on creating a hollow tube mold of plastic, similar to preforms, but for blow molded plastic.
The output of this method is usually plastic containers, drums, vats and complex shapes, usually higher tensile strength, thicker walls and solid colors rather than transparent finishes.
The most commonly used materials are HDPE, LDPE or PVC.
Due to the favorable properties of PET plastic and its use for beverage bottles, the methods of injection blow molding and stretch injection blow molding are desirable.
Automatic PET blow moulding machine
This type of injection molding refers to the one-step device. Of course, several processes are required to produce the bottles in this case.
These processes are carried out by the same pet blowing machine. It is essentially a production line housed in one piece of equipment, taking care of three or four separate steps.
Each of these stations is automated, so the equipment can operate continuously without human assistance. This can help increase your overall productivity in the factory and then distribute the finished bottles directly to the next stage of your production line.
By reducing the number of machines, you can save valuable floor space and run a leaner operation overall.
This style of blow molding machine is the most economical solution, especially when producing large quantities of containers and bottles for mass use. However, it comes with a higher initial capital to purchase the equipment.
The plus side is that you will save on your electricity bill because the preforms are not allowed to cool and no reheating step is required.
Semi-automatic or manual PET blow moulding machine
The semi-automatic or manual molding process requires the use of preforms. These are PET plastic molds with the opening and thread of the bottle pre-made.
Your hand blown machine takes the PET preform and heats it to the temperature you need before blowing it to the size and shape with pressurized air.
Once sufficiently cooled, these finished products can be transferred to the next stage of your bottling operation to be quality checked, filled with liquid, and then labeled.
This method allows bottles up to 1 liter to produce high quality output.
Two-stage stretchable PET blow moulding machine
Also known as ISBM (injection molding), this method is favored by those wishing to produce very high volumes of bottles, which are popular for PET use.
After the preforms are heated to temperature, they are blown with hot, food-grade air, as in standard two-step molding. However, this method has another important step.
Using a metal core rod, the soft plastic is drawn into the desired shape before cooling.
Stretching PET plastic in this way results in optimal strength. In this way, the heated polymers respond and create a stronger molecular structure.
Also, improved gas permeability in the process are the two main reasons why carbonated drinks are usually filled in this type of PET bottle. They do a great job of keeping the contents intact under pressure and retain the gas when the end users come to enjoy their drink.
Bottles up to 2 liters can be produced with high precision using this method.
Why use PET for bottle production?
Polyethylene terephthalate (PET) is a common thermosetting plastic for beverages and beverage bottles for the following reasons:
Glossy and smooth finish
Does not release chemicals such as BPA or phthalates into existing liquids.
Due to the contents of the drink inside, it does not degrade or spoil.
The construction cost is relatively low.
It can be transported effectively.
Gas permeability properties are very low, so compared to other plastics, it holds carbonated drinks well.
This plastic is safe and approved for use worldwide by health and safety organizations such as the FDA in the United States, the Food Standards Agency in the United Kingdom, or the TGA in Australia.
Preforms can be ordered to meet exact specifications or manufactured in bulk and then stored without problems until needed.
You can create an identifiable, brand-specific bottle shape that stands out from your competition.
As you can see, these are very compelling reasons to use PET over other composites for beverage packaging.
When you want to choose the right type of PET for your bottle production, there are two types that are useful to know:
APET (amorphous polyethylene terephthalate)
CPET (Crystalline Polyethylene Tetraphthalate)
Since you are interested in producing bottles, the type of PET used will be APET. It has the most suitable properties for application.
What are the disadvantages of using PET?
As we may rely on the widespread use of PET for beverage applications, like any other material, it has its drawbacks or disadvantages. It’s best to be aware of that when deciding which avenue to explore for your bottling plant.
Here is a list of perceived disadvantages to using PET in bottles:
Can’t be pasteurized inside bottles because too much heat causes them to warp and change shape, specially designed PET can withstand temperatures of around 75°C.
PET bottles can absorb a small amount of flavoring, so a little more is needed.
Acetaldehyde produced during bottling can spoil the taste of the contents, especially when water is used to fill the containers. It may be minor but it is noticeable.
Inefficient for recycling.
Low melt temperatures can cause problems in bottles or preforms if exposed to high temperatures in storage, shipping, or otherwise.
Complex shapes are not produced as quickly as possible in contrast to extrusion blow molding and other plastics.
To produce the best bottles, they should be made using the injection stretch molding technique.
Low tolerances and high precision are required, which isn’t necessarily a bad thing, but it makes the manufacturing process less forgiving and has less margin for error.
Here at Bottling, we supply accessories to meet your bottling plant needs. Our two-stage stretch blow molding machine can help ensure a consistent and reliable output of up to 15,000 bottles per hour.
These high-quality produced bottles have a volume of up to 2 liters, and the blow molding machine is able to work 8 holes in a day and night, making your operation more productive.
Buy a PET blow moulding machine
Types of PET blow moulding machine in different dimensions Mega PET blow moulding machine (mg) and other PET blow moulding machine for producing semi-automatic and fully automatic plastic water bottles with an output of 1000 to 8000 bottles per hour that can meet the needs of different customers. Our products have unique features to meet all the needs of customers. Pars Company is the manufacturer of the best semi-automatic and fully automatic PET blow moulding machine with the best quality and the most reasonable price.
To get advice and guidance for buying all kinds of manual and automatic PET blow moulding machine, contact our sales experts on 02144983107 and WhatsApp 09336768109.