Blow Molding Machine丨Working Principle, Process Flow and ...

The principle of the bottle blowing machine

The blowing process of the bottle blowing machine is divided into two parts.

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1. Warm-up

An infrared high-temperature lamp irradiates the preform to heat and soften the preform. To maintain the shape of the bottle mouth, the preform mouth does not need to be heated, so a particular cooling device is required to cool it. 

2. Blow moulding

The preheated preform is placed in the blow mould, and the inside is inflated with high pressure to blow the preform into the required bottle. The automatic bottle blowing machine combines the two operations of bottle blowing through the operation of the manipulator, eliminating the need for the manual process of putting the preheated preform into the blowing mould. Significantly accelerate the rate of production. 

The process flow of the bottle blowing machine

The blow moulding machine process of the bottle blowing machine is a two-way stretching process. In this process, the PET chain is extended, oriented and arranged in two directions, which increases the mechanical properties of the bottle wall. It improves the tensile, tensile, and impact strength. It has good airtightness.

Although stretching helps to increase strength, it should not be overstretched. It is necessary to control the stretch-inflation ratio:

Do not exceed 3.5-4.2 in the radial direction and 2.8-3.1 in the axial direction. The wall thickness of the preform should not exceed 4.5mm.

Blowing is carried out between the glass transition temperature and the crystallization temperature, generally controlled between 90 and 120 degrees. The PET exhibits a highly elastic state in this interval and becomes a transparent bottle after rapid blow moulding and cooling, and setting.

This temperature is determined by the length of the cooling time during the injection moulding process (such as the Aoki bottle blowing machine), so the relationship between the injection and blowing stations must connect.

The blowing process includes stretching-blowing once-blowing twice. The three actions are concise, but they must be well-coordinated, especially the first two steps to determine the overall distribution of the material and the blowing quality.

Therefore, it is necessary to adjust: stretching start timing, stretching speed, pre-blowing start and end timing, pre-blowing pressure, pre-blowing flow, etc.; if possible, it is better to control the overall temperature distribution of the preform, bottle The temperature gradient of the inner and outer walls of the blank. In the process of rapid blow moulding and cooling, induced stress is generated in the bottle wall. For gas-filled beverage bottles, it can resist internal pressure, which is beneficial. Still, hot-filled bottles must ensure that it is fully released above the glass transition temperature.

Common problems and solutions in the blowing process of the bottle blowing machine

1. What should I do with the bottom of the bottle blown by the bottle blowing machine?

The common factor for bottle accumulation is that the stretching rod is not adjusted in place. It is recommended that the stretching ratio between the preform and the bottle body is preferably 1:2.5 (excluding the mouth part), and at the same time adjust the heating temperature to extend the pre-blowing.

2. What should I do if the bottle’s mouth-blown by the bottle blowing machine is deformed?

Bottle mouth deformation Generally, during the heating process of the preform, the transmission chain drives the bottle base to transfer the temperature to the preform mouth. During the heating process, the temperature continues to accumulate, and the bottle mouth bulges and deforms. It only needs to increase the air-cooling or water-cooling of the bottle mouth. If the customer’s conditions permit, you can refer to the imported machine to install central air-conditioning in the production workshop to keep the ambient temperature of the workshop at an average temperature.

3. How can the bottle-blowing machine be operated, and which accessories should be checked?

As long as the equipment is controlled strictly following the method in the instruction manual and the performance of each safety door is checked regularly, the equipment as a whole is safe. However, the most significant hidden danger of the equipment is mainly on the seals of the water jacket and air jacket. For example, the water and air jacket are damaged, and the maintenance works are more troublesome.

4. How much chiller is needed for the carbonated beverage bottle blowing machine to blow the bottle?

The chiller for the carbonated bottle is about five times larger than the chiller for the water bottle. A simpler algorithm can be calculated at bottles/hp; for example, bottles/hour can equip with a 30-hp chiller. To ensure the stress requirements of the carbonate bottle bottom, the cooling time is generally 1.2 seconds, and the bottom mould temperature is 11 degrees. The number of lamp zones in the heating furnace can refer to the configuration of the hot filling machine, and the adequate heating time of the preform should be no less than 33 seconds.

5. What is the highest temperature resistance of the non-crystalline bottle mouth of the hot-filling bottle blowing machine? How many grams of preforms are needed?

At present, the preform mouths used in the production of hot-filled bottles in the industry are generally divided into crystalline mouths and non-crystalline mouths, and non-crystalline mouths are divided into 28 months and 38 months.

As far as the bottle mouth is concerned, the crystalline mouth can withstand 100 degrees without deformation, but the upper limit of heat resistance of the non-crystal mouth is only 92 degrees.

The preform and grammage used for blowing the medium-temperature bottle are best selected according to the requirements of hot filling. Suppose it is designed according to the single-mode bottles/hour. In that case, the single-mode cycle is 2.1 seconds, of which 1/4 of the time is the time to unlock the mould, and the remaining 3/4 of the time is the processing time, minus the balance; sealing, stretching, and pre-blowing is 0.2 seconds. The time for high-pressure forming and pressure-holding crystallization is only 1 second, the time for cold blowing and setting is 0.3 seconds, and the time for closing and closing is 0.1 seconds.

The time allocation mentioned here is only a reference value, and the specific time should be adjusted and guaranteed in real-time through the control panel during production.

Strictly speaking, compressed air must be processed by a freeze dryer before it can be used for high blowing and cold blowing. Because the pipeline between the air compressor and the bottle-blowing machine is long, to avoid the pipeline from being exposed to the sun, The compressed air pipeline used for cold blowing and shaping must be covered with thermal insulation cotton to ensure that the temperature of the air source is not affected.

Your blowing machine parts PDF Download

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Three Things You Need to Know About the PET Blow Molding Machine

PET bottles have long gone deep into every part of people’s lives, whether it’s food, beverages, cosmetics, or even the drugs we use, and you can see it. But how are these PET bottles with different shapes and functions produced? The answer lies in the rotary PET blow machine. This paper gives a detailed description of the production principle, application scene and production advantages of blow molding machine, in order to help you have a preliminary understanding and get some inspiration.

What is the PET stretch blow molding machine?

PET bottle blower is defined as a production machine used to make bottles of different shapes and sizes. How it works is not complicated: depending on the applied air pressure, the bottle blower blows air into the heated bottle preform and is shaped with a specific PET bottle mold wrapped around it.

What is the overall production process of the bottle blowing machine?

The first step is to pre-heated. The PET bottle preform body was heated to a suitable molding temperature, and the inner and outer walls of the preform body were heated evenly. Because the mouth of the bottle is stereotyped, there is no need for heating. Therefore, the bottle mouth needs to be cooled during preform body heating.

The second step is to blow the bottle. The uniformly heated bottle preform is sent into the bottle blow mold through the chain, and the aseptic high pressure gas is blown into the bottle preform through the middle of the mandrel for circumferential stretching, so that it is inflated to close to the mold wall, and then cooled.

The third step is demoulding. After blowing the bottle, the machine begins to exhaust and demoulding.

Step four, transmit. The molded PET bottle is sent to the next bottle station through the conveyor belt, and it is pulled out and blown out by the lower cylinder. If it is in the blowing-filling-capping combiblock machine, it will be transmitted through the steel wave wheel to the next process.

preform heat tunnel

Where can I use the bottle blower machine?

If you look around at the products that use PET bottles, you can see that PET bottles can hold not only liquids, but also semi-solids. The use of plastic blow molder is in the factories that produce these products, including:

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The pharmaceutical industry.

The food industry.

Beverage industry.

Cosmetics industry.

Of course, packaging companies that provide PET plastic bottles for the above industries can also use PET bottle blow molder suitable for mass production.

What are the advantages of using sixth-generation PET bottle blowing machine?

Since the introduction of the first PET bottle blowing machine, people have been constantly improving the bottle blowing technology. As a leader in the liquid industry.

Flexible. Today’s sixth-generation PET bottle blowing machine is no longer a backward machine that can only produce a single product. 

High degree of trust. As a leader in China’s high-end liquid packaging industry after 30 years of precipitation.

High Speed Production. We have carefully designed a production increase plan based on the rapidly growing production demand of today’s producers, and the maximum productivity per hour has been greatly increased to 48,000BPH.

Stable Quality. Due to the unified mold and rotary bottle blowing system, PET bottle blowing machine can be produced on a large scale to maintain the unity and stability of product quality.

Choosing a reliable supplier of PET bottle blowing machine is the key to efficient production.

We do not forget its original ideal and ambition, and insists on providing customers with PET bottle solutions with high output, energy saving, productive line and less waste. this sincere attitude has attracted countless high-quality customers’ cooperation, and even some customers have become our loyal fans and have carried out many project in cooperation. With such a high reputation and strong strength, I believe we are your best partner!

If you are looking for the PET bottle blow molding equipment, please feel free to contact us.

What are PET Blow Molding Machines?

Single Stage Blow Molding Machine

While PET bottle development was proceeding in the US, a large manufacturer of injection molding machines in Japan, was leading a project to develop a machine to make biaxially oriented PP (polypropylene) containers. They recognized that the prototype machine could be used to produce the new PET bottles and, in December , the One-stage ASB-150 injection stretch blow moulding machine for making the new biaxial oriented PET bottles was unveiled. All one-stage injection stretch blow moulding machines derived from this original Stretch Blow design are referred to as classic one-stage machines, as the concept has long since been extended into other PET developments. The classic one-stage machines design is extremely versatile in that the same basic machine design can be used to make a wide variety of bottles and jars in all shapes and sizes.

Two Stage Blow Molding Machine

In the early developments, performs were made by continuously extruding a PET tube. To make these prefroms, a perform manufacturing machine that took a continuously extruded PET tube, heated and closed one end, and then heated the other and formed a thread finish by blow moulding. This process had a faster output rate, at preforms per hour, than the early injection moulding routes of 8 and 16 cavity moulds. Being extruded, the performs could be multilayered with barrier materials. The system was overtaken by injection moulded performs as the cavitation increased to 32 and beyond. The quality of the injection moulded (IM) neck, adding for example vent slots, made the IM finish preferable. Moreover, IM technology is available from more than one company, giving customers greater technical and commercial choice. Two-stage technology machines with six blow moulds operating at around bottles per hour. Subsequent mould and cooling development increased the output to bottles per hour.

Two stage PET processing includes:

Making performs by Injection Molding

Blowing bottles by Stretch Blow Molding

Because it is more flexible than one step processing, it is widely accepted in Plastic packaging market. You may choose to make preforms only or blow bottles only if you want to do one of them specially.

Integrated Two Stage Blow Molding Machine

In Integrated Two Stage approach the performs were made by more conventional injection moulding routes (with the number of cavities optimized to match the required output) and then, while still hot, were carried to a separate blowing machine with the optimized number of blow moulds to suit the required output. This was the first ‘integrated ‘approach to PET bottle making. Equipment developers took the ‘single-stage’ approach. Here the equipment had the same number of injection cavities as blowing moulds. This was a more compact approach and proved ideal for small batch output with excellent glossy surfaces.

How Does a Blow Molding Machine Work?

Of the many different machines used for manufacturing products, the blow molding machine is one of the most fascinating and useful. Known as extrusion blow molding, the simple explanation as to how this blow mold design works is that air is blown into a parison, shaping the hollow bottle as it inflates. However, there is much more to the plastic extrusion blow molding process.

The Blow Molding Process

The extrusion blow molding process produces plastic bottles of various sizes and shapes. Millions of people use these bottles daily for soda, water, cleaning products, food, and more. With this process, low-pressure air of around 25 to 150 psi is forced into a parison. Multiple materials are used, including Low-Density Polypropylene (LDPE), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Polyethylene Terephthalate (PET), and Polypropylene (PP).

A parison with a conventional downward extrusion is inserted into the mold cavity until reaching the required length.

The neck ending catches and holds while the bottom end pinches closed as the tube closes.

A blow-pin

is interested into the neck end of the hot parison while compressed air inflates it to the shape of the mold cavity. Simultaneously, the process creates the threaded opening.

Once the mold sufficiently cools, it opens, ejecting the finished bottle along with excess plastic that was trimmed off from around the neck and bottom portions.

For the highest-quality molding machines, Pet All Manufacturing is a respected and trusted source. To view all of our products, we invite you to visit our website. You also can reach a company representative by .

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