The PET bottle blow moulding process works by reheating a pre-moulded PET preform which is then automatically positioned into a mould. High pressure food grade compressed air is then injected into the preform which expands to form the shape of the mould.
Polyethylene terephthalate is an inert plastic material that doesn’t react when in contact with chemicals, beverages, and organic material. PET is resistant to microorganisms and doesn’t biologically degrade. It is also light weight, durable and easy to transport. The unique properties of PET make it a preferred packaging material for food & beverage products, shampoo, hand soap etc.
PET packaging is more cost-effective and environmentally friendly than aluminum and glass packaging. Making a PET bottle produces 70% less CO2 than glass, and when you factor in the logistical efficiency of transporting PET the number can be as high as 90% less CO2. PET bottles and packaging are created through a process called Blow Molding. A PET preform is heated and positioned inside a mould. Compressed air at high pressure is injected into the PET preform. The preform expands to take the shape of the mould. Once the plastic cools down, the moulded PET product is removed and sent for additional processing. Any common plastic water bottle that you find on supermarket shelves is made in this way.
Air compressors requirements for PET manufacturing
A 2005 study concluded that improvements in compressed air efficiency at plastic manufacturing plants can result in an annual savings of about $27,143. Several improvements were suggested, the most important of which were repairing leaks, buying the right size of compressor, and regular maintenance.
Most of these improvements relate to the proper matching of air compressor size, type, design, and air quality, with the application. Plant managers and owners find the most benefit when they work directly with an air compressor manufacturer who can evaluate the needs of the plant and design a customized solution for their PET application.
When consulting a professional from an air compressor manufacturer,speak with them about:
- Your air quality requirements, your expected operating hours, and your required blow pressure. Air quality of the compressed air can affect the taste and odor of the contents of the PET bottle or packaging. Ask how the air compressor manages filtration and if it follows ISO standards for blow molding.
- Start by looking into oil-free air compressors and what will be the final dew point and water content in the compressed air and inquire about multi-stage filtration systems that can be attached to it.
- Ask about how much pressure your equipment needs and let the consultant suggest options in that range. High blow pressures create more heat within the air compressor which could mean: shorter maintenance intervals and higher energy costs. Optimal blow molding pressure is preferred over excessive pressure because excess leads to wasted energy.
- Give the air compressor consultant an accurate expectation of how many hours per year your blow molding applications coz Compressed air present 30% of the cost of producing PET bottle .
- We recommend you invest in a compressor service contract with the manufacturer because regular maintenance and durability is the key to maximum up-time.
In return for working directly with a respected air compressor manufacturer you will get:
- Energy savings by reducing leaks, pressure dips, and excess energy use.
- Maximum pressure for their PET manufacturing processes.
- Correct air temperatures and air purity levels.
- Durable filtration systems that clear contaminants and regular drainage of excess fluids.
- An extended life cycle for the air compressor.
Energy efficient PET bottle compressors
Atlas Copco has produced a range of air compressors that are specifically designed to handle your PET bottle blowing needs while offering maximum energy savings.
