Specifically in the FMCG and F&B sectors, products like household commodities, soft drinks, bottled water, alcoholic beverages and packaged food, are growing in double-digits. This growth has a huge impact on the packaging industry and each sector is enhancing its need for producing high quality products in large volumes. The need for superior quality packaging machines and equipment with increased automation, lower power costs, faster speed and uptodate technology has in turn increased. One such sector is that of the plastic packaging industry, which is known to be capital-intensive.
Most recognised packaging companies will tell you that their clients, usually leading brands, look for one vendor that can provide total solutions that cater to all their sizes and volumes. This translates to production of different sizes of packaging solutions, different material to be used depending on the nature of the product, attractiveness of the packaging and many other factors that need to be looked into. For a packaging company that needs to cater to such varied requirements, it is only beneficial to make high investments in machines and equipments; and this accounts for a sizeable share of its capital. Unless the machine runs with an Overall Equipment Effectiveness (OEE) of 85%, the business is likely to be unprofitable. A major role of this efficiency depends on the allied equipments and ancillaries that go hand-in-hand with the production.
We have, over the last two decades in the industry, worked with and employed various kinds of equipments, and have witnessed the advancements made in technology. While the costs simultaneously rise, there can be no doubts about the benefits of high quality or state-of-the-art machinery. Going by the accepted industry standards, below is a list of some of the allied equipments and machinery that are good choices for any PET packaging brand.
Dryer
PET is a hygroscopic material and one of the most important factors in the processing of PET bottles is that the material should be free from moisture, to avoid defects in the finished products. If not taken care of, some of the problems that can occur are haziness, spaces and sliver streaks in the PET bottle. These flaws also come in the way of gaining better physical and mechanical properties. It is said that PET in its amorphous form absorbs moisture more rapidly than in its crystalline form. (The high level of crystallinity in PET (>50%) helps in slower moisture absorption rate.) The amount of moisture absorbed also depends on factors like time, temperature, atmospheric humidity and the crystallinity of the fragment.
Packaging experts will know that presence of moisture breaks polymer chains that lead to a reduction in the molecular weight. This creates issues during preform moulding and will affect final container properties. Resins with lower molecular weight also crystallise faster than ones with higher weight resulting in hazy or white appearance. Hence, it is advised that to obtain maximum product performance, it is essential to reduce the moisture content to less than 0.004% (40 parts per million), prior to melting. And a drying procedure done at the right temperature and for a certain duration will ensure that there are no quality issues like crystallisation, haziness and, un-dried material. A dryer would take care of such flaws.
Dryers circulate hot and de-humidified or dry air on the resins, suck it back, dry the air and then pump again in a closed loop action. This process reduces moisture level in the PET resin. What one must also note is that the efficiency of moisture removal depends on the air dew point. If the air dew point is not apt, then chances of moisture remaining are high in the chips. One must also avoid excessive drying as very high temperatures can lead to thermal and oxidative degradation.
Dryer consists of two major parts:
(a) Hopper: The material that needs to be dried is placed in this. There are two common methods of connecting this to the injection unit. Either directly fixing it over the injection unit, or by placing it on a stand and connecting the hopper exit to the container with a flexible high temperature withstanding hose.
(b) Drying Unit: This is placed in a separate cupboard like structure closer to the hopper.
(c) The only connection between both the units is flexible hoses, which can withstand high temperatures. These are used for carrying dry and return air. The air first comes in contact with the material through the diffuser, which is attached at the lower portion of the hopper (*A diffuser spreads the air across the entire cross section of the hopper). Most hoppers will have a converging bottom as well as an internal distribution cone, to ensure plug flow of chips through the system. The dry air then passes upward and re-enters the drying unit after passing through the after cooler and filter. This closed loop process makes this an efficient drying process. The air dryer is designed to remove moisture from the return air and to re-circulate. First, the air is cooled down in a heat exchanger to around 40°C and then passed through a filter.
Chiller
The second most important equipment required in production of PET container is a Water Chiller. During the moulding stage, molten PET material is injected into a mould. For formation of the product, the moulds need to be circulated with chilled water to complete the entire molding process. The reaction of hot PET material with water chilled mould is what creates the product. While a Cooling Tower is used for heat removal in the running of the machine, a chiller acts specifically for cooling the moulds at 16ºC - 18ºC.
Cooling Tower
Cooling Towers are used for removing the waste heat from machinery. In case of PET Moulding, the cooling tower is used to circulate water at low temperatures in the machine to cool the hydraulic and moving parts of the machine, which get heated during production.
Mould Dehumidifier
Hygroscopic plastics materials such as PET cannot be dried effectively by conventional hot air dryers, as such dryers are dependent on ambient conditions and are relatively less efficient in reducing moisture contents. Mould sweat de-humidifiers are designed to remove the moisture sweat from condensing on the mould surface. Forming of moisture sweat on the mould surface is due to the use of chilled water to reduce moulding cycle time, particularly while moulding of the PET preforms. These machines generally use the honeycomb rotor to carry out a dehumidifying function, which generates dry airflow with a dew point ranging from 0~100ºC, and ensures the surrounding air of the mould remains in a low dew point temperature. It provides constant low dew point surrounding air to the mould surface all year round without being influenced by the change of seasons.
MTC (Mould Temperature Controller)
Apart from the above, other allied equipments such as a Mould Temperature Controller (MTC) help check quality. The MTC is an equipment used primarily to make bottles which require stiffness and uniform wall thickness. The MTC aids in cooling the inside sections of the PET preform to 80ºC as against the exterior temperature of 110ºC. This difference creates the best possible preform before the blowing stage and leads to better quality. Most of the Pharma and Liquor applications need the services of MTC.
Pick and Place Robos
During the ejection stages, bottles are expelled in a free fall manner under normal conditions. These bottles are prone to scratches and dents during this period. In order to avoid this problem, ‘Pick & Place’ Robos are used to transfer the bottles directly from the machine on to a conveyor which is installed near the machine. This process allows bottles to proceed to the next stage of being collated in a scratch-less format.
Collating / Bagging Machine
After the bottles are ejected from the machine and placed on a conveyor, they are then moved to a collating machine, which is nothing but a bagging machine where all the bottles are packed in a systematic fashion in a plastic poly bag. While such equipments come at a high price, it is helpful, especially for high volume production where there are no or very less mould changes.
All of the above equipments are essential and good investments for a manufacturer. There exists today a strong reliance on imported technologies and purchase of specialised machinery from other countries is quite common; however, the allied equipment industry in India has tremendous scope. The industry is growing and there are good indigenous brands that have high performance value. Many packaging companies will agree that the demand from the FMCG, F&B and various other sectors is increasing. One of the wisest ways to add value to clients is by ensuring superior quality of designs and producing sustainable products by using high quality machinery - those that give you error-free results and also help save resources.
We, at Manjushree, use all of the machinery mentioned above, to help make our processes more efficient. While a certain amount of human intervention will always be part of the production process, adopting new technologies and bringing on board state-of-the-art machinery will help save time and resources, and will ultimately have a positive impact on production capacity.
