In the packaging industry, molten products generally refer to products that must be liquefied before they can be automatically packaged by filling machinery. Some examples of molten products would be candles and other wax products, some pastes and even some deodorants. When these products are put to use by the end user, they are in a solid, or at least semi-solid, state. Liquefying the products allows them to be placed into glass jars, tubes or other plastic containers for consumption.
Liquefying the products will normally involve raising the temperature of the product significantly. Due to the increased temperature, certain modifications will be made to different packaging machines, while other equipment will work just as well for heated products as for more typical liquids. Generally, the machinery and components that work with, or come in contact with, the product itself will need some modification, while those that encounter the product after it has been properly packaged and cooled will not require modification.
Pre-Fill Packaging Equipment
Pre-fill packaging equipment may include items such as loading turntables, unscramblers, rinsing machinery and other equipment to prepare bottles for the packaging process. It would take a very unusual project for these items to require modification, as they all perform their duties prior to the introduction of the product. So the same machinery that would work for just about any typical, non-heated liquid product would also work for molten products. However, many of these products are packaged into unique containers, such as glue sticks or uniquely shaped candle jars. Custom equipment may be necessary to handle the unique containers, but this will be due to shape or size of the containers, not the molten nature of the product.
More than any other piece of equipment, the filling machine will be affected by the type of product or products being run. Molten products, as we have already noted, require heating prior to filling. Not only must the product reach a specific temperature or temperature range, but it must remain at that temperature or range throughout the fill. This means that the product must reach the temperature in the supply tank and maintain that temperature through the tubing, fill bar, nozzles and all of the other elements of the product pathway. If the heat is not maintained, the viscosity of the product will change, causing issues with the flow of the liquid, clogging of the nozzles and other problems that can lead to inconsistent filling and excessive downtime.
Conveyor systems used on molten product lines may differ in a couple of different ways from systems used for non-heated liquids. First, the belting itself may be a heat-resistant type of belt, helping to prolong the life of the system and protect against spills and splashes. In addition, most packaging systems for molten products will also include a cooling conveyor, which will be found right after the liquid filler. The cooling conveyor, not surprisingly, allows the molten product to cool, often to its solid or semi-solid state. This is necessity for several different reasons. First, the heated product can have an effect on bottles, caps and other components. To move the product and container immediately to a capping machine, labeling machine or other equipment could affect how that equipment works. Allowing the product to cool allows and/or settle also allows the capping machines, labeling equipment and other packaging machinery perform consistently and reliably.
Second, immediately capping or otherwise manipulating the product may cause some liquids to settle unequally, cave or otherwise fill the container inconsistently. The cooling conveyor gives each container and product the time to settle and solidify in a consistent manner. These conveyor systems may include a fan cooling system to speed up the process or they may simply be designed to add an extended length of time between the filler and the next packaging component using a serpentine conveyor, vertical space or whatever other room is available for cooling.
Post-Fill, Post-Cool Equipment
The equipment that follows both the filling and the cooling of molten products may vary greatly, though almost all will include a capping machine and a labeling machine at the least. Other equipment could include coding machines, packing machinery, case tapers, pallet wrappers and more. Much like the pre-fill packaging equipment, once the molten product is filled and cooled, modifications based on the fact that the product is molten are highly unlikely. Again, any modifications will usually stem from unusual containers, bundling or packing.
Like with any packaging project, the best equipment for a molten product will be determined by examining every aspect of the project, from products to containers, caps, labels, production speed, space and more. Only after all of these aspects have been discussed can the perfect solution be discovered.