A GUIDE TO HEAT SEALING AND TRAY SEALERS
THE ADVANTAGES OF HEAT SEALING
- Heat Sealing produces a hermetic seal (airtight), this is especially important if using MAP (modified atmosphere technology) to extend shelf life
- Heat Sealed Packs can be used to enhance the shelf appeal of products
- Heat Sealed Packs can be stronger than packs sealed by other methods contributing to less damage in transportation, storage and in the Retailers
THE VARIABLES
Heat sealing is a process that uses three variables; Heat, Force (pressure) and Time. The heat is transferred through the sealing film to the tray with a given force for a length of time. By increasing or decreasing any of the three variables, and by using different materials (the tray and film) the seal strength can vary from a welded seal to a peelable seal.
THE PROCESS
- With the top tool in its raised position the sealing film is fed across the top of the trays which have been placed in the bottom tool
- The top tool is lowered with a degree of pressure and heat, sealing and trimming the film to the packs
- The top tool is raised and the waste film is wound on and replaced ready for the next cycle of trays
- The sealed packs are ejected from the base tool
TRAY AND FILM MATERIALS
Depending on the process that you wish to be applicable to the product (i.e. frozen, chilled, oven cooked or microwaveable) there are many different tray materials which may be suitable for example; CPet, APet, RPet, PP, Aluminium, Board. There may also be other deciding factors such as aesthetic qualities, consumer perception and price.
Likewise there are different sealing materials, PP, Pet, Foil etc….Normally the choice of film would be dependent on the tray choice as they need to be compatible.
OPTIONS
- How many packs a minute do i need to be able to seal?
- Do I need my sealing machine to be bench mounted, or on a frame? Portable or static?
- Do I want my Tray Sealer to be Manual, Semi-automatic or Fully-automatic?
- Do I want the film to be “Profile cut” i.e. closely follow the shape of the tray? With or without an easy peel tab on the corner?
- Do my products require MAP for extended shelf life?
- Budget – How much do i want to spend?
- Will my Tray Sealer be part of an in-line process? (i.e.linked to other equipment such as tray denesters or depositors?)
- What are my in-feed and out-feed requirements?
POINTS TO CONSIDER
- Reliability and ease of use
- Flexibility – Can i upgrade my machine if my production expands?
- Is the equipment I am considering good value for money?
- Is it versatile? Can it be adapted for other sealing options such as Skin Pack or Slice Pack?
- Die Costs – How reasonable is it to have another sealing die for a different tray?
- How hygienic is my machine? Is it easy to clean?
- Expertise, knowledge, training and support from my supplier
- Cost of support and service
At Vortech we can help you choose the right equipment for your processes now and in the future. We will support you through the process and can supply you film and trays offering you a “one-stop” shop. Please feel free to contact us with any questions you may have or to enquire about pricing……..
