Thermoforming Heat Sealing Machinery

Thermoforming accounts for a vast proportion of packaging and has an estimated market value of around $45million globally. Thermoformed packaging is relatively low cost, lightweight and almost infinitely adaptable to a vast range of products. It is also exceptionally good at protecting products from physical damage and contamination, and is generally tamper-proof. Thermoformed blister packs can also be designed to look very appealing to consumers, with many printing and finishing options for logos, graphics and text.

Thermoformed packaging is all around us, and predominates in food, beverages, personal care products, cosmetics, pharmaceuticals, electronic goods and many other sectors. Thermoforming heat sealing machinery is also used to produce disposable plastic cups and lids, plant pots and pouches. 

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How do thermoforming heat sealing machines work?

Thermoforming machines heat plastic sheets until they are pliable. The heat sealing machinery then moulds them to a specified shape. Products are placed in the moulded plastic and a lid is placed on top and heat-sealed. The result is a sealed package which goes on to be bulk packed for onward transportation. 

Thermoforming moulds can be made to almost any shape or size, and so provide a tailor-made packaging solution for an enormous number of products. Standard sizes and shapes of packaging are also available.  

Thermoform packaging equipment usually carries out the following operations:

  • Plastic trays are formed using moulding equipment 
  • Cardboard or foil backing is printed with glued edges 
  • The product is placed in the tray and card, foil or film is placed over it
  • Heat is applied to the pack
  • The heat melts the glued edges to seal the pack
  • The sealed pack is moved into cartons or other types of outer packaging

To form trays, vacuum forming is most commonly used, although pressure forming is an alternative.

Plastic vacuum thermoforming

A plastic sheet is heated until soft and then draped over a mould. A vacuum sucks the sheet into the mould. 

Pressure thermoforming

A sheet of plastic material is heated to become pliable. It is then pressed against a 3D mould by applying air pressure over the plastic sheet.

Thermoform heat sealing machinery

Sealing machines for thermoforming are usually based on heat sealing a plastic film over a tray containing one or more products. The application of heat can be by a heated plate which is pressed onto the pack, or by heat bars which are applied to the edges of the pack. The heat generated can be used to melt the plastic material to form a seal, or to melt glue applied to the film, foil or cardboard used in the thermoform pack.

What are the types of thermoform packaging?

Blister packs and clamshells are the principal types of thermoform packaging. For consumer markets, thin-gauge, disposable materials are used although there is an increasing focus on recyclable materials. Thermoformed thick-gauge materials are used for non-packaging items such as fridge linings, plastic pallets and product prototyping.

Thermoform blister packs

Thermoform packaging is most widely used for blister packs, especially for the pharmaceutical industry. Pills, tablets and capsules are placed in individual pockets in trays formed of lightweight plastic, and heat-sealed usually with foil printed with the details of the contents. 

Blister packs can also be made of stronger grades of plastic for use with heavier, delicate and more angular products such as toys, automotive parts and household goods. For heavier non-food packaging, card is frequently used to seal the pack.

Thermoforming heat sealing machines can create various types of blister pack, including

  • Face seal blister packs, formed around the product with heat-sealed cardboard lids. For added strength, full-face seal blister packs add an extra layer of plastic over the card backing.
  • Full card blister packs are also a strong form of packaging, featuring an overlap of plastic which allows the card to be slid into, or stapled onto, the plastic.  

Clamshell thermoform packaging

In clamshell packaging, the plastic is formed with a hinge which allows the top and base of the pack to be closed to form a box-like container. The clamshell can be heat-sealed or closed with a moulded button, often with an adhesive label added to ensure the pack stays closed and to give evidence of tampering. 

Clamshells are the preferred form of packaging for many foods including bakery, fresh meat and salads. One of the attractions for producers is that their products can be seen through clear clamshell plastic. Clamshells are also useful for multipart sets of products such as lightbulbs and sets of cosmetics or gifts.  

Thermoforming plastic

A vast range of plastics are amenable to thermoforming, with more materials becoming available on a regular basis. The focus on sustainability is resulting in machinery which avoids the use of excess of plastic (especially cut-offs), and new thermo-formable plastics are offering increased levels of efficiency and environmental-friendliness.

Most clear packages are formed using PVC, PET, RPET, PETG and styrene, and they are among the many types of plastic used in packaging:

  • PVC (Polyvinyl Chloride)
    One of the most widely used plastics in the world due to its diverse range of properties
  • PET (Polyethylene Terephthalate)
    A globally recognized safe, recyclable packaging material, also known as PETE
  • RPET (Reprocessed Polyethylene Terephthalate)
    Recycled PET
  • PETG (Polyethylene Terephthalate Glycol) 
    Modified PET with Glycol, PETG offers better sealing properties and durability than regular PET
  • Lightweight ABS (Acrylonitrile Butadiene Styrene)
    A moderately heat resistant plastic
  • Acrylic (Polymethyl Methacrylate, Plexiglass or PMMA)
    Easy to machine and available in a range of colours and surfaces
  • HDPE (High-Density Polyethylene)
    A recyclable plastic used in a variety of packaging applications
  • HIPS (High-Impact Polystyrene)
    durable, low-cost plastic that’s easy to form and print on 
  • HMPWE (High Molecular Weight Polyethylene)
    Tough and durable material mainly used for industrial and medical applications
  • KYDEX (PPMA/PVC blend)
    Rigid, hard-wearing and resistant to chemicals, mainly for industrial uses
    Plastic used for CDs and DVDs, used in certain specialist packaging requirements
  • PC (Polycarbonate)
    Tough, stable, transparent plastic which is easy to mould 
  • Pennite (Glass-filled nylon)
    Durable glass-reinforced nylon designed for thermoforming
  • PEI (Polyetherimide Ultem)
    Strong, mouldable thermoplastic with high heat resistance 
  • PET (Polyethylene Terephthalate)
    A globally recognized safe, recyclable packaging material, also known as PETE
  • PETG (Polyethylene Terephthalate Glycol) 
    Modified PET with Glycol, PETG offers better sealing properties and durability than regular PET
  • RPET (Reprocessed Polyethylene Terephthalate)
    Recycled PET
  • Post-Consumer RPET
    25% – 100% Post-Consumer Recycled PET
  • PLA™
    A corn-based plastic that sometimes used as an alternative to petroleum-based plastics
  • PP (Polypropylene)
    A versatile material used for various types of packaging applications
  • Royalite 
    High performance, fire-rated thermoplastic
  • TPO (Thermoplastic PolyOlefin)
    Tough and durable material, used in a variety of applications including car bumpers 
  • Vinyl
    Plastic widely used for floor tiles, clothing and occasionally in packaging 

Thermoforming heat sealing machines FAQs

What is thermoforming?

Thermoforming is the moulding of various plastics which become pliable when heated into trays for packaging. The moulded trays, once filled with products, are sealed with a covering of foil, film or cardboard. Thermoforming is a very widespread process used throughout the world in multiple packaging operations.   

What is vacuum forming?

Vacuum forming is part of the thermoforming process. Plastic is heated to become pliable and a vacuum is created between the plastic and a mould, so that once cooled a shaped plastic is created.

Is thermoforming and vacuum forming the same?

Vacuum forming is one of the techniques of thermoforming. The other principal technique of thermoforming is pressure forming. 

What plastic do you use for vacuum forming?

Plastics for vacuum forming are usually thinner polymer films such as HDPE, LDPE, HIPS, PVC and PET. Heavier grades of thermoform plastics are more commonly pressure formed. 

Is thermoform packaging recyclable?

With rising awareness of environmental issues in industry and among consumers, recyclable plastic for thermoforming is an area of significant research. PET is in common use and is widely recycled. RPET is made from PET recycled from the manufacturing of packaging. In Post-consumer RPET a significant proportion of material is made from PET which has been recycled after being used at least once by consumers. Alternative packaging such as PLATM is a thermoplastic polymer made from plant starch, and is one of the most commonly used bioplastics. 

Find Thermoforming Machine Suppliers with PPMA Group

See a full list of PPMA Member companies who supply a comprehensive range of thermoforming machines for packaging.