The five common heat sealing issues are

1. Wrong Heat Settings
2. Wrong Cooling
3. Badly Warn Or Burnt Tapes And Sealing Pads
4. Incorrection Machine
5. Incorrect Material Or Bag Being Used

Here are some points to ensure your heat sealing machine makes a good seal

• Check you have the right machine for your material
• Adjust the heat correctly on the heat sealer you are using
• Make sure the sealing pads and also any tapes are clean and not torn
• Do not overuse the machine by trying to seal quickly
• Allow the machine to cool between each sealing operation

Heat seals can be made on a variety films that can be softened and fused together by applying pressure at the same time. These machines are often called thermoplastics. Below are some examples

• Polyethylene (PE), including LDPE and HDPE.
• Polypropylene (PP).
• Polystyrene (PS).
• Polyvinyl Chloride (PVC).
• Polyethylene Terephthalate (PET), also known as Mylar, used for its high tensile strength, transparency, electrical insulation, and dimensional stability.
• Nylon
• Paper/Foil Laminates.
• Film/Foil Laminates.

Heat sealers work by applying heat and pressure at the same time, they can either be a constant heat sealer or an impulse heat sealing machine.