It’s important to consider the principles of heat sealing packaging.  

• When you heat seal something, 99% of the time you are ‘melting’ a low temperature coating which has been applied to a material that doesn’t melt at the sealing temperature.   For example, a clear top film of plastic film with a heat sealable coating or a cardboard folded pack with a heat sealable coating.  
• The ideal seal will be the perfect combination of Time, Temperature and Pressure.  
• All Soken machines have excellent temperature control.  
• In the smaller machines, (ie HS22) the operator controls the time and pressure as they have to actively push down the heated plate.  

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Gradually, moving up the line of products, the machines can control the pressure that’s applied (either by pneumatic operation or electrical actuators)  (ie HS34) and then the more sophisticated machines can also activate pressure places controlling the timing too (ie HS36). The more the machine controls the better the consistency of the result. The top of the line machines can be programmed with recipes so that different trays / materials / products can instantly be set to the right parameters.