The question is often asked “What temperature setting do I use to seal my bags?” This question is pretty straight forward but the answer to it can be effected by many variables. Setting your heat-sealing machine to the right temperature is only one factor. Other factors include how long heat is applied to the material (dwell), and how much pressure you apply while sealing. One temperature, Dwell, and PSI setting is not uniformly recommended for each material. For example a better seal can sometimes be obtained with a lower temperature allowed to dwell longer allowing the sealant layer polymers to fully melt together.
Heat Sealer Settings
Here is a table of heat sealer settings which are a good starting point for your testing process.
Material | Temperature Range | PSI | Dwell Time |
---|---|---|---|
CareSilver | 375 F - 400 F | 40 PSI | 1 Sec |
CareFoil | 400 F - 450 F | 40 PSI | 1 Sec - 1.5 Sec |
CareFoil-N | 450 F - 500 F | 40 PSI | 1.5 - 3 Sec |
CareKraft | 400 F 425 F | 50 PSI | 2 Sec |
CareClear | 350 F - 375 F | 40 PSI | 1 Sec |
Factors effecting heat sealer settings
Many customers focus on the machine settings when dialing in their heat seal settings, but all the factors below should come into consideration to get the highest strength heat seal.
Material Type
Seal strength, and sealer machine settings will be adjusted to the physical properties of the material being sealed to. Clear PET based material generally will use different settings than nylon or foil based material. The material thickness, flange or surface design, physical pouch configuration, size, and feature placement will also be considerations. Some materials like Carefoil reduce the amount of heat that can get through to the sealant layer so they require more heat or long dwell time. Material Thickness can effect the overall mount of dwell that is required.
Dwell
Dwell time relates to how long heat is applied to the pouch. Heat and dwell time are not independent variables, they go hand in hand and should not be evaluated separately. Dwell time requires adjustment based on the same factors that effect temperature. Some heat sealable flexible barrier materials require lower heat for a longer time to properly sell. While you can "seal" a bag with high heat for a short duration. The sealant layer may not form a high strength bond.
PSI
The pressure at which heat is applied to the pouch can effect bag seal strength.The amount of pressure applied by the heat-sealing equipment will create differences in the heat and dwell settings. Thicker materials and those which are more rigid such as CareKraft require more pressure, while with thinner materials if too much pressure is applied the heated selant layer can be pressed too thin.
Fouling
Fouling can occur during the loading process particles, dust, or liquid we left in the sealing zone. If so, these contaminates can affect the settlings required on your sealing machine to seal the bag properly. Foreign material in the seal zone can also reduce the seal effectiveness. Powder products are notorious for causing fouling. Dust acts like corn meal on the bottom of a baking pan inhibiting the polymers from adhering to each other.
Type of Machine
The type and condition of your heat-sealing machine will create another variable to consider. There are several types of heat-sealing machines and how these machines apply heat. Types of heat sealers include Impulse sealers, roller sealers, platen seal.
External Environment
Ambient temperatures, and humidity can have a small impact on heat or dwell time as well.
There isn’t going to be an exact specification because proper temperature will vary widely based on the conditions mentioned in this article. But here are some of the settings that have been reported to us by customers, as well as our own understanding.
The information provided should only be used as a starting point for the customer’s own investigation, and testing when determining the best settings for your heat sealer machine.