Heat Seal Temperature Calculator

Last updated: April 2026

Getting the right heat seal temperature is critical to producing strong, consistent seals on your packaging line. Too low and seals are weak or incomplete. Too high and you risk burning through the film, causing shrinkage, or degrading heat-sensitive products inside. This calculator provides recommended temperature ranges, dwell times, and pressure settings for the most common packaging films used in Australian packaging operations.

The optimal sealing temperature depends on three main factors: the film material, the film thickness, and the type of heat sealer you are using. Thicker films generally require higher temperatures and longer dwell times to achieve full seal strength. The condition of your PTFE heat seal tape also plays a significant role — worn or degraded tape creates uneven heat transfer, leading to inconsistent seals even at the correct temperature.

Use the calculator below to find the right starting parameters for your material, then fine-tune on your machine. Always run test seals and perform peel or burst tests before committing to a full production run.

Heat Seal Temperature Reference Chart

The table below summarises recommended heat seal temperatures and dwell times for common packaging films. Use these as starting points and always verify with test seals on your specific machine and material combination.

Note: Add 10–20°C for films thicker than 80 microns. Actual settings may vary by machine, film supplier, and seal geometry.

What Factors Affect Heat Seal Temperature?

Achieving a strong, reliable heat seal involves balancing several interrelated variables. Understanding these factors helps you troubleshoot seal failures and optimise your packaging line.

• Film material and composition: Each polymer has a specific melt range. Multi-layer laminates seal at the temperature of the sealant layer, which may differ from the outer layer.
• Film thickness: Thicker films require more energy (higher temperature or longer dwell time) to bring the sealant layer to its melting point.
• Sealer type: Impulse sealers apply short bursts of high heat, while constant-heat sealers maintain a steady jaw temperature. Band sealers apply heat while the film moves through the machine.
• Jaw pressure: Sufficient pressure ensures full contact between the film layers during the seal cycle. Too little pressure causes incomplete seals; too much can thin the film at the seal line.
• PTFE tape condition: The PTFE tape covering the seal jaw acts as a non-stick barrier and heat transfer medium. Worn or damaged tape creates inconsistent heat distribution.
• Ambient conditions: Cold environments may require slightly higher temperatures. Product temperature inside the package can also affect seal formation.

How to Test Seal Quality

After setting your initial temperature, always validate seal integrity before running production:

1. Visual inspection: The seal should be uniform with no wrinkles, bubbles, or burn marks.
2. Peel test: Attempt to peel the seal apart by hand. A good seal should cause film failure (tearing) rather than peeling open at the seal line.
3. Burst test: Squeeze the sealed package to check for blow-outs or channelling along the seal.
4. Dye penetration test: For critical applications, apply dye solution along the seal and check for leaks.

Maintaining Your Heat Sealer for Consistent Results

Even with correct temperature settings, seal quality degrades if the machine is not properly maintained. Key maintenance tasks include:

• Replace PTFE tape at regular intervals — see our guide on how often to change heat seal tape.
• Check heat sealing bands for wear, distortion, or uneven resistance.
• Ensure jaw alignment is correct and pressure is evenly distributed across the seal width.
• Calibrate temperature controllers periodically — displayed temperature may drift from actual jaw temperature.
• Keep seal surfaces clean and free from melted film residue.