Managing Fill Line Appearance In Cannabis Vape Cartridges

“Why is my vaporizer cartridge low? Why didn’t you fill my cartridge up fully?” These are serious issues that cannabis vape manufacturers face, leading to returns and chargebacks. This article covers the factors that lead to low fill line appearance, including filling temperature, capping time, and cartridge design, and offers mitigation techniques to address these issues. This discussion assumes the reader understands the vacuum lock principle and the contributing factors to low fill line appearance in vaporizers.

Contributing Factors

Contributing Factors

Factors That Lead to Low-Fill Line Appearance

The temperature of the extract is too high during filling

Temperature causes the extract to have lower viscosity temporarily; while this allows for easier time injection fluids into a cartridge, the result is that the extracts soak through the core/wick faster, resulting in a lower fill line appearance. It is best to run fill temperatures at 60C or below to mitigate unnecessary viscosity including low fill lines and leaking.

Slow capping speed

Slow capping speed slows down or prevents the formation of the vacuum lock. Without the vacuum lock, there is no force “pulling” the extract into the tank, leading to a lower fill line appearance. The ceramic core during filling is constantly absorbing extracts and if capping is too slow, the core will have drawn about 100mg-200mg of extracts leading to some cartridges appearing half filled.

Cartridge design

Certain carts have large internal reservoirs that hold extracts before vaporization. This will over time “draw down” a vaporizer cartridge regardless of extract viscosity. There are mitigation methods for reducing the internal reservoir at the cost of increased leak rates.

Mitigation techniques for low-fill lines in carts

Fast Capping — capping as fast as possible will maintain the highest possible fill line for cartridges regardless of viscosity. While it can be difficult to consistently have filling operators strain to cap each cart as it is filled, this will greatly impact fill line height. Systems like the Xylem X4 automatically caps with 2 seconds to give the highest possible fill line appearance.
Lower Extract Fill Temperature (45C-50C)—This filling method is difficult for manual fillers as it strains hands and wrists due to the force needed to press extracts through a syringe or cannula. This technique slows down the absorption time for the core/wick to soak leading to a higher appearance.
Modified internal reservoir – Only experienced extractors should consider this modification. Reservoir modification can move the fill line up or down and needs to be matched with a solution viscosity.

Closing

Low-fill line appearance is impacted by many variables to varying degrees. Lab managers and extractors need tocarefully evaluate their products & processes to determine which ones impacting product quality need to be mitigated,to improve customer experience.