Why lipstick material get stuck or leaking when filling in the machine?

The issue of lipstick "stuck and leaking" during filling usually points to a problem with temperature or mechanical timing. Essentially, if the filling nozzle doesn't retract cleanly, the sticky wax can get stuck; if the seal fails, the hot liquid leaks.

Here are the 4 most common technical reasons this happens:

●  Valve Retraction Timing (The "Stuck" Cause): If the filling nozzle retracts too slowly, the sticky liquid stretches into a "tail" that gets pinched when the mold closes. Fix: Install a "non-drip" or anti-drawing nozzle for a clean cut.

●  Thermal Expansion (The "Leak" Cause): Hot liquid expands. If the tube is filled too full at high temperatures, pressure builds as it cools, forcing product past the seal.

●  High Temperatures (Thins the Product): If the melted wax is too hot, it becomes watery. It will then seep through microscopic gaps in the seal that thicker wax would normally plug.

●  Mechanical Seal Wear: The metal piston and cylinder expand at different rates when hot. Once they wear or seize, liquid will leak back up around the piston.

How to fix it:

●  Check the temperature: Ensure the holding tank isn't overheating.

●  Adjust the draw-back: The machine needs to suck a tiny amount back into the nozzle to break the surface tension before retracting.

●  Leave an air gap: Do not fill the container all the way to the brim.

●  Use High precision two-piece filling pump,This pump has High sealing performance in case of leaking. To avoide material stuck inside, it can be opened to clean up conveniently. This is main part to have Smooth filling  for high quality lipstick.