Why does bottom sealing pressure matter more than sealing temperature on a paper bowl machine?

Temperature makes the coating tacky, but pressure is what actually presses the two surfaces into contact so the bond forms. A die that is hot enough but lightly loaded leaves microscopic gaps that pass liquid under a leak test, and those gaps are invisible at the machine. Because pressure is what converts a soft coating into a bonded seam, a bowl machine that controls temperature tightly and pressure loosely still produces leakers, which is why pressure is the variable to specify and monitor.

What causes a bowl to leak on only one side of the base?

A one-sided leak almost always points to uneven loading rather than insufficient total force. A tilted platen, a worn guide, a mis-set spring, or a base die that is not parallel to its opposing surface concentrates the force on one sector and starves the rest. The symptom follows the geometry: the seam holds where pressure is high and passes where it is low. Check parallelism and guide wear before turning the pressure regulator up, because adding force to an already tilted die simply moves the defect.

How should pressure control be verified during acceptance?

Run the machine on the buyer's own bowl stock at target speed and leak-test a defined sample from each hour of a full shift, not a short burst. Record the pressure setpoint and the measured force at the die, because a gauge on the supply line does not show what the die actually receives. Ask for the parallelism tolerance and the force repeatability the supplier commits to, and keep the shift-long leak-test record with the machine file as the baseline for later comparison.

Paper Bowl Machine Bottom Sealing Pressure Control: Force, Dwell and Leak-Proof Bases

Published: 2026-09-17 | Author: Yoco Group Editorial