Deformation of heat sealing molds for packaging machines can cause problems such as seal wrinkles and seal failure, which directly affect production efficiency and packaging quality. This article combines industry practical experience to provide a complete technical solution for mold deformation detection, repair and prevention, helping factories to quickly restore equipment performance and extend mold life.
1. Mold deformation detection and evaluation
Visual inspection and basic measurement
Check whether there are dents, warps or cracks on the mold surface, and focus on observing the flatness of the sealing blade.
Use a feeler gauge to detect the gap between the mold and the bottom mold. If the local gap is greater than 0.1mm, it is determined to be moderate deformation and needs to be corrected.
3D scanning and data comparison
Use a non-contact 3D scanner to obtain mold deformation data, compare it with the original design drawings, and generate a deviation heat map.
Areas with deformation greater than 0.3mm need to be repaired first to avoid affecting the uniformity of the seal.
Material performance test
Take samples of the deformed mold to test the hardness (HRC value) and wear resistance to determine whether the deformation is caused by material deterioration.
2. Mold deformation correction technology
Mechanical pressure correction
For local concave areas, a hydraulic press is used to slowly restore the shape by step-by-step pressure (pressure ≤ 80% of the mold compressive strength).
After correction, annealing treatment is required to eliminate internal stress. The annealing temperature is set according to the mold material (such as H13 steel is recommended to be 500-550℃).
Temperature-pressure joint adjustment compensation
Slightly deformed molds can be compensated by adjusting the heat sealing parameters of the packaging machine:
The sealing pressure is reduced by 10%-15%, and the temperature is simultaneously increased by 5-10℃ to balance the heat distribution.
Extend the holding time by 20%-30% to ensure that the sealing layer is fully fused.
Surface repair and coating strengthening
Laser cladding repair is performed on the worn or micro-cracked areas. The coating thickness is recommended to be 0.2-0.5mm.
Spray titanium nitride (TiN) wear-resistant coating to improve the mold surface hardness and reduce thermal fatigue deformation. 3. Deformation prevention and maintenance specifications
Periodic inspection and maintenance
Clean the residue on the mold surface every week to avoid carbon deposition and accelerated local wear.
Check the parallelism and clearance of the mold every month, record the deformation trend and intervene in advance.
Environment and operation optimization
Control the temperature fluctuation of the workshop ≤±5℃ to reduce the mold stress caused by thermal expansion and contraction.
Avoid overloading the packaging machine (such as continuous operation for more than 12 hours, the mold needs to be stopped to cool down).
Mold use specifications
Match the mold and packaging material thickness (such as lightweight molds are recommended for films below 0.08mm).
When changing packaging materials, the pressure and temperature parameters of the packaging machine need to be recalibrated.
