How to Control the Production Process of Flexible Polyurethane Foam?

1.Dynamic analysis of the foaming process

1.1 Batch foaming machine foaming

1.2 Continuous foaming machine foaming

Cross-sectional view and development trend schematic of the foaming process

Longitudinal and transverse schematic diagrams of the foaming process

2.Analysis of relative material movement

2.1 Observation of synchronized material discharge

Top-down perspective view of black-white material transition point

Transverse cross-section diagram of black-white junction (shaded area represents black material)

Longitudinal cross-section diagram of black-white junction

2.2 Typical problem phenomena

Landslide phenomenon

Crescent-shaped pit partial surface schematic

Backflow and impinging flow schematic diagram

Film and foam; Edge film and foam

Edge of release paper and foam

Vertical fold and unfolding of the edge on release paper

2.3 Wrinkle influence mechanism

Side vertical release paper forms wrinkles due to changes in movement direction, as shown below.

The wrinkled side vertical release paper pulls and compresses the foam, then stretches it. The wider the paper edge, the larger the compression and expansion amplitude, as shown below:

Example image of cracking (cracks wide enough to insert a finger or palm)

3. Foam appearance defects

3.1 Cracking types: floral cracks, splitting cracks, bottom edge cracks, top blowholes, hollowness

3.2 Shrinkage types: surface skin shrinkage, bottom shrinkage, edge shrinkage, bottom cavity, four-side shrinkage, overall shrinkage

3.3 Pore types: large pores, chaotic pores, bean-sized pores, pinholes

4. Foam physical performance defects

4.1 Structural defects: brittleness, easy to rot

4.2 Mechanical defects: insufficient elasticity, low elongation, large permanent deformation

5.Production control

Emergency handling incidents

Material flow interruption

Mixing head failure

Pumping failure

Conveyor malfunction

Cutting blade failure