In the refrigerator manufacturing process, polyurethane foam injection molding is one of the key processes that determine the production cycle and product performance. With the increase in order density and labor costs, how to shorten the foaming cycle time while ensuring the stability of foam quality has become the focus of major refrigerator manufacturers and equipment suppliers.
Here are some effective ways to significantly shorten the foam injection process cycle:
1. Optimize injection process parameters
By increasing the injection rate (e.g. from 2 seconds to 1 second), the time it takes to fill the mold can be significantly reduced. At the same time, with the anti-flash and flow mark control technologies, the stable distribution of the material and the sealing of the mold edge can be ensured.
- Reduce idling time and improve injection consistency.
2. Improved mold temperature control accuracy
The dynamic mold temperature control system consisting of steam heating and ice water cooling cycles is used to control mold temperature fluctuations within ±1°C, quickly establish thermal balance, and help accelerate the foam maturation reaction.
- Precise temperature control ≈ early demoulding.
3. Rapid demoulding and parallel operation
By synchronizing the robot’s picking up and mold closing actions, the waiting time after demolding can be compressed from 3 seconds to 0.5 seconds, realizing the parallel execution of “demolding + next round of mold closing”.
- Saving 2 seconds per cycle increases the output of a shift by about 5%.
4. Catalyst system optimization
Optimizing the amine catalyst ratio (such as using A-33 or Am-1 catalysts) can shorten the reaction time from foaming to gelling and improve the debonding efficiency.
- The demoulding time is shortened by more than 30% , reducing the risk of foam sticking to the mold.
5. Formula upgrade: polyether + physical foaming agent combination
The use of a new polyol system combined with an environmentally friendly physical foaming agent (such as HFO) can achieve rapid demolding in 130 seconds at a mold temperature of 45°C, reducing the waiting time by 57% compared to traditional formulas.
- More environmentally friendly and more efficient.
6. Negative pressure foaming rhythm optimization
By controlling the vacuum timing (such as starting negative pressure 100 to 160 seconds after the foaming agent is injected), the pores can be effectively avoided from bursting, making the foam more stable and early demoulding possible.
- The airflow in the mold is stable, which improves the success rate of demoulding.
Overall benefit assessment
By comprehensively applying the above optimization strategies, the overall cycle of the refrigerator foaming process can be shortened by 15%-30% .
- Daily output can be increased by about 33%
Solutions we provide
- High speed injection system
- Intelligent temperature control mold system
- Automatic robot and ejector synchronization unit
- Professional polyurethane foaming formula customization service
- Catalyst recommendation and commissioning guidance for rapid demoulding
Welcome to visit our demonstration plant or contact our technical team to obtain exclusive process upgrade solutions.