Improved airtightness and durability by applying silicone material to the outer periphery of the microwave door

When cooking with heat, microwave ovens generate high temperatures, steam, oily smoke, and odors inside the oven. If these leak out of the oven, it not only has a negative impact on the user’s environment, but also reduces the product’s lifespan and safety. For this reason, it was essential in the product design to reliably seal the slight gap between the door and the housing to maintain airtightness. The outer periphery of the door in particular is subjected to repeated stress every time it is opened and closed, so the sealing material must be highly durable, flexible, and adhesive, and silicone is commonly used.

However, controlling the dispensing and application of this high-viscosity silicone material is extremely difficult, and conventional dispensing equipment has presented the following challenges:

• Unstable coating line
  High-viscosity materials have low fluidity, making it difficult to achieve stable discharge with existing equipment, which resulted in frequent cases of the coating line being interrupted or meandering, resulting in partial gaps and defective products that could not be airtight.
• Need for frequent discharge adjustment
  Because viscosity fluctuates depending on temperature and storage conditions, the amount of material dispensed had to be adjusted frequently, which was a significant workload. Continuing production without proper adjustments resulted in insufficient or excessive application, leading to increased rework and waste. This resulted in reduced production efficiency and increased material loss.

The combination of the newly introduced high-viscosity fluid dispenser and high-pressure valve has significantly improved the unstable dispensing line and frequent adjustment work that were previously an issue, and has produced the following benefits:

• Stable dispensing of high viscosity materials
  By combining a high-pressure pump and a dedicated valve, it is now possible to stably discharge high-viscosity silicone materials, which was previously difficult.Since it is possible to form a continuous seal line without interruptions or meandering, it is easy to ensure uniformity, and the yield loss caused by line defects has been greatly reduced.
• Stabilizing quality and improving airtightness
  The uniform silicone coating reliably seals gaps around the perimeter of the microwave door, preventing heat, humidity, and odors from leaking out, significantly improving product safety and comfort. Since the coating quality remains stable, even during mass production, product reliability has improved and the number of complaints after shipment has been reduced.
• Total cost reduction
  The reduced defect rate has led to less reprocessing and waste, which has directly led to a reduction in material loss. In addition, stable discharge has reduced nozzle clogging and component wear, resulting in less maintenance frequency. As a result, overall running costs have been reduced, contributing to improved cost performance for the entire production line.

SV47とAUTOCANThe combination of “Stable line application of high viscosity materials”This has enabled us to achieve both quality improvement and cost reduction in products that require high airtightness and reliability, such as microwave ovens.

High pressure spool valve SV47

The SV47 is a spool valve that can stably dispense high-viscosity liquids such as sealants and grease at high pressure. It is ideal for dispensing products where airtightness is important, such as microwave ovens, and achieves uniform line formation.

• Maximum fluid pressure17.2MPaUp to
• Simple structure makes operation and cleaning easy
• Highly durable design for long-term stable operation
• Stable flow control is possible even at high pressure, making it ideal for forming airtight lines