Calculation of mold riser module, selection of insulation sleeve and control of loss cycle | Low pressure and differential pressure casting shrinkage system
Insufficient riser modulus and damaged insulation sleeve resulted in concentrated shrinkage holes in large areas of 43% thickness, leading to unqualified X-ray batch.
The riser modulus is less than 1.1 times the hot spot modulus of the casting, resulting in insufficient shrinkage compensation ability and inability to continuously supply aluminum liquid to compensate for shrinkage.
The thickness of the aluminum silicate insulation sleeve is less than 10mm, causing rapid heat dissipation, premature solidification of the riser, and closure of the shrinkage channel.
The insulation sleeve undergoes long-term high-temperature pulverization and cracking, with debris falling off and mixed into the aluminum liquid to form inclusions. At the same time, the insulation performance deteriorates by more than 45%.
The section of the connection neck between the riser and the casting is too small, causing the connection neck to solidify first and cutting off the channel between the riser and the casting.
The height of the riser is too low, and the potential energy for gravity compensation is insufficient. It relies solely on pressure compensation, resulting in poor rebound during pressure fluctuations.
Low pressure die-casting molds (LPDC), reverse pressure casting molds (CPC), differential pressure casting molds for wheel hubs, low-pressure casting molds for wheel hubs, gravity casting molds, motorcycle wheel hub casting molds, structural component casting molds, aluminum alloy wheel hub molds, aluminum casting forming molds, low-pressure casting tooling molds, and insulation risers are key fixtures for low-cost improvement of yield. Zhejiang Xinfeng Machinery Selection: The thickness of the insulation sleeve under normal working conditions is 10-15mm; for high pressure CPC molds, 10mm can be taken, and 15mm is preferred for thick gravity hot joints. The connection neck modulus is controlled at 0.7-0.9 times the hot joint modulus to ensure that the casting sets first, the neck sets later, and the riser sets last. The conventional service life of the insulation sleeve is 800-1500 cycles. If it cracks and pulverizes, it must be replaced immediately and cannot continue to be used. Many customers wait until the riser is clearly malfunctioning to replace it in order to save consumables, resulting in phased batch defects with losses far greater than the cost of insulation sleeves.
FAQ
1. Question: What is the bottom line of the ratio of riser modulus to heat node modulus?
Answer: The riser modulus is greater than or equal to the heat node modulus multiplied by 1.1.
2. Question: What is the recommended thickness range for insulation sleeves?
Answer: The standard is 10-15mm, and for thick and large joints, 15mm is taken.
3. Question: What is the control range of the neck module?
Answer: 0.7-0.9 times the thermal modulus.
4. Question: What is the typical service life of insulation sleeves?
Answer: 800-1500 cycles, replace if cracked.
5. Question: What are the two major hazards of damaged insulation sleeves?
Answer: Insulation failure, shrinkage, and inclusion caused by refractory debris.
6. Question: What are the core principles of riser design?
Answer: Casting → connecting neck → riser, solidification is carried out in a step-by-step sequence.
