Causes, detection scheme, and safety interlock design of insufficient reset of the mold ejector plate | Low pressure casting tooling mold safety mechanism
The reset of the ejector plate was not in place and continued to close the mold, resulting in 44% of accidents such as bending of the ejector pin, damage to the mold cavity, and extensive damage to the mold.
The elastic force of the reset spring decays by more than 30%, the return thrust is insufficient, and the ejector card is stuck in the middle position, which is difficult to identify with the naked eye.
The tension on the reset guide post and the accumulation of aluminum slag increase the frictional resistance, and the spring cannot overcome the resistance to complete the full stroke reset.
The installation of the travel switch is offset, and the signal is falsely reported as "reset". However, there is still a residual protrusion of 0.3-0.8mm on the actual ejector plate.
The wear clearance of the guide sleeve of the ejector plate is too large, the ejector plate is tilted, one side is stuck, and the reset is not synchronized.
No secondary confirmation of mechanical reset lock, relying solely on electrical signals, and direct collision occurs when the sensor fails.
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, export overseas mold customers attach great importance to mold safety interlocking. Zhejiang Xinfeng Machinery Overseas Project Unified Configuration: Mechanical Reset Pin+Electrical Travel Switch Double Confirmation, Both are indispensable. Spring selection reserves a safety margin, and high-temperature resistant alloy springs are selected for high temperature conditions. Ordinary springs experience rapid elastic decay in an environment of 250 ℃. The spring is sampled for elasticity every 4000 molds, and if it decays by more than 30%, it should be replaced directly without waiting for the mold to collide. Many old casting machines in Southeast Asia lack mold locking protection, and the mold side must be equipped with mechanical hard limit protection. After the mold collision, the cost of repairing the cavity, inserts, and top rod is extremely high. In severe cases, the entire mold may be scrapped, and overseas maintenance cycles can last for several months. Provide training to customers during delivery: manually jog and reset the ejector after each mold change, verifying that the signal is synchronized with the mechanical position.
FAQ
1. Question: How much does the spring elasticity decay require replacement?
Answer: The elasticity attenuation is ≥ 30%, and the return thrust is insufficient. It is recommended to replace it.
2. Question: What is the recommended reset protection solution?
Answer: Double interlocking of mechanical reset pin and electrical travel switch.
3. Question: What are the hidden dangers of ordinary springs under high temperature conditions?
Answer: Under continuous high temperature, the elasticity rapidly decays and the reset fails.
4. Question: What are the hazards of travel switch offset?
Answer: False alarm reset signal, resulting in compression molding accident.
5. Question: What are the consequences of wear and tear on the guide sleeve of the ejector plate?
Answer: The ejector plate is tilted, stuck on one side, and the reset is not synchronized.
6. Question: What are the characteristics of repairing collision accidents?
Answer: The damage is severe, the overseas repair cycle is long, and the cost is extremely high.
