Classification and treatment of overflow and flash on the parting surface of low-pressure casting molds | LPDC parting surface adhesion control
The continuous overflow and flying edge of the parting surface have caused a surge in grinding costs for 41% of castings, damage to the parting surface, and premature failure of the mold.
The gap between the parting surfaces is greater than 0.025mm, and the aluminum liquid bursts out under the filling pressure, forming visible continuous flying edges.
The local collapse and depression of the parting surface are mostly caused by long-term high-temperature pressure and insufficient hardness of the mold frame. It is difficult to self repair after the depression is greater than 0.03mm.
The carbon and aluminum slag in the parting area are repeatedly rolled, resulting in indentation. The indentation location continues to move, and the more pressing it becomes, the more severe it becomes.
Insufficient clamping force, pressure fluctuations in the locking cylinder, slight opening of the mold surface during filling and pressure rise, intermittent generation of burrs.
The exhaust groove on the parting surface is too deep, and the exhaust groove extends to the parting sealing belt, resulting in insufficient effective sealing width and easy aluminum penetration.
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. Overseas factories generally dislike burrs, and the labor cost of post-processing is much higher than the cost of mold repair. Zhejiang Xinfeng Machinery Standard Seal Design: The segmented sealing tape reserves an effective sealing width of 8-12mm, and the exhaust groove terminates on the inside of the sealing tape, without cutting through the sealing area. Slight indentation can grind the parting surface and re nitriding; The large-scale collapse belongs to the creep of the formwork, and the formwork can only be replaced. Regularly check the coloring rate of the parting surface with red lead. If the coloring coverage of the sealing tape is less than 85%, the machine should be stopped for research and assembly. Many factories blindly increase the pressure of mold locking, which may have short-term effects, but it will accelerate the fatigue deformation of guide columns and mold frames, which is a temporary solution.
FAQ
1. Question: What is the upper limit of the safety sealing gap on the parting surface?
Answer: ≤ 0.025mm, exceeding it can easily result in continuous flying edges.
2. Question: What is the recommended effective width for the sealing tape?
Answer: 8-12mm, the sealing tape cannot be cut off from the exhaust groove.
3. Question: What are the qualified standards for red lead coloring?
Answer: The coloring coverage rate of the sealing tape is ≥ 85%.
4. Question: What is the root cause of the collapse of the parting surface?
Answer: Insufficient hardness of the mold frame leads to permanent indentation caused by high-temperature creep.
5. Question: What are the drawbacks of simply increasing the locking force?
Answer: Accelerate the fatigue of guide columns and mold frames, resulting in faster deformation.
6. Question: Is intermittent flying edge prioritized for troubleshooting?
Answer: Fluctuations in mold locking pressure and excessive pressure rise rate during aluminum liquid filling.
