Solving Hole Defects in Zinc Castings: A Die Casting Case Analysis

Case Analysis: Solving Hole Defects in Zinc Castings at the Slag Discharge Position

Precision is paramount in the Die Casting process. A small defect can compromise the integrity and aesthetics of a product, leading to costly waste and production delays. A common issue encountered in zinc die casting is the presence of holes or defects at the slag discharge position. Here at saivs, we analyze and solve such challenges to ensure our clients get the highest quality products. This case study on a zinc casting for e-cigarette parts provides valuable insights into how to diagnose and correct this specific issue.

1. Casting Information

Product Name: E-cigarette Parts
Product Request: No Defects On The Surface
Product Process: Die casting machine tonnage 160T
Nozzle Caliber: 13 MM
Choose Material: 3# Zinc alloy
Whether To Use Regrind: Yes

The product's requirement for a flawless surface is a critical factor. The use of 3# zinc alloy and the 160T die casting machine are standard, but the presence of regrind material can introduce impurities if not managed properly. While regrind itself isn't the primary cause of this defect, it's a variable that needs careful consideration in Quality Control.

2. Product Issue

The primary issue identified was a hole defect located specifically at the slag discharge position of the casting. This defect compromised the part's aesthetic quality and could potentially affect its functionality.

3. Product Analysis

After a thorough analysis by our technical team at SAIVS, the root cause was identified as an unreasonable classification and positioning of the slag discharge. This led to a significant problem: difficulty in both slag discharge and proper air exhaust from the mold. In die casting, molten metal fills the mold cavity at high speed, and any trapped air or impurities (slag) can create voids or holes in the final product. The slag discharge and exhaust system are crucial for allowing these gases and impurities to escape the mold.

In this particular case, the positioning of the slag discharge was incorrect, leading to premature sealing. This trapped air and slag, manifesting as the undesirable holes in the final product. It is a classic example of a design flaw in the mold's venting and discharge system.

4. Improvement Measures

Based on our analysis, SAIVS recommended the following improvement measures to resolve the defect:

Adjustments to the Original Plan

The initial plan had a significant flaw in its slag discharge design. Our expert team at SAIVS proposed a revised approach to rectify this:

• Do not seal off the original slag discharge: The original design's error was in prematurely sealing the slag discharge. It must be kept open to allow impurities to escape throughout the filling process.
• Increase or increase the slag discharge of the sliders on both sides: By adding more slag discharge channels, we can create more pathways for slag and air to exit the mold, ensuring a complete and defect-free fill.

The parting of the mold structure was also a key consideration. The mold reopening must be staggered with the feed to prevent premature sealing of the exhaust channels. This ensures that the slag discharge operates correctly at the end of the filling process, where it is most effective.

5. Key Tips for Slag Discharge and Die Casting Success

This case is a typical example of common die casting challenges. To help you avoid similar issues, SAIVS offers the following principles for optimal slag discharge:

The Principle for Slag Discharge Position

Position at the End of the Filling

The slag discharge channel should, as far as possible, be placed at the end of the filling process. This is the last area the molten metal reaches, making it the ideal location for trapped air and slag to be pushed out.

If the channel is opened during the filling process, it is easy to seal the exhaust in advance, which interferes with the normal flow of the molten material. This leads to defects like the holes seen in this case. The timing and placement of the slag discharge are critical for maintaining the integrity of the casting.

At SAIVS, we understand the intricacies of die casting. Our expertise in Mold design and manufacturing ensures that we create tools and products that are free from such defects. Our comprehensive services include not only high-quality manufacturing but also in-depth analysis and problem-solving for all your casting needs. Partner with us to achieve flawless results and maximize your production efficiency. Contact SAIVS today to learn more about our solutions for die casting and how our expertise can benefit your business.