Discussion on the Deep and Fine Hole Investment Casting Shell Process

I've been working in the investment casting industry for over 20 years. I'd like to share the operational details and process design of the deep and fine hole investment casting shell process for your reference.

As shown in the figure above, the product has abnormal casting nodules and fins. This problem is a typical problem caused by insufficient strength after shell making in the hole. The insufficient strength comes from the following reasons and corresponding measures are as follows:

1. The mold shell is not dense and the strength is low.

Reasons for the mold shell not being dense:

(1) The slurry viscosity is high and cannot flow fully into the hole;

Measures: Reduce the viscosity

(2) The sand material is coarse, and the sand on the mold shell is bridged and not dense;

Measures: According to the size of the hole, select the appropriate sand material particle size to meet the principle of shell making density.

2. The paint deteriorated and its own strength was insufficient;

Measures: Daily maintenance of the slurry should be done.

3. Insufficient drying and insufficient strength;

Measures: The drying temperature, humidity, wind speed and time should be controlled. Consider using special drying tooling when necessary. New technologies: Quick-drying adhesives, infrared drying, and vacuum drying can be used.

4. Surface tension prevents the coating from being fully applied.

Measures: Add sufficient wetting agent and defoaming agent to the slurry mix; consider using compressed air to actuate the slurry during application; pre-wetting should be used to remove microbubbles from the slurry and improve its fluidity; ensure sufficient mixing time during slurry preparation to allow the slurry to mature and maintain good fluidity.

5. Unreasonable sharp corners on the hole edges can lead to stress concentration.

 #Lost-wax investment casting enthusiast Venda, hopes to discuss the lost-wax investment casting process with you.

#Lost-wax investment casting enthusiast Venda, is willing to contribute to the foundry industry with lost-wax investment casting enthusiasts around the world.