There are many visible defects in the process of investment casting process like blowholes,sink mark,flow lines or mold flash.But how to avoid these defects? We have some advice for your reference.
One is adjustment of the injection wax process parameters
1 Adjust pressure
Adjust wax injection pressure according to the wall thickness of the products.Low pressure can prevent incomplete filling while high pressure avoids blowholes and mold flash
2.Adjust temperature
Strictly set the temperatures of wax tank and injection nozzle,keep temperature difference evenly controlled
3. Adjust injection speed
For thin-wall castings,adopt slow wax injection to exhaust air,for thick-wall parts,use segmented speed regulation to reduce sink marks.
4. Hold pressure
Sufficient holding time compensates the shrinkage of wax during cooling to eliminate sink holes and depressions
The second is optimize mold management.
- Optimize the wax runner and injection gate to prevent direct impact of the wax flow,which would cause flow lines and ripples.
- Arrange vent holes reasonably to rapidly exhaust air inside the mold cavity and completely eliminate surface blowholes.
- Perform regular polishing and maintenance of mold to keep the mold cavity smooth without scratches or rust,so as to prevent wax adhesion,flow lines and other defects.
