Porosity Growth Prediction Module
CAPPORO
What is CAPPORO?
CAPCAST's CAPPORO is the next step in the evolution of process analysis software. Used in conjunction with CAP, CAPPORO takes data from solidification and makes highly accurate predictions about the location and amount of porosity formed in your casting. CAPPORO can also be used to estimate several mechanical properties of your casting such as tensile strength and yield strength.How does it work?
CAPPORO was developed based on research done by Dr. Kimio Kubo of EKK Japan. In his research, he theorized that by making certain assumptions about gas pressure in the material, evaluating pressure drop during solidification, and cooling rates, one could predict where porosity will occur in a casting on a macroscopic level.
If you want to find out more, please take a look at Kubo's paper, originally published in 1985. Click HERE
Porosity and Shrinkage Detection in Iron Casting
- Generally in aluminum castings, the solidification pattern gives a good indication of where shrinkage porosity will be located. Directional solidification in aluminum castings reduces (or eliminates) porosity.
- Nodular Iron is different. The carbon present in the iron tends to expand during solidification. Even if shrinkage is predicted by looking at the solidification pattern, it tends to be reduced in the real casting because of that expansion.
- Directional solidifcation in iron castings does not always mean quality castings as shrinkage can often occur near gates and risers. This renders general solidification analysis less useful for nodular iron castings.
- CAPCASTporosity software goes beyond conventional solidifcation analysis and analyzes how gas pressure, metal pressure, thermal expansion, and cooling rate influence the growth of porosity. It gives a more accurate prediction of porosity in iron castings because it does not rely exclusively on solidification patterns.
Following is an example with a x-ray verification of CAPPORO's ability to accurately predict where porosity was likely to occur in nodular cast iron knuckle.
What makes it better than everyone else?
Most other software analysis packages base their porosity prediction on qualitative analysis of the solidification pattern. In plainer terms, when looking at their solidification analysis they note any isolated regions during solidification. Unfortunately, this method neglects the fact that sometimes porosity can form even when the solidification characteristics of the casting are quite good. Which makes them a lot less accurate then ours.
The following images of an aluminum control arm prove this point. Click on the images to get a larger view.
On the left is the casting solidification pattern. Most analysis codes would be incapable of detecting porosity in this casting because of good "Directional" solidification. There are no isolated regions for shrinkage to occur.However, CAPPORO tells a different story. The image on the right is a representation of where CAPPORO predicted where porosity was likely to occur.
CAPPORO's predictions were backed up by a physical investigation of the actual casting.
What else does CAPPORO do?
Because of the linear relationships between some solidification characteristics and mechanical properties, CAPPORO can be used to make predictions about the mechanical quality of your castings once they are produced.
Click on one of the images to see a larger picture.
Brinnel Hardness
Proof Strength
...and Tensile Strength
among others.
