Method of drying a sand mold using a vacuum
A method of drying a sand mold mixture containing moisture includes restraining the sand mold mixture and exposing the sand mold mixture to a vacuum. The vacuum flashes off the moisture within the sand mold mixture thereby drying the sand mold mixture to create a solidified sand mold. The restraining member prevents voids from forming in the sand mold during exposure to the vacuum.
1. A method of making a sand mold, comprising:
a) placing a sand mold mixture containing moisture into a pattern;
b) restraining the sand mold mixture in the pattern; and
c) exposing the sand mold mixture to a vacuum, the vacuum being low enough to flash off the moisture in the sand mold mixture thereby drying the sand mold mixture to create a sand mold, the restrained sand mold mixture preventing voids in the sand mold.
2. The method of claim 1 , the vacuum being less than 100 Torr.
3. The method of claim 2 , the vacuum being preferably 4 to 5 Torr.
4. The method of claim 1 , the sand mold mixture being exposed to the vacuum for less than 30 minutes.
5. The method of claim 1 , further comprising heating the sand mold mixture before placing the sand mold mixture into the pattern.
6. The method of claim 5 , the sand mold mixture being at least 140° F. when placed into the vacuum chamber.
7. The method of claim 1 , the sand mold mixture containing approximately 1.5 to 2.0% moisture by weight of the sand mold mixture when placed into the pattern.
8. A method of making a sand mold, comprising:
a) placing a sand mold mixture containing moisture into a pattern;
b) placing a restraining member onto the pattern, the restraining member restraining the sand mold mixture within the pattern; and
c) exposing the restrained sand mold mixture filled pattern to a vacuum, the vacuum being low enough to flash off the moisture in the sand mold mixture thereby drying the sand mold mixture to create a sand mold, the restraining member preventing voids in the sand mold.
9. The method of claim 8 , further comprising heating binder coated sand and mixing the binder coated sand with water to create the sand mold mixture.
10. The method of claim 8 , the binder coated sand being heated to approximately 180 to 200° F.
11. The method of claim 8 , the sand mold mixture being at least 140° F. when placed into the pattern.
12. The method of claim 8 , further comprising heating water to approximately 150° F. before mixing the water with the binder coated sand.
13. The method of claim 8 , the vacuum being less than 100 Torr.
14. The method of claim 13 , the vacuum being preferably 4 to 5 Torr.
15. The method of claim 8 , the sand mold mixture being exposed to the vacuum for less than 30 minutes.
16. The method of claim 8 , the restraining member including apertures having a hydraulic radius of 0.5 inch or less.
17. The method of claim 8 , the sand mold mixture containing approximately 1.5 to 2.0% water by weight of the sand mold mixture when placed into the pattern.
18. A method of making a sand mold, comprising:
a) placing a sand mold mixture containing moisture into a pattern;
b) restraining the sand mold mixture in the pattern by placing a perforated lid on the pattern, the perforated lid having apertures with a hydraulic radius of 0.5 inch or less; and
c) exposing the pattern containing the sand mold mixture to a vacuum, the vacuum being low enough to flash off the moisture in the sand mold mixture thereby drying the sand mold mixture to create a sand mold, the perforated lid preventing voids in the sand mold.
19. The method of claim 18 , further comprising heating the sand mold mixture before placing the sand mold mixture into the pattern.
20. The method of claim 18 , the vacuum being less than 100 Torr.
21. The method of claim 20 , the sand mold mixture being exposed to the vacuum for 30 minutes or less.
22. The method of claim 18 , the sand mold mixture containing approximately 1.5 to 2.0% moisture by weight of the sand mold mixture when placed into the pattern.