The V-process consists of seven steps.  The first four steps are:

1.  A precision pattern with vent lines is positioned on a pattern carrier with a vacuum line.  

2.  A heat-softened polymer sheet is positioned on the pattern and the vacuum draws the sheet down to form a conforming polymer film on the pattern.

3.  A flask with vacuum lines is placed over the film covered pattern. The flask is filled with very fine, dry, unbonded sand. The flask is vibrated to settle the sand into all the pattern features. 

4.  The sand is leveled and a sprue cup is formed in the mold.  A plastic film is placed on top of the mold to form a vacuum tight seal. A vacuum is drawn on the flask to rigidize the sand in the mold.