Last, but not least is the machine shop where pieces are brought in to be smoothed out and machined until they are the desired color/sheen.
Firstly, a grinder or sander is used to take off any grit left on the casting. After that, a CNC machine usually takes off any small amount of size needed. Finally, colored paint may be sprayed on or applied to make the product more visually stimulating or prevent corrosion for customers.