These are blow molded retaining wall blocks which were conceived to function as re-usable sand bags. Being blow molded they are hollow & can be filled with sand.
For this project the customer already had the product completly designed by someone else, they hired me to make the mold which could produce their design.
This is a photo of the mold after it had been rough machined & the finish passes were just starting. The finish passes start from the bottom of this picture and move towards the top.
After finish machining the mold still require hand finishing with sand paper, scotch brite, and diamond files. Luckily the product this mold made called for a lightly textured matte finish, so we didn't have to polish the mold to a mirror finish, we masked off the mold & sand blasted the surfaces which formed teh part.