Before thermoforming process must not be missing two steps one of which is to extrusion sheets and the other is to make the mold, we roughly use two kinds of aluminum molds, with which mold is based on your needs for the product. Casting aluminum mold and block aluminum mold, respectively. Casting mold’s surface might have some small holes, so the surface of the casting mold is not as quality as block mold, Using casting aluminum mold is the most common way for solid color products, unlike transparent products, solid products can not see the other side from one side, so it does not matter to have small marks or dust on the assembly surface. The price of the casting aluminum mold is also cheaper than block mold, Cause the thickness of thermoforming mold is around 15-20mm, too thick to drill through the aluminum, so we will need CNC to dig out some aluminum, which wastes the aluminum, and add the work. so the price will be more expensive. Basically, for transparent products, we generally recommend using block aluminum molds.
Here are some molds which we have made before.
Here is the video to show you the whole process of making mold. Here is a mold with sliding bolck for product which has undercut.