As you may know, here at PelHeat we focus on small scale pellet production solutions and we only offer ring die pellet mills. This is a video uploaded by General Dies who manufacturer larger ring die pellet presses in Italy. In this video you can see how the die is made. A specialist drill is used which can rotate and shift the die precisely to position the drill head in the right position. As you can see on these larger dies there are thousands of holes, to achieve this task with a manually operated drill would take far too long. If you notice the holes have already been drilled, so you maybe wondering what the drill is actually doing? Well the drill is now putting the taper on the holes. The angle of the taper is crucial as it effects the compression ratio as the material is forced into the die holes by the rollers during pellet press operation. Each material is different and you require a different angle for say wood and animal feed. Say for instance you didn’t put any taper on the holes and it was just a vertical compression. This maybe ideal for some forms of animal feed which you do not want to be compressed too much as the animals will not feed on pellets which are as hard as rocks. However say you tried to run sawdust through that same die to produce wood pellets. The result would be no pellet at all as there was no horizontal force to build pressure to heat the wood, to melt the lignin. Therefore a wood pellet mill die will have a taper on the holes. However if the taper is too shallow the forces the die generates will be greater than the pressure the roller can apply, this will lead to a blocked die. So you see the taper angle on the die plays a significant role in how the pellet forms. What you will also notice from the video is the drill is constantly lubricated, this helps to provide a better hole finish. We have used flat die pellet mills which have rough holes, and more often than not they block up. A poor quality die makes poor quality pellets, so if your die is not good enough nothing else really matters.