Micro pellets are easier to handle, do not produce dust, and have a high bulk density as well as good flow characteristics. However, these properties do not always assure good results in the molding process. The lack of fines in the micro pellets delays the start of the melting cycle in the mold, resulting in longer cycle times.
It is a fact, that some parts only form well in the mold when ground material is added to the micro pellets.
Why then use two different forms of the same material? Using only powder for this process is the most logical choice.
The expense of making Micro pellets in-house is feasible only when coupled with other processes, such as compounding the material for coloring.
When compared to conventional compounding, pelletizing, and pulverizing equipment, extrusion and pelletizing equipment to produce Micro pellets is a more costly investment. Not only is the equipment more complex, but it is also more difficult to operate and maintain.
If the size of Micro pellets is adequate to use in a mold, then using 900 microns or even 1mm size powder in the same mold should also work.
Taking this observation further, why not have all rotomolders pulverize their material with coarser screens in the sifter? By making this change, production rates from the pulverizer would increase and the whole process would become more simple and cost effective.
It is our opinion that for rotomolding, using 500 microns powder with good flow properties, produced from a fine tuned pulverizer, is superior to using Micro pellets.
Pulverizing also provides flexibility in that it can be done to other materials as a different process.
We invite you to view some of the YouTube clips to see Orenda’s newest pulverizing technology, the AirForce® pulverizer, and to listen to some of the comments made by the most experienced professionals in the industry.