In this article, we demonstrate open laboratory hardware aiming at automation of the compounding process. In particular, we present: 1) the dispensomixer, which aims to handle the automated material input to the extruder and facilitates changing the material composition during the loading process, and 2) a pellet distributor aimed at the task of the automated collection of the material output from the pelletizer with weight-dependent sorting. Our contribution can facilitate preparation of diverse batches of materials for high-throughput screening studies. Furthermore, it is relevant to the development of Material Acceleration Platforms (MAPs), also known as Self-Driving Laboratories (SDL), aimed at thermoplastic-based nanocomposites. Our group has recently demonstrated an SDL for optimization of 3D printing parameters for a given thermoplastic material. The hardware presented here is a key step towards introducing a capability to explore the composition space of such materials.