One-step injection molding compounding (IMC) is an innovative process to manufacture shortfiber-reinforced polymer composites. The aim of combining compounding and injection molding into one
process is to enhance component quality and minimize environmental impacts. In this study, a screening Life
Cycle Assessment (LCA) is conducted to evaluate and compare the environmental impacts of the IMC process
with standard two-step manufacturing. Two scenarios for the IMC are considered, each differing in terms of
machinery requirements, energy consumption, and material usage. Mechanically recycled polypropylene and
glass fiber are used, and considered in the LCA employing a simple cut-off approach without awarding credits
for substituting (primary) materials. The functional unit is the composite produced via the respective process,
assuming equal functionality. Inventory data are obtained from initial experiments, literature, and the ecoinvent
database. The impact assessment method selected is ReCiPe2016. Results indicate that the environmental
performance improvement achieved by the IMC compared to the reference process is minimal in the
conservative scenario where energy and material usage can be reduced but machinery usage is increased.
However, in an optimistic scenario, the IMC can reduce the impacts of composite manufacturing by 34 %. The
contributions at the midpoint level vary, and metal usage and energy consumption are the main contributors in
all scenarios. A variation of the energy source for manufacturing shows the dependency of environmental
impacts of components produced in both processes on the geographical location of production and its electricity
supply. Methodological choices, such as the definition of the functional unit and modeling of recycled
materials, have a large influence on LCA results, and alternative options are discussed.