Which printing parameter is directly affected by the viscosity of the material?

The printing parameter most directly affected by the viscosity of the material is the extrusion flow rate or extrusion multiplier. Viscosity is a measure of a fluid's resistance to flow. Materials with higher viscosity require more force to extrude, which directly impacts the achievable flow rate. If the viscosity is too high, the extruder might struggle to push the material through the nozzle at the desired rate, leading to under-extrusion. Conversely, if the viscosity is too low, the material might flow too easily, causing over-extrusion or stringing. The nozzle temperature is also affected, but the relationship is more indirect. A material's viscosity is highly temperature-dependent, so adjusting the temperature is a way to indirectly control the viscosity and thus the flow rate. However, the flow rate setting in the slicer software is the parameter that directly controls the amount of material extruded per unit time and must be adjusted based on the material's viscosity to achieve accurate and consistent printing.