Table 2.

Toolpath parameters.

Printing Parameter	Depiction	Description	Impact on dimensional accuracy identified in analysed studies from an increase (↑ top row) or decrease (↓ bottom row) in printing parameter value.
Nozzle gap height (NGH)		Also known as layer thickness, the measured displacement from the tip of the extruder nozzle to each successive layer of deposited material. NGH can also influence the defects listed: Circularity, Cylindricity, Porosity, and Surface Roughness.	↑	[10, 22, 25, 32, 33, 37, 46, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76]
			↓	[12, 26, 27, 31, 34, 35, 36, 44, 45, 53, 54, 62, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112]
Filament volumetric velocity (FVV)		Also known as feed rate, the volume of material extruded through the nozzle per unit distance travelled. FVV can also influence the defects listed: Geometrical accuracy, Porosity, and Surface Roughness.	↑	[38, 67, 71, 100, 105, 113, 114],
			↓	[73, 84, 103, 115]
Print head velocity (PHV)		Also known as print speed, the velocity the extruder head traversers across the build envelope during deposition and non deposition. PHV can also influence the defects listed: Circularity, Geometrical accuracy, Surface Roughness, Shrinking, and Warping.	↑	[25, 31, 37, 53, 54, 61, 65, 72, 73, 88, 99, 100, 109, 114, 116, 117]
			↓	[32, 34, 36, 68, 71, 76, 92, 106, 108, 112, 118]
Air Gap (AG)		The measured lateral distance between the centre points of deposited adjacent filament strands. AG can also influence the defects listed: Geometrical accuracy, Porosity, and Surface Roughness.	↑	[12, 21, 22, 44, 86, 110, 119, 56]
			↓	[22, 45, 46, 120]
Raster angle (RA)		The angle between deposited adjacent strands with respect to the X axis. RA can also influence the defects listed: Geometrical accuracy and Surface Roughness.	↑	[21, 44, 60, 88, 119, 120, 121],
			↓	[12, 22, 45, 46, 56, 66, 70, 78, 104, 110]
Road width (RW)		Also known as raster width, the width of a deposited stand, which is a function of the extruder nozzle diameter and toolpath parameters. RW can also influence the defects listed: Geometrical accuracy and Surface Roughness.	↑	[12, 22, 45, 53, 60, 61, 66, 83, 120, 120, 121]
			↓	[21, 25, 27, 36, 44, 46, 56, 63, 64, 110, 119, 122]
Contour width (CW)		Also known as perimeters and number of shells, the thickness of the outer wall of a printed part. CW can also influence the defects listed: Geometrical accuracy and Surface Roughness.	↑	[10, 21, 28, 39, 46, 85, 121, 123]
			↓	[10, 36, 38, 44, 65, 77, 87]
Contour print head velocity (CPHV)		Similar to print head velocity, this sets the velocity of the extruder head whilst depositing the contours of the part. CPHV can also influence the defects listed: Geometrical accuracy, Surface Roughness, and Warping.	↑	[105]
			↓	[67, 113]
Infill print head velocity (IPHV)		Similar to contour and print head velocity, this sets the velocity of the extruder head whilst depositing the infill layers of the part. IPHV can also influence the defects listed: Geometrical accuracy and Porosity.	↓	[113, 124]