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34 TECHNOLOGY JUL/AUG 2026 FDM ASIA | www.fdmasia.com

pxhere.com and perimeter count. Three infill densities were considered
The investigated printing parameters were infill density

(20 percent, 30 percent, and 40 percent) together with
three perimeter configurations designated as 1P, 3P, and 5P,
corresponding to one, three, and five outer walls, respectively.
Using a 0.4 mm nozzle, these configurations resulted in

approximate shell thicknesses of 0.4 mm, 1.2 mm, and 2.0 mm.
The first layer was printed at 50 mm·sễ¹ for perimeter walls
and 105 mm·sễ¹ for infill. For the remaining layers, printing
Connector Design and Printing Parameters speeds of 60 mm·sễ¹ for perimeter walls, 300 mm·sễ¹ for infill,
The dovetail connector was designed as a 3D-printed polymer and 270 mm·sễ¹ for sparse cubic infill were applied.
insert intended for mechanical load transfer between two All printing parameters, except for infill density and perimeter
wooden members. count, were kept constant throughout the experiment.
The connector slots were designed according to the geometry The filament mass for each configuration was estimated
of the modified dovetail connector and the technological by the slicing software, ranging from 2.57 g (1P20) to 5.09 g

limitations of CNC machining. The slots were machined on a (5P40). The assembled specimens prepared for mechanical
CNC machining centre using a 5 mm diameter spiral end mill. testing were conditioned for 6 days at 20 deg C and 60
The connector and the wooden slot were designed with percent relative humidity until constant mass was achieved,
identical nominal mating dimensions, corresponding to a resulting in a final wood moisture content of approximately
nominal zero-clearance fit (0.00 mm). The connector thickness 10.5 percent.
was 14 mm.
All connectors were manufactured using fused deposition Mechanical Testing and Finite Element Analysis

modelling on a Bambu Lab X1C 3D printer equipped with a Mechanical tests were performed using a universal testing
0.4 mm nozzle. Prior to printing, the filament was dried for 8 machine. The specimens were loaded in compression within
hours at 55 deg C. The nozzle temperature was set to 220 the plane of the frame corner joint.
deg C, the textured PEI build plate temperature to 55 deg Each specimen consisted of two beech wood members
C, and the layer height to 0.2 mm. with a thickness of 18 mm connected by an FDM-printed
Printing preparation and slicing were carried out in Bambu dovetail connector.
Studio software. The connector orientation on the build plate The longitudinal grain direction of the beech members
was selected to align the primary material deposition direction was oriented parallel to the longitudinal axis of each joint arm.
as closely as possible with the expected loading direction of Six replicates were tested for each connector configuration.

the connector. The mechanical response of the joints was recorded as
Three top and three bottom solid layers were used and a load-displacement curve. The measured maximum load
printed with a monotonic pattern. The deposition paths in the was then used to calculate the maximum bending moment
outer solid layers were oriented at 45° to the longitudinal axis of the joint.
of the connector, while the middle solid layer was rotated by The load levels corresponding to 10 percent and 40 percent
90° relative to the adjacent layers. The internal structure of of the maximum load were used to define the approximately
the connector was printed using a cubic infill pattern. linear region of the response, and this interval was subsequently