To ease fabrication, given the materials and fabrication methods available, the initial CAD model was modified as shown in Fig. 1.
Fabrication of Links
The links, guide arm and carriage were additively manufactured (with Fused Deposition Modelling - FDM). This greatly simplified the task of fabricating the complex geometry of the guide arms in addition to reducing machining time required. PLA was the fabrication material of choice as it is less susceptible to warping compared to other materials available for fabricating with FDM (e.g. ABS - see failed build with ABS in Fig. 2). Also, it provided enough strength and smoothness for the sliding of the rollers on the guide arms. To ensure holes were dimensionally accurate and properly-aligned, they were undersized in the CAD models and then drilled to the right sizes on a milling machine after printing.
Fig. 2: Failed build of guide arm caused by excessive warping of ABS
Fabrication of Gears
The driver and driven gears transmitting motion from the motor were also fabricated with FDM. The gears were designed on geargenerator.com and exported to STL format for printing. Dimensions were chosen to amplify the motor's torque output (MA=2.5).
Base Plate and Stand
The base plate was laser-cut out of acrylic while the stands were wade of wooden blocks.
Fig. 3: Base plate
Assembly
Mounting hubs, set screws and additively-manufactured retention rings were used to achieve tight-fits between the shafts and bearings.
The final assembly is shown below:
Fig