Design of an Open-Source, Low-Cost Bioink and Food Melt Extrusion 3D Printer

In this procedure we will demonstrate how to construct ADDME, a low cost, open source, melt extrusion and bioink 3D printer. Melt extrusion and bioink 3D printers can cost thousands of dollars and are typically closed source. ADDME is an open source, customizable 3D printing platform that costs less than 350.

ADDME enables the production of complex 3D geometries with a wide variety of materials for applications within food processing, polymer composite material production, and bioprinting. This video offers a hands on demonstration of how the various components come together to construct and test ADDME. After connecting the one through nine acrylic parts, check the figure labels to ensure that each piece is located correctly and use M3 screws and an M3 Allen key to secure the pieces.

Then, place the M10 threaded rod through the purpose made holes in acrylic members six, eight, and 10, and secure the rod with M10 washers and nuts, tightening the nuts with a variable spanner. To assemble the Y-axis and printing bed, slide two pillow blocks onto each eight millimeter shaft and slide the end stop onto one of the eight millimeter shafts. Use M2 screws and an Allen key to secure the mechanical end stop and use M4 screws to secure all four pillow blocks to the mounting bed.

Secure the belt clamp onto the mounting bed using the M3 screws and an Allen key and secure the printing bed onto the mounting bed using an M3 screw, nut, and spring arrangement. Next, use M2 screws and an Allen key to secure two of the shaft holders to both the back and front panels and use M3 screws to secure the stepper motor holder to the back panel. Then use additional M3 screws to secure the stepper motor to the stepper motor holder and to secure the belt idler to the front panel.

To insert the printing bed sub-assembly into the frame, match up each end of an eight millimeter shaft to a shaft holder. To assemble the left side of the X-axis sub-assembly, place a brass nut inside the nut holder and use M3 screws and the Allen key to secure the nut to the X-axis pillow left. Using M4 screws and an Allen key, secure the pillow block to the X-axis pillow left and secure the X-axis idler one to the X-axis pillow left with M3 screws.

Align the center holes of the idler, the X-axis idler one, and the X-axis idler two and fix these materials together with M3 screws and the Allen key. To assemble the right side of the X-axis sub-assembly, place a brass nut inside the nut holder and secure the nut to the X-axis pillow right with M3 screws. Secure the pillow block to the X-axis pillow right with M4 screws and secure the X-axis right to the X-axis pillow right with M3 screws.

Use additional M3 screws to secure the stepper motor to the X-axis right and thread each of the threaded rods into each of the brass nuts. Slide two of the eight millimeter shafts into each of the pillow blocks vertically and slide two of the eight millimeter shafts horizontally. Next, use M2 screws to secure two of the shaft holders to both the top panel and to the electronics enclosure top and use M3 screws to secure the pillow block bearings onto the top panel.

Secure the stepper motors onto the electronics enclosure top with M3 screws and use the M2 Allen key to tighten the lower grub screw to secure the coupler over the shafts of the stepper motors. To place the X-axis sub-assembly into the frame, align the vertical eight millimeter shafts with the shaft holder and tighten the shafts with M2 screws and the Allen key. Then, use the M2 Allen key to tighten the upper grub screw to secure the threaded rod into the other end of the coupler.

For the extrusion of the sub-assembly, use M4 screws to secure the two pillow blocks onto the extruder back plate and use M3 screws to secure the extruder belt clamp onto the extruder back plate between the pillow blocks. Use M3 hex screws to secure the extruder back plate to the extruder motor holder and to secure the two stepper motors onto the extruder motor holder. Tighten the lower grub screw with an M2 Allen key to secure the couplers over the shafts of the stepper motors and tighten the upper grub screw to secure the threaded screw within the couplers.

Slide the heating jacket into the extruder motor holder and use M3 screws to secure the brass nuts inside plunger lock one. To mount the extrusion head onto the X-axis, slide the eight millimeter shafts found on the X-axis into the pillow blocks on the extruder head and wrap the drive belt through the idler in idler toothed on the left and right axis assemblies. Then use M3 hex screws to secure the drive belt in the extruder belt clamp.

When the frame assembly is complete, use M3 screws to mount the Arduino into the acrylic part seven electronic shroud and inserts a RAMPS board on top of the Arduino board with the USB plug facing the acrylic part six back panel. Mount the DC power supply jack into the acrylic part six back panel and fix the connector to the power supply. Then, using a wiring diagram and labels to avoid installing the connections in a reverse manner, connect the motor controllers, stepper motors, end stops, heater, and thermocouple, to their respective pins.

Line testing involves using a series of movement commands, called G-code, to print a filament back and forth on the build plate in a basic pattern to evaluate individual filament properties, such as thickness or consistency. The printing parameters used for the line tests are included in the table. To create complex 3D objects, the object to be printed must be inputted into a standard tesselation language file into Repetier and sliced into 3D printable G-code.

The parameters for printing the 3D objects are included in the table. To determine the dimensional accuracy of the additive manufacturing melt extrusion printer used for these experiments in the X, Y, and Z directions when printing a semi-solid material, a one centimeter by one centimeter by one centimeter cube was printed. The cube was then 3D scanned and dimensionally compared against the original cube computer aided drafting data.

The original model and 3D scan were then compared using the open source Cloud Compare software program. Before connecting the system or turning on the power supply, make sure that the wiring has been done correctly and that it has been checked by a qualified technician. ADDME is an open source and customizable platform for studying the melt extrusion process with applications in food and barring 3D printing.