2. Assembling printed parts

What You Need

3D printed components:

• head_main_body.stl
• piezo_clamp.stl
• fixed_mount.stl

Hardware:

• 3 Ball Bearings 1/4" or 6.35 mm diameter
• 2 Magnets 20 mm diameter x 3 mm thick
• 10 M3 Heat Set Inserts
• 1 M6 Hexagon nut
• 1 Small O-Ring 1/4 outer diameter, 1/8 inner diameter, 1/16 width
• 3 rubber washers 1/4 outer diameter, 1/8 inner diameter,1/16 width
• 3 10-24 to 1/8 inch barb
• 1 large O-Ring 1 3/8 outer diameter, 1 1/4 inner diameter, 1/16th width
• 1 Piezo-Electric Disc 35mm diameter
• 6 M3x18 Bolts
• 1 Compression spring 9/32" x 3/4" or similar
• 2 no.10 x 24 tpi Heat Set Inserts
• 1 M3 x 20 mm Bolt
• 6 1/8" diameter x 1/2 long Steel Dowel Pins
• 3 M3 x 14 mm Bolts
• 4 M4 x 8mm Bolts
• 8 M5 x 8mm Cap-Head Bolts
• electrical wire (1 red, 1 black 28AWG flexible stranded wire recommended)
• Electrical Solder
• 2 small diameter pieces of heat-shrink tubings
• 1 Hose
• 4 Zip ties
• Superglue
• 1 Ender3 / Makerbot Design Endstop Component - like here
• 2 Ferrules
• Stepper motor Nema 17 or 23
• M6 3D printer nozzle

Please note: versions released before 8/15/2025 used an M7 3D printer nozzle and nut with cad files to match. The last release with M7 hardware can be found in commit 8f0fe0c744801a5e135758f032cbbc193d6f0c22

Assembling the Nozzle

1. First, carefully remove the 3D printing supports on the nozzle, either with small pliers or with your fingers. If necessary, use the 3D CAD files to see what needs to be removed.

2. Carefully press the three ball bearings into the round indentations in the center part of the nozzle component. Optionally, use a soldering iron with a heat-set insert tip to slightly melt the filament around the pellets so that it encloses the ball bearings.

3. Turn the centerpiece of the nozzle part over. Using a small wooden stick, spread the round indentation in the middle with superglue and insert one of the magnets.

4. Turn to the bottom part of the nozzle component and place it on the flat side of the table. Arrange six of the M3 heat-set inserts in the vertical holes arranged in a circle so that the twisted bolt-like part of the inserts is in the 3D print. Use a soldering iron with the tip of a heat-set insert and carefully apply pressure to each heat-set insert until the height of its top matches the 3D print. Make sure you hold the soldering iron as vertically as possible to insert the inserts straight.

5. Place the hexagon nut with the round side facing up in the center cavity of the droplet nozzle. Once you ensure that it is straight, use a C-clamp to push it into the 3D print until its top reaches the height of the 3D print.

6. Use tweezers to insert the small O-ring into the hexagon and ensure it lies "flat" where it meets the hexagon. Screw in the 3D printer nozzle with the desired droplet diameter.

7. Use a #10-24 hand-held screw tap to cut a thread in the 3D-printed hole. Turn the tap until it comes out the other side of the sidewall. Take a washer and a 10-24 - 1/8 inch barb and place the washer on the short side of the barb. Then carefully screw the barb into the hole, making sure it seals.

8. Turn the component so that the funnel-shaped side is facing you. Place the larger O-ring on the inside and ensure it has no dents and is aligned with the 3D print. Place the piezo on top and insert the wires of the piezo into one of the tube-shaped cavities. Take the centerpiece of the nozzle part, rotate it so that the magnet faces the piezo, and place the two parts on top of each other.

9. Take six of the M3x18 screws. Insert them into the six holes in the centerpiece and screw them tight to connect the lower and middle parts of the nozzle section. At first, only screw the screws tight enough to keep them in place, but do not tighten them yet. Then tighten the screws evenly in a star pattern so that the O-ring stays in place. The screws should be snug but not too tight, just enough to compress the O-ring and seal the 3D print to the piezo.

10. Now turn to the upper part of the nozzle module. Take six 1/8 x 1/2 steel pins and gently push them into the elongated shapes with your finger, then use an Allen wrench to support the push until the flat round end meets the 3D print. Do not use too much force. If the steel pin does not insert easily, ensure it is properly aligned. Similar to the ball bearings, you can use a soldering iron with a heat-resistant tip to melt the filament that encases the pins and ensures they stay in place.

11. Then place the upper part of the nozzle module with the circular indentation facing upwards on the flat side of the remaining droplet nozzle. Place the magnet WITHOUT superglue in the circular indentation to check which side must face the 3D print so that the magnets attract and do not repel each other. Remove the magnet and only then spread superglue in the indentation and then place the magnet with the correct side in.

12. Place the upper part of the nozzle component on the table with the magnet facing upwards. Take two more M3 heat-set inserts and insert them in the same way as you did with the inserts in the lower part of the nozzle.

Assembling the Reservoir

1. As with the nozzle component, carefully remove the 3D-printed supports from the reservoir. If necessary, use the CAD files as a guide for the parts to be removed.

2. Place the base of the reservoir on the table with the funnel-shaped side facing upwards. Place the heat set insert as before, ensuring it is placed as straight and vertically as possible. Using tweezers, insert the spring into the vertical opening on the longest rectangular side of the reservoir. It should be fitted straight at the top and bottom.

3. Close the reservoir with the lid. Insert the 3Mx20 screw into the previously inserted heat-set inserts above the spring. Using a soldering iron with a larger soldering tip than before, insert the 10x24 heat-set inserts as you inserted the previous ones.

4. Take the two remaining rubber washes and place each on the shorter end of one of the two remaining 10-24 to 1/8-inch barbs. Then carefully screw the barbs into the 3D print, again with the shorter side facing down, into the heat-set inserts.

Mounting everything to the Motor

1. Place the clamp and the upper part of the nozzle section together. Make sure that the magnetic side of the nozzle part is facing the clamp. Connect the two parts by tightening the M4x8 screws from the clamp side.

2. Screw the clamp to the shorter rectangular sides of the stepper motor linear actuator using the M5x8 screws.

3. Now align the container so that its long rectangular side is facing the long rectangular side of the stepper motor linear actuator. Attach the container to the motor using four M5x8 Ball-Ended Thrust Screws and an Allen wrench.

4. In the same way as you attached the container to the stepper motor linear actuator, now attach the lower supports to the actuator using four more M5x8 Ball-Ended Thrust Screws.

5. Place the lower part of the nozzle component on the upper part, which is attached to the clamp and the motor. Then hold one end of the hose to the barb on the nozzle and the other to the center barb on the reservoir to measure the length. Let the hose hang loose in the middle to give it extra length. Cut the hose to the measured length and slip one open end of the hose over one barb and the other end over the other barb, making sure that it seals so that no liquid leaks later. Hold one end of the hose to the edge of the reservoir and the other to the table to measure how long the hose needs to be for the overflow container. Then cut it to the measured length. Slip one opening of the hose onto the barb of the reservoir and leave the other open.

6. Now the piezo wires must be extended through the solid wires. To connect them, use the same color of piezo wire and solid wire. Heat a soldering iron with a flat tip, if possible. Melt some of the solder wire onto the solid wire and onto the tip of the soldering iron. Then place the solid wire on the piezo wire so that they are touching and heat the previously applied solder on the solid wire so that it melts onto the piezo wire and thus connects the wires. Potentially, add more solder wire if necessary. Repeat the process with the other colored wires.

7. Thread a heat-shrink tube onto each solid wire and shrink them with a heat gun. Form an oval loop from the piezo wire. Take a cable tie and thread one end into the center of the loop and the other end around the tube and solid wires and tighten the cable tie. Repeat the process with a second cable tie and then carefully pull the cable ties apart so that the oval loop expands and becomes flat. The cable ties serve as strain relief and ensure that the piezo is not pulled out of the component if the wire is accidentally pulled. Twist the black and red solid wires together and attach them to the hose with two cable ties: one at the minimum height of the hose connecting the nozzle and container, and one in the middle of the minimum height and the nozzle.

8. Take two ferrules and place one around the end of each of the solid wires. Use a ferrule crimper to crimp them onto the wires.

9. Attach endstop to linear actuator with hot glue or foam mounting tape. The endstop should be positioned such that the switch is depressed by the linear actuator carriage before the carriage reaches its mechanical limit.