Introduction: DIY Syringe Pump

About: Account to share rapid-prototyped scientific devices used in the Harris Lab at Brown Engineering. Our hope is that our posts will serve as accessible launching points for your future applications and designs.…

I chose the materials based on what was most available to me at the time so there is still a lot of room for the design to be simplified and improved. As a result, I’ve attached all the files I used to fabricate the laser cut and 3D printed components so that the design can be directly edited. Hopefully this design is a useful starting point for future iterations.

Step 1: Materials List

Step 2: 3D Printed Parts

Step 3: Laser Cut Parts

Step 4: Fabrication Steps

For reference, this is what the syringe pump looks like when completely assembled. Some key steps in the assembling process will be detailed in the guide below.

Step 5: Wiring the Stepper Motor

The stepper motor is wired to a driver plate which is interfaced with an Arduino according to the schematic (Figure 1, Source:link) above. The driver plate is a nice way to simplify the wiring of the stepper motor but is by no means necessary. I followed this step by step guide which additionally includes sample Arduino code and a library that I also used.

Step 6:

Using a vice, I press fit two sleeve bearings and one ball bearing into the “shaft housing part” I 3D printed. I fabricated two of such components. I also press fit two additional sleeve bearings into the carriage I 3D printed.

Step 7:

The linear translation carriage has a small housing for a square nut as illustrated below. We epoxied the square nut in the housing to prevent slop, but you could just as easily directing tap this part of the carriage.

Step 8:

I then laser cut a base plate (Base (p1)) out of acrylic for the frame of the pump. This plate will hold all the components in place.

Step 9:

I additionally laser cut a mount to directly hold the stepper motor in place.

Step 10:

I then assembled all the aforementioned components as illustrated in the image below. I did this by first threading the ¼-20’’ rod though the carriage and passing the rod through each ball bearing. I then slid the linear shafts through each sleeve bearing and added lubrication in the process.

Step 11:

I was able to connect the threaded rod to the stepper motor using the shaft coupler. Here, I had to turn down the diameter of the threaded rod so that I would fit the (5mm) inner diameter of the coupler.

Step 12:

I also attached the stepper motor to the mount using two 4-40 screws and some nuts. The image below illustrates this more clearly.

Step 13:

After these steps are completed, everything should fit onto the Base (p1) plate nicely. Note that for us, 3D printed parts tightly fit onto the acrylic plate so no additional epoxy was used.

Step 14:

We additionally added two screws and a small acrylic plate for clamping the syringe. This addition isn’t included in the original STL file, although the side holes are.

Step 15:

A second base plate was then laser cut out of acrylic (Base (p2)). The purpose of this base plate is so that the shaft housings have more support to sit on. Two frames were additionally laser cut out of acrylic.

Step 16:

The second base plate the the frame were then attached to the existing assembly. The images below illustrate in greater detail how this was done.

Step 17:

The second base plate the the frame were then attached to the existing assembly. The images below illustrate in greater detail how this was done.

Step 18:

Then 3 ¼-20’’ rods and nuts were used to fasten the whole frame together.

Step 19:

A screw and nut (on each side) were added to directly connect the shaft housing to the frame. This helped us reduce slop since the 3D printed housing started to move around after repeated use of the pump.

Step 20:

Acrylic stands were added beneath the stepper motor to support it.

Step 21:

Finally, I attached the 3D printed clamp to the shaft housing. I additionally wrapped a neoprene sheet around the syringe to prevent it from slipping.