Build and Test of Open Source 3D-Printed 5 mL Syringe Repetition Pump

 

Overview and Scope:

In this post we build and test an open source 3D printed 5 mL syringe repetition pump. The files for this post were uploaded by JorBraMar on Thingiverse. This build is a continuation of the construction of a series of pipettes, which originated from the recreation of the open source 3D printed 1000 μL micropump. This 5 mL syringe repetition pump is more intricate than the previous designs, therefore it is more labor intensive. However, the extra work is worth it, as this apparatus works surprisingly well. It is also a great way to get your hands on some essential biological sciences equipment at a very cheap price.

 

Parts List:

Printer Settings:

  • Sliced using Ultimaker Cura 4.10.0

  • Filament: eSUN PLA PRO (PLA+) 3D Printer Filament, Dimensional Accuracy +/- 0.03mm, 1kg Spool, 1.75mm, Blue

  • Standard Quality - Resolution: 0.20mm

  • Infill: 90% for all components

  • Supports: tree, 45% overhang, zigzag pattern

  • Extruder Temperature: 215°C

  • Bed Temperature: 60°C

  • NOTE: See upload for original printing parameters

Components and STL Files:

There are eleven components which need to be 3D printed for this 5 mL Syringe Repetition Pump

 

Assembly:

The PDF document titled, SYRINGE_REPETITION_PUMP_MANUAL, is included in the uploaded files on Thingiverse and provides the specific assembly instructions required to construct this apparatus. The assembly of the repetition pump will not be explicitly outlined in this post, as the creator of this device provides excellent assembly instructions in their PDF document. Reference the PDF document directly to assemble this apparatus.

Thingiverse files link: https://www.thingiverse.com/thing:3144072/files

 
 

Assembly Discussion:

The Syringe Repetition Pump was fairly straightforward to print. It is essential to use supports for many of the components, otherwise they will not print perfectly. This apparatus is more complicated to construct than the pipettes in the previous posts. After all of the eleven components are 3D printed, the only difficulty in constructing and assembling the apparatus is finding some of the specific parts listed in the assembly instructions document. All of the components needed are metric, and the most difficult components to find were the 5M x 4.1 cm threaded rod and 5M x 13 cm threaded rod. Instead, a 5 mm x 100 mm threaded rod was procured and cut to 4.1 cm using a saw, which worked perfectly. Since there were no conveniently available 5M threaded rods over 100 mm in length, a 10-32 x 6” threaded rod was substituted and cut to 13 cm in total length. The shortened 10-32 threaded rod worked very well in lieu of the 5M x 13 cm threaded rod. Another difficulty was finding the best springs to fit this apparatus, as only the general lengths of springs are provided in the assembly instructions document. The parts list in the document calls for the following springs: a 9 mm diam. x 3.2 cm spring, a 6 mm diam. x 8 mm spring, and a 6 mm diam. x 5 mm spring. Several 9 mm diameter and 6mm diameter springs were obtained to ensure at least a few would fit. If one cannot obtain specific metric springs conveniently, one can simply buy multiple springs that are similar in size to what is required, as was done in this post. If needed, the springs can be cut with pliers to be used as substitutes. Finally, the parts list in the assembly instructions document calls for a 5 mm x 8 mm metal sheet. For this, a thin piece of aluminum sheet was cut using metal sheers to the approximate dimensions of 5 mm x 8 mm. The metal sheet was then carefully filed down to the exact size required using a metal file and sandpaper. The components were then carefully assembled and glued appropriately, according to the assembly instructions document. Once all of the components had cured, they were placed in the 3D printed body of the syringe repetition pump and the two halves of the body were screwed together carefully. When everything was lined up and seemed to be correctly in place, the screws were fully tightened. The finished syringe repetition pump worked perfectly and surprisingly had no issues, despite the fact that many parts had been substituted and custom made. The apparatus was ergonomic and had a unique weight and balance to it, which made it feel like a commercial product.

 

Operation:

To operate the syringe repetition pump, one must first place a 5 mL luer lock syringe in the designated slot. One must then place the tip of the syringe in the liquid, push the circular button, then pull the plunger to withdraw the liquid into the syringe. After 5 mL of liquid is withdrawn into the syringe, one must adjust the size of the steps (aliquots dispensed by each press of the syringe plunger) by turning the volume adjustment knob. When the size of the step has been decided, one must simply press the syringe plunger and the syringe repetition pump will dispense a preset volume of liquid. One can either gauge the volume of the liquid dispensed and adjust the volume to be dispensed by turning the volume adjustment knob, or simply press the syringe plunger again to dispense another, identical aliquot of liquid. The syringe plunger can be pressed until the liquid is completely dispensed. This is basically all that there is to the operation of this apparatus. Although it is mechanically intricate, it is very simple, streamlined, and smooth to operate. This pipette is very impressive and feels very solid. When tested, it was very reliable and practical. There were no malfunctions or need to adjust any of the internal components after extensive testing. Although the apparatus does not allow the user to set exact volumes to be dispensed, because it does not have a numerical volume indicator, one may create an ad hoc volume indicator. This was accomplished through the use of a sharpie to mark the volumes dispensed based on the relative distance between the pointer and the body of the pump. Using a sharpie to mark preset volumes worked very well for the scope and purposes in this post and allowed for easy repeatability in dispensed volume. There are many other ways in which one can conceivably create a series of demarcations to improvise a simple volume indicator. In my opinion, this is what makes projects such as these worthwhile and fulfilling; the user can change and customize their creation as they see fit in order to fulfill their specific needs. The recreation of this series of pipettes, which were all designed and uploaded by JorBraMar, was a learning experience and a lot of fun. All of the credit goes to the designer of these beautiful instruments, as each was very well designed, practical, accurate, and reliable. I highly encourage anyone who recreates these pipettes to leave a like or comment on JorBraMar’s respective Thingiverse uploads.

 
Talon KosakComment