Modifying a 3D Printer to Print with Unconventional Materials
Honors Thesis · Computer Science · Macalester College · 2025
Independent Research · Hardware Prototyping · Material Exploration
I modified a low-cost 3D printer to extrude paste-like materials, exploring how existing hardware could make unconventional-material printing more accessible.
Materials tested: Porcelain, Mashed potatoes, Cream cheese
I wanted to experiment with ceramic 3D printing for another research project, but I did not have access to a ceramic printer. Specialty printers were expensive and posed their own set of limitations. Many modifications exist but they vary in technical expertise and equipment required and often do not share all the relevant information.
Modify a conventional printer into a practical, affordable paste-printing system that researchers and experimenters could use without specialized equipment or advanced technical knowledge.
My approach was built on existing research: I found a study that used a syringe-and-needle system on a different type of printer to extrude a much thinner bio-material. I adapted that idea for my own printer and for thicker, paste-like materials, simplifying the connections and widening the material path where needed.
I replaced the conventional filament extruder with a needle, using the printer’s existing motor and a 3D printed gear mechanism to push material through a syringe into the needle.
Left: Extruder detached from printer, blank extruder plate
Above: Modified printer printing cream cheese
Wider tubing, connectors and needle to accommodate thicker materials
Fewer connectors to reduce bottlenecks during extrusion
A single, shorter needle to increase vertical printing space
Swappable syringe for longer prints needing more material
Additional 3D printed parts to attach the needle to a standard printer
A diagram illustrating the syringe extrusion system. Arrows indicate connection points creating the biggest potential bottlenecks.
Assembled core of modification
Assembled Syringe and needle system
I considered a peristaltic pump system instead of a syringe for my modification but ultimately went with the latter. A comparison of the two is outlined:
Syringe vs Pump
lower cost
limited capacity
readily available
easy to use and clean
can be pushed using printer's existing motor
I worked with existing software to slice and print models with the new system. I used PrusaSlicr but the steps I took translate to most standard slicing software available.
I updated 4 lines of code from PrusaSlicr's interface to enable extruding cold material.
The printer’s existing profile was designed for filament, not paste. I had a guiding principle that extrusion height should be approximately one-third of line width, but no established settings profile for my modified setup.
In addition to the typical settings adjusted based on the model being printed, I also had to adjust the extrusion multiplier, layer heights and extrusion width. I tested all my materials and found settings that stay consistent for a given material and others that change depending on the object being printed.
Adjust printer settings and material consistency.
Print simple shapes, including squares and circles.
Observe line consistency, flow, and shape retention.
Identify under-extrusion, over-extrusion, and layer height issues.
Refine settings based on material behavior.
PrusaSlicr interface highlighting the only changes made to G-Code. Blue dots indicated commented out code, green indicated added line.
Screenshots showing adjusted Filament and Extruder settings for porcelain in PrusaSlicr
Testing clay, mashed potatoes, and cream cheese revealed different problems with resistance, flow, and shape retention.
Clay was the hardest material to work with. It had significantly higher resistance than the other two.
The motor initially struggled to push the clay.
Pressure built up and the syringe shifted in its holder.
I tested needle size, clay consistency, and extrusion settings to find a balance.
I struggled with adhesion of the clay to my printing surface. However, the lines created by clay could be incredibly thin.
The wings of the syringe were bent at 90 degree angles from the immense pressure created by the clay.
Extruded relatively easily and produced clean lines with boxed mix.
Held its shape well enough for a delicate, single-wall spiral form.
Homemade mashed potatoes had a chunky texture, creating thicker and irregularly extruded lines
Very tasty
Produced smooth, crisp lines.
Excess extrusion dragged material through the fish’s body.
The softer material tended to droop at room temp, limiting taller structures.
Chunky Mashed Potato Cat was difficult to see without the 3D model next to it. Thicker material and chunky texture led to loss of detail
Clay stressed the system and once the syringe was at it limit, the gears began slipping revealing less than strong connections that I was able to improve in future prints.
Despite thinning the clay, I struggled with adhesion of the clay and high elasticity. I later connected that the porcelain available to me was a particularly elastic blend that did not lend itself well to such an application without being very thinned down to overcome the elasticity.
Adapt what exists. Rethink what doesn't. This project taught me to treat existing research as a starting point rather than a finished solution. The challenge was to understand why a published approach worked in its original context, identify where it fell short for my application, and adapt it to meet a different set of constraints.
It also reinforced that accessibility is shaped by more than cost alone. The equipment, software workflow, and technical knowledge required to use a system all affect who can experiment with it. By considering these barriers alongside the mechanics of extrusion, I learned to approach technical design as both a problem of making something work and a problem of making it usable by others.
Ultimately, the project showed me how research, hardware prototyping, and iterative problem-solving can work together to make new possibilities more approachable.
A collection Lines and Globs
