Cartesian 3D Printer
Overview
I was introduced to the concept of 3D printing from a video shown by my dad. The fact that you can quite literally “print” any 3D object from thin air was akin to wizardry for me. Even though I didn’t pay much heed to it then, as I thought it wasn’t feasible, the idea kept me intrigued at the back of my mind. A few days later, my dad took me to a 3D printing expo in our city, where I got to see these magical things with my own eyes. As much as I wanted to take one of these home and start tinkering, the prices ranging from Rs. 50,000 — 88,000 (~$750–$1350) held me up. As I had previously made a Quadcopter, I took this up as a challenge to make a 3D printer under Rs. 10,000 (~$150) which was fully functional. This ensued in an eight month long journey of learning and experimentation and the device shown above is the end result of this effort.
I was 13 years old when I built the printer, and I hadn’t had any prior experience with machining and fabricating parts. The only tools I had available were a Hand-drill and a Hack-saw. Most of the 3d printer designs available consist of 3d printed parts, since I didn’t have one I had to design it myself.
Specifications
Printing Speed : 100mm/s
Printing volume: 200mm x 200mm x 200mm (Length x Breadth x Height)
Printing Nozzle: 0.4mm
Power Supply: 12V, 18A
Can print PLA.
Parts Used
- Hot End (E3D V6)
- Extruder Frame
- Arduino Mega
- RAMPS 1.4
- Endstop switches
- Stepper Motors (NEMA 17)
- Stepper Motor Drivers (A4988, DRV8825)
- Linear Bearings (LM8UU, SC8UU)
- Pulleys (GT2, 5mm bore)
- Belts (GT2)
- Motor Couplers (5mm to 8mm)
- Threaded rods/ACME Rods (8mm) ( I prefer threaded rods as they are inexpensive and don’t impact the printing quality)
- Smooth Rods (8mm)
- T nuts (8mm)
- Pieces of wood, aluminium for the frame
- Glass Bed (Optional: Heated Bed)
- L Brackets (NEMA 17)
- Power Supply (ATX 450W)
- PC Fan
- LCD (2004/12864) Optional
- F2F wires
Tuning
There were many improvements which could be made to increase the print quality. I listed some problems below and how I solved them.
Stepper Drivers
Had an extremely hard time dealing with the A4988 drivers, which used to randomly blow up during the prints. Switched to the DRV8825s and didn’t have any problems.
Bowden Extruder
The Bowden setup induced a lot of friction causing the extruder stepper to heat up significantly, which resulted in it shutting off or killing itself. After some designing and fabricating, I mounted the extruder directly on top of the hotend.
Frame strength
When the belts are fully tightened, the tension between the motor and idler is pretty significant, this caused the aluminium to bend. To solve this I switched out the aluminium for thicc wood. And instead of going for an I3 style design, I fixed everything on a 25mm thick wood, which gave the printer immense rigidity.
Over extrusion
As the default value in Marlin is for a geared extruder, had to change the E-steps of the extruder in Marlin.
Z-banding or Z-wobble
Changed the linear rails of the Z-axis to better linear rails. Removed the Z-axis threaded rod(not an ACME lead screw), and created a mechanism where the Z-axis motors pull the X-axis gantry via nylon strings. The Z-axis motors were stuck on a structure made with PVC pipes. It was very similar to this, although a lot less fancy.
Unfortunately don’t have any pictures of the above contraption.
Layer height
My caveman brain had a hard time figuring out why the prints weren’t coming out well after I had fixed the over extrusion issue. When the printer was over extruding, the diameter of the filament coming out of the nozzle would have been much greater than 0.4mm, so even with 0.4mm layer height, there would be layer adhesion.
0.4mm nozzle so 0.4mm layer height. Right?
After smashing my brain against the keyboard for a month. I had one of the biggest facepalm of my life. Immediately set the layer height to 0.3mm and the prints came out pretty well.
Timeline
Although this may have only taken 10 minutes to read, the time it took to iron out the problems in the printer took quite a bit more.
March 2017, Started with part sourcing and design.
Sourcing all the parts and building the first frame.
October 2017, The first successful print.
Tried to tune it.
February 2018, Ditched the first frame and started work on a new frame.
Put a lot of effort to get the prints right.
July 2019, Stopped with the mods.
Takeaways
I spent way too much time on this project, even that would be an understatement. The 2 year journey, from scrap wood to a fully functional 3d printer, was pretty fun.
The amount of knowledge and experience gained during those 2 years is immeasurable.
Throwing it away has been pretty hard, all good things must come to an end somehow.
