Prusa Went Wrong — Mini-CNC Project

10 Most Common Pitfall YOU CAN AVOID — Episode 2 — Ardu_Series #79

J3
Jungletronics
4 min readAug 18, 2019

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Hi, Two long weeks in this project…that’s what it takes to me…and now I will report all the pitfall I suffered while I was working in my Prusurinha mini CNC so you can prevent harsh time tinkering.

Fig 1. Video from Episode 1 — 78° Mini-Prusurinha Printer — A Funny Tiny Prusa Printer

Welcome!

1º Motor short circuit

Although I have made the solder acceptable enough, occur that when I was packing the motor in the styrofoam structure I accidentally make a short circuit in the motor, and one of them begins to malfunction. The symptom of this error is abnormal heating of the motor…

This takes me some miserable days to discover :/

Avoid it— give the wires that poke through the motor enough space.

Fig 2— Giving the wires that poke through the motor enough space \o/

2º Excess of Solder shorting circuit the motor

This is another stress source in your life as a CNC designer.

Avoid it — Be professional while you are soldering the motor terminals. The stepper’s terminal is very next to each other, so be patient!

See the photo below and you get a vision how this solder is amazingly next to each other :/

Fig 3. See how the terminals are amazingly delicate. Take your time when soldering it!

3º Do not use white glue in the motor

My motor sleep working properly, but runs erratically in the next morning:/

Avoid it — by using hot glue instead of white glue to fix the motor in the structure. Or nuts and bolts, a better solution :)

Fig 4. the corrosion caused by white glue (Polyvinyl acetate). Argh!

4° Split the Power

This is an important issue! Both motors draw about 1 A of current. By using the laptop USB bus that gives us only roughly a half ampere (.5A) the motors would claim for more current.

Avoid it — Do not connect the Arduino VCC to the motor. Make an external feed for the motors.

5° Spill Instant Glue at the axes and ruined everything ”/

How many errors are allowed in my project? Sorry…but be advise o/

Fig 5. Instant glue (Cyanoacrylate) ruined my axes!

6º While Dismantling the hand-make PCB and Arduino Micro Is a Goner!

Then I have to change the Arduino Pro-Micro for Arduino Pro-Mini; Now a UartUSB driver is necessary; don’t worry, here’s my tutorial to get you up and running as quickly as possible: Arduino Pro Mini — Flashing — Having Trouble Flashing ProMini? Ardu_Serie#67

Fig 6. As Arduino Micro Is a Goner welcome Arduino Pro-Mini!

7° Use Wire Ultra Flex in abundant length — be generous!

Fig 7. Wire Ultra Flex

8° Implement the lift of the pen with this mini-micro servo:

Fig 8. 4 Wire 2 Phase DC micro stepper motor — Miniature stepper motor from aliexpress.com

9 º Styrofoam manufacture also uses hydrofluorocarbons (HFCs), which negatively impact the ozone layer and climate change so GET ALTERNATIVE!

As rapid prototyping that’s fine, but the upcoming version 3 I will use another material. Do you have any idea which one is the best?

10°

I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success. Such emotions make a man forget food, sleep, friends, love, everything.— Nikola Tesla

What is important to understand is that the interactive, cyclical nature of these modern, real-world models looks nothing like the linear, step-by-step design models of scientific method found in most textbooks ;)

Here is an infographic from Jeremy Blum translated into Portuguese and aimed to guide you toward the creation of a Minimum Viable Product (MVP) so these docs are good illustrations of what we mean by that :)

In the next episode of this series, we’re gonna explain the code. Be tuned!

Thank you!

Download All Files For This Project

Related Posts

78° Mini-Prusurinha Printer — A Funny Tiny Prusa PrinterEpisode 1 — Ardu_Serie # 78

79º Prusa Went Wrong — Mini-CNC Project — 10 Most Common Pitfall YOU CAN AVOID — Episode 2 — Ardu_Series #79

Credits and References

How to make a Homework machine for Students by TecH BoyS ToyS

Invent to Learn: Making, Tinkering, and Engineering in the Classroom Book by Gary Stager and Sylvia Libow Martinez

Fig 9. Prusurinha Version 2!

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J3
Jungletronics

Hi, Guys o/ I am J3! I am just a hobby-dev, playing around with Python, Django, Ruby, Rails, Lego, Arduino, Raspy, PIC, AI… Welcome! Join us!