16. Wildcard Week¶

Assignment¶

• Design and produce something with a digital fabrication process (incorporating computer-aided design and manufacturing) not covered in another assignment, documenting the requirements that your assignment meets, and including everything necessary to reproduce it. Possibilities include (but are not limited to): machines (like laser cutting), welding, molding and casting, folding, robotics, electronics, embedded programing, food, materials, biotechnology, textiles, composites.

After reading this week assignment I tried to learn how to use the Rotrics DexArm, because is a machine that can be use in a lot of different ways. This feature is aligned with fabacademy goal.

Rotrics DexArm¶

The Rotrics DexArm , It is a 4-axis desktop robot arm with modular design and 0.05mm high repeatability. It works around 4 different modules:

• Laser Engraving Module
• Pen Holder Module
• 3D Printing
• Air picker (I don’t have this module)

It’s important to do the calibration every time the DexArm is turned on. It’s not a big deal, before turning it on, stretch all the arm up. It should like the picture below: After stretching the arm, turn it on and plug it to your computer.

Pen Holder Module¶

Module that’s responsible for holding the pen making it possible to do writings and drawings with the pen. It’s all controlled by Rotrics Studios, a Software that enables us to draw and write freely. We can also import .svg files. The final format of the file is a G-code.

Rotrics Software¶

The Rotrics software can be download in this link, and a nice tutorial can be found in this page.

With a simple interface and easy to use, the Rotrics software is really intuitive and practical to adjust what you’re trying to print.

First Experiment - Drawing & writing¶

First I’ll write “Fab Academy” with the pen module

• Step 1 - fix the paper 15 cm in front of the robot arm
• Step 2 - Press the “home” button in the control area to centralize the DexArm

• Step 3 - Select Write&Draw option in the left side of the program

• Step 4 - Choose one of the options above:

Sticker: preset stickers, click to load into canvas. Svg: upload SVG files to draw images. Text: enter texts, suitable for writing letters or greeting cards.

• Step 5 - adjust the image size: Drag the image to the target position. Adjust the image size by changing the Width and Height value. After that, flip your image to don’t get a mirrored result.

• Step 6 - Set working parameters:

Jog Speed: this is the speed of DexArm travel without drawing, the suggested jog speed for write/draw is 400 mm/min. Work Speed: this is the working speed of DexArm, the suggested speed for write/draw is 400 mm/min. Pen offset*: this is the height that DexArm moves up during travel, the suggested pen height is 10mm

• Step 7 - Click Generate G-code button to generate G-code.

• Step 8 - Click Start Send

Video01 – Jog Pen

Errors¶

Beyond x/y/z limit the pen started to jump. New versions of the program are kind of bugged, i tried the old version in the archives. (Video in the archives*)

Laser engraving module¶

Module that uses a laser to make engravings in wood. It supports 4 modes: - Black and white(png,JPEG and PNG) - Greyscale(png,JPEG and PNG) - Vectorial mode(SVG) - Text mode.

Rotrics Software¶

Similar to the Pen-Holder module, all the options are really intuitive and easy to use.

Note: Again I’m using that version to avoid bugs.

Second Experiment - Laser engraving¶

For this experiment I’ll engraving “Fab Academy 2021 - Manaus” with the laser module.

• Step 1 - Focus laser mode:

Note: wear the Safety Goggles before setting up and throughout the laser engraving process! Note2: nobody was close to me inside the lab when start the process.

With Rotrics studio:

- Step 1.1 - Switch to the Laser panel, click “control”  and click “home “ to move the arm to the HOME position (0, 300, 0).
- Step 1.2 - Click Laser slider button at the bottom, turn ON the laser, and set power value as 1.
- Step 1.3 - Place the engraving material below the laser module, spin the circle under the laser module to focus the laser module, keep spinning until you get the smallest laser spot.

• Step 2 - After focusing, click Set Work Height to set this point as the work height.

• Step 3 - choose what should be engraved on the wood where you have written the commands: B&W, Greyscale, svg, text

B&W: black and white mode, supports jpg, JPEG, PNG files. Greyscale: greyscale mode, supports JPG, JPEG, PNG files. Svg: vector mode, supports SVG files. Text: enter text mode, enter text and cover to vector lines for engraving.

• Step 4 - Set image position parameters and engraving parameters and preview engraving effect.

  • If you have selected B&W mode, you can only upload PNG and JPG files. Refer to the following instructions for parameter adjustment:
    • Black on White: according to the image color, adjust the black and white ratio of the image. The larger the value, the higher the proportion of black, and the darker the picture.
    • Line Direction: This determines the motion direction of laser engraving. Horizontal, Vertical, Diagonal, Diagonal2. Select the direction which is consistent with the picture direction to save engraving time.
    • Density: This determines the density of the engraving. The larger the density value, the better the engraving quality and the more time it takes. The range is 1-10 pixel/mm, the recommended setting is 10.
    • Invert: swap black and white areas
  • If you have selected GREYSCALE mode, you can only upload PNG and JPG files. Refer the following instructions for parameter adjustment:
    • Invert: swap black and white areas.
    • Contract: This determines the contrast between light and dark colors. The larger the value, the more obvious the contrast.
    • Brightness: The larger the value, the brighter the image is 100.
    • Algorithm: select the algorithm for processing the image.
    • Density: This determines the density of the engraving effect. The larger the density value, the better the engraving quality and the more time it takes. The range is 1-10 pixel/mm, the recommended setting is 10.
  • If you have selected GREYSCALE mode, you can only upload PNG and JPG files. Refer the following instructions for parameter adjustment:
    • Invert: swap black and white areas.
    • Contract: This determines the contrast between light and dark colors. The larger the value, the more obvious the contrast.
    • Brightness: The larger the value, the brighter the image is 100.
    • Algorithm: select the algorithm for processing the image.
    • Density: This determines the density of the engraving effect. The larger the density value, the better the engraving quality and the more time it takes. The range is 1-10 pixel/mm, the recommended setting is 10.
  • If you have selected VECTOR mode, you can only upload SVG files. A good program to help with images and making SVG files of then is InkScape.
  • If you have selected TEXT mode, just write down your text as you made in the pen holder module

Note: When using text mode, enable “Fill” to have better results.

• Step 5 - Set laser output power and working speed.
  • Work Speed(mm/min): the speed when DexArm is engraving.
  • Jog Speed(mm/min): the speed when DexArm is moving without engraving.

Suggested Settings: For 2.5W laser module, the suggested output fixed power is 60% and work speed is 250mm/min

• Step 6 - Click Generate G-code button to generate G-code.

• Step 7 - Recommended setting HOME as work height to get the biggest working area.

• Step 8 - you can click Run Boundary to preview the laser engraving area after G-code generated. Move the material to locate the best engraving position.

• Step 9 - Click Start Send to start Drawing.

Video02 – Laser engraving

Errors¶

• If laser does not engrave:
  • Try to focus the laser as shown before again, make sure that you enabled the “fixed power option” and changed it to 60%.
• Text is inverted or almost invisible
  • Use the option “Invert” and select the better option in your case to make the text correct. Enabling the option “Fill” will make your text shows better.

The 3d Print module I had some problems, next week I will try to used it.

Adding Amazon Forest materials¶

I had a meeting with my international evaluator and we have a very nice chat how to improve this week.

So, to bring a little of the Amazon to the Project, we had the idea of producing my own paint using regional fruits. The indigenous people of the region use annatto to paint their skin, so I thought about using the annatto to make the ink that the Rotrics DexArm would write on paper.

For this, it was necessary to go after annatto in the region in such quantity that it was possible to grind the seeds of the fruit, mix it with yeast to obtain the powder. In the pictures below we can see the tree, fruits and process of mix of Annatoo. The indigenous name is Uruku.

Now that I had the annatto powder, the next step was mix it with water and glue in the same proportion to obtain the ink.

With the ink, it’s time to program the robotic arm to make use of it. Using the pen holder module, I placed a brush on the tip of the robotic arm and make it dip in the ink, then return and uses it to write the word FAB on paper, which can be seen in the below video.

Conclusion¶

This week was possible to learn how to use the Rotrics DexArm, it is a good tool, but… I remembered a saying:

“A duck can swim, walk and fly. But an eagle flies faster and more skillfully, fish are better swimmers and just about anything on legs can outrun a duck.” In other words, ducks can do a lot of things but they are not experts in any of them”

For more information about the arm tools like lase power, pen tool grip power and grip diameters can be found in the Manual.

• All the programming files of this week assignment can be find in the repository

Files