this has all the designs: https://cad.onshape.com/documents/f0edc675ec6e7dd579a916ba/w/8ae7a773a962de3b1e73e6d8/e/a93e4edb635fdcd076b4d8c3
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rpi 5
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rpi level shifter
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rpi lcnc gpio <-> parallel port
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cnc breakout board https://www.amazon.com/dp/B07S5JSWC6
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3 nema 17 steppers https://www.amazon.com/dp/B0B93J9QZY
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3 a4988 stepper drivers https://www.amazon.com/gp/product/B07BND65C8/
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6 guide rods https://www.amazon.com/gp/product/B09VDHKQLB/
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gt2 timing belts https://www.amazon.com/dp/B08R93QQ8Z
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gt2 pulley wheel
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linear rail mgn15h https://www.amazon.com/dp/B07QZ25F53
grbl stuff
C:\Users\anand\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17\etc\avrdude.conf
avrdude -p m328p -D -PCOM4 -c arduino -b 115200 -U flash:w:grbl_v1.1h.20190825.hex -C C:\Users\anand\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17\etc\avrdude.conf or use xloader2
grbl settings https://github-wiki-see.page/m/gnea/grbl/wiki/Grbl-v1.1-Configuration
todo:
done:
todo:
- fix bom (30 mins)
- microstepping and try the quieter drivers
- try to take a short video of it drawing using a rpi camera or gopro, I'm down to just hold it cuz I don't have a long enough cable
- replace xidler with the new tensioner
- load cell on pen, have control over force applied to page
- beam bending physics, work out the expected deflection given the mass of the z axis
- make the pen holder way longer - requires making the z wider so that the pen can be taken out upwards
- redesign it to be a supported gantry
- for the gantry, do the physics to see how much longer the y axis can be made
- look at how bed leveling works on a 3d printer, it would be cool to do that, but it would mainly be measuring deflection since that is way more of a change than how flat the wood board is
- find out what it would take to do closed loop with angular encoders
- improve the testing situation- it would be nice to log information on the page printed about what type of pen- what grbl settings and what cad settings were used to produce an image
- have some actual gcode written tests, like a bunch of lines spaced 1mm apart, and a big circle, stuff like that
- art- try a really thick pen (requires cad change) and try to draw some cool graffiti
- think about tool changing
- far out but could use the z axis to control rolling paper across
- mount a time of flight on the z axis and do bed leveling or rather more a measurement of deflection
- use a 775 spindle
done:
- add little clamps to hold paper down instead of using tape
- make the pen holder even longer (closer to ground to improve deflection)
- finish assembly and hardware for the whole design in onshape
- fix tensioner to not limit travel in x
- minimize threaded insert usage and opt for tapping (particularly for thru holes, threaded inserts in blind is ok)
- instead of slotted nut put a cbore under rail, because the support removal for slot is a nightmare
- also for the cbore on the bolt that goes thru rail need to increase diam
- cbore on the bottom nuts for x axis motor and currently they are super inaccessible
- pegs for belt holder are too weak and can easily break (3mm to 4mm)
- slot for belt tensioning is UX nightmare terrible mechanism
- try 2 sets of linear bearings on Y see if deflection improves
- redesign the rail holder parts so stepperx is on other side, the screws can actually be put in, and the rail actually gets fully surrounded, on the idler side, make a slotted section to more precisely control belt tension, also surround rail and make more rigid and so screws can actually be installed