Simple Scara Robotic arm (part 3) Fixing the noise
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- เผยแพร่เมื่อ 10 มิ.ย. 2024
- fixing the terrible noise the Z axis was making with a redesign and some nice new components.
still a lot of work to be done but we are getting there :)
servo stepper motor link : s.click.aliexpress.com/e/_DF8... - วิทยาศาสตร์และเทคโนโลยี
Pretty darn good so far - nice work - congratulations.
Those stepper to servo boards seem like a good advancement in technology and they seem to have decent driver chips as well.
If I may, one or 2 observations...
The servo that controls the outer arm ( "B" arm ) needs to be moved back to be above the pivot point of the first arm ( "B" arm ).
Where it is right now it is causing a lot of force to be placed on the "A" arm stepper due to the inertial weight being maybe 100mm from the rotational axis and therefor moving at a higher speed than if it was directly above ( or at least MUCH closer to ) the pivot of the "A" arm.
Also, double up on the linear bearings on the Z axis and maybe even think about going to 10 or 12mm rods spaced more widely to prevent the assembly that moves up and down from twisting left to right as the arm assembly swings around.
The most stable 3D printed arms I saw were done in 2 halves along the length and the inside cavity was half round to take a carbon fiber tube.
The whole thing was epoxied together and clamped to form the final arm.
Carbon fiber tubes are highly resistant to torsional ( twisting ) forces as well as "bending" forces.
My interest in Scara machines is that I want to build one ( eventually ) that I can use a spindle motor as an end effector and do engraving but for that to happen the tool MUST be restrained pretty well - in fact DARN WELL...
Thanks, yeah I 100% agree those are the 2 main things I still want to fix with this design. But it’s pretty hard to design a easily 3D printed part that can stack both motors. A carbon fibre tube might not be a bad idea. I am going to see how expensive they are and maybe I’ll use them. Thanks for the idea
You can get silent stepper drivers for 3D printers too, the TMC2209 are commonly used ones. It’s generally cheap printers that have cheap stepper drivers and they are loud. More expensive drivers drive the coils more smoothly which is what reduces the noise, both by reducing coil whine but also just make the motor physically move smoother. I believe the TMC2209 drivers do it by using 256 step microstepping rather than the
Additional support points on vertical rails are needed. You have only two of them - and they all tend to break due to the weight of the horizontal arm. Add additional carriages to the rails.
The shield doesn’t really make more pins, it just lays out the pins in a better way for connecting the stepper drivers and other things. It does add extra power and ground pins but in terms of arduino pins it doesn’t make any more.
Some shields might add more pins using gpio expanders or servo drivers though.
For making custom software to drive this it should be quite easy once you have the kinematics figured out, basically so you can set a position for the end of the arm and calculate what each joint angle should be. Then all you would need is a basic GUI similar to the jog buttons on the universal Gcode sender.
Maybe add cables and pulleys on each side of the lead screw, fixed to the top of the frame and a counterweight like for an elevator.
Good Job, this is from PCBWay, will you be able to look up the the note we dropped on your thingiverse?
one of the best diy scara. i want to make one but little bit customized for my job. can you share the assembly ?
I am still updating the design but once I'm done I will make all the files available
Creative video, thank you :)
what is the software you use?
Universal Gcode sender
the belts for the Z axis are a good idea you should build that
everyone who tried belts for Z in 3d printers swears it causes tons of play/backlash/deflection, no matter how tight you make them.