Limit switch arms

LowRider CNC Troubleshooting
1

Hello, finished my build of LR3 24x48.
Going thru the movements and functions to become familiar with its functions.
But I keep having a problem with arms or levers on the y axis constantly coming off, (both).
Course I don’t realize till I home y .
Is there a trick to keeping them in place? Could I eliminate the arms with a different end stop, or am I opening up a bag of worms.

CarlJ

2

Hall effect switches for Y axis are on my to-do list after seeing Steve’s build. That or 3D print a guard/shield that prevents them from being proud. Maybe there’s more robust switch options?

I keep knocking the switch arms off when moving LR3 between table/sled/dev-station.

Curious if/how you/others improve y axis Endstops. Am happy with x and z axis stops.

2 Likes
3

Thank you I will check it out.

4

Currently… If/when the metal spring arms falls out, I carefully bend the spring arm legs wider to help them not fall out of the plastic housing, as much, until they get knocked again…

1 Like
5

My Hall effect switches work so well, I also added one to the upper Z, for homing the Z axis before I use the touchplate to re-home Z-zero to the material or spoilboard surface.
These Hall Effect Switches (AH3391Q; not analog Hall sensors) have the following advanges:

  1. Cheap. Much cheaper than inductive sensors.
  2. Very reproducible (15 microns repeatability)
  3. The chip and magnet are very small so don’t get in the way or hook on things.
  4. Won’t ever break due to mechanical wear or metal fatigue.
  5. Not susceptible to dust or a metal object near them (unless it is the South pole of a magnet)
  6. Switching is in a few ns, with NO bouncing.
  7. I verified that by using the least-sensitive variety available, they are not influenced by the Earth’s magnetic field (important for a portable CNC).
  8. They can be powered off anywhere from 3 to 28VDC.

They do require a pull-up resistor (1k) and capacitor (10-100nF) but those can be located near the controller instead of by the switch where I put them.

4 Likes
6

They are going for 70p each from Farnell UK.
Here is the datasheet: https://www.farnell.com/datasheets/2263968.pdf

2 Likes
7

Would you be willing to share an Amazon link or tell which item listing is the right thing on this search result?

https://www.amazon.com/s?k=Hall+Effect+Switches+AH3391Q&crid=3NBNVDZK1RGVJ&sprefix=hall+effect+switches+ah3391q%2Caps%2C59&ref=nb_sb_noss

8

I believe A3391 by Allegro should work same as mine which are about 275 Gauss for the Bop:
https://www.amazon.com/EPLZON-Effect-Magnetic-Detector-Arduino/dp/B09PG3PGH6/

Here is the datasheet: https://www.mpja.com/download/a3144eul.pdf

Just make sure you are getting a switch, not an analog sensor, by reading the datasheet for whatever you use.

1 Like
9

Thank you!

10

Are you using the limit switches shipped with recent LR3 hardware kits? If so, I had the same problem and ended up buying the “previously recommended” switches here https://www.amazon.com/dp/B07X142VGC - no problems since replacing.

1 Like
11

I’ve also got the ones with the red rollers, haven’t had any problems so far.

12

Another option, slip on y limit guard/fender…

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Edit: Updated pics with v2. Created LR3 Mod topic for a simple guard/fender solution at LR3 Mod, Y limit switch guard/fender. Still interested to see how hall effect switch solution turns out for folks.

13

This doesn’t sound normal, able to share pic of your build with gantry near Y-min? are the arms snagging, getting caught on something? Are the switches from V1E shop?

14

Yes the switches are from V1E shop.
I did snag them, since then I can’t seem keep them on. Damage probably already done.
Leaning toward the Hall effect, and the switch guard
Thank you all for the response’s, it is really appreciated.
CarlJ