My ends stops were working but not working well. The carriages would crash into the them on the fast homing and then visually overshoot a little on the slow homing. It ended up pulling the belt out of one of the connectors so it was down for a day while i reinforced them.
I added ends stop debounce to the config and glued some plastic at the top of the carriages so they switches has something nice and flat to hit (before the carriages only made partial contact to the ends stops metal levers). I thought this solved the problem because the machine was working beautifully last night and all day today. I got some AMAZING quality prints that were blowing me away.
Now all of a sudden, the problem is back and I did not change anything at all. They crash into the end stops on the fast home and on the slow home they overshoot a bit and sometimes crash a little. When I do a second home while they are sitting a Zmax, they got up a bit and crash again before doing a slow home. I can hear the switches click before the carriages stop. Its like the signal to stop is not making it to the board in time and everything is very slow to react.
This is really bothering me as is it damaging parts and I cannot get a consistent home. Has anyone experienced this? By the way, my endstop wires are twisted and running the board under the print bed.
I’ll add that its not specific to one end stop. When the problem started again, they all get very close to crashing and one or more crash ~80% of the time. On the slow home they click and overshoot a few mm but rarely crash again. Once they all crashed hard on the slow home and it tried to keep going for a few seconds before I pulled the plug. Why isn’t the board getting the signal to stop?!
Have you tried slowing down the homing speed for both fast and slow homing. When I set my printer up, the homing speed was far too high. The first time it homed the printer almost jumped in the air when it hit the limits. I cannot check at the moment, however I think my homing settings are something like 100mm/s and 10 mm/s. For diagnostic purposes you could go much slower, say 30/5 to get a clear idea of the problem.
With hard end stop crashes, it may be that the end stops have moved, or the switch arms have been bent, something worth testing manually.
I know that they are a significant cost, but I installed hall effect end switches on my printer with buffers to eliminate the possibility of the magnets hitting the switchs. They work really well and are simple to set up. I also installed spring belt tensioners, these keep the belts in tension, but allow for some give if the carriages crash or get stuck for some reason, reducing the likely hood of damage.
I have tried slowing things down but to no affect. I even bent the metal switch arms so the distance between the click and the carriage is increased. No affect. What’s puzzling is that they were working great recently and stopped immediately at the click for a while. My home was a little off and using the paper test they fluctuated up to about .5mm. But now they click and then keep going until they bump into the switches a bit before doing slow home. I swear it’s as though the motors don’t get the signal to stop in time. Before on slow home they would stop right at the click. Now they click and go further, ending up nearly touching the switch body (and sometimes hitting it a bit)
If you have a multimeter, it may be worth testing each of the switches to make sure that they are functioning correctly. It may also be worth checking how the switches are wired. I have mine set as normally open to ground. You can check the partial configuration file I pasted into the other thread for how they are setup. It is also worth checking that only Z is set to machine height, X and y are set to 0. Sorry if this seems obvious, but eliminating simple problems will narrow the area where the fault lies.
Yes they give the correct status with M119.
I have mounted the X5 mini under the print bed so the wires run down the vertical supports on my kossel, across a bottom support and then directly to the board. They are not excessively long but I guess they’re as long as possible given the design of the kossel.
Yes, I twisted them with a drill. The wires are 20 gauge I believe.
OK so I have solved this problem and I hope others can find this because I could see this being a major problem for some. UNMOUNT THE BOARD/SD CARD FROM YOUR MAC BEFORE USING REPETIER/PRONTERFACE ETC. This causes a bad reaction and homing movements are affected.