Corexy homing/endstops



  • Hi All,

    As my planning continues regarding my v-core corexy build, I'm now looking at endstops. I have to really plan ahead, as China and Australia are now really not getting along, and deliveries are taking forever.

    The whole plan is heavy duty, no fluffy fancy features and utilitarian all over.

    I was going to try sensorless homing on the XY axis's, but it seems that issue has a few hairs on it still. I'll be running RRF 2.whatever/latest by the way. Is sensorless homing on the XY reliable/recommended? It sure would be nice to have less wiring and components, especially on the swinging bits.

    One part of it that can't be planned prior is whether the cast ally bed turns up dead flat. It does have a tolerance, and my experience is that it may or may not be perfect on delivery. If it does turn up dead flat and my print surface of choice also meets that flatness, I would be tempted to go with a switch/sensor on one of the Z uprights and have nothing on the carriage. If it's not dead flat, obviously I'll be getting into a z probe of sorts and bed mesh leveling.

    I have seen Mark refer to these sort of optical switches, and the results look real good to me. Not like they're expensive either.

    https://www.aliexpress.com/item/32852113543.html?spm=a2g0o.cart.0.0.38953c00ardQdR&mp=1

    I might not get into his screw adjuster jigger, as I'm more likely to get it really close, lock it off and use a bit of Z offset from there. I tend to enter a value that works best for a certain material in the slicer, and save it as a part of that materials profile.

    So my questions are:

    1. Is sensorless homing of the XY axis's the done thing, or is it a bit hit and miss? The bed is 400x400, by the way.

    2. Are these optical switches a tried and proven good thing?

    3. Any recommendations/other ideas/pitfalls I should be aware of?

    I really enjoy pre planning these things, as I do have tools and experience in making nice wiring looms. I'd really like to get this all robust and neat hopefully the first time, and not be back in there molesting it with alterations/afterthoughts.

    Cheers again,



  • Hi,

    I use IR beam break sensors for all my end stop needs.

    However I don't worry about getting the sensor to trigger at either the actual min or max on an axis, just something close to it.

    Then I adjust the actual position using G92.

    I also have a BLTouch v3 Z probe but I don't use that for homing, only for setting Z=0 and height map creation.

    Frederick



  • @fcwilt said in Corexy homing/endstops:

    Hi,

    I use IR beam break sensors for all my end stop needs.

    However I don't worry about getting the sensor to trigger at either the actual min or max on an axis, just something close to it.

    Then I adjust the actual position using G92.

    I also have a BLTouch v3 Z probe but I don't use that for homing, only for setting Z=0 and height map creation.

    Frederick

    No worries,

    So it's just like some sort of printed plastic peg has to fit between the 2 black "boxes" on the sensor?

    And you use one of these and a BLTouch in combination? Is your bed not flat, and if not wouldn't the BLTouch be enough? Is the optical sensor a backup/redundant/failsafe for your Z axis or something like that?



  • @Corexy said in Corexy homing/endstops:

    @fcwilt said in Corexy homing/endstops:

    Hi,

    I use IR beam break sensors for all my end stop needs.

    However I don't worry about getting the sensor to trigger at either the actual min or max on an axis, just something close to it.

    Then I adjust the actual position using G92.

    I also have a BLTouch v3 Z probe but I don't use that for homing, only for setting Z=0 and height map creation.

    Frederick

    No worries,

    So it's just like some sort of printed plastic peg has to fit between the 2 black "boxes" on the sensor?

    And you use one of these and a BLTouch in combination? Is your bed not flat, and if not wouldn't the BLTouch be enough? Is the optical sensor a backup/redundant/failsafe for your Z axis or something like that?

    I use something like this IR beam break sensor

    Before I installed the BLTouch I was homing X,Y,Z with these beam break sensors.

    Since they were installed and working fine I saw no reason to remove the Z axis unit and home with the BLTouch.

    The BLTouch does the Z=0 setting and the height map creation.



  • No worries,

    They look pretty much like the ones I've linked to above, and I'll be buying some other stuff from Triangle Labs at the same time.

    I'll be getting a water jet cut plate in 8-10mm precision cast ally plate, and like I said if it's flat enough I won't even bother with mesh leveling. Hopefully I'll get by with one of the optical sensors...nice and boring and reliable.



  • @Corexy said in Corexy homing/endstops:

    I'll be getting a water jet cut plate in 8-10mm precision cast ally plate, and like I said if it's flat enough I won't even bother with mesh leveling.

    I purchased a machined plate with this description "Cast Aluminum Plates have a precision machined surface for superior flatness, flat within .015'', and +/- .005'' thickness tolerance".

    But on top of that I have a borosilicate glass plate.

    And on top of that I have a BuildTak FlexPlate System.

    I have other glass plates with different build surfaces and they are easy to change out.

    The result requires using mesh compensation if I want to use all of the area.

    Frederick



  • @fcwilt said in Corexy homing/endstops:

    @Corexy said in Corexy homing/endstops:

    I'll be getting a water jet cut plate in 8-10mm precision cast ally plate, and like I said if it's flat enough I won't even bother with mesh leveling.

    I purchased a machined plate with this description "Cast Aluminum Plates have a precision machined surface for superior flatness, flat within .015'', and +/- .005'' thickness tolerance".

    But on top of that I have a borosilicate glass plate.

    And on top of that I have a BuildTak FlexPlate System.

    I have other glass plates with different build surfaces and they are easy to change out.

    The result requires using mesh compensation if I want to use all of the area.

    Frederick

    Yep, I doubt I'll get away without some compensation.

    I'll either use a spring steel/pei coated magnetic plate, or Printbite like I have on my other machine stuck straight to the cast ally plate.



  • @Corexy said in Corexy homing/endstops:

    .......................Yep, I doubt I'll get away without some compensation....................

    This is an old video I did about 3 years ago - 6mm float glass on top of 10mm aluminium tooling plate. NO compensation of any sort. https://www.youtube.com/watch?v=U733PMTou7M.

    (It's a boring video - skip through it).

    Edit. When I say NO compensation - that includes no auto bed levelling as well as no flatness compensation of any sort.



  • @deckingman said in Corexy homing/endstops:

    @Corexy said in Corexy homing/endstops:

    .......................Yep, I doubt I'll get away without some compensation....................

    This is an old video I did about 3 years ago - 6mm float glass on top of 10mm aluminium tooling plate. NO compensation of any sort. https://www.youtube.com/watch?v=U733PMTou7M.

    (It's a boring video - skip through it).

    Edit. When I say NO compensation - that includes no auto bed levelling as well as no flatness compensation of any sort.

    Yes I know.

    I use no compensation or leveling on my Duet/Zortrax as well, just a feeler gauge about a year ago. I'll see how it goes when I get my bed made for this new printer.



  • @Corexy Personally, I think that some peoples problems might be of their own making, but it's just a hunch. You can distort tooling plate if the frame you fix it too is bent.



  • @deckingman said in Corexy homing/endstops:

    @Corexy Personally, I think that some peoples problems might be of their own making, but it's just a hunch. You can distort tooling plate if the frame you fix it too is bent.

    Especially with 4 leveling screws...


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