Looking for ABL ideas
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So I've built/modified my first IDEX printer with an MB6HC and expansion board, but in the process I seem to have painted myself into a corner with respect to bed leveling.
I plan to use the printer for small-scale production of flexible parts (82A and lower hardness) with TPU and TPE, and having had great luck with glass and glue stick in the past, I elected to go that route with this build as well.
The printer that provided the bones for this transformation was a Tenlog Hands 2, which used VGA cables between the enclosure and the hotends to transmit any and everything. I chose to stick with it and this solution has been pretty nice, with the exception of the tedious soldering.
Now comes the problem.
The varying functions of the hotends take 12 of the 15 pins before I get to any ABL module. This leaves 3 pins for ABL, and I elected to go with the DC42 IR probe.
The probe itself works well, but in concert with the "microporous coating" on my glass bed, things get a little wonky. It reads full 1mm+ differences in unpredictable places and times. Putting a piece of paper down gets more predictable results but isn't really a full solution to the problem.
I thought about switching to a spring steel or magnetic bed, but getting flexibles off of those can be a nightmare. Then I thought I would just switch to a plain old BLtouch, but remembered I don't have the 5 pins to spare that it would require. So now I'm here.
Here's a photo of the hotend/extruder in question to inform any advice you're kind enough to share.
(the IR probe is back behind the nozzle/heater block)
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@terbospaghetti said in Looking for ABL ideas:
I don't have the 5 pins to spare that it would require.
That depends, 2 of those are 5v and 2 ground. You might be able to piggy back off existing pins for those. Otherwise the BLTouch requires 1 wire for trigger signal, and 1 wire for servo signal.
https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_BLTouch
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@terbospaghetti go with a Euclid or clicky probe
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@terbospaghetti said in Looking for ABL ideas:
I thought about switching to a spring steel or magnetic bed, but getting flexibles off of those can be a nightmare.
A few drops of IPA on the boundary between the part and the bed (PEI in my case) makes removing of TPU much easier. A syringe with IPA and a blunt needle can be very useful here.
Edit: this is how the Euclid (recommended above) works with a sliding bed printer. It requires a simple input from the controller and senses the surface mechanically like the BL touch. I the developer of the Euclid is a member here.
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@phaedrux said in Looking for ABL ideas:
@terbospaghetti said in Looking for ABL ideas:
I don't have the 5 pins to spare that it would require.
That depends, 2 of those are 5v and 2 ground. You might be able to piggy back off existing pins for those. Otherwise the BLTouch requires 1 wire for trigger signal, and 1 wire for servo signal.
https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_BLTouch
Or something like this? I think it was you who pointed me to this in the past.
https://www.thingiverse.com/thing:3303618 As said, take the 5v and grd from two wires and then a signal for the deploy/retract.
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@phaedrux I'm a little confused about those 4 power leads on the BLtouch. If they're all 5v, why are there 2 sets? Or am I misinterpreting something there?
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@terbospaghetti said in Looking for ABL ideas:
@phaedrux I'm a little confused about those 4 power leads on the BLtouch. If they're all 5v, why are there 2 sets? Or am I misinterpreting something there?
definitely misinterpreting. There is a single 5v wire, 2 ground wires (for some unknown reason), a trigger signal wire, and a servo control wire.
So if you already have 5v and ground on your print head you only need 2 additional wires for trigger and servo.
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@phaedrux ok, and there's no problem running those two grounds to the same place? That is weird.
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I've never found a good explanation for why there are two. Eventually they both go back to ground so... I dunno.
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@terbospaghetti yep they are internally connected.
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Alternately try underbed piezo sensors and probe with the nozzle.
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I think I'm gonna be a chicken about the piezos/FSRs. They seem cool, but ultimately I'm looking for the simplest solution.
I guess that means switching my heatsink fan out for a 5V and sharing power for that with a BLtouch. That's the only way I can come up with to make enough wires in the 15 pins I've got.
At present, they are:
1-4: Extruder step/dir
5/6: Heater
7/8: Thermistor
9/10: Heatsink fan
11-13: 3 wires currently run to DC42 IR probe
14/15: Part cooling fan I haven't installed yet.Current plan is to get the BLtouch, install it using the three leads from the IR probe, along with the two as-yet unused cooling fan leads to get up and running for speed tuning. I'll order some cheap 5v fans to replace the heatsink fan, and once they arrive I'll piggyback them off of the BLtouch's 5v leads.
That should still leave me with the two pins I need to run a cooling fan.I tried a couple of beds, but I'm pretty much married to glass at this point. Just can't beat the peel-off with TPU lol.
Ok thanks for listening if you're still here
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@phaedrux said in Looking for ABL ideas:
I've never found a good explanation for why there are two. Eventually they both go back to ground so... I dunno.
I would think that they are separated for the same reason that people pass separate +VIN wires to their heatsink and material cooling fans. Logically they represent two independent functions, a servo and an open collector switch.
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TAP Nozzle Contact sensor also looks nice (requires some custom manufacturing, but nothing too fancy).
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If you can find a way to implement the klicky probe I am a huge fan.
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@alex-cr said in Looking for ABL ideas:
klicky probe
Klicky probe is a cool concept, but won't work for anyone who has a printer in a real shop unless you painstakingly clean the magnets of every metal fiber they've been near before each leveling.
Neat, but impractical in the real world.
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@terbospaghetti hmm open 3d printers at a shop with metal chips flying around it's not good... Enclose the printer at least.
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@pcr "metal chips flying around" isn't accurate at all, but thanks for the tip.
I've got 5+ years of printing in the environs in question with absolutely no problems at all, but I'll go ahead and pay several hundred dollars to enclose them so I can maybe make a cool magnet idea work....
Doesn't pass the smell test, sorry dude.
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@terbospaghetti said in Looking for ABL ideas:
Doesn't pass the smell test, sorry dude.
It's one of the most popular probes on Voron printers. People like it because it works well also in higher chamber temperatures (compared to inductive and bltouch), mechanically senses the top surface (compared to inductive and IR), not sensitive to dirt on the nozzle tip (compared to piezo), provides a simple two wires dry contact (compared to more complex interfaces such as bltouch), doesn't take much real estate on the moving head, easy to customize, and inexpensive.
That's a clear winner.
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@zapta all of that is true, but it could also be a description of a BLtouch. And you left out the part about how there's magnets to grab anything light and ferrous, which will cause the same problem as the dirt on your nozzle with a piezo.
Glad it's working for some people, but in my case it's very clearly the wrong move. I've got magnets on my bulletin board right now with tiny shavings on them that came from god-knows-where. To assume that magnets attached to a 3d printer would not have that same issue would be pretty foolish of me.
And let's not pretend there's anything simple about that setup, what happens when you heat cycle those magnets so many times their field characteristics change? Maybe not a big concern for most, but I often heat my bed to 110°c or more. Can't be doing wonders for a magnet.
