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Comment by numpad0 | Hacker News Reader

IME, ABL is not that important. Personally I spray bed with a hairspray and tweak leveling screws while first layer is going on[1], that's just fine.

Old Marlin ABL also has bug/tendency to report erroneous tilt towards the last corner it measures, I suspect due to Z axis missing step from microstepping. Ultimately it was too finicky for me without resorting to closed-loop drivers, which also almost completely solved the leveling problem.

1: I know it is a big flat NO to touch a robotic equipment in operation, unless said robot is specifically designed to be almost completely incapable of applying any force to any parts of a human body, but I'm smart and I consider my printer a co-bot so it's okay(it's not okay. A better solution is needed).

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ABL is not that important if you don't mind babysitting the printer. But it's an amazing quality of life improvement otherwise. Especially if you're printing stuff that needs precision.

Manually leveling an ender 3 was tolerable to me for about a month while learning 3d printing and figuring out if it was something I would be into long term, but over the course of a year I went from that, to trying various ABL sensors and bed replacements, to now a custom built Mercury One.1 with 3 point kinematic auto bed leveling, and it's such a night and day difference in terms of usability.

It physically levels the bed and automatically determines the z offset, so I don't have to do anything when using different print surfaces and when operating at different temperatures/in an enclosure. Heat expansion is pretty noticeable (I've destroyed pei plates with the nozzle by calculating z offset when cold but attempting to print when hot), and while sticking your hand under the bed of a printer printing PLA is not that dangerous, with ABS the bed is at 110C, not at all worth the risk, so autoleveling is very helpful.

It makes it so much easier to just submit a print job, forget about it and find it finished perfectly, without involving any finicky adhesives.

3D printing has a bifurcation in the hobby; some people enjoy it for the objects they can make, some people enjoy it for the printers themselves. I pass no judgement either way, just an observation. I saw the same thing in the photography world; some were gearheads, some couldn't care less, and were focused on the image.

As for me personally, I spent many entertaining, delightful, maddening and frustrating years playing with a frankendelta of bodged parts, broken firmware and hacked wiring. Learned a ton, don't regret any of it. But the moment I got an X1C, the Rostock has been relegated to Spiral Vase mode only. And I can't help but note my actual printing volume has increased dramatically when the process became less of a babysit.

Yeah, that I can agree with. However I'm very much in the "gearhead" camp :)

That's why I went with a DIY design. Similarly learned a ton, lately I'm finishing up a multi-material unit, then I'll start again by rebuilding and modding the disassembled Ender 3 to gift to a relative who has a slight interest in DIY stuff.

I'm with you, adding an auto bed leveler was the single biggest upgrade on my 3D printer, for the type and printing I do and the frequency I use, it's really just made it fire and forget (I'm sure I could improve it /even/ further) where as previously I felt I had to re-level after every print.

I haven't levelled my bed in months or maybe years... Sure, it was a pain to level it the first time, but once it's level it should stay level unless you disassemble the printer.

Thermal expansion (especially in long cycles) tends to warp beds.

Glass and aluminium do expand and might bend when heated, but they don't bend more when heated hundreds of times. Therefore as long as you calibrate it when hot, it should stay calibrated (unless you let the calibration screws vibrate+turn or something)..

I have a 10-year glass bed on my Prusa clone that would like a word with you :)

(I replaced it with a garolite sheet, am very happy with that)

Interesting. I don't think I've ever knowingly encountered heat expansion of the bed itself affecting the prints.

I print on glass and only occasionally have to do anything about bed leveling. No need to pry or pull and mess up the leveling when all you have to do is just wait a few minutes for the print to cool and it pops right off. Never printed ABS on glass though, so I can't say if it works as well for that. Autoleveling would be cool, but I have very little interest in it because I haven't needed it and it seems like an added point of failure.

I print working firearms and firearm parts. I follow the bed levelling method detailed in GP, and I have never had a gun failure due to lack of precision, which is critical in firearms. I also do this with Nylon and TPU, zero issues. Sure, ABL is nice, but I'd rather use the budget on a proper hotend and direct drive.

> ABL is nice, but I'd rather use the budget on a proper hotend and direct drive.

I agree with you, 5 years ago. But now days even cheaper china designed hotends can be decent. And direct drive is de facto standart.

ABL is cheap and convenient.

This is all true, but FOSSCAD world is a little different, and a good hotend makes much more difference than ABL. Microswiss is the minimum. I need perfect extrusion, not perfect alignment along a non-critical axis. For the hobbyist, you are correct.

Interesting. I recently saw a video where they used normal Nylon CF and PLA+ for the orca gun system. What makes FOSSCAD so different when it comes to hotend demand?

I disagree about the hobbyist comment. You can be a hobbyist and try to print PEEK and ULTEM, or you can be commercial and print nothing but PLA. I would say someone who does it commercially wants to spend less time on bed leveling.

the probe I use for ABL is Klicky PCB which cost 20 bucks. You can print it yourself and use a normal switch and magnets and probably get it for 5 bucks. I don't see why this is a either / or discussion. It's so cheap.

FOSSCAD is different because we're generally printing parts that function near the end of the filament's capabilities. When I'm printing a lower receiver, I need perfect temperature consistency, because uneven cooling will introduce internal tension to the part, reducing its overall strength slightly. That's not an issue for a coat hook, but it is an issue for a Glock.

I also need absolutely perfect extrusion, because a layer shift or missed infill section is a huge deal, not just aesthetically like for a normal print.

I'm not saying ABL is bad in any way, simply that I have higher priorities. I have an Ender with it, and it's nice to have for sure. It's just not what I'd prioritize.

I'm using "hobbyist" as shorthand for "normal 3d printer user", i.e not printing things that can explode.

I have twelve 3D printers and I bought my first machine, an Ultimaker 1, in 2011.

I managed fine without it but every advancement that means less fiddling is a huge quality of life improvement that I always strongly prefer. I got ABL for the first time by modding it in to a printer I had. I then modded it in to my other printers, and now would never consider or recommend a printer without ABL unless someone is very broke and can only afford the cheapest Ender 3.

The Prusa Mk4 improves upon older automated bed leveling techniques by using a load cell in the nozzle itself to measure exactly where the nozzle touches the bed, rather than using a sensor near the nozzle which then requires manual height calibration. I have five Prusa Mk3s but I really want the Mk4 in large part for that.

I am so bleeping tired of fiddling with my 3D printers, I just want them to work.

With proper bed leveling and the right bed temperature you don't need to bother with hairspray.

Having to resort to glue is often a sign that something else in your setup isn't tuned correctly. ABL is one thing that helps.

It also helps to clean the build plate from time to time too.

Over time grease from your fingers will make it onto the surface (no matter how careful you think you are). Some filaments also seem to leave behind an oily residue that builds up after a few prints.

I haven't done much research on what I should be using so I have a bottle of iso and a sponge that I use to wipe down the surface. (A microfiber cloth would probably be better).

Mine is a 300x300x600mm frankenstein gantry build loosely based on Tronxy X1, so that's indeed on myself. But Marlin ABL didn't seem worth it even before I'd done upgrades.

The idea of having to put anything on your bed and fiddling with adjustment knobs seems so wrong when there are plenty of printers out there that are good enough now where I can send a print to them and maybe check on them in 10 minutes to make sure the first layer didn't fail and be confident that they will complete. From the very first time I used it I realized that ABL is a must on any printer now.

Maybe if you don't care much about the budget.

I don't need a printer and only use it sparingly, so I chose an Ender v2 for like 250€. It has bed-leveling problems, but it's not enough of an inconvenience to be worth it to me to cough up 3x of the money for Prusa.

If all else fails I use a glue stick, like the GP. There's nothing wrong with that, it works.

> Maybe if you don't care much about the budget. > I don't need a printer and only use it sparingly, so I chose an Ender v2 for like 250€.

Now days you can get an Bambulab a1 mini for ~335 that has auto leveling, auto z offset, nozzle pressure sensor and can do a 14 minutes benchy.

You can also get a Prusa mini is ~2 times the money of your Ender v2.

They both have smaller printable areas and +40%/+100% is still a pretty big price difference.

Sure sure, but you can care about budget and get a printer with decent sensors for auto z and bed level.

I started with bed screws, and never want back to printer without probes or flexible bed sheet.

I struggled with the cheaply built printer that requires a lot of upkeep the first time like many (Tevo Tarantula in my case), and in the end I realized that between the upgrades to just make it work safely, and the time wasted just fiddling around with getting it to print made the Prusa well worth the money.

Buy the Ender if you want working on 3D Printers to be your hobby, if you want 3D printing to be your hobby, then buy something actually reliable. I would take a small build volume and high reliability over something larger every single time.

> if you want working on 3D Printers to be your hobby, if you want 3D printing to be your hobby

Those two go hand in hand for all hobbyists I know, including the Prusa owners. I don't struggle with Ender, actually I was surprised how good it is, since my reference point was much older (and much more expensive) printers.

Maybe I have lucked out on the build quality, I don't know.

ABLs are nice to have and printers should have them. But every so often, a manual bed level with a piece of paper goes a long way. Especially if you have a budget friendly printer.

I have a long history of woes with this stuff. I initially had a Wanhao that didn't have ABL, that worked fine as long as I didn't change anything. Then, I got a BLTouch, which made it worse because the Z distance would always be inconsistent somehow.

I realized that Marlin must have some sort of bug, because it claimed to be able to print on tilted beds with ABL, but mine just didn't. I upgraded to Marlin 2.x and that was fixed.

However, now I have this problem where the print lifts on certain regions of the bed. I have no idea what's up with that, I use one of those golden, textured PEI sheets and it works fine, except for these holes in areas.

I wish someone would put a pressure sensor on the nozzle so it would always know the exact distance in real time and could compensate for anything, but we seem to be far from that.

> However, now I have this problem where the print lifts on certain regions of the bed

If it's the edges of wide, flat prints, search for problems with "warping". Draughts and uneven heating can cause it, especially combined with poor adhesion to the bed.

It's not, it's a very odd issue in the middle of laying down a layer line, where a tiny mm raises/blisters, then in the next layer the raised part gets a bit longer, then a bit longer, until it becomes a big hole within twenty layers of this. It's very odd.

I had a similar problem with my old Rostock Max, and it turned out to be integer math errors in the delta>cartesian conversion step. FWIW.

I never got ABL to work with marlin, despite trying all possible configurations and versions, so I just did it the same way you do. With Klipper, it just worked when I first installed it. Never looked back.

> unless said robot is specifically designed to be almost completely incapable of applying any force to any parts of a human body

Be careful, but don’t beat yourself up over it. Many CNC milling shops regularly run jobs that cannot succeed without a human gripping the workpiece to control vibration.

The folks I really worry about are the waterjet cowboys. The garnet particles that lend a waterjet the power to cut titanium get embedded inches from the site of the wound, if that stream touches skin. Amputation one or two joints up from the wound is standard treatment.

I click print in my slicer and move on to do other things, casually looking at the camera feed a couple of times during the 1st layer

I can't agree with you on this. With bigger printer beds (I've got a 500mm x 500mm x 500mm machine) it's crucial to have ABL working, as the height of certain points of the print bed can be within a range of over 0.2mm, which, as I'm sure you know, is the thickness of a layer a lot of times.

With simpler/smaller printers, sure, you can get away without an ABL probe.

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