Heat of the night

[PerranOak]

I’m trying to get into 3D printing but, of course, am having trouble choosing a printer.

It’s an impossible question to answer (i.e. which one do I get) so I’ll ask about another thing that’s concerning me.

I was shocked to see how slowly they print with YouTubers routinely talking about prints of 5, 10, 30 hours!

There is no way I’m leaving a 200degC piece of metal whizzing around in the tinderbox that is my “lab”, overnight.

Therefore, one of my criteria must be speed (the Ender 7 seems fast). Is this sensible or am I being too careful?

[bdunham7]

Oh dear, no.  Speed almost always results in low quality.  I just printed a small lampshade with translucent PLA and I used 'medium-slow' (just a description, the actual settings are more detailed) settings to keep the print time to 40+ hours and although it turned out OK, I sort of regret not using even slower settings.  If you only print small things, you can limit the time to a few hours, but I routinely run multi-day prints on a not-very-large 3D printer (Ender 3 Pro).

[dferyance]

You are right to be concerned about fire. There are fire alarm and suppression options for 3d printers and you can look for printers that have increased safety features.

There is only so much you can do about speed due to the way FDM printers work. If you need to make a bunch of copies there are printers that can do two at a time.

Depending on what you are making, it doesn't have to be all one part. I have a small printer so I always have to print smaller parts and join them together. Fasteners, adhesives, solvent welding, and heat welding are all options.

[Lindley]

Some printers will have more self protection  than others , but never seen any site do a comparison on that point.
Would assume the more expensive the printer the better the protection ?

We use our own temperature and smoke detectors in the printers enclosure which will independantly cut the mains power and sound an alarm etc.
Also the whole room (outdoor workshop)   is covered by a smoke alarm connected to the houses buglar/ fire alarm system.

If in any doubt house it in some  isolated outbuilding/shed etc and use remote control like Octoprint which also has a camera function and believe you can also program it use a temp sensor to turn the printer off.

[thm_w]

Go for speed if you want, but it will come at a large cost.

Any modern printer should have thermal runaway protection.
Combine this with:
- A smoke alarm
- A non-flammable bench/plate/enclosure for the printer
- Checking the wiring and grounding on the printer
- Crimp all wires with ferrules

and you should be fine

Some printers will have more self protection  than others , but never seen any site do a comparison on that point.
Would assume the more expensive the printer the better the protection ?

[PerranOak]

Cheers all.
I did think of putting it in the shed. Problem is the shed is very cold at night and the printer would rust over time.
Therefore, I would have to keep taking it out there and bringing it back in.
Can 3D printers take this kind of treatment or do they really have to be left in one place?

[MarkF]

Trying to print in a shed that gets cold will not work.
Some filaments (ABS for example) will not print even if there is cool air movement.  Hence, printers within an enclosure.

Also, you will not want to move your printer after you get it setup and tuned.  Getting your printer adjusted and dialed in can take some time.  And when you get it just right, you don't want to redo it before every print. 

My printer, a Creality CR-10 Mini, is actually in two parts connected with cables.  Not something to be moved around often.

Any print other than very small ones will take hours to print.  Just a fact of 3D printing.
However, you can keep an eye on your print, even if you're away from home, and shut it down if you see a problem.  I setup Octoprint on a Raspberry Pi with a webcam.  You can stream video and control your printer from the internet via your phone.  Not ideal but better than nothing.

[Jeroen3]

I have mounted a smoke detector above my printer and have a raspberry pi with camera and obico* pointing at it, there is also a smart plug that I can turn off.
That means I can monitor the prints from my phone, it will tell me when it's going bad, and it will beep when it's on fire. But I'm confident my prusa won't ignite itself.
I still don't want to go very far when it's printing, but I'm comfortable printing through the night when I've seen the first layers being a success.

The workplace bought an Ender 3S1, and I don't trust that thing at all, it needs custom firmware before it's even capable of doing it's basics.

*former 'the spaghetti detective'

[PerranOak]

Cheers both.

That gives me another problem: I have restricted height in the only place I could leave it inside.

Lots of them have the spools on top and so would probably not fit. Specs usually don’t give the machine dimensions in a way that I can be confident that the spool is included.

[MarkF]

You don't need to put the filament spool at the default location for the printer.
I have seen spools placed in plastic boxes with a bowden tube running the filament to the printer.
Thingiverse has several different styles, one example.

Or, the perfect first cad design.  I use FreeCAD. 
There was a recent topic discussing which cad program people use (you'll have to do your own search for it).

[PerranOak]

Hmm. Interesting.

I was considering the Ender 3 S1 Pro which is a direct drive - so no Bowden tube - would this still apply?

[Jeroen3]

You can guide the filament from a spool holder next to the printer with some ptfe tube. Doesn't matter on what side the extruder is. It just is more hassle when unloading filament.

Do not buy the ender 3 s1, get the older ender for which there is working firmware.

[PerranOak]

Cheers.

Yes I saw that there was a software (firmware) problem with the S1! So, the Ender 3 Pro is a better choice? I guess this can be made direct drive in the future?

[RoGeorge]

If you want fast 3D printing, without noise and without the risk of fire, then you may want to look for a photo polymerization based printer (sometimes called SLA).  The printing resin is apparently more expensive, but this might not matter at all for occasional printing.  Other advantages is that resin printers require no fiddling, and the finish surface looks much better.

Fused deposition printers (the "normal" plastic wire filament printers) are complicated to run, quality is not repeatable and the printer requires constant maintenance and very fine tuning, even the room humidity matters, often requiring multiple prints until the right size and speeds and temperatures are guessed in order to produce a perfect object.

Resin printers are better in everything when compared with filament printers, except the cost per printing volume.

[Jeroen3]

What other requirements do you have for your printer and what would you like to print? Where is it going to live?

[janoc]

If you have a long print and aren't comfortable with leaving it work unattended (good idea!) then look into the printers which support resuming print after a power failure. In that way you can stop the print before calling it a night and resume it in the morning.

However - doing this would likely require applying some sort of glue or something to the heated bed or leaving the bed warm overnight because once the bed cools down it is likely the part will detach. Doesn't always happen (depends on the surface of the bed, design of the part, material you are printing, etc.) but if it happens there will be no way to resume the print anymore because you wouldn't be able to re-align the machine with the part.

Another option is to print larger objects in multiple smaller pieces and gluing them together (or using screws).


Generally speaking, there are limits with FDM printers how fast you can go. And unless you want to build a custom high-speed machine, you will not be able to print very fast simply because the cheap printers are not sufficiently rigid/stiff. Regardless of whether the machine is flinging the hotend/extruder around or the bed is moving (or both), beyond certain speeds you will have problems with vibrations, frame flexing, stepper motors losing steps, various resonances, etc.

Also the hot end and extruder must be actually capable of pushing and melting huge amounts of plastic for fast printing. None of the cheap machines (or even the hobby-level expensive ones like Prusa's or Lulzbot) can do that with the stock extruders and hot ends. You could buy replacement high performance components (like the Hemera extruder, Volcano hotend, etc.) - but you will still not be able to overcome the mechanical stiffness and performance limits mentioned above without essentially rebuilding the machine from scratch.

Oh and the molten plastic also needs to actually manage to cool down quickly enough so that it is sufficiently solid to support the layers above it - but not cool down so fast as to cause deformations and cracks (e.g. ABS is notorious for this).

So don't focus on high speed printing. Unless you are planning to print huge pieces, then you should be able to fit it into a day. If the piece requires more than 12+ hours print time, you should probably look into a different fabrication method. Don't get stuck with the "I have a 3D printer ergo everything needs to be 3D printed" mindset. Many things make a lot more sense to build using other methods. Or even to buy something that exists already and repurpose it, possibly using 3D printing for building some pieces for it. 

3D printing is great for fabricating small details like various brackets, fasteners, gears, etc. Not huge structural or even decorative pieces that take ages to print and increase the chance of failure exponentially (and also cost arm and leg in filament!). That some Youtubers do that doesn't mean it is a sensible thing to do (or that you will get sponsored printers and filament like they do!)

[MarkF]

An aside:

Creality printers use to come with the Cura Slicer. The latest version of Cura dropped support for Windows 7.  I just switched to the Prusa Slicer.  I'm liking it much better and it seems to perform about the same as Cura.  The Prusa Slicer supports many printers besides the Prusa ones and has a custom printer if you can't find their pre-configured printer.  Most of the Creality printers are included.

[janoc]

Resin printers are better in everything when compared with filament printers, except the cost per printing volume.

I guess you aren't using one, are you? 


I suggest the OP does a bit of research of what a typical consumer resin printer can do and what is involved (nasty toxic resin, washing with IPA, UV light curing, dealing with a ton of support material), strength of the parts, max build dimensions ...

(Consumer) resin printers are at best a complement to FDM printers, certainly not "better at everything".

[Jeroen3]

If you want fast printing you should build a voron kit, just look at this guy...



And prints can take 12 hours don't need to be "big", there are other parameters that increase time. Such as perimeters.
I printed these for someone, both legs in one go with 5 perimeters. This took 14 hours on a mk3s.

[janoc]

If you want fast printing you should build a voron kit, just look at this guy...

Not the best advice for a newbie. He could do that - and then be totally screwed because he would in waaay over his head. Both with the cost and assembly of a Voron machine and also because just it being a Voron doesn't mean it is able to print super fast.

One still needs to use suitable extruder, hot end, lot of tweaking, etc. However, at least with a Voron one has a chance to upgrade it to something that will eventually be able to print fast because it has been designed to be a very solid printer, not necessarily a cheap one.

And prints can take 12 hours don't need to be "big", there are other parameters that increase time. Such as perimeters.
I printed these for someone, both legs in one go with 5 perimeters. This took 14 hours on a mk3s.

Sure. But:

a) You could have split it easily up into two batches and do it over two days (so no need for overnight printing).

b) What is the point of doing the design like that - apart from "looking pretty"? Sure, that's maybe a sufficient reason for someone but there you always have a choice and don't need to spend so much time printing it.

c) The design likely isn't optimized for fast printing (see the previous point).

d) If one wants surface quality and thus uses small layer height, it will take ages. Alternatively one could print fast using thick layers, large nozzle (and possibly using adaptive layer height in places requiring detail) - but then putty and sanding are required.

e) There is always an option of having a complex or large part printed professionally. Plenty of services do it - Shapeways, Sculpteo, even PCBWays offer 3D printing these days.

So there are always options.

[Lindley]

The head design of the S1 does look like it needs a top mounted spool , side mounted on that would perhaps add too much strain ? whereas the the Pro or V2 take their feed from the side so its no problem to have the spool on the side of the machine or even on the bench.

We have the V2 and think its the slighty better buy over the older Pro,  you can always update the Pro or V2  to a Direct Drive if neeed, they are very adapatable machines with plenty of aftermaket bits and pieces.

Creality printers can be assembled easily But there are a few things find out / know about  that help you get good prints easier , they can take some finessing and there is little in the user manual to tell you how to do that, Ytube has  lots of detail on the Enders  , CHEP being one of the most popular.

Check out Creality uk own site as they often have good value flash sales.

If you want something that works more out of the box, think its the Prusa printers you should look at, though a lot more expensive.

[Jeroen3]

Yeah, the voron is special. It's not a product but an open sourced design you have to build yourself, from almost scratch. Some components kits are available though. Can be fun.

@janoc
a) Yes, but then my printer would be doing nothing for 5 hours during the night, and I would need two evenings.
b) Someone is paying for it. Other manufacturing methods would be even more time consuming and expensive.
c) It's not that bad, the smooth corners don't require much deceleration, and with so many perimeters you need minimal infill.
d) This is a structural part. If smooth surfaces are required you can sand and paint it.
e) see b.

The ender 3 s1 has the filament runout sensor all the way up on the top horizontal bar. Not ideal.
From experience I know the default firmware it comes with is very limited. mrisoc on github offers custom firmware for it, which is a better experience.
But take a while to recognize what I'm saying here: if you buy it the first thing you should do is flash custom firmware. Is that typical?

You should know that the hardware of a 3D printer is not complicated or expensive. Everyone with basic mechanical engineering can make that.
I mean, you can buy a printer the same footprint as an ender for €99 on aliexpress.

The software is what makes the printer a good experience to use or not.
Now people who are already committed to their ender will probably say this is a rubbish statement and their printer is fine. ^{After many hours of tweaking.}

[MarkF]

Personally, I would pick a printer that can/is running the stock Marlin firmware.  Then you can go in and select the options you're most interested in having instead of the ones the vendor has.  Runout sensor, type of bed leveling, LED lights, fan animation, g-code filename sorting on the display, custom logo, etc. (I'm referring to the stock CR-10 display.  I'm not familiar with the other displays.) 

My CR-10 Mini can't run the Marlin 2.0 versions because of program space limitations.  However, I even went in and made code changes beyond the standard options in the configuration.h and configuration_adv.h

The other advantage is that you can have the very latest Marlin version as soon as it comes out and not have to wait on the vendor to incorporate them into their firmware customization.

[janoc]

Yeah, the voron is special. It's not a product but an open sourced design you have to build yourself, from almost scratch. Some components kits are available though. Can be fun.

Yep. I am actually thinking about it but a full kit is >1000€ + shipping. I am still using my Nophead's Mendel90 kit, with a lot of modifications. That one was like 800€ back in 2014

@janoc
a) Yes, but then my printer would be doing nothing for 5 hours during the night, and I would need two evenings.

Sure, but the issue is running the machine unattended. That would avoid it, without having to rely on hacks like the resume on power failure feature some printers have.

b) Someone is paying for it. Other manufacturing methods would be even more time consuming and expensive.

If one wanted a purely functional design, cutting those two things out of a sheet of plywood would likely do the same job. Or, heck, even a single slab of wood ... Both would be a lot faster to manufacture and almost certainly cheaper too, compared to the day long printing time (it is not just the filament cost but also the electricity, wear on the machine and the time needed to "babysit" the machine - even if for no other reason than to make sure it doesn't catch on fire ...)

Of course, having someone else pay you for doing that is a different matter. However, if we are talking only about printing times then my approach to making parts on my Mendel is to always print only things that really are difficult/inconvenient to manufacture otherwise - e.g. by cutting off and drilling a piece of wooden or metal stock (esp. for structural parts). A typical build uses e.g. cheap hardware store aluminum profiles joined by 3D printed components and perhaps a sheet of thin plywood to mount electronics on instead of 3D printing everything. As a result I rarely have to print pieces that take longer than 2-3 hours (no, the Mendel is really not fast, esp. not with its heavy direct drive Wade extruder sitting directly on the x carriage).

The software is what makes the printer a good experience to use or not.
Now people who are already committed to their ender will probably say this is a rubbish statement and their printer is fine. ^{After many hours of tweaking.}

I would look for a printer where there is either open source firmware for the controller board (e.g. a variant of Marlin supports the board) - or the board can be replaced/upgraded later for a more advanced one.

AFAIK (I don't own any Ender variant), Enders use Marlin, so if you don't like what the firmware does, it can be always reflashed with stock Marlin configured to your liking. I am sure there are even pre-made configs for these machines already.

Tweaking will be always required either way, IMO - each printer is slightly different, materials are different, people print different things, the machines need constant maintenance - so tinkering is to be expected.

That said - no amount of tinkering with firmware can fix a rubbish printer where every corner has been cut. So maybe buying that $99 wonder is not the best idea.

[PerranOak]

I would like to able to print some useful stuff but I also like to “tinker” with things so that I understand them better.

However, 3D printing seems to require NASA level tinkering skills! I’m surprised that any noob has ever printed anything!

BTW has anyone ever had or even heard of actual fires started by them?

[Jeroen3]

However, 3D printing seems to require NASA level tinkering skills! I’m surprised that any noob has ever printed anything!

It does not have to require tinker skills. When I bought my mk3s I only had to assembly it following the lego-technic level assembly manual. Follow the firmware's setup instructions, and it printed properly first try.

Designing things that print properly is a different game.

Most printer fires I've read about are due to bad connections, not properly tightened screws, bad crimps, or just cheap connectors or worn wires. (the thing is moving)
Typical stuff even your blender can kitchen oven fire by, except your oven had tertiary protection by thermal fuses. But even ultimaker has some reports of molten pcb terminals on the web.
The entire debacle started with, iirc, ANET printers catching fire more than incidental. Then there were concerns, because the open source firmware most printers work on didn't have thermal protections enabled by default. And many cheap printers just had the default settings, because why put in effort.

If you want a hobby with a high level of tinkering, get into CNC machining.

[janoc]

I would like to able to print some useful stuff but I also like to “tinker” with things so that I understand them better.

However, 3D printing seems to require NASA level tinkering skills! I’m surprised that any noob has ever printed anything!

Nonsense. However, a 3D printer is a machine tool. The same as a lathe or a CNC mill. So yes, you do need to know what you are doing, how to do it safely and how to adjust and maintain your machine. The cheaper the machine is the more "tinkering" and maintenance is usually going to be required.

If you want the "push-button-and-done" experience, then you need to order your parts 3D printed online.

BTW has anyone ever had or even heard of actual fires started by them?

Plenty of reports around. Did you try to Google actually?

https://www.reddit.com/r/3Dprinting/comments/3lv5ld/heres_a_reminder_to_not_leave_your_printer/

or the infamous Anet 8:

https://www.fabbaloo.com/2018/12/3d-printer-safety-another-anet-a8-burns

https://www.thissmarthouse.net/dont-burn-your-house-down-3d-printing-a-cautionary-tale/

Etc.

So yes, 3D printers do catch fire, especially the cheap crap where every corner has been cut - e.g. the Anet 8 had a very poor heated bed connection and lacked the thermal runaway protection in the firmware. Even today you can still buy machines that have the same flaws!

But even the expensive machines had some spectacular failures.

[thm_w]

For tinkering, a 24V heated bed might be safest, if you don't want to be worrying about mains power.
Ender 3 is 220W (9A), which seems reasonable.

[PerranOak]

Cheers all.

Yes, the tinkering comment was tongue-in-cheek. Anyway, I like to tinker, I'm just surprised that so many people seem to have them; they can't all be tinkerers, surely?

My purpose in asking about fires here is that I trust this community and wanted this community's opinion. Googling gives every kind of response to every kind of question: my aunt (newish silver-surfer) has Google-diagnosed herself with every kind of cancer under the sun and is still fit as a fiddle!

[Whales]

My first and only 3d printer is cheap kit:  Geeetech i3 for about $200 AUD.

The printer took two whole days of work to assemble.  I had to fill in the gaps of the instruction manual and had to work out how to tweak many, many things myself to get it to a good working state.  Some parts were missing (lubricants, decent washers, etc), others were incorrect (spade connectors for connecting to limit switches).

It now prints beautifully and happily at 1/2 the total print time of my boss' multi-thousand-dollar 3d printer and has been doing so almost uninterrupted for a year, barring me replacing the hotend recently because the PTFE in the old one had swollen.

I print with a max speed of 100mm/s in PLA, 0.4mm nozzle and 0.25mm layer height.  For some PETG models I was easily able to up it to 150mm/s max linear motion.  Those vorons shown previously can do 1,000mm/s alas that doesn't mean 10x the speed of mine as corners are still much slower, but it's still much more impressive.

My print bed is masking tape (on glass).  It works really well (too well for PETG sometimes) and it's soft so it increases your tolerance for non-level beds.  I used to have to level my bed all of the time, until I discovered (1) how to quickly & reliably straighten the Z axis on its two steppers and (2) mounting it on my shelves/wall instead of the bench keeps it from changing shape.  Now I re-level the bed once every couple of months.

I do NOT recommend getting a cheap printer like this if you are not mechanically minded and do not have lots of spare time.  My printer is very much a hobby to use, not an off-the-shelf tool like a dropsaw or drill press.  If you want a tool that's already in working condition, and is more likely to stay working without random fiddling, then you're probably looking at spending around $1000 on a 3D printer.  I have not used one, but I've heard that the Prusa i3 series is reasonably reliable and predictable. 

I have not had it catch fire yet.  At the end of the day the hotend in any printer is basically a soldering iron, so you can't really leave it unattended. Marlin's hotend runaway detection seems really good (good thing too, I tried running it once with the heating cartridge uninstalled).  I have however had plastic char on the outside surface of the hotend and I don't trust the power supply with my life.

[Whales]

If you're not up to spending the money on an expensive one and you're not up for the tinkering on a cheaper one: see if you have any local Universities that run free or open hackerspaces.  Often they let you use their (pre-calibrated) printers.

As other people have mentioned: there are services for ordering 3d printed parts.  I had OK luck last time I tried them, but I can never make a part perfect on the first try, so having a machine within arm's reach is super useful.

[PerranOak]

Sorry, I’ve given the wrong impression. I do like tinkering it’s just that it sometimes seems like you have to be a genius just to get one of those little boats printed; I’m probably exaggerating.

I did see a YouTube vid where the guy had a mains relay device (110V unfortunately) in place but I can’t seem to find one - a fully complete one rather than the actual component relay.

[Mechatrommer]

Dont put or use combustible/flammable material near or in your 3d printer. You can make external monitoring circuit to cutoff mains supply in case strange thermal happens.. etc etc... if one thinks its nasa level tinkering is because he is not interested in mechanical or electrical field..nobody can help him with that.. car burned up, are you afraid to buy car?.. matches can burn house, are you afraid to buy matches? Car can hit you while you walk outside, are you going just to stay in house? Its a risk management issue if you want to do anything. And to  manage it, you need knowledge. Dont want to take risk or manage it? Pay premium or die in your sleep, no offense my friend

[PerranOak]

None taken. 

[janoc]

I have not had it catch fire yet.  At the end of the day the hotend in any printer is basically a soldering iron, so you can't really leave it unattended. Marlin's hotend runaway detection seems really good (good thing too, I tried running it once with the heating cartridge uninstalled).  I have however had plastic char on the outside surface of the hotend and I don't trust the power supply with my life.

I am just in the process of fixing that sort of issue on my Mendel90 too - the fan shroud for cooling the hotend and the part (Mendel has only one fan for both things) has cracked and the back was touching the hotend. So it is nicely melted and charred now and I have found that only by accident while doing some unrelated periodic maintenance (cleaning, oiling, etc.)  Bullet dodged ...

Really, don't underestimate these risks.

Sorry, I’ve given the wrong impression. I do like tinkering it’s just that it sometimes seems like you have to be a genius just to get one of those little boats printed; I’m probably exaggerating.

Well, one certainly doesn't need to be a genius. However, if you expect a 3D printer to be like a regular paper printer or a coffee machine that you just turn on, push a button, wait a bit and a good part comes out,  you are in for a very steep learning curve and a rough ride.

Even the 1000€ Prusa machines (which are otherwise excellent and have a first class support) or 3000-5000€ Zortraxes require maintenance ("tinkering"), setup and an operator who has a clue and isn't just winging it, thinking it will be all fine. With the cheap machines like the various Creality CR10s and Enders it is even worse because corners were cut and things wear out or break faster (or weren't even working properly to begin with). So one has to invest time and money into "tinkering" to get (and keep) them working.

That's the same thing as with cars - if you don't maintain yours properly and drive it like an idiot to boot, it will not last long and it will fail you at the worst possible moment (or you kill yourself in it). It used to be a  completely normal thing that a car driver carried a box of tools and spare parts in the boot in order to fix the inevitable breakages on the road. These days most people don't even know how to replace a blown lightbulb or change oil - but that doesn't mean it doesn't need to be done, only that they have to pay a mechanic to do it for them.

If you are comfortable with mechanical and electronic work and don't mind having to spend time working on your machine, then the cheap printers like the Enders could be good investment (and a lot of fun too). You could even build your own printer, whether from scratch or a kit (like those Vorons or various RepRap machines).

However, if your goal is to use it as a tool that has to work whenever you need it, reliably producing good parts and you don't want to spend time on the machine itself (which is totally fine!), you better add a zero (or two) to your budget - or use a printing service, letting someone else deal with the problem for you.

You need to decide where between these two extremes your comfort zone and needs are and shop accordingly.

[Mechatrommer]

I had few cases where people managed to screw up their normal 2d paper printer.. among the worst are ear ring or cloth pin/clip etc got stucked inside paper feed and mouse renovated the ribbon cable to give way for the sweet home inside.. the most common is they dont know how to do nozzle cleaning.. mostly families and friends that want it to get done for free.. i cant imagine when 3d printer become common in household. Sometime i feel like its better for me to look like a fool who doesnt know a rat ass about printer..

[thm_w]

I did see a YouTube vid where the guy had a mains relay device (110V unfortunately) in place but I can’t seem to find one - a fully complete one rather than the actual component relay.

There are relay modules that will shut off the printer after the print is completed: https://www.biqu.equipment/products/bigtreetech-reply-v1-2-automatic-shutdown-module-after-printing

Another option, for the same $10, is a WIFI mains switch. But you'd have to either have it turn off the power at a set time daily, or enter in a timer when you think the print will be done.

[PerranOak]

This thing looked good in the vid (https://youtu.be/tTJfASOHojo) but is only 110V despite it being a UK vid.

[Ian.M]

This thing looked good in the vid (https://youtu.be/tTJfASOHojo) but is only 110V despite it being a UK vid.

Why would you use such a hack?  240V AC Zero volt release (NVR) switches are readily available.  Ideally get one with an externally accessible coil terminal, e.g. https://uk.rs-online.com/web/p/push-button-switches/3985279

Then its simply a matter of your supervisory circuit interrupting the coil power of the NVR switch by cutting low voltage power to a NC relay. 

However I think the video's reliance on thermal fuses as sensors is also flawed.  Certainly they may be beneficial as a fail-safe for the PSU and SSRs or MOSFET modules, but for simplicity/reliability they should be wired  to cut power to/through what they are monitoring directly, provided they are rated appropriately.

What is needed is redundant monitoring of bed and hot end temperatures, and heater power by an independent monitor circuit (although it may tap into the controller's bed and hot end thermistors to reduce the number of extra thermistors and connections required).  Setup the printer controller firmware to limit heater power to 99% (PWM) and if it ever goes to 100% after the MOSFET, the MOSFET has failed.    If the hot-end heater power is high but temperatures aren't responding appropriately its likely the heater cartridge has become loose or has even fallen out. Carefully positioned flame and smoke sensors could also be beneficial, though if either are detected you probably are in need of an automatic fire suppression system, not just a power shutoff.   Current sensors for all heaters may also be beneficial as they could be used to detect unexpected increases in heater circuit resistance which would indicate a failing connection or wire, hopefully before the bad connection burns up.

IMHO AC powered heaters are inherently more dangerous - if you are going down that route for a moving bed heater, a 120V heater powered from a 110V grounded center tap site transformer would be the way to go, with redundant SSRs, one in each lead controlling it.

Its also dubious to put 3D printed fan ducts in close proximity to the hot block unless fire retardant filament is used to print them.

[janoc]

IMHO AC powered heaters are inherently more dangerous - if you are going down that route for a moving bed heater, a 120V heater powered from a 110V grounded center tap site transformer would be the way to go, with redundant SSRs, one in each lead controlling it.

That's more a feel-good setup than anything really practical or actually useful IMO. Even that 120V powered heater can kill you or start a fire. Even a DC powered 12 or 24V heater is good enough for starting a fire, like on those Anet 8 printers. The doubled SSRs will only protect you from one failing short but not from e.g. the firmware crashing and leaving the SSR conducting full time. Failed SSR is not the real danger there, those things are normally pretty reliable - plus a well set up printer would notice due to the thermal runaway sensing and abort/alarm.

The main dangers there are twofold:

- Many printers have crap wiring for the bed (insufficient strain relief, poor quality connectors, etc.). So as the thing moves, the wires either wear through or the connectors become high resistance - and you get a fire (that was the Anet 8 case) or electric shock from the mains heater wiring. Transformer could potentially prevent that but won't stop two adjacent wires wearing through together and shorting.

- Mains powered bed heaters are problematic because many of these machines are not earthed at all (despite metal construction) and having good earthing on a moving bed is difficult in any case.

Instead of messing with an isolation transformer one shouldn't use a mains powered heater at all - and actually make sure the printer is properly earthed. The bed is the least of one problems when the AliExpress special power supply blows and sends mains to the frame of the machine!

Its also dubious to put 3D printed fan ducts in close proximity to the hot block unless fire retardant filament is used to print them.

Pretty much all printers do that - and not only fan ducts. If the printer is constructed correctly and has the thermal runaway sensing, there is no way that plastic would get anywhere hot enough to catch on fire even after prolonged period. Melted, deformed sure (like mine). Fire, no. The hot end doesn't reach high enough temperatures for that - unless you have a thermal runaway for some reason - and the machine is unable to sense it (e.g. because idiot vendor didn't enable the option in Marlin).

Heck, you have a plastic filament going directly through the hot end, often sitting there for long minutes without movement while the machine is waiting for something - e.g. getting the bed hot or doing some preparatory work.  Good luck with a flame-retardant filament there ...

A smoke detector and not leaving the machine unsupervised is a much more practical solution. Technology can never account for all possible unexpected issues.

[Ian.M]

Yes, I agree there is little justification for AC mains bed heaters.  I believe the argument for them is that the lower current allows thinner, more flexible wires to be used, and causes less problems with connectors, but opposing that are the safety issues you have noted and also that the higher voltage almost guarantees that an internally broken wire will continue to arc, and significantly increases the risk of overheating terminals or PCBs developing conductive carbon tracking across the AC supply, both significantly increasing the fire risk over even a 12V bed of similar max. power, provided said 12V bed is wired with appropriate ampacity fine-stranded extra-flexible wire with connecters rated for the current with plenty of safety margin, and appropriate strain relief is used.

The flame retardant plastics issue is more nuanced.  Obviously, if the hot end heater cartridge comes loose, the firmware *SHOULD* detect that from the thermistor reading, abort and shut off the heaters, but assuming the failure is a shorted heater control MOSFET, on a printer without a software controlled PSU, there is little the firmware can do to alleviate the situation.  Its therefore worth minimizing the fuel available to the potential fire.  Hopefully the heat break cooling fan will be able to keep the filament temperature at the top of the heat break below its flash point, and the firmware certainly shouldn't continue to feed filament into an over-temperature hot end.  Personally I use a thin aluminum part cooling fan duct bent up out of heavy gage stiff foil and held together by interlocking tabs and aluminum foil tape, rather than a 3D printed one.

 

[janoc]

Yes, I agree there is little justification for AC mains bed heaters.  I believe the argument for them is that the lower current allows thinner, more flexible wires to be used, and causes less problems with connectors, but opposing that are the safety issues you have noted and also that the higher voltage almost guarantees that an internally broken wire will continue to arc, and significantly increases the risk of overheating terminals or PCBs developing conductive carbon tracking across the AC supply, both significantly increasing the fire risk over even a 12V bed of similar max. power, provided said 12V bed is wired with appropriate ampacity fine-stranded extra-flexible wire with connecters rated for the current with plenty of safety margin, and appropriate strain relief is used.

The main reason for the mains powered heaters is not really the wiring. Even for 12V the wires aren't that thick - we are talking cca 10A only for a normal sized bed. If the printer is one of the more modern ones, they tend to use 24V and the current is about half. That doesn't need any sort of thick or unwieldy cable - e.g. my 12V Mendel uses a regular 20ish conductor ribbon cable, split in half and the conductors soldered in parallel. The cable never gets significantly warm (apart from the radiated heat from the bed). Moreover, if you use mains, what you save on copper has to be "paid back" in the insulation thickness because of the higher voltage and risks if the wire wears through.

Mains powered beds are used mainly because of much faster heat up times because more current is available without requiring beefy (and thus more expensive) power supplies. Common printers use about 200W supplies, with about half of the capacity going to the bed and the rest powers the electronics, motors and the hot end. The common PCB heater 12V bed on a printer without enclosure takes about 5-10minutes (depending on the type of the bed) to get to 90 degrees. Mains powered one only about a minute or two.

A bit faster bed preheat when starting the print would be certainly welcome but I have never felt it was limiting me in what I do. I may upgrade the machine to 24V at some point, though.

The flame retardant plastics issue is more nuanced.  Obviously, if the hot end heater cartridge comes loose, the firmware *SHOULD* detect that from the thermistor reading, abort and shut off the heaters, but assuming the failure is a shorted heater control MOSFET, on a printer without a software controlled PSU, there is little the firmware can do to alleviate the situation.  Its therefore worth minimizing the fuel available to the potential fire.  Hopefully the heat break cooling fan will be able to keep the filament temperature at the top of the heat break below its flash point, and the firmware certainly shouldn't continue to feed filament into an over-temperature hot end.  Personally I use a thin aluminum part cooling fan duct bent up out of heavy gage stiff foil and held together by interlocking tabs and aluminum foil tape, rather than a 3D printed one.

The firmware could at least send out an alarm (assuming you have that set up).

You also likely have a lot of other things that are potentially flamable there. E.g. the extruder parts (unless you are using bowden, of course), enclosure (usually made out of polycarbonate/plexi), touch probe like the BL Touch (which is completely plastic and right next to the hotend), the filament itself which is in direct contact (by definition) and which will conduct the flame upwards where there is likely much more plastic to be had, the wiring (PVC insulation) ...

Also, if the cartridge comes loose (as opposed to the thermistor), then it could land on the plastic on the bed.

If the MOSFET shorts, it is likely that something on the electronics/driver board will catch fire before the hotend does. So this really doesn't worry me that much - or rather it is a risk that one needs to mitigate against in a different fashion along with the other issues. Such as by having that smoke detector there, a camera pointed at the machine, not leaving it completely unattented, etc.

A blown MOSFET or SSR aren't going to cause much damage if the operator checks on the machine every once in a while (I usually do every 30 minutes or so at least) and monitors the print progress (and any alarms). Even if there is a failure it does take a while for the hotend or bed to get sufficiently hot that they could start a fire. And even then it does take some time before it could do significant damage.

[thm_w]

Yeah my heated bed is 500W AC. I could use a 24V DC power supply but the one I had was noisy, heavy, etc. 110V AC though, fair bit safer than 220V.
I'm not too worried about anything falling down on the bed and burning as its a glass bed.
Earthed the metal portion of the bed, and the frame.

Ideally everything would be in a large metal enclosure but I don't have the tools or materials.

[boyddotee]

I would like to able to print some useful stuff but I also like to “tinker” with things so that I understand them better.

However, 3D printing seems to require NASA level tinkering skills! I’m surprised that any noob has ever printed anything!

BTW has anyone ever had or even heard of actual fires started by them?

No fires,  I keep mine in a closet. I'm no pro I've had a ctc maker bot clone (with USB key debacle, I was involved in it going out the window 🤣), a copymaster (no longer available but a good direct drive printer). And I have 2 creality ender 3, one is now a mix of the copymaster for larger format.

Have to say it's the bed leveling that's caused most of the issues you can have the perfect surface of x material (I've tried a lot) but go with a auto leveling system. I use creality's own but the bl touch is also an option and glue stick. No problems since on a glass bed.

[Lindley]

 I have 2 creality ender 3,

Have to say it's the bed leveling that's caused most of the issues you can have the perfect surface of x material (I've tried a lot) but go with a auto leveling system. I use creality's own but the bl touch is also an option and glue stick. No problems since on a glass bed.

Which Glass bed have you fitted , Crealitys own like on our V2 or something else ?

What was your problem, filament not adhering to the bed or not being able to remove it when finished ?

Do you use a particular brand of glue stick, Eg Pritt

[janoc]

 I have 2 creality ender 3,

Have to say it's the bed leveling that's caused most of the issues you can have the perfect surface of x material (I've tried a lot) but go with a auto leveling system. I use creality's own but the bl touch is also an option and glue stick. No problems since on a glass bed.

Which Glass bed have you fitted , Crealitys own like on our V2 or something else ?

What was your problem, filament not adhering to the bed or not being able to remove it when finished ?

Do you use a particular brand of glue stick, Eg Pritt

(Attachment Link)

Throw away those glue sticks and use something like Dimafix:

https://dimafix.com/

Yes, it does cost more but works wonders. Once the bed is hot the print sticks like, well, glued on. And once it cools down, it just pops off, unlike with glue sticks where I had the print either not wanting to stick properly, coming off mid-print or stick so well that it took out the top surface of the glass too. I am regularly printing PETG and ABS with this on glass - which wouldn't stick at all otherwise. PLA doesn't need any glue and can be printed directly on glass as long as it is heated.

I am using normal borosilicate glass. Nothing special. Even normal window glass or cheap mirror will work but I wouldn't trust it to withstand heating and cooling for a long time without cracking.

[Lindley]

Throw away those glue sticks and use something like Dimafix:

https://dimafix.com/

Yes, it does cost more but works wonders. Once the bed is hot the print sticks like, well, glued on. And once it cools down, it just pops off, unlike with glue sticks where I had the print either not wanting to stick properly, coming off mid-print or stick so well that it took out the top surface of the glass too. I am regularly printing PETG and ABS with this on glass - which wouldn't stick at all otherwise. PLA doesn't need any glue and can be printed directly on glass as long as it is heated.

I am using normal borosilicate glass. Nothing special. Even normal window glass or cheap mirror will work but I wouldn't trust it to withstand heating and cooling for a long time without cracking.

Thanks,    Do you prefer the Stick or the Spray Can

Will be looking for a new Glass as the V2 coating has already come off with a print during a very difficult release with PLA.

[janoc]

Thanks,    Do you prefer the Stick or the Spray Can

I have actually bought both. The spray is easier to apply on a larger surface (do it away from the printer - you don't want to gum the machine up with the glue!) but then after the print is removed, you will want to re-apply the glue at the used-up areas. If you don't, in those places the new print could stick so well it will rip off the surface of the glass. Go figure - one would assume it won't stick there at all since the glue was removed by the previous print but I have damaged the glass plate multiple times like this already.

Re-applying is easier with the stick because you only touch-up the used areas. Otherwise you will need to wash the glue off (water removes it easily), dry the glass and re-spray the entire surface. With the spray can it is difficult to apply it to only a smaller area without having a very uneven surface coating.

[MarkF]

I use hair spray on glass with a heated bed.
Just print, let it cool down, pop off and start another print.  No cleaning in between prints.
One thin coat of hair spray last me 10 to 20 prints before needing replacement.  I usually clean with 99% IPA or just water until the glass is clear without streaks.  Sometimes I'll spray a small touch-up on some bad places.

Leveling the bed for that first layer was a long long learning process for me.  That made all the difference in getting my prints to stick.  I print PLA and PETG with just an increase in temperature for bed and hotend and a lower fan speed are basically the only changes I do for PETG.

[gmb42]

I use the standard coated borosilicate bed on a CR6-SE, just clean it every few prints with soap and water, dry off with a microfibre cloth, job done.

Great adhesion with PLA, PLA+ and PETG, prints just slide off when the bed has cooled, no need for any messy glue or extras.

[janoc]

I use the standard coated borosilicate bed on a CR6-SE, just clean it every few prints with soap and water, dry off with a microfibre cloth, job done.

Great adhesion with PLA, PLA+ and PETG, prints just slide off when the bed has cooled, no need for any messy glue or extras.

For PLA and PLA+ you don't need any glue when printing on (clean!) glass, even though it doesn't harm.

Glue is needed for printing ABS, maybe ASA and nylon because those filaments don't stick to glass at all without help. Also, those filaments shrink more as they cool, which tends to cause the prints to warp and peel off the bed prematurely. Glue helps with that.

PETG - depends. E.g. my G-FIL roll doesn't stick so well to glass, so it works better with Dimafix coated glass.

If you don't like using glue then PEI surface works quite well. Just don't try to print PETG on it or your will destroy it - it is almost impossible to peel the print off after it cools from the PEI sheet. Another good alternative is garolite (i.e. normal FR4 laminate without the copper cladding).

Obviously, if the bed isn't level or the z-offset isn't set up correctly, then no amount of glue will fix that.

[pipe2null]

Just throwing my 2 cents at OP:

I always, always recommend first time 3DP-ers get a Prusa if you can fit it into your budget.  If you want to get into tinkering, buy the Prusa kit and build the machine screw by screw, but with excellent build instructions and support.  Prusa's firmware includes a series of pre-flight checks that self-tests for the most common build screwups and ensures wiring and whatnot are in working order.  For the most part, Prusa's are mostly automated bed leveling, plus automatic mesh bed leveling prior to each print.  6 months ago I bought my first Creality and discovered just how spoiled I have been with my Prusa Mk3S/MMU2.  Don't get me wrong, there are some things I really like about my Creality, but getting it up and running with usable print results was a significant PITA compared to getting my prusa built from scratch and running with reliably good print quality.

I have not heard of any Prusa's catching fire overnight.  If your lab is a tinderbox, it's probably a good idea to keep some fire extinguishers and working smoke detectors in there anyway, regardless of whether you have a 3d printer running.

[Ranayna]

To second @pipe2null:

My first 3D printer was an ANET A8. I got that, and immediatly ordered additional parts, putting the total cost to around 200 Euro, after reading about the ANET in a german magazine.

I *loved* building it. I loved tinkering with it. I was aware of its limitations and dangers, i never ran it unattended.
I got decent print quality out of it, after significant work, but i ever used it only for PLA. Due to its flimsy frame i never got rid of ghosting, and i had to reduce speed in general quite a bit.
But it was a learning experience.

I was never really happy with it though, since it needed adjusting for each print.
Well the topic concluded itself, after i dropped the thing during move

So the search for a new printer started. I again wanted a kit, with as much to assemble as possible. I did not want another A8, because of its limitations. I wanted something better.
And the only thing i was able to find was the Prusa i3 MK3s+ kit.
The build experience was great. Almost boring though, not nearly as much tinkering required as with the A8
And the thing printed flawlessly from the start, and still does. Absolutely no hassle: Plug in, swab the bed with bit of IPA, load filament, print. I only ever had issues with crappy filament, never with the printer itself.
The only maintenance i do is occasionally cleaning the rods, and applying a bit of lubricant.