Aluminum alloy for heated bed?
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Float glass is entirely adequate provided that you have an aluminium heat spreader between it and the heater so that it gets heated evenly. I have been printing on float glass on top of aluminium for nearly 4 years. The only issue I have had with it is that a couple of times prints have stuck to the glass so well that when the print was eventually released, it brought a small chip of glass with it - but other people report that happening with borosilicate glass beds too.
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Just a word on aluminum heated build plates.
I have a 300mm x 600mm build machine. I originally began using 12 mm cast aluminum with a silicon heater glued to the underside of the build platform.. I ran into nothing but problems with this ….as it headed I could actually measure the warping of the plate every time the heater would cycle regardless if it was in bang bang mode or pid mode. This was driving me crazy. The solution was to go with granite in my case I used 19mm thick polished one side and then gluing the heater pad to the underside. What a difference....I can now print the whole platform without any issues. My first layer adhesion was great...(I use a PLA Glue Water Slurry to paint on the granite) ....think twice before using aluminum -
Float glass is entirely adequate provided that you have an aluminium heat spreader between it and the heater so that it gets heated evenly. I have been printing on float glass on top of aluminium for nearly 4 years. The only issue I have had with it is that a couple of times prints have stuck to the glass so well that when the print was eventually released, it brought a small chip of glass with it - but other people report that happening with borosilicate glass beds too.
David, at what kind of max bed temps have you been printing ordinary floatglas if I may ask? And how thick a glass was it?
It is not only uneven heat that causes a problem, it is also heating too quick to too high temps. I can imagine going to 90C on a 12V heater (which takes many minutes) is no problem. But when on 24V or AC mains you could heat to 120C in a minute. I don't think a 4mm ordinary floatsheet will endure that very long. And if it brakes you can get very small sharp splinters. I know you know your stuff, but I think th3d-print scene uses boro glass for a valid reason. -
Just a word on aluminum heated build plates.
I have a 300mm x 600mm build machine. I originally began using 12 mm cast aluminum with a silicon heater glued to the underside of the build platform.. I ran into nothing but problems with this ….as it headed I could actually measure the warping of the plate every time the heater would cycle regardless if it was in bang bang mode or pid mode. This was driving me crazy. The solution was to go with granite in my case I used 19mm thick polished one side and then gluing the heater pad to the underside. What a difference....I can now print the whole platform without any issues. My first layer adhesion was great...(I use a PLA Glue Water Slurry to paint on the granite) ....think twice before using aluminumToo what deviation did the heating of a 12mm alu plate lead? And to what temperatures were you heating? I do see significant other probe values at room temp and at 90C, for sure, but I don't think it is the alu bending. I can see that my Onyx is waving creating space between the alu and the the Onyx. I use three clams to fit the plate, so I get a fairly even surface. Nothing Duet autocalibration can't handle
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…..................I would not recommend normal floatglass because it is just not heat resistant enough. It breaks and splinters easily under thermal stress. Borosillicate is better of course, but more expensive then thick alu sheets
As another long term user of float glass, I have to disagree. It's sudden thermal shock that might cause it to fracture, but that situation does not apply when using it over a thick aluminium base. Borosilicate glass is prone to being easily chipped, for example when trying to remove a large printed part which has adhered a little too well. I have 3 sheets of 400m x 400 x 6mm float glass that I regularly swap between. From time to time I have accidentally dropped one or dropped something heavy on top of one and never had an issue- it's surprising;y difficult to break. A word of warning though - do not be tempted to have the glass toughened as the toughening process will cause it to distort (I know from experience) - plain float glass is best IMO.
Edit. I've used it at 120 deg C with PrintBite stuck to it in attempt to get that to work, and I have a 400W 240v mains heater. I've also read many many posts from people who have never tried float glass telling me that it can't be used.
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…..................I would not recommend normal floatglass because it is just not heat resistant enough. It breaks and splinters easily under thermal stress. Borosillicate is better of course, but more expensive then thick alu sheets
As another long term user of float glass, I have to disagree. It's sudden thermal shock that might cause it to fracture, but that situation does not apply when using it over a thick aluminium base. Borosilicate glass is prone to being easily chipped, for example when trying to remove a large printed part which has adhered a little too well. I have 3 sheets of 400m x 400 x 6mm float glass that I regularly swap between. From time to time I have accidentally dropped one or dropped something heavy on top of one and never had an issue- it's surprising;y difficult to break. A word of warning though - do not be tempted to have the glass toughened as the toughening process will cause it to distort (I know from experience) - plain float glass is best IMO.
Edit. I've used it at 120 deg C with PrintBite stuck to it in attempt to get that to work, and I have a 400W 240v mains heater. I've also read many many posts from people who have never tried float glass telling me that it can't be used.
That sounds convincing. I googled around a bit in search of my source of wisdom and it is: MHackney
I recommend reading this post before deciding on floatglass:
http://forum.seemecnc.com/viewtopic.php?t=9422#p80683(as a motivation to actually read it: glass shards were stuck into the wall…)
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That sounds convincing. I googled around a bit in search of my source of wisdom and it is: MHackney
I recommend reading this post before deciding on floatglass:
http://forum.seemecnc.com/viewtopic.php?t=9422#p80683(as a motivation to actually read it: glass shards were stuck into the wall…)
That just demonstrates why it's not a good idea to stick a heater, which will have local hot spots, directly onto the back of a sheet of glass. We are talking about using glass on top of a thick aluminium heat spreader.
Edit - The other side of the coin http://richrap.blogspot.co.uk/2016/02/glass-3d-print-build-surfaces-are-not.html
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Float glass is entirely adequate provided that you have an aluminium heat spreader between it and the heater so that it gets heated evenly. I have been printing on float glass on top of aluminium for nearly 4 years. The only issue I have had with it is that a couple of times prints have stuck to the glass so well that when the print was eventually released, it brought a small chip of glass with it - but other people report that happening with borosilicate glass beds too.
David, at what kind of max bed temps have you been printing ordinary floatglas if I may ask? And how thick a glass was it?
It is not only uneven heat that causes a problem, it is also heating too quick to too high temps. I can imagine going to 90C on a 12V heater (which takes many minutes) is no problem. But when on 24V or AC mains you could heat to 120C in a minute. I don't think a 4mm ordinary floatsheet will endure that very long. And if it brakes you can get very small sharp splinters. I know you know your stuff, but I think th3d-print scene uses boro glass for a valid reason.Mostly I print with a bed temperature of 70C, but I had a phase of printing ABS using 110C. The bed is 5mm thick 330mm diameter aluminium with a 350W AC mains heater on the underside, and I had 4mm thick 330mm diameter float glass on top of it.
I also know of someone using a 3mm 210x210mm sheet directly on top of a PCB heater at 100C bed temperature, but I don't advise that.
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Edit - The other side of the coin http://richrap.blogspot.co.uk/2016/02/glass-3d-print-build-surfaces-are-not.html
Nice info, thanks!
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Mostly I print with a bed temperature of 70C, but I had a phase of printing ABS using 110C. The bed is 5mm thick 330mm diameter aluminium with a 350W AC mains heater on the underside, and I had 4mm thick 330mm diameter float glass on top of it.
Okay, I use the same thickness alu sheet with PEI directly on top. It has enough thermal mass to keep it (autotuned) within 1,5 degree variation. Also the variation across the bed is very little. Where I often got more than 7 degrees difference from center to bed using only boroglass on the PCM, that has been reduced to not more than about 2 degrees. So 5mm alu does in fact do a nice job. However I think that the thin heatspreaders you see in some shops are really too thin. It is mass that counts…
I also know of someone using a 3mm 210x210mm sheet directly on top of a PCB heater at 100C bed temperature, but I don't advise that.
Yes, that really is the danger I wanted to warn about. Seeems that a good thick alu heatspreader fixes that, but on the other hand a good thick heatspreader makes the glass unneeded if you want to use it together with PEI. I have a second bare heatspreader, in case there would be a time that I would want to print on bare glass. But PEI works just fine for me up till now. No tricks at all needed for PLA, ABS and PETG. Have not tried others yet
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I'm another float glass user. Been using float glass for 3-1/2 years of printing at temps from 60C to 100c without issues. I too "hot swap" the glass bed when running production runs of parts. I've broken 3 plates in my years,
1 because I dropped an extruder motor on it. The second was when I stepped on on I had sitting on the floor by my printer. And the third was broken by a large part that stuck so well it actually snapped the plate when it cooled. It didn't shatter it just snapped in half.
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I'm a PEI fan. It's been around 3 years since it was installed and it stills performs like a champ. Others suggests to sand it, but personally, never did that and prints sticks great to it. Just clean it with some isopropyl alcohol and it's good to go.
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On my Ormerod I print PLA on plain uncoated float glass. I wipe it with distilled vinegar between prints. It works very well with good-quality PLA filaments if you prepare the glass correctly and avoid finger-marking it. Bit some PLA filaments won't stick to it.
On my delta I have one float glass bed with PEI on top and another with PrintBite on top. I mostly use the PrintBite one, because the PLA I use sticks too well to PEI.
My Scara printer prints on to unheated blue tape on the desk in front of it.
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Hi all, quick question, I'm about to have some parts water-cut and need to buy the aluminum sheets.
I wanted to buy MIC6 but it seems that it doesn't exists around here, so what would be a good alloy for the heated bed?6061? 5083? 7xxx? other?
Thanks in advance
MartinI do not know if he already solved it, I'm new here. Undoubtedly I would choose aleaceon 6061, you just have to think about which temple T will ask for it, 6061 is used in aircraft, it is secret is the temple, in T4 it would be well machined well.
