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Glass is always level, easy to clean, easy to work with.

Aluminium allows for the addition of automatic bed leveling with an inductive sensor and distributes heat a little more evenly.

When printing mostly ABS and PLA, which one is better?

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    $\begingroup$ Just to note, you can get foil tape to use auto leveling with glass $\endgroup$ – Daniel M. Feb 5 '16 at 19:13
  • $\begingroup$ Interesting... Do you have a link handy to the exact kind of foil tape you are referencing? $\endgroup$ – Chase Westlye Feb 5 '16 at 23:02
  • $\begingroup$ How does the foil tape affect adhesion? $\endgroup$ – Leo Ervin Feb 5 '16 at 23:06
  • $\begingroup$ I can't recommend an exact one, but anything that's conductive should work. I got the recommendation from here. Some people just use aluminum foil. Most likely, it would go on the corners or under the bed so adhesion shouldn't matter. Alternatively, you can use a contact sensor, such as the BLTouch, which is material independent. $\endgroup$ – Daniel M. Feb 5 '16 at 23:48
  • $\begingroup$ The guys who make the DeltaPrintr have found a pretty neat solution to auto calibration where they put pressure sensors at each foot of the bed. Although not as straightforward to use with "normal" printer firmware, it means that you no longer need any specific mechanism on the end effector itself. deltaprintr.com/shop/3d-printers/deltaprintr-kit $\endgroup$ – Tormod Haugene Feb 6 '16 at 11:24
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I believe printing directly on aluminium is unwise, simply because it will expand when heated, typically giving the bed a concave or convex shape. Glass, on the other hand, does not (at least not significantly).

As pointed out in the comments below, the heat expansion of aluminium could potentially be mitigated by increasing the thickness of the bed, as well as heating it evenly. Also, a common solution is to place a glass plate on top of an aluminium bed, at the cost of a slightly longer heat-up time.

In my experience, printing directly on heated glass can be very practical and give a nice surface finish for some PLA variants and other materials that support it. I don't know if printing directly on aluminium can give similar benefits.

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    $\begingroup$ It seems that this can be mostly mitigated by getting quality aluminium, 3+mm thickness, and ensuring that the entire plate is heated evenly. Thoughts? $\endgroup$ – Chase Westlye Feb 5 '16 at 23:01
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    $\begingroup$ On the other hand, many 3d printers have an aluminum bed then a glass on top of the aluminum. $\endgroup$ – Leo Ervin Feb 5 '16 at 23:07
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    $\begingroup$ @LeoErvin,Chase. Very good points. I have updated the answer. $\endgroup$ – Tormod Haugene Feb 6 '16 at 11:07
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    $\begingroup$ hairsrpay or abs slurry is the way to go with bare glass and ABS. Or PET tape or Kapton tape on it. The latters also work with bare aluminum but not sure about the former. $\endgroup$ – Leo Ervin Feb 6 '16 at 11:40
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    $\begingroup$ I print directly on my heated aluminium bed with glue stick on it. It works well for PLA (not tried with ABS). The bed shape don't change (3 mm thick but it's a Delta with a small diameter). I've got a nice surface finish. $\endgroup$ – Maxence May 18 '16 at 15:20
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I have aluminium 3 mm thick and 110x110 mm big, and it bends when heated. Inevitably the center becomes higher than the sides. It is not a problem with PLA and nylon, but noticeable with ABS.

I use Kapton on top of it, and the print sticks easily with PLA. ABS requires hairspray on top of it, and nylon requires glue stick (but it fails anyway if the piece is big).

If you use glass with a top layer for proper adherence, you should be fine. Aluminium below could help spreading the heat, but... it will bend and push the glass, therefore you increase the risk of breaking: the glass does not bend much, but internally it is ALREADY withstanding a lot of stress when hot, and aluminium below could push it to the limit.

Edit: it appears however that aluminium beds are in general the best ones:

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Aluminium gives low adherence. Probably because its top of surfaces gives temperature fast. But using conductive metals is the right direction. There are some benefits:

  • Electromagnetic induction allows to heat faster and reach higher temperatures with same current.
  • Non-transparency allows to use mirror under bed to make heating bonus.

But's:

  • It will expand when heated.

I tried titan. Here is prooflink. Using 0.5 mm it gave good results on printing with temperature 120 degrees Celsius. But as I had bit crooked plate, I had to stop using it. Needing to heat it up 20 degrees more than glass makes it pointless, unless using microwave. Try borosilicate glass.

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  • $\begingroup$ I print on Aluminium and on glass on several printers, there is no difference, both work very well; the mirror shine on glass printed parts is a little more beautiful though. $\endgroup$ – 0scar Apr 16 '19 at 12:09
  • $\begingroup$ @0scar, it is generally may be good for PLA, yes, but you may experience bends for ABS as it needs higher temperature. Is it 3mm? $\endgroup$ – Sergei Apr 16 '19 at 13:15
  • $\begingroup$ Yes it is 3 mm, but it also works for PETG and high temperature co-polyester filaments, no problem. $\endgroup$ – 0scar Apr 16 '19 at 13:38
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I have used glass from the beginning and it works perfect. (From old picture frame and old scanner)

I have tried glass with tape, glass with hairspray and have had very good luck on printing on both. Prefer hairspray :)

I have tried printing on the heated aluminum, but experienced the aluminum plate tend to warp due to temperature changes.

With a glass plate on top of the aluminum, you have a flat surface that don't warp. :)

So I would give glass thumps up!

EDIT: Printed on Glass with glue-stick. Wow. Sticks really good.

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I have only printed on an aluminum build plate but I agree with Craig Anderson. I use Marlin RC6 (I really should update to RC7 but I am lazy and RC6 is working well for me) and the mesh bed leveling system. WELL worth the time to get it setup. I use blue painter's tape and I print in both PLA and ABS, but mostly ABS. I have very few issues with the part(s) not sticking to the build plate, actually the problem I have tends to be the opposite LOL! I started to get good, repeatable results when I switched to mesh bed leveling and then great results when I changed my first layer to be 200 % flow. YMMV but I print with 110 °C bed and 235 °C print head, use blue painters tape and mesh bed leveling.

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I've got a full frame i3 with a glass printing surface, and an Anet A8 with an aluminium surface.

According to my optical thermometer there is a 15 to 20 °C temperature loss between the bed sensor and the glass surface at 65 °C, which is how hot I have to run the i3 to get adhesion with PLA.

I have not tried printing ABS yet on either printer, but I cannot see getting the glass surface temperature high enough to give good adhesion.

I use dilute PVA adhesive as on both surfaces, but it does not adhere well to the aluminium.

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  • $\begingroup$ If your glass has nothing on it than your stated method of taking the temperature is not accurate due to emissivity of materials. Basically, the sensor is going to read the temperature of what is reflected off the glass and not the actual temperature of the glass. You need to coat the glass in something non-reflective to get an accurate temperature or use something that contacts the glass physically. See here for more information - raytek.com/raytek/en-r0/ireducation/emissivity $\endgroup$ – tjb1 Jan 3 '17 at 12:55
  • $\begingroup$ Here is a picture that demonstrates the above - blog.brixandersen.dk/wp-content/uploads/IR003969.jpg If you notice the axial resistor which according to the scale is ~300C but the block around it is showing a much lower temperature because it's brass and reflective. You'll also notice the tip is showing ~200C, this is because it more than likely has plastic smeared on the outside. $\endgroup$ – tjb1 Jan 3 '17 at 12:56
  • $\begingroup$ @tjb1 The emmisivity of glass is much higher than that of aluminium or brass. The measurement should be fairly accurate. It doesn't have anything to do with reflections: the amount of infrared radiation emitted by an object depends on its material and its temperature. Smooth, metal surfaces happen to have low emmisivity (i.e. do not give off much radiation) and thus are not read accurately, on the other hand glass has rather high emmisivity and should work fine. $\endgroup$ – Tom van der Zanden Jan 3 '17 at 14:45
  • $\begingroup$ Have you tried to match the temperature in between the heatbed thermistor and your optical thermometer ? It might be the case that the thermistor does not yield the same temperature as the thermometer for the same temperature. That might also influence the difference you notice in temperatures. $\endgroup$ – Nicu Surdu Apr 5 '17 at 11:40
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I use a 200 mm x 200 mm aluminum bed over an aluminum heated plate. It is attached by bolts in the corners. I use a proximity probe to run a leveling program and I print on the aluminum. I don't see where my bed is bowing or causing attachment problems. I run the leveling program with the plate at temperature (110 °C) and any bowing is handled by the software. It works very well with ABS. I haven't used much PLA and am still experimenting.

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    $\begingroup$ Hi, welcome to the site! The question asks for a comparison between aluminium and glass. Your answer seems to only focus on aluminium. If you have any experience printing on glass you might include that in your answer as well, as in its current state it doesn't really address the question. $\endgroup$ – Tom van der Zanden Aug 16 '16 at 18:53
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you could always slightly slot the holes on your aluminum bed so its not corner constrained and forced to bow in the middle..

My advice is use both and hairspray currently testing the effectiveness of insulation on the bottom of the plate

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    $\begingroup$ Could this be reworded? As it stands right now it's not answering the question being asked $\endgroup$ – Diesel Mar 22 '17 at 16:40

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