<p>Printing directly onto aluminum is something I've never seen before, likely due to the fact that PLA (and other materials) do not adhere reliably to aluminum. Instead, many opt to use blue tape, kapton tape, PEI, buildtak/commercial build surface, or an additional build surface, such as glass. When heated, clean glass can be directly printed on. The use of a glue stick, wood glue, isopropyl alcohol, the above adhesion aids, and others can help adhere your part better hot or cold.</p>

<p>Can you remove the glass, add any of the above to the aluminum plate, and print on that? So long as it's a clean, flat surface, yes. But it'll be more work for you to replace or clean the build surface, as you won't be able to simply remove the glass and replace it. You're not gaining much by taking out the glass. A slightly faster bed heat-up, perhaps.</p>

<p>As for <em>why</em> Ultimaker went with an aluminum transfer plate, that is a slightly more <a href="https://engineering.stackexchange.com/questions/14722/why-does-the-ultimaker-3d-printer-has-a-heater-heater-transfer-plate-aluminiu/14725#14725">engineering</a> oriented question.</p>

CC BY-SA 3.0
2017-04-11T06:07:20.713Z
Also, glass is a lot more scratch resistant, so less likely to damage the bed when removing the model, and since it's not directly attached to the source of the heat, it can easily be removed to aid in taking the model off!
AndrewP
CC BY-SA 4.0
2018-09-07T13:13:54.667Z
I've ditched the tape as of day one and print directly onto the aluminium heatbed using 3DLAC print adhesion spray (sort of a very strong hairspray) and printing like this for almost 2 years, see [this answer](/a/6861). I have never had any adhesion problem.
0scar
CC BY-SA 3.0
2017-04-10T22:23:02.530Z
2017-04-10T22:23:02.530Z
2017-04-13T12:51:48.717Z
K .
<p>According to <a href="http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html" rel="noreferrer">this page</a>, heat transfers more evenly across an aluminum build plate than with just glass. But as Kevin pointed PLA adheres better to glass because it doesn't flex as much as aluminum under heat.</p>

<p>The link above shows that aluminum has a much higher thermal conductivity at 205 <sup>(<a href="http://www.engineeringtoolbox.com/conductive-heat-transfer-d_428.html" rel="noreferrer">W/(mK)</a>)</sup> vs glass at 105 <sup>(W/(mK))</sup> at 25 &deg;C <sup>(77 &deg;F)</sup>.</p>

<p>Because of this conductivity difference, you may find that it takes longer to heat the glass plate, but it should heat more evenly.</p>

CC BY-SA 4.0
2018-09-07T13:17:07.130Z
I print directly onto the aluminium build plate, see [this answer](/a/6861), it is 3 mm thick, I never have experienced more flexibility using the bed on temperature, for very thin heated plates (like Ultimaker uses) you might be right.
0scar
CC BY-SA 3.0
2017-04-10T23:07:48.913Z
2017-04-11T14:32:02.733Z
2017-04-11T14:32:02.733Z
tbm0115
<p>Why does the Ultimaker 3D Printer has a Heater + Heater transfer plate (aluminium) + Glass?</p>

<p>I wonder why a glass plate, and if is possible to remove the glass and print directly in the aluminium plate adjusting the heating.</p>

<p><a href="https://ultimaker.com/en/products/ultimaker-3" rel="nofollow noreferrer">Link to the ultimaker</a>.</p>

<p>Pictures:</p>

<p><a href="https://i.sstatic.net/hBsTd.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/hBsTd.jpg" alt="Ultimaker view"></a></p>

<p><a href="https://i.sstatic.net/uf2vc.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/uf2vc.jpg" alt="PCB Heater view"></a></p>

CC BY-SA 3.0
2017-04-12T10:36:50.223Z
Asking for *why* Ultimaker made this design decision will just result in an opinion-based guessing game (since nobody outside of Ultimaker knows). I think it would be better if you just asked whether you can print on the bare aluminium.
Tom van der Zanden
CC BY-SA 3.0
2017-05-02T16:34:34.783Z
Please do not cross post questions, see [Is cross-posting a question on multiple Stack Exchange sites permitted if the question is on-topic for each site?](https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-qu).
Greenonline
<heated-bed><ultimaker-3>
Why does the Ultimaker 3D Printer has a Heater + Heater transfer plate (aluminium) + Glass?
Kevin Mamaqi
# Why does the Ultimaker 3D Printer has a Heater + Heater transfer plate (aluminium) + Glass?

(Asked by: username_0 on 2017-04-10)

Why does the Ultimaker 3D Printer has a Heater + Heater transfer plate (aluminium) + Glass?

I wonder why a glass plate, and if is possible to remove the glass and print directly in the aluminium plate adjusting the heating.

[Link to the ultimaker](https://ultimaker.com/en/products/ultimaker-3).

Pictures:

[![Ultimaker view](https://i.sstatic.net/hBsTd.jpg)](https://i.sstatic.net/hBsTd.jpg)

[![PCB Heater view](https://i.sstatic.net/uf2vc.jpg)](https://i.sstatic.net/uf2vc.jpg)

**Tags:** heated-bed, ultimaker-3
> **Comments:**
> **username_1**: Asking for *why* Ultimaker made this design decision will just result in an opinion-based guessing game (since nobody outside of Ultimaker knows). I think it would be better if you just asked whether you can print on the bare aluminium.  
> **username_2**: Please do not cross post questions, see [Is cross-posting a question on multiple Stack Exchange sites permitted if the question is on-topic for each site?](https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-qu).  

---

## 2 answers

### Answer by username_3 on 2017-04-10. Score: 2 | Accepted answer

Printing directly onto aluminum is something I've never seen before, likely due to the fact that PLA (and other materials) do not adhere reliably to aluminum. Instead, many opt to use blue tape, kapton tape, PEI, buildtak/commercial build surface, or an additional build surface, such as glass. When heated, clean glass can be directly printed on. The use of a glue stick, wood glue, isopropyl alcohol, the above adhesion aids, and others can help adhere your part better hot or cold.

Can you remove the glass, add any of the above to the aluminum plate, and print on that? So long as it's a clean, flat surface, yes. But it'll be more work for you to replace or clean the build surface, as you won't be able to simply remove the glass and replace it. You're not gaining much by taking out the glass. A slightly faster bed heat-up, perhaps.

As for *why* Ultimaker went with an aluminum transfer plate, that is a slightly more [engineering](https://engineering.stackexchange.com/questions/14722/why-does-the-ultimaker-3d-printer-has-a-heater-heater-transfer-plate-aluminiu/14725#14725) oriented question.

> **Comments:**
> **username_4**: Also, glass is a lot more scratch resistant, so less likely to damage the bed when removing the model, and since it's not directly attached to the source of the heat, it can easily be removed to aid in taking the model off!  
> **username_5**: I've ditched the tape as of day one and print directly onto the aluminium heatbed using 3DLAC print adhesion spray (sort of a very strong hairspray) and printing like this for almost 2 years, see [this answer](/a/6861). I have never had any adhesion problem.  

---

### Answer by username_6 on 2017-04-10. Score: 5

According to [this page](http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html), heat transfers more evenly across an aluminum build plate than with just glass. But as Kevin pointed PLA adheres better to glass because it doesn't flex as much as aluminum under heat.

The link above shows that aluminum has a much higher thermal conductivity at 205 ([W/(mK)](http://www.engineeringtoolbox.com/conductive-heat-transfer-d_428.html)) vs glass at 105 (W/(mK)) at 25 °C (77 °F).

Because of this conductivity difference, you may find that it takes longer to heat the glass plate, but it should heat more evenly.

> **Comments:**
> **username_5**: I print directly onto the aluminium build plate, see [this answer](/a/6861), it is 3 mm thick, I never have experienced more flexibility using the bed on temperature, for very thin heated plates (like Ultimaker uses) you might be right.  

---

