<p>It really took me a little while to understand why you thought that it was subtractive, but I <em>can</em> now see your point. Which is, that seeing as the resin model is created <em>within</em> the tank/bath, you are saying that the bath is analogous to a block of aluminium which is whittled away, using CNC, to make a 3D model. The resulting aluminium model was once within the block of aluminium, as was the resin 3D model - therefore, you posit, resin 3D printing is subtractive.</p>
<p>The more I thought about it, the more it seemed as if you were, actually, correct.</p>
<p>However, then I realised that we were neglecting the hardening process. It is the hardening of the resin that is done in an additive manner, in order to slowly build up the model, therefore the process is additive.</p>
<p>You aren't removing/subtracting non-hardened resin from the model (which would result in a non-hardened wobbly model), but instead, as <a href="https://3dprinting.stackexchange.com/a/18556/4762">user10489's answer</a> states, you are adding hardened resin layers.</p>

CC BY-SA 4.0
2023-12-30T22:25:54.190Z
2023-12-30T22:25:54.190Z
Greenonline
<p>Resin printing (aka stereo lithography) was actually invented before (FFF/FDM) filament extrusion printing.  The term 3D printing was more or less created as a generic way to name and describe both along with a handful of other methods.</p>
<p>It is additive because you add layers to other layers to build the part rather than carving up an original solid block.</p>
<p>Resin printing is no more subtractive than removing the tip of the filament in FFF is subtractive.</p>

CC BY-SA 4.0
2021-12-14T08:18:06.900Z
Very nice punch line! `Resin printing is no more subtractive than removing the tip of the filament in FFF is subtractive.` :-)
0scar
CC BY-SA 4.0
2021-12-14T00:15:07.403Z
2021-12-14T06:04:43.820Z
2021-12-14T06:04:43.820Z
user10489
<p>Subtractive manufacturing has been the way of the world for a while, but additive manufacturing, which is synonymous with 3D printing, has disrupted all of that.</p>
<p>If extrusion-based printing is considered additive, then can we call resin printing additive?</p>
<p>Resin printers start with a resin bath and then essentially &quot;subtract&quot; the material it needs (via UV light). This is just a matter of terminology, no big deal.</p>

CC BY-SA 4.0
2021-12-13T22:14:49.543Z
your bath is the equivalent of a spool of material.  you "subtract" the material you need from a spool.  sadly one cannot add matter to existence easily thanks to laws of conservation; something added is always subtracted from elsewhere.  if with a conventional mill, your goal were to add chips to the floor...
Abel
<extrusion><resin><terminology>
Is resin 3D printing considered "additive"?
Jonathan L.
# Is resin 3D printing considered "additive"?

(Asked by: username_0 on 2021-12-13)

Subtractive manufacturing has been the way of the world for a while, but additive manufacturing, which is synonymous with 3D printing, has disrupted all of that.

If extrusion-based printing is considered additive, then can we call resin printing additive?

Resin printers start with a resin bath and then essentially "subtract" the material it needs (via UV light). This is just a matter of terminology, no big deal.

**Tags:** extrusion, resin, terminology

> **Comments:**
> **username_1**: your bath is the equivalent of a spool of material.  you "subtract" the material you need from a spool.  sadly one cannot add matter to existence easily thanks to laws of conservation; something added is always subtracted from elsewhere.  if with a conventional mill, your goal were to add chips to the floor...  

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## 2 answers

### Answer by username_3 on 2021-12-14. Score: 9 | Accepted answer

Resin printing (aka stereo lithography) was actually invented before (FFF/FDM) filament extrusion printing. The term 3D printing was more or less created as a generic way to name and describe both along with a handful of other methods.

It is additive because you add layers to other layers to build the part rather than carving up an original solid block.

Resin printing is no more subtractive than removing the tip of the filament in FFF is subtractive.

> **Comments:**
> **username_4**: Very nice punch line! `Resin printing is no more subtractive than removing the tip of the filament in FFF is subtractive.` :-)  

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### Answer by username_2 on 2023-12-30. Score: 1

It really took me a little while to understand why you thought that it was subtractive, but I *can* now see your point. Which is, that seeing as the resin model is created *within* the tank/bath, you are saying that the bath is analogous to a block of aluminium which is whittled away, using CNC, to make a 3D model. The resulting aluminium model was once within the block of aluminium, as was the resin 3D model - therefore, you posit, resin 3D printing is subtractive.

The more I thought about it, the more it seemed as if you were, actually, correct.

However, then I realised that we were neglecting the hardening process. It is the hardening of the resin that is done in an additive manner, in order to slowly build up the model, therefore the process is additive.

You aren't removing/subtracting non-hardened resin from the model (which would result in a non-hardened wobbly model), but instead, as [username_3's answer](https://3dprinting.stackexchange.com/a/18556/4762) states, you are adding hardened resin layers.


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