<p>Is there a classification of method of control most (FDM) 3D printers fall under?</p>

<p>From a 1986robotics textbook<sup>ref</sup> I was reading they defined three classes of control:</p>

<p>1) Pick and place</p>

<p>2) Point to point</p>

<p>3) Continuous path</p>

<p>However, both point to point and continuous path control are stated as requiring servo motors.</p>

<p>I know that the majority of 3D printers are actuated with stepper motors as opposed to servo. Does the continuous path classification still apply? Or is there another classification?</p>

<p>ref - <em><a href="https://www.springer.com/gp/book/9789401167703" rel="nofollow noreferrer">Todd, D.J.(Ed.):Fundamentals of Robot Technology: An Introduction to Industrial Robots, Teleoperators and Robot Vehicles - Kogan Page 1986</a></em></p>

[{'answer_id': 11357, 'author': '0scar', 'author_id': 5740, 'author_profile': 'https://3dprinting.stackexchange.com/users/5740', 'pm_score': 3, 'selected': False, 'text': '<p>The question is if robots classification terminology the textbook sketches applies to 3D printing?</p>\n\n<p>Servos (closed loop) are used in robots to guarantee position (you don\'t want to accumulate an error after repetitive movement), most 3D printers use open loop steppers that are instructed on a point to point basis through G-code instructions, implying that the use of servos is not a "requirement" for point to point control.</p>\n\n<p>It <strong>is</strong> a requirement if you want to be absolutely sure that the position is reached. In 3D printing where the loads are generally low, this requirement is frequently dropped. But, there are printers that use servo control. </p>\n\n<p>Note that many CNC machines (operating at much higher loads than a 3D printer) even don\'t use servo\'s but (open loop) steppers, these are generally larger and more powerful (more torque).</p>\n'}, {'answer_id': 11358, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 1, 'selected': False, 'text': '<p>3D Printers fall under additive manufacturing and then can be classified by the material first. Usually, the material dictates entirely what the design looks like and it would be foolish to not differentiate what you look at by this first. For some materials, there are a couple of subtypes that tell us about which method for fusing the material is used, but usually, there is just one.</p>\n\n<ul>\n<li>light curing resin\n\n<ul>\n<li>projected light</li>\n<li>Laser</li>\n</ul></li>\n<li>Paste, gel or air curing resin\n\n<ul>\n<li>direct deposit from syringe</li>\n</ul></li>\n<li>Foil\n\n<ul>\n<li>Laser1</li>\n</ul></li>\n<li>Powder\n\n<ul>\n<li>Laser</li>\n</ul></li>\n<li>Filament (FFF/FDM)\n\n<ul>\n<li>direct deposit</li>\n</ul></li>\n</ul>\n\n<p>Of all these printers, only the FDM/FFF Group has a large diversity in how they are designed on the outer side, with the main 4 designs (and one example) being</p>\n\n<ul>\n<li>Cantilever (TronXY X1)</li>\n<li>Core-XY (Hypercube)</li>\n<li>Portal (Prusa)</li>\n<li>Delta (Kossel)</li>\n</ul>\n\n<p>Now comes the kicker: Most FDM/FFF Printers do use only stepper motors and use G-Code that is derived from CNC - just like the whole idea of FDM was invented as <em>reverse CNC</em>. Only very few use an encoder at all. Marlin, the main firmware used in 3D printers, executes usually <em>point-to-point</em> instructions (<a href="http://marlinfw.org/docs/gcode/G000-G001.html" rel="nofollow noreferrer"><code>G0 X10 Y10 Z0 E5</code></a>), but some implementations are able to perform arcs (<a href="http://marlinfw.org/docs/gcode/G002-G003.html" rel="nofollow noreferrer"><code>G2 E7.85 R5 X-5 Y5</code></a>). Usually, printers run in <em>relative coordinates</em> (to the last position of the nozzle/tool), but for some operations <em>absolute coordinates</em> (mainly start or end codes) are used. </p>\n\n<p>Among the printers that use servos instead of steppers are, to my knowledge, mostly laser-based systems.</p>\n'}, {'answer_id': 11359, 'author': 'FEA42', 'author_id': 19038, 'author_profile': 'https://3dprinting.stackexchange.com/users/19038', 'pm_score': 1, 'selected': False, 'text': '<p>Upon further research these defined classes of control (from a robotics perspective) only apply to servo motors.</p>\n\n<p>At the highest level the methods of control being categorised as:</p>\n\n<ul>\n<li>Servo</li>\n<li>Non-Servo</li>\n</ul>\n\n<p>The three categories I listed in my question are all subsets of the Servo category and rely upon feedback from the servo.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/11356', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/19038/']