The truth is worth digging. How accurate is the desktop FDM 3D printer?|

[Tianji.com Enterprise Channel] Due to the lack of contact, or the hype of manufacturers, or the gap between theoretical knowledge and actual use, people have doubts or form a topic discussion around the accuracy of desktop-level FDM 3D printers. Many netizens said that the accuracy that the FDM model can achieve in actual use is not as high as theoretically, and even feels that the accuracy can only reach 0.1mm. For the sake of interest, the author wrote this article to let more friends know about FDM (Fused Lamination Molding) and the difficulty of improving the accuracy of FDM models.


Picture source network, this picture only describes the principle of FDM model

The hot discussion is like this, "As we all know, the accuracy of desktop-level FDM models may actually be around 0.2mm. In theory, all manufacturers are marked with 0.1mm, but some people say that their FDM machines can reach 0.02mm, which is indeed worth considering. ”, this question was launched in the “Toutiao·Today’s Topics” of the 3D printing website 3D Tiger. Let's take a look at the printing accuracy of the FDM model in detail!

Factors related to FDM periphery and accuracy

FDM is also known as FDM. The finished product is manufactured by moving the stepping machine back and forth, left and right, and the forming platform moving downward. The materials are collectively referred to as wires (the materials used in FDM models are generally made into a "wire" type), so in this process , Stepper, wire, nozzle play a very important role. The speed at which the stepper moves, the speed at which the nozzle sprays the melted wire, etc. can all have an impact on the accuracy. Even, there is a paradox in the 3D printing industry that "accuracy and speed cannot be combined".

There is a saying about the accuracy of 3D printing, similar to the printing quality in 2D printing, which mainly depends on the comprehensive performance of the printed objects in all aspects. The 3D printing accuracy is related to the layer thickness. Even if the layer is thick, the finished product may fail when printing the support, that is, the traces or the outside of the object are also filled completely, resulting in the overall aesthetics and practicability. So rather than accuracy, it is better to think of accuracy as layer thickness. Now there are various opinions about the degree of layer thickness that can be achieved, which are roughly 0.1mm, 0.2mm, and 0.025mm. How thick do you think the printing layer can be in actual use?

Practice Tests the Truth

In theory, the layer thickness is related to the radius of the nozzle and the speed of the stepper, but the most critical factor is the precision of the calculation. Compared with DIYing a 3D printer with parts purchased from open source, the 3D printer produced by regular 3D printing manufacturers has higher precision. However, some FDM model manufacturers have made some achievements in accuracy, and can even achieve 0.025mm. However, the manufacturer's publicity is one aspect, and whether it can achieve this accuracy is another matter. The editor believes that it is reasonable that the FDM model can achieve an accuracy of 0.2mm, and 0.1mm or even smaller layer thickness, we need an extrusion head with a smaller radius.

Because of whether this precision can be achieved, in theory, as long as the radius of the extruder is reached. But this is theoretical. In actual use, there are other additional conditions. For example, the wire is too thin and easy to break, and the printing time is too long to ensure the continuity of printing. These are all problems encountered. Regarding the high accuracy of 3D printers, we can only try it ourselves. After all, practice is the only criterion for testing truth. Regarding "trying", the author has some methods for reference.

Three methods for reference

Contrast is one of the tried-and-true methods. In general, 3D printer manufacturers will configure a desktop software specially used to adjust the size, orientation, layer thickness or speed of the model. Under the operating software, users can change the model format to Gcode. format so that it can be easily read by a 3D printer. That is, under the desktop software, users can print objects with a layer thickness of 0.1mm, a layer thickness of 0.2mm, and a layer thickness of 0.025mm, and the printed objects can be compared. If there is a difference, it is of high precision.


You can print some hollow objects, the source network


You can also print objects that need to be supported, image source network

3D printing difficult objects is also a way. It is recommended to hollow out objects or print objects with supports. We know that for inclined, hollow objects, the 3D printer must print a little support so that the entire object can be printed completely. If the accuracy is not high, hollow objects or supporting objects are likely to be out of shape, which is also a way to test the precision.

The paradox of FDM 3D printers

As mentioned earlier, FDM models have a paradox: speed and accuracy cannot be combined. On the one hand, when the accuracy is high, the material described by the nozzle is more detailed, and the speed of the stepper will slow down, so generally printing will require everyone's patience, and in this process, the user has to worry about the problem of wire breakage or the wire is blocked, which eventually leads to the failure of the entire printing. That is to say, high-precision 3D printing generally consumes a long time and is slow.

When the speed is fast, the stepper and the nozzle cannot describe the printed object very well, so that the phenomenon of the object is serious, and even there is a phenomenon of missing one piece or one more piece. Obviously, such 3D printing is not perfect. Accuracy is greatly reduced. Therefore, the industry has been discussing how to improve the printing accuracy without affecting the speed and how to improve the speed while ensuring the accuracy. Obviously, there are more studies on the second type.

words written on the back

The accuracy that FDM models can achieve also requires the support of many additional conditions. Debating the accuracy of FDM is only to better understand this technology. After all, the truth is discussed. In this article, the author expounds his own views on the accuracy that FDM 3D printers can achieve. Theoretically, things need the support of many conditions. If we need to understand the accuracy of this product, we need to listen more, see more, and try more. After all, if the FDM can reach 0.25mm, then the SLA model will not be so expensive.