The Truth Is Worth Digging. How Accurate Is The Desktop FDM 3D Printer

Because of little contact, or the manufacturer's hype, or the gap between theoretical knowledge and actual use, people have doubts or formed a discussion about the accuracy of desktop FDM 3D printers. Many netizens said that the accuracy of the FDM model in actual use was not as high as that in theory, and even thought that the accuracy could only reach 0.1mm. For the reason of interest, the author has written this article to let more friends know about FDM (Molten Deposition Molding Technology) and the difficulties in improving the accuracy of FDM models.

Figure source network, this figure only describes the principle of FDM model

The hot discussion is as follows: "As we all know, the accuracy of desktop level FDM models may be about 0.2mm in practice, and theoretically all manufacturers are 0.1mm, but some people say that their FDM machines can reach 0.02mm, which is really worth considering." This issue is launched in the "Headline · Today's Topic" of 3D Tiger, a 3D printing website. Now let's take a look at the printing accuracy of the FDM model!

FDM perimeter and precision related factors

Melt deposition molding technology, also known as FDM, uses the way that the stepper moves back and forth, left and right, and the molding platform moves downward to manufacture finished products. The materials are generally called wire rods (the materials used in FDM models are generally made into "wire" type). Therefore, the stepper, wire rods, and nozzles play a very important role in this process. The accuracy may be affected by the moving speed of the stepper and the speed of the nozzle spraying the melted wire. Even, the 3D printing industry has a paradox that "precision and speed cannot be combined".

There is a statement about 3D printing accuracy, similar to the print 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 thickness is thick, the finished product may fail in the printing support, that is, the wiring or the outside of the object is filled completely, resulting in the overall aesthetics and practicality. Therefore, it is better to regard accuracy as layer thickness rather than accuracy. Now there are many opinions about the extent of layer thickness, which are generally 0.1mm, 0.2mm and 0.025mm. How thick do you think the print layer can be in actual use?

Practice tests truth

Theoretically, the layer thickness is related to the radius of the nozzle and the moving speed of the stepper, but the most critical factor is the precision of the calculation. Compared with DIY, a 3D printer for parts purchased from open source, the 3D printer produced by a regular 3D printing manufacturer has higher accuracy. However, some FDM manufacturers have made some achievements in accuracy, even reaching 0.025mm. However, on the one hand, whether the manufacturer can achieve this precision is another matter. Xiao Bian believes that it is reasonable for FDM models to achieve an accuracy of 0.2mm, while for 0.1mm or even smaller layer thicknesses, we need extruders with smaller radii.

Because whether this precision can be reached, theoretically, it is OK as long as the radius of the extruder reaches. However, this is theoretical. In the actual use process, there are other additional conditions, such as the wire is too thin and easy to disconnect, and the printing time is too long to ensure the continuity of printing, which are all problems encountered. As for the accuracy of the 3D printer, we can only try by ourselves. After all, practice is the only criterion to test the truth. As for "try", the author has some methods for reference.

Three methods for reference

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

It can print some hollow objects and source network

You can also print objects to be supported, map source network

3D printing is also a way to print objects with great difficulty. It is recommended to print hollow objects or objects with supports. We know that the 3D printer must print some supports for inclined and hollow objects to make the whole object print completely. If the accuracy is not high, the hollowed out objects or supporting objects are likely to be out of shape, which is also a way to test the fineness.

The paradox of FDM 3D printer

As mentioned earlier, the FDM model has 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 moving speed of the stepper will slow down, so the general printing will require everyone's patience. In this process, the user has to worry about the problem that the wire is broken or the wire plug, which eventually leads to the failure of the entire printing. In other words, 3D printing with high accuracy generally takes a long time and is slow.

When the speed is fast, the stepper and the nozzle can not describe the printed objects very well, which leads to serious threading of objects, even the phenomenon of missing one or more pieces. Obviously, such 3D printing is not perfect, and the molding 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 many researches on the second type.

Words written at the back

The accuracy that the FDM model can achieve also needs the support of many additional conditions. The debate about the accuracy of the 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 to be supported by many conditions. We need to know more about the accuracy of this product, so we need to listen, see and try more. After all, if the FDM can reach 0.25mm, the SLA model will not be so expensive.