All of us, finding ourselves analyzing the characteristics of a printer, perhaps the object of our desire, we asked ourselves the question: What is meant by resolution of a 3D printer? How important is it to have satisfactory prints? We can start by answering the first question: What is the resolution of a 3D printer?
Z-axis minimum layer height: Resolution
When we talk about resolution in 3D printing we are talking about the minimum movement that the printer can make in a given axis, this value in the vast majority of cases corresponds to the minimum height of the material that can be deposited on the plate, expressed in microns. FDM/FFF 3D desktop printers typically have resolutions ranging from 250 to 10 microns (0.25mm and 0.01mm). Obviously, the thinner the layer of material deposited, the less you will notice the layers after printing, as you can see in the picture.
X and Y axis resolution
Although not much mentioned in the data sheets, there is also the resolution of the X and Y axes. It is normally snubbed because the movements of these axes are more influenced by accuracy than by resolution. The resolution would be the smallest detail. Accuracy is the precision of the return to a given point. With a practical example we can say that: the nozzle is at a certain point and moves to another. Accuracy is the physical precision with which it returns to the exact starting point. Not only illustrated by the display, but physically. The sarsa accuracy translates into errors and signs in the printing more or less obvious.
In addition, you can intervene with upgrades, software and hardware to make the steps of the engines more and more micro. All this precision has, however, an insurmountable physical limit: the measurement of the nozzle.
The size of the nozzle must be considered, as it is an essential part of the creation of the printed details. Can we create a line or part smaller than the nozzle size? NO. So we’re not talking about the X and Y resolution simply because it’s too much affected by the size of the nozzle, which is 400 microns in the case of the very diffuse 0.4 mm nozzle.
Some might argue that the nozzle is interchangeable with smaller nozzle sizes, which gives more detail, 0.3 mm and 0.2 mm. All this is certainly true but the increase in detail brings, with proportional probability, the possibility of a clogging of the nozzle in motion, which in effect can have more disadvantages than advantages.
Time in printing
We also need to make a point that does not directly relate to the resolution. As the resolution in Z increases, we can reduce the thickness of the layer with good precision. However, we must consider an increase in time to complete the printing because the same measure in height of the object will correspond to a double or triple number of layers.
First we said that the nozzle affects the final yield of the parts that can be represented. If we want to reduce the output hole we must expect a proportional increase in time for the realization of the object.
Wanting to take full advantage, as far as possible the maximum resolution is likely to take days to print a small object.
In the light of what we have seen so far, how important is the resolution?
We can say with confidence that it is not important to chase the best resolution, a printer well firm, calibrated and maintained can make excellent prints already with resolutions not pushed.
However, if you intend to print very small objects, of the order of a few centimeters, and with many details, which require a very high resolution, then we do not recommend the purchase of an FDM printer. Today there are on the market SLA (DLP for accuracy) resin printers at very favorable prices, see the new Wanhao D7, sold for about 700.00 €. that will certainly manage to make details unthinkable, until now, to common FDM printers on that price range.
Obviously the other side of the coin is there and is, to date, the cost of resin, for a good product we are around 100/150 euros per liter.
First we talked about objects of the order of magnitude of a few inches, and now we discover the reason. Larger prints, with resins at this price are very expensive, especially if made by fans without any economic return.