I’ve already talked about the first layer, in the posts where you can see the most common problems you can run into when printing in 3D.
We talked about it in the adhesion guide and also in the most common problems that lead the printer not to extrude at the beginning of printing and certainly in other posts that now escape me.
We’ve always brought it up in combination with some problems, today instead we’ll consider only this, and how to analyze it.
The first layer is the foundation of the press, and as they always say… who starts well is in the middle of the work. Below will be listed a series of measures to improve the start of our print, and strive for perfection:
good first layer: Perfectly calibrated bed
The first and fundamental rule to get a great first layer is to work with a plate perfectly set. If you have any doubts about the procedure you can rely on our calibration guide. Having a deformation-free and calibrated print bed will allow us to have a first layer without discrepancies. Getting a first layer uniform in height and composition is a good starting point for any print.
good first layer: Extruder at the right distance
The second but perhaps most important point is the printing distance between the plate and the extruder.
This is a very important parameter. An excessive distance will be recognizable by the lines drawn by the nozzle. These lines will not match each other as they should, but will have spaces between them. In addition to the aesthetic factor we may also find a very low adhesion to the platter, which could compromise the success of the printing.
On the contrary, when the distance is too small, we find a pile of material spread on the plate. Although bringing the nozzle closer to the pan can in some cases reduce some adhesion problems, it can certainly create others. First of all we can have losses of material when this finds an outlet (See photo). Another rather common problem is the loss of steps in the extruder motor. In some cases the motor cannot push all the filament that should with the little space available between the plate and the extruder. This could eventually damage the whole system.
Here you can see different types of lines, from the extreme left: a line too flat, the center: the perfect line and on the right the line that forms when the nozzle is too high.
You will have to have training to recognize them, but it will be a skill that will not abandon us anymore.
good first layer: Slow Down
Slowing down the movements for the start of the print reduces the forces applied to the molten material, reducing the possibility of poor adhesion. It is recommended to reduce the speed of the first layer to 50%/60% of the rest of the print and to go below this threshold only in case of particular problems.
good first layer: No Cooling.
Although cooling is one of the essential elements in obtaining quality prints for PLA printing, it is strongly discouraged to ventilate the first layer. The longer the first layer stays warm, the more it binds to the plate and cools down little by little. In fact, all the slicers have as a default setting the ignition of the cooling at least from the second layer of material. However, it does not hurt to repeat it, no cooling, at least for the first layer.
Those described so far are the main principles, and applying them will certainly get excellent results, if not we want to give a few more tips, not to leave anything to chance.
Pro tip: Properly calibrated extrusion
It is very important to have the extrusion quantity well set as you may mistake an underextrusion/overextrusion for incorrect platter positioning. Obviously in these cases the corrective manoeuvres at the level of the bed would not bring any benefit. If even after bubbling and distance calibration you find yourself with a first layer that does not suit you, before checking and re-performing the entire calibration, you can lose a few minutes and test if the amount of extruded material is correct, through the dialogue program that you usually use.
pro tip: Increase the height of the first layer
A higher layer height will provide more flow. Therefore more heat, adhering better to the print bed. A thicker first layer also has the property of increasing the tolerance of the plate to leveling error. It is recommended to increase the height of the first layer in combination with the nozzle diameter, e.g. with a 0.4 mm nozzle it is recommended not to exceed 0.3 mm.
pro tip: Temperature increase
To increase the adhesion, application and appearance of the first layer you can also set a temperature slightly higher than that normally used. A 5/10 degree increase in nozzle and plate will make the plastic more viscous and help improve printing.
The temperature can be set by slicer or by hand, in the latter case remember to return to the usual temperature once the first layer is completed.
If you have followed this guide carefully you will see something like this: