As we have already said, and we will continue to repeat it in the future, for the adhesion to the printing bed there are a few really salient and decisive phases, and the analysis of the first layer is even the most important.
A nice first layer without smudges and very smooth guarantees us 90% of an excellent final result, except for different problems that may occur during printing.
The biggest difficulty we can encounter in managing the first layer is the adhesion of the extruded filament to the printing bed.
First of all, we have to start by saying that when the material of which the printing plate is made varies, the remedies do not vary, we can have plates of aluminum, steel, glass, blue tape (scotch) but the principles remain the same.
Adhesion to the printing bed: Check your settings!
The most common cause of non-adhesion at the beginning of printing is incorrect leveling of the extruder against the plate;
- If there is too much space between the extruder and the plate, the filament will not stick to the plate but will continue to crawl on it. The filament needs to be slightly squashed between extruder and plate. In theory the height of the layer set in the slicer should be the exact distance between the nozzle and the bed. The adjustment of this distance is done manually by raising the plate, using the 4 setting screws (if any). Or by using the software and changing the offset distance. It must be kept in mind that, given our plane with 0 negative offset values, the extruder approaches the plate and positive values distance it from the plate.
If we see that despite having tried all the options in this list our filament still does not attack, then we can decrease this distance even further. In this way we will make the extruder spread the filament. This can be done by manually approaching the plate or adjusting the slicer offset z. This process ensures a very strong seal but has serious drawbacks. The worst is the alteration of the final size in Z, so it should only be used in desperate cases!
- Basically a different problem, but almost the same problem presented before is caused by the incorrect flattening of the printing plate. Printing on an inclined plane makes sure that at the point of maximum height the filament is squeezed on the plane and in the other points does not touch sufficiently, having the same effect described in the previous point. This problem is easily solved by the levelling of the plane by the automatic probe or can be done manually. You can consult this article that explains step by step the calibration of the plate.
So far we have talked about problems that do not allow the press to join, now we will move on to explain how to improve membership.
Adhesion to the printing bed: Temperature
The temperature itself improves the adhesion and is indispensable for the adhesion of the ABS filament and other plastic filaments. This is because plastic polymers tend to shrink in volume during cooling. The recommended temperature to prevent ABS prints from detaching from the plate in whole or in part is about 100°.
Even the loaded PLA or PLA filaments benefit in adhesion from the temperature increase, even if in this case 50°/60° may be sufficient.
Obviously, the ventilation of the extruded filament is strongly discouraged, both for ABS, where it is always not recommended, and for PLA, where we can set the ventilation from the second layer upwards.
Adhesion to the printing bed: Blue tape/paper tape
To increase adhesion, you can use paper tape (for Pla filament) or the so-called Blue Tape, created and developed for this purpose (for PLA and ABS), especially if there are inductive sensors that detect the distance from the metal plate.
Adhesion to the printing bed: Hairspry/Glue
If we do not have problems with inductive probes instead we can use a glass or a mirror on top of the bed, resist well to temperature changes without the deformations that may affect the metals (the normal aluminum plate tends before or after boarding) and are easily removable for cleaning. In this case we can use a simple extra strong hairspray, a thin layer significantly improves the adhesion, so much so that we can print the ABS holding the plate at about 70°/75° and the PLA with the plate cold.
The hairspray is also ideal when it comes to cleaning, a light rinse under running water and it dissolves and is removed without particular effort.
Also in the case of glass/mirror, if we noticed that the lacquer was not enough we could also use the glue stick, spreading a layer over the glass, improves adhesion but intensifies the cleaning sessions.
-We are talking about the use of glass/mirror or in any case an over-plate when we talk about spraying or spreading products. Cleaning the original plate, being difficult to remove, would become difficult.
Adhesion to the printing bed: Speed reduction
In desperate cases, adhesion can also be helped by a significant reduction in the printing speed of the first layer.
Adhesion to the printing bed: Brim and Raft
We can also use Brims and Rafts as long as they are at least a few millimetres. Here is the complete guide to these adhesion supports.