3D Printing Basics: In 9 steps to the perfect first layer
No 3D printing is 100 percent predictable. Nevertheless, there are ways to reduce the number of surprises. The first layer of a 3D print is particularly important here - the entire component is based on it. If the first layer does not adhere well to the printing bed or is applied incompletely, there is a high risk that the rest of the model will shift and be finished with errors.
In just 9 steps you can create the optimal conditions for printing this first layer and thus your entire component.
Step 1: Check whether the 3d printing filament is being fed correctly
Usually a small cogwheel is the worker in the 3D printer, which transports the filament towards the nozzle. Its teeth grip into the plastic and transport it through the extruder. This process should run as smoothly as possible to ensure a constant supply of filament for printing.
What can go wrong?
If you buy cheap and/or low quality filament, the diameter of the material can vary by up to 1.5 mm. This causes the teeth of the gear wheel to attack the material - possibly resulting in plastic chips that can block the conveying process.
Another scenario is that the teeth on the wheel tear the filament to such an extent that the guide no longer grips. As a result, the promotion of filament is severely hampered.
What can you do in advance?
Step 2: Is the extruder free and unclogged?
It goes without saying that for a good 3D print and a perfect first layer, the extruder must be free of blockages.
However, a foreign body can clog the nozzle unnoticed, for example cooled material from the previous pressure.
One way to check if the extruder is free of foreign matter - and before your part gets defects - is to use a skirt. You can adjust a skirt using your slicer software. It causes the 3D printer to describe a circle and only then to start the actual printing of the component.
For the extruder this means:
If the skirt is good, then the nozzle is not clogged. If the skirt is bad, cancel the pressure and try the following: Removal and subsequent disassembly of the extruder may be useful. Depending on the printer model this task will be different. Find a good tutorial video or a manual from the manufacturer.
Another alternative is so-called cleaning filament. This filament cleans your extruder, loosens blockages and carries dirt out. This saves you the time-consuming dismantling of the extruder. A good cleaning filament is the eSUN Cleaning Filament.
Step 3: Does the 3d printing filament flow evenly from the extruder?
To ensure that your first layer is applied regularly, it is best to check whether material is coming out of the extruder from the very beginning.
The reason for this is that there can be an undersupply of material, especially at the beginning of printing. The trigger is when either the extruder is preheated before the pressure, or the extruder has cooled down only slowly after the previous pressure. Both allow the filament in the nozzle to become liquid at an early stage, which leads to so-called oozing. In this case, the plastic runs out before the printing has even started.
If the pressure then starts, no filament comes out of the nozzle. Only when new filament is fed through the extruder and liquefied through the heating element, a layer can be applied. However, it may take a few moments before this happens. This problem is called under-extrusion and causes your precious first layer to have gaps.
Prevention made easy:
It is important that the nozzle is filled with material as soon as it starts with the first layer of your 3D model. One way to do this is to set a skirt in the slicer software. This method allows you to identify possible further problems before printing starts, which is why I would like to suggest this option.
Alternatively you can use the control panel of your 3D printer to control the feed to the nozzle. If your 3D printer has a free moving feeder, you can also feed material manually without damaging your device permanently.
Under-extrusion can generally also be caused by the pressure bed, so check that the rails or bearings on the Z-axis are not deformed, contaminated or excessively oiled before starting your pressure. Alternatively, the pressure bed may not be properly aligned, therefore:
Step 4: Align the pressure bed correctly
A poorly aligned pressure bed can lead to a variety of annoying problems. If your printing plate is crooked, your nozzle will be too close on one side - the nozzle will virtually clog and deliver too little or no material, see also step 6 - and on the other side the nozzle will be too far away. Among other things, the adhesion of the filament often suffers. Adhesion is essential for a perfect first layer and therefore for your entire component.
Does your 3D printer have an adjustable print bed? Then it is certainly a worthwhile thing to check every now and then that it is correctly aligned. An appropriate adjustment not only saves time and filament, but also a lot of nerves.
Here's how it works: the 3D printer has its own leveling function. Click through the printer menu and follow the instructions on the display.
Step 5: More grip of the first layer due to clean pressure bed
In this step, remove dust particles and other substances that could prevent your first layer from adhering properly to the plate. It is best to use clean water or a dry cloth for cleaning. For heavier soiling or cleaning of a coated plate, you should Isopropanol use.
If the print bed is clean, but you have more problems with adhesion, you can consider coatings, such as adhesive tapes (there are several, Scotch blue tape for PLA and Kapton adhesive tape fs for ABS), temporary glue or spray for the upper side of the printing bed. Important: If you want to use a spray, spray your printer plate at a safe distance from your 3D printer to avoid soiling or damaging the essential parts of your printer.
For example, we use the continuous pressure bed "Filaprint„ from Filafarm. It is suitable for PLA as well as ABS and all kinds of other materials (you can read about it on the corresponding page I linked to you). Filaprint is heatable, which gives a better adhesion. After cooling down, the prints will come off well. The manufacturer calls the coating "wafer-thin heat-resistant transfer adhesive layer" and we have made very good experiences with it.
Step 6: Distance nozzle to pressure bed is correctly adjusted
To ensure that the filament is evenly applied to your prepared printing bed, the distance between the nozzle and the printing plate must be correct.
If it is too large, the filament will not stick to the printing plate. If the distance is too small, the filament does not flow out in sufficient quantity - the nozzle behaves as if it is blocked. While the printer is trying to apply the first layer, no material comes out. Only when the nozzle moves away from the printing board - i.e. only a few layers later - can sufficient filament flow. A perfect first layer looks different and on top of that your printing bed suffers because the Nozzle scratches over it.
This can be remedied by regularly scaling the distance between nozzle and pressure bed
This procedure is not necessary for every new print, but especially before larger projects you should take the time to make sure that no problems occur here. The distance can be set correctly either by an automatic program of your 3D printer (only for certain models).
If you have a 3D printer without this function, you may know the practice of pushing a piece of paper between the nozzle and the printing bed and adjusting the distance so that the paper can just be pulled out. Practical, because who does not have a piece of paper at hand quickly? But paper is not the same and the thickness varies. We made good experiences with thin thermal paper. Just take an old receipt and use it to adjust your printing bed.
Adjustment is particularly easy with larger leveling screws. These facilitate the exact setting of the correct distance.
The better the tool, the more accurate the result
To have a reliable measuring instrument, a feeler gauge is worth considering. A feeler gauge is made of metal and is available in different thicknesses to match your 3D printer model and the size of the Nozzle. This is then pushed through between the nozzle and the printing bed like the paper and allows a calibration down to 0.05 mm. Since a layer in 3D printing is usually 0.2 mm thick, you can adjust the distance with sufficient accuracy.
For our printing bed, for example, the manufacturer recommends starting with a printing height of 0.3-0.5 mm and then moving to the optimum height in 0.05 mm steps.
Step 7: Set speed for first layer
The first layer should adhere reliably to the printing plate. To maintain this adhesion properly, it is common practice to print the first layer at a lower speed than the rest of the component.
Because if the first layer is applied at the same speed as the rest of the model, it can happen that it does not adhere properly to the printing plate and the component may be displaced.
The key is the slicer software
If you can only set one speed for all layers with your slicer software, the speed for the first layer should be directional. This increases the duration of your pressure and the time until your component is ready. At the same time, however, this is still better than receiving a faulty part and having to start all over again.
If you are using slicer software that allows you to control the speed of the first layer independently of the rest of the part, you can throttle the speed of the first layer as a percentage of the standard speed. Depending on the component and printer model, you can then adjust this value.
Step 8: Adjust temperature and cooling
No matter what material you use for 3D printing, one way or another your part will do one thing: shrink. Typically for plastic that cools after heating, the degree of shrinkage, or "shrinking", varies depending on the material and the cooling rate. It is recommended that the manufacturer's specifications and the respective material properties be taken into account.
In general, however, shrinking can be kept within limits if the cooling is more leisurely. For this purpose it is advisable to use a heatable printing plate which slows down the cooling process. This is particularly interesting for the first layer, which is also the first to cool and shrink.
Shrinking is not enough
Although shrinking can be reduced, it will not be entirely avoidable. This causes the component to detach from the printing plate when cooling down. This is called "warping." If you have a heatable printing bed as mentioned before, you can adjust it so that your filament sticks especially "gladly" and thus warping occurs less often.
Concrete values are 60-70°C for PLA and 100-120°C for ABS. To help you, you can turn off the cooling fan of your 3D printer either for the first shift only or for the whole print, so that the appropriate temperature can be maintained.
Step 9: How to 3d print small objects
Small objects have a particularly hard time with the adhesion of the first layer. Basic physics tells us: less surface area equals less adhesion. If the first shift doesn't work at all, there is one last emergency remedy (or two): Brim and Raft.
Brim means to make a kind of hat brim for the 3D model, i.e. a bead around the component to give it more surface and thus more adhesion.
A raft is directly translated a raft, a plate. In practical terms, it is a kind of platform that is printed underneath the actual component to improve adhesion. Doesn't look good, but the pressure works.
Even more optimization - Curious?
If you have followed all 9 steps, you have created optimal conditions for a perfect first layer, at least for your 3D printer. Whatever the reason for a poor quality 3D print: an insufficient 3D model as a template.