Basics of 3D Printing:
9 steps to the perfect first layer
No 3D print is not fully predictable. However, there are ways to reduce the number of surprises. The first layer of a 3D print is particularly important - the entire part 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 only 9 steps you are able to ensure optimal conditions in advance for printing this first layer and thus your entire part.
Step 1: Check if the filament is conveyed correctly
Usually a small gear wheel is the worker in a 3D printer, transporting the filament towards the nozzle. Its teeth engage 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 inferior quality filament, the diameter of the material can vary by up to 1.5 mm. This causes the teeth of the gear wheel to damage the material - this may result 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 guiding is no longer effective. As a result, the production of the filament is severely impaired.
What can you do in advance?
Check the diameter of your filament. With good filament the deviations are less than 0.1 mm.
Still looking for the right filament? We recommend the following products. We have had excellent experience with both plastics.
Step 2: Is the extrudere free and unobsructed?
It goes without saying that for good 3D print and a perfect first layer the extruder must be free of blockages.
However, a foreign object can clog the nozzle unnoticed, for example cooled material from previous printing.
One way to check if the extruder is free of foreign matter - before your part gets damaged - is to use a Skirt. You can set up a Skirt with your slicer software. It causes the 3D printer to run a circle and only then begins with the actual printing of the part.
For the extruder this means:
If the Skirt is good, then the nozzle is not clogged. If the Skirt is bad, stop printing and try this: Unmounting and disassembling the extruder may make sense. This task will vary depending on the printer model. Look for a good tutorial video or instructions 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 filament flow evenly out of the extruder?
To ensure that your first layer is applied regularly, it is best to check whether material comes out of the extruder right from the start.
The reason for this is that there may be a shortage of material, especially at the beginning of printing. This is either caused when the extruder preheats before printing or the extruder has cooled down only slowly after previous printing. Both allow the filament to become liquid in the nozzle at an early stage, which leads to oozing. This causes the plastic to leak even before printing has started.
If printing then starts, no filament comes out of the nozzle. Only when new filament is conveyed through the extruder and liquefied through the heating element a layer can be applied. However, it may take a few moments before this is the case. This problem is called sub-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 up a Skirt in the slicer software. This method allows you to detect possible further problems before printing begins, which is why I would suggest this variant.
Alternatively, you can use the control panel of your 3D printer to control the nozzle feed. If your 3D printer has a freely movable feeder, you can also manually feed material without permanently damaging your device.
Under-extrusion can also generally be caused by the printing bed, so check if the rails or bearings on the Z-axis are not deformed, dirty or oiled to an excessive degree before starting your print. Alternatively, the printing bed may not be properly aligned, so:
Step 4: Correctly align the printing bed
A poorly aligned printing bed can lead to a multitude of annoying problems. If your printing plate is crooked, your nozzle will be too close on one side - the nozzle will be virtually clogged and deliver too little or no material at all, see 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 the key to a perfect first layer and thus for your entire part.
Does your 3D printer have an adjustable printing bed? Then it is certainly a thing worthwhile to check from time to time whether it is correctly aligned. A corresponding adjustment not only saves time and filament, but also a lot of nerves.
This is how it works: the 3D printer has its own levelling function. Click through the printer menu and follow the instructions on the display.
Step 5: More grip through a clean printing 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 printing bed has been cleaned but you have increased adhesion problems, you can consider coatings such as adhesive tapes (there are different Scotch Blue Tape for PLA and Kapton adhesive tape for ABS), temporary glue or spray for the top of the printing bed. Important: If you want to use a spray, spray your printer’s plate at a safe distance from your 3D printer to not contaminate or damage essential parts of your printer.
For example, we use the "filaprint" from Filafarm. It is suitable for PLA as well as for ABS and all kinds of other materials (you can read about it on the corresponding page that I linked for you). Filaprint can be heated, resulting in better adhesion. After cooling down, the prints peel off well. The manufacturer calls the coating "wafer-thin heat-resistant transfer adhesive layer" and we have had very good experiences with it.
Step 6: Distance from nozzle to printing bed is set correctly
For the filament to be evenly applied to your now prepared printing bed, the distance between nozzle and printing plate must be correct.
If it is too large, the filament will not adhere to the printing plate. If the distance is too small, the filament will not flow out in sufficient quantity - the nozzle behaves as if it was clogged. When the printer then is applying the first layer, no material will come out. Only when the nozzle is moved away from the printing bed - i.e. only a few layers later - enough filament is able to flow. A perfect first layer looks different and your printing bed suffers as the nozzle scratches over it.
A regular scaling of the distance between nozzle and printing bed provides remedy
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 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 adjust your printing bed with it.
Adjustment is particularly easy with glarger 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 metal feeler gauge is available in different thicknesses to match your 3D printer model and nozzle size. Like the paper, this is then pushed between the nozzle and the printing bed and allows a calibration of up to 0.05 mm. Since a layer in 3D printing is usually 0.2 mm thick, you can set the distance sufficiently precisely.
For our print 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 steps of 0.05 mm.
Step 7: Setting the speed for the first layer
The first layer should adhere reliably to the printing plate. To maintain this adhesion, it is common to print the first layer at a slower speed than the rest of the part.
If the first layer is applied at the same speed as the rest of the model, it is possible that it does not adhere properly to the printing plate and the part shifts.
The key is the slicer software
If you are only able to set one speed for all layers with your slicer software, the speed for the first layer should point the way. This increases the duration of your print and the time until your part is ready. At the same time, however, this is still better than getting a faulty part and having to start over.
If you use slicer software that allows you to control the speed of the first layer independently of the rest of the part, you can reduce it as a percentage of the standard speed. You can then adjust this value depending on the part and printer model.
Step 8: Adjust temperature and cooling
No matter what material you use for 3D printing, in one way or another your part will do one thing: shrink. Typically for plastics that cool down after heating, the degree of shrinkage or "shrinking" varies depending on the material and cooling speed. It is recommended for the manufacturer's specifications and the respective material properties to be taken into account.
In general, however, shrinking can be limited when cooling down more slowly. The use of a heatable printing plate, which slows down the cooling process, makes sense. This is particularly interesting for the first layer, which is the first to cool off and shrink.
Not enough with shrinking
Although shrinking can be reduced, it cannot be prevented completely. This means that the part can detach from the printing plate when it cools down. This is called "warping". If you have a heatable printing bed mentioned above, you can set it so that your filament "likes" to stick and thus warping occurs less frequently.
Concrete values are 60-70 °C for PLA and 100-120°C for ABS. Additionally you can switch off the cooling fan of your 3D printer either only for the first layer or for the complete print, so that the corresponding temperature can be maintained.
Step 9: Printing of small objects
Adhering of small objects is particularly difficult for the first layer. Basic physics tells us: less surface is less adhesion. If the first layer will not work out at all, there is one last means of emergency (or two): brim and raft.
Brim means making a kind of hat brim for the 3D model, i.e. a bead around the part to give it more surface and thus more adhesion.
A raft is literally a raft or plate. Practically it is a kind of platform that is printed underneath the actual part to improve adhesion. It doesn't look so good, but the print will work.
Even more optimization - Curious?
If you have followed all 9 steps, you have at least created optimal conditions for a perfect first layer with your 3D printer. What could be the reason for a 3D print of inferior quality: an 3D insufficient 3D model as a print template.