Adherence to the bed: the warping
One of the most important factors to consider when it comes to doing a 3D print is the adhesion between the first layer and the printing plate. Without this connection, the entire print cannot be built correctly. In this article, we’ll talk about some of the most common causes and problems of first layer print adhesion and how to fix them.
Common mistakes: The bed is not leveled properly
Most 3D printers have a bed that can be adjusted by means of screws positioned in the four corners. If the bed is not level, one of the sides of the bed may be too close to the printing hotend, while the other is too far away. If you have a problem with the first layer not sticking to the bed, it is important that you check the level and flatness of the plate.
Common mistakes: the nozzle too high
Before starting a print, make sure that the nozzle is positioned at the correct height with respect to your printing plate. This will help ensure that the bed is neither too close nor too far from the nozzle so as to allow for optimal adhesion.
We can adjust this parameter, called z-offset, either by modifying the parameter stored in the control board of our hardware or in a software way. for the first we will be able to access the menu on our printer or by connecting via the command terminal of our print host; while for the second it will be enough to add the appropriate g-code among the print start settings of our slicer.
For example, if the G-Code offset of the Z axis is set to 0.05mm, the nozzle will start printing at a distance of 0.05mm higher than our z-stop.
Common mistakes: the first layer printed too fast
Ideally, the plastic that will be used for the first layer should be able to bond to the build platform before printing the next. This is because if the first layer prints too quickly, it may not have time to adhere properly.
In addition, setting the speed of the first layer in the process settings will help ensure that the part is built correctly. For example, if the speed of the first layer is set to 50%, the part will take approximately 50% longer to print than the rest of the part.
Common mistakes: Temperature or cooling settings
Since plastic tends to separate when it cools, it’s important to keep an eye on the 3D printer’s temperatures and cooling settings when it’s time to start printing.
Plastic tends to shrink as it cools, which is why it is important to keep the print bed temperature at an appropriate level. For example, if the part is molded with ABS plastic, the plastic is likely to cool immediately after leaving the hot nozzle.
Many 3D printers that are designed to print high-quality materials such as ABS also have heated beds. This feature will keep the first layer warm to prevent it from cooling down.
In general, the base temperature of the bed should be around 60-70C for PLA while at around 100-120C it will work better for ABS. To change the temperature of the dish, go to the settings menu of your slicer and click on the Temperature tab to set it.
Some 3D printers also have cooling fans that can speed up the vitrification process of the printed material. However, this can lead to a sudden change in temperature and an excessive reduction in volumes: for example, if the part is printed with an ABS plastic material, cooling to an ambient temperature of 30C will also reduce it to almost 1.5 mm.
If your 3D printer has a cooling fan, then you may want to disable it to prevent the first few layers from cooling too quickly. For example, if you want to start the first layer with the cooling fan off, then turn it back on when the fifth layer is finished. All these options can be changed by your slicer easily.
Grip on the printing surface
Before starting to print, make sure the bed is free of dust, grease and oils. Doing this will also help prevent the print bed from being damaged. Many 3D printers also feature a flexible and in some cases magnetic cover (to stick to the plate) which are designed to work seamlessly with different plastics. For example, some 3D printing companies use a buildTak sheet on the top surface of their beds.
A more homemade method is to use various types of adhesive tape to help adhesion. These strips of tape can be easily removed and replaced if you want to use a different material. Many people have also reported having great success using hair spray or other sticky materials on their build platforms.
When all else fails: skirt, brim and raft
Sometimes it happens that a small part does not have enough surface to adhere to the print bed completely. To increase the surface area, try using a border. This feature adds rings around the outer surface of the wall. To enable the use of skirt, brim and raft, go to the appropriate menu each slicer is equipped with.