3D Printer Bed Adhesion How to Get the Perfect First Layer
The first layer you print dictates how well the entire project turns out. It is the foundation of every design you make as it supports the entirety of the model. If the first layer doesn’t adhere properly, your print can dislodge itself or it can end up warped and distorted. In either case, without a strong foundation, the print will be unsuccessful. On the other hand, over-adhesion is just as bad because it can make it difficult for us to remove the model from the print surface. Therefore we need to find the right balance to get the perfect first layer.
Many things can affect the model’s first layer and its adhesion to the print bed. You need to learn how to optimize your print settings, choose the right materials, keep the print surface clean and leveled, and go through a few more checks otherwise you might end up with an unsuccessful print. So let’s go through each step and learn how to get the first layer just right.
Adjust the print settings
The first step is to make sure you’re printing your model using the correct first layer settings. You can fine-tune them in the slicer software by focusing specifically on the first layer. Most printers let you make these adjustments separately from the rest of the model. So let’s take a look at the most important settings:
- First layer temperature and bed temperature: The slicer allows us to adjust the temperature of the first layer separately. It also lets us select the bed temperature specifically for printing the first layer. For the foundation of the model we generally need a higher temperature to make sure the material adheres to the print surface. So, while within the filament’s safe temperature margins, increase the temperature in 5℃ increments.
- First layer print rate: We can adjust the speed during the printing of the first layer separately, just like the temperature. This setting will determine how fast the material is extruded. The slower we print, the more time the filament has to melt, and the faster we print, the more we need to raise the temperature to compensate. Take note you’ll have to adjust this setting based on the temperature settings, as well as the height and width settings.
- First layer height: You can adjust the height of the first layer. Using higher values may compensate for small mistakes in leveling. If you’re using the typical 0.4 mm nozzle, you can raise the first layer height to 0.3mm.
- The line width: This setting controls the width of the extruded material. To get a solid first layer you should increase this value up to double the size of the nozzle.
- Brims, rafts, and skirts: To ensure proper adhesion, we can increase the surface area by using adhesion helpers, such as rafts and brims.
Once you’re satisfied with your settings, you need to make sure you’re working with a clean print bed.
Print surface maintenance
Working with a dirty print surface is a recipe for disaster. It often gets dirty or contaminated with your skin oils, so make sure you clean it regularly. All you really need to do is wipe it after printing a model. If that’s a bit inconvenient, you might get away with cleaning it every few prints, just don’t ignore it for too long.
The easiest way to clean the print bed is by using a paper towel and a bit of isopropyl alcohol. Alternatively, rubbing alcohol will work as well. If you’re the forgetful type like some of us, you should keep a roll of paper towels and a spray bottle filled with isopropyl alcohol within reach.
Remember that each material has a different melting point and different properties. All the temperature, height, and width adjustments you make depend on the type of filament you use. Furthermore, the material from which your print surface is made will have an impact on adherence as well.
Once you do everything you can through the printer’s settings, you can apply an adhesive agent to improve the adhesion of the filament as well as the print bed. The most commonly used adhesives are the simple white glue stick that can be removed with hot water, painter’s tape, and hairspray. These products may not be impressive on their own, but they help the filament stick to the surface. In addition, they also help when it’s time to remove the model from the plate and prevent it from getting stuck to it.
As a final note on materials, you should never print PETG and TPE straight on the print surface. They adhere too well to the print bed and when removing them you’ll probably damage them. So make sure you use a release-helping agent to prevent that from happening.
Tramming the machine
The preparations and adjustments you make before printing will make all the difference. Tramming is one of these preparations. Before getting started, you should check that all the vertical components of the printer are at 90 degrees to the horizontal ones. Therefore the X gantry should be parallel to the print platform and at 90 degrees to the Z-axis.
A lot of printing enthusiasts think all they need to do is incline the X gantry and then level the print platform based on that, but if that’s all you do, you’ll probably end up with asymmetrical models and angled vertices. So inspect your machine thoroughly, it’s worth the time.
Level the print bed
Always make sure the print surface is properly leveled. For optimal adjusting, you should level it while it’s heated up together with the nozzle at the temperature you’re planning to use. Adjust the heights in small increments and watch out for any of the corners being thrown off. Once you think the bed is leveled, you can perform a live test.
Live leveling is popular because it’s accurate. All you need to do is set up a skirt with two to four layers and print it before printing the actual model. Keep in mind that the skirt should be printed away from where the model is going to be. During this process, you can fine-tune the leveling by adjusting the knobs carefully. This is a fool-proof solution, so give it a shot.
Is the print surface flat?
The first layer is affected by the tiniest variations if the print surface is warped even in the slightest. You might even think it’s correctly leveled, and it probably is in most spots, but other areas on the bed will be closer or further away from the nozzle. So make sure you check the flatness of the print bed.
To do that, all you really need is a metal ruler. Place it across the print surface and use a flashlight under it from one side. While doing that, try looking through the opposite side of the ruler. You shouldn’t see any light escaping from under it. If you do, then the surface is warped. Try this procedure from every direction by going in a circle.
If the bed turns out to be warped, you can correct it by placing thin pieces of aluminum under the bed until it evens out. Alternatively, you can purchase a perfectly flat bed material, such as borosilicate glass.
Adjust the gap
After making all the adjustments we discussed above, you can start focusing on the gap. Take note that if the space between the nozzle and the print bed is too large, the filament travels over a larger distance and has more time to cool off and harden. This will prevent it from adhering to the plate and it might even continue to follow the nozzle until more filament piles up on top. This is obviously a very bad thing. You need a low gap and to squeeze the first layer against the print surface to make sure it adheres properly.
On the other hand, if the gap is too low you’ll squish the material too much and ruin the layer. In that case, you need to do the opposite and enlarge the gap in small increments until the filament isn’t too close anymore. To find the ideal gap, keep making adjustments until the filament is extruded on the print surface wider than if extruded in the air. If the width is maintained consistently, then you found the perfect setting and the solid sections of the model will fill completely and the material will adhere.
Keep in mind that you’ll have to experiment a bit to find the ideal gap because it depends on the material you’re using. For instance, PLA and PETG have different characteristics, so while PLA might be squished, the same setting might work on the PETG filament. It all depends on the filament, the surface material, the size of the nozzle, extrusion rate, and much more. Therefore you’ll have to get used to making tweaks over time.
That being said, the one guiding principle that you can follow is that the first layer needs to be roughly half the size of the nozzle. So to get started, if you’re using a 0.4mm nozzle, the gap should be around 0.2mm. From there you can fine-tune the setting.
Use the right print bed
When it comes to print surfaces we have a lot of choices. As mentioned earlier, we can use hairspray, painter’s tape, and various types of glues to improve the filament’s adherence. And while using these tricks is a good idea, by doing so you’ll have to spend additional time cleaning the print bed. Not to mention you’ll have to spend money regularly to buy these consumables. But some alternatives might make your 3D printing days a bit easier.
One of the most commonly used print surfaces is made out of polycarbonate. This material offers good adherence for most filaments, as long as they aren’t extruded at very high temperatures. PETG will stick if you aren’t very careful. Alternatively, you can print on glass, but you’ll have to perfectly set the gap and the level.
Finally, if you print very hot materials, you can use Kapton tape or PEI (polyetherimide). These surfaces are a lot more resilient to high temperatures than polycarbonate so the PETG and ABS filaments will stick better. As a bonus, PEI can be cleaned quickly with alcohol or acetone and you can even make good as new by rubbing it with steel wool.
That being said, you should try out different surfaces and see what works best for you and your projects.
You’re now ready to start printing new models with solid foundations. Keep all of these tips and tricks in mind and make sure to take enough time to prepare your hardware and adjust the settings. If something goes wrong with the first layer, start troubleshooting step by step. This is a natural part of the 3D printing process and everything can be fixed!