Most slicers default to 0.2mm first layer thickness. This can work fine if your printer is well-calibrated, your bed is clean and level, and you’re right there ready to stop the print if anything were to go wrong. But when you’re printing on an automated system, reliability is of utmost importance, and thicker first layers result in more reliable prints.
Our recommendation is that your first layer should be at least 0.3-0.4mm thick. Why? Here are 10 reasons!
More wiggle room: A thicker first layer gives you more tolerance on your first layer. That means there are a wider range of Z-offset values that will result in a good first layer!
Compensate for a warped bed: If you have many parts on the bed, or you have one large part to print, a warped bed can make it really hard to print evenly across the whole part. With a thick first layer, it’ll help smooth over the high and low parts of the bed.
Level less: You don't want to be constantly calibrating your printer. So by having a really thick first layer, you end up levelling the bed a lot less. If you're on a manual printer (not a Quinly or a belt printer) scraping parts off, or taking the bed off, flexing it and putting it back is going to change the bed level, but with a thicker first layer, this change in levelness might be negligible.
Compensate for inaccurate ABL probes: If your auto-bed levelling probe is not that accurate, that's OK! A thicker first layer is less susceptible to issues related to probe repeatability.
Protect your bed: A thicker first layer protects your print bed from accidentally getting scratched by the nozzle. If your first layer height is 0.1mm and your probe is wrong by 0.1mm, well now your nozzle is touching your bed, and that’s not good!
Improve bed adhesion: With more material, there is more heat, so the plastic will stay liquid for longer. This means it won't immediately peel up! You will also want to increase your nozzle temperature to further improve first layer adhesion.
Make your thin parts stronger: If you have thin parts, then a thick first layer will greatly increase strength. 1 thick solid layer is going to be stronger than 2 thin layers.
Compensate for slow first layers: If you pump more material per second, then you don't have to feel so bad printing a slow first layer, since you're pretty much getting 2 layers for the price of 1!
It looks really cool? Check out the thickest first layer I've ever done:
The sky's the limit: If you're using a 0.8mm nozzle (who doesn't love big nozzles?) you can go as high as 0.6mm without any problems!
Before you crank up your first layer thickness to the maximum, take a moment to consider the possible downsides.
Aesthetics: Your first layer will stand out compared to the rest of your layers, so if consistent layer height is important to you, then you might want to keep your first layer the same thickness a bit more modest.
Physics: Going too thick can be a problem. If your first layer height is too thick, then your filament might have trouble sticking to the bed properly. A good rule of thumb is to start with a first layer height that is 75% of your nozzle diameter.
Elephant’s foot: With a thicker first layer, it can be easier to accidentally squish the first layer too much. This is why I usually add some “initial layer horizontal expansion” to compensate for the squish that might occur. A good starting value is -0.2mm. This setting applies an inset to the entire first layer so that extra space is created on the edges.
Height Is Just Half The Story
A filament line cross section is two-dimensional, so it has not only height but also width. Check out the next article explaining how a WIDER first layer results in more reliable prints!
Continue The Conversation
Why do you use a thick first layer? Reliability? Aesthetics? So you can take a picture and brag about it? Let us know in our Discord server: https://discord.gg/JN9EDP8