3DPrinting
3DPrinting is a place where makers of all skill levels and walks of life can learn about and discuss 3D printing and development of 3D printed parts and devices.
The r/functionalprint community is now located at: or !functionalprint@fedia.io
There are CAD communities available at: !cad@lemmy.world or !freecad@lemmy.ml
Rules
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No bigotry - including racism, sexism, ableism, homophobia, transphobia, or xenophobia. Code of Conduct.
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Be respectful, especially when disagreeing. Everyone should feel welcome here.
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No porn (NSFW prints are acceptable but must be marked NSFW)
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No Ads / Spamming / Guerrilla Marketing
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Do not create links to reddit
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If you see an issue please flag it
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No guns
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No injury gore posts
If you need an easy way to host pictures, https://catbox.moe/ may be an option. Be ethical about what you post and donate if you are able or use this a lot. It is just an individual hosting content, not a company. The image embedding syntax for Lemmy is 
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So let’s recap the way a FDM printer works.
In a sense it’s like a hot glue gun.
Step 1 is to heat the filament. That makes it molten and fluidic.
Step 2 is to exert pressure with new filament (like pushing unmelted hot glue to push out the melted glue) into the melt zone. This pressure squeezes the melted plastic out the nozzle.
Too much pressure and it’s too wide. Too little and it doesn’t make a line wide enough.
A lot of times tuning the first layer is about getting these figures just right and the distance of the nozzle where it’s expected.
So why the purge line?
Because it takes a little time to get consistent push for consistent lines with the newly melted plastic. Just like pressing the trigger of a brand new hot glue gun with a brand new glue stick doesn’t give you glue right away. It has to be “primed”.
So the purge line does it. It’s a line that you draw so that the filament has time to be consistent (since new filament, different temps, different pressures and even retractions will change how much is available to come out as soon as the printer “pushes” on the filament)