Hi folks. Just got my first print running, was very simple after I’d worked out my rubber nozzle needed a good squeeze.
I’m trying to understand the processes that are taking place during the printing processes, I’m completely new to SLA. I’ll describe what I see as I don’t know the technical terms.
The platform is lowered.
My inner circle spins for about a minute.
Laser zips around (quite impressively) for a couple of seconds.
Pause.
Move tank, raise platform, wipe.
and repeat.
It’s step 2 I’m most interested in, what’s going on here, is this allowing time for the resin to settle under the platform, is the laser’s path being calculated, or some other alchemy?
It’s this step that’s taking up the vast majority of the printing time, although now I notice around layer 20 this step is vastly reduced in time, so is this the extra curing time for the initial ‘stick’ layers?
No problems, no complaints, just trying to understand it all.
I notice around layer 20 this step is vastly reduced in time, so is this the extra curing time for the initial ‘stick’ layers?
Exactly.
During the first few layers the platform is pressed against the tank and only after a while does the laser start lasing. This process is there to improve first layers adhesion reliability, at this step is critical to the success of the rest of the print.
I suspect the reason for the wait in particular for the first 1 to 3 layers or so, is to guarantee that the resin has filled the little gaps and surface defects on the build platform, to guarantee maximum surface area for these first layers.
After a few layers, as you have observed, the laser starts almost immediately after the platform has stopped moving and cycle time increases dramatically.
The first layers have a higher exposure to make sure the print sticks securely, so the laser is going to be moving more slowly.
The print will also stop at times to check the resin level and add more resin if necessary.