Hello. I have been putting the new SM2.0 to the test lately, and I have been printing in the black PLA they sent, and have also tried some black PETG (Polymaker Polymax).
I’m having strange results, however. It seems that the surface of the print that is in contact with the bed has a white-grey color that is extremely unpleasant; an unsightly blemish on an otherwise good print. What is happening here? I’ve made sure my bed is completely clean. I’ve printed with the bed at temps from 50 - 90 degrees… it doesn’t seem to matter. If the bottom of the print is the side that is in contact with the bed, then no big deal, but often times this is not the case, and it puts me in a terrible pickle, as many of my models will be unusable. This never happened to me on the SM1…
Any ideas on what is going on here? What I can do to alleviate it? You can see in the following images what I mean. The top side is beautiful, the bottom side is very much UN-beautiful:
Reason 1: the surface of the print sheet is broken, which will make the first layer fails to be formed in time.
Reason 2: There are many streak-like defects, which may be because the surface of the print sheet on the bottom has a lot of depressed horizontal lines, and the first layer is affected.
Solution:
you can use the opposite side of the print sheet.
you can use the 3D printing tape to make the print sheet flatter.
It looks somewhat like your lines are not making contact with each other in certain spots. If you aren’t using any adhesive on your build plate, there wouldn’t be much reason for the part to have that sort of color on the bottom. Have you tried passing a heat gun over the bottom of the part in attempt to remove the color?
@Edwin The surface of the print sheet looks good ( I have a couple bad spots where the nozzle plunged into it, but I avoided that area). Pristine, in fact, in the area I’m using. I see any streak like effects, I’m not sure what you are referring to… perhaps the striations? They don’t really look like streaks, because they are totally dry… they almost look like someone blew talcum powder on the print, and it stuck. I feel like the stress of it being removed from the plate after print is causing the material to strain and discolor or something…
@ADCertifiedUser No adhesive. Just a clean plate (cleaned with windex). A heat gun huh…? that is a great idea, I’m going to try that. If the discolorations are stress induced, that might help… I’ll post back when I try that.
The heat gun definitely addressed the issue. So I do think the discoloration is the strain on the plastic as it is removed from the bed. It probably isn’t noticed on lighter plastics, or maybe it is peculiar to the black pigment… but either way, the heatgun helpd. The only issue there is that I had to heat it a little more than I’m comfortable doing… I feld like if I stayed 1 second more, the part would have warped or drooped… in fact, there is a slight warp to it now… I wish I would have paid closer attention to see if it was warped prior to using the heat gun… Perhaps a carefully applied blow torch might help keep from heating the whole part (higher temp, lower duration).
You can see in this picture, I applied the heat gun to just over half the print. Quite a difference.
In any event, now that we’ve proven what is causing it, I feel like I’m in a much better position to do something about it. Thanks again.
Glad to hear that the heat gun suggestion helped! I do agree that if you were to have a nicely controlled torch (maybe a mini-torch) it would allow for you to precisely apply heat to a specific area.
