Print quality question

[JoeD]

Now that I spent 9 hours today trying to figure out how to post a picture....lol...anyway.  as you can see I'm getting a frosting line on my prints.  I have a Photon Mono, printing at 2.5 per layer and .05 layer height.  I have 6 machines and it routinely does this on any or all of them when printing flat.  When I am printing rectangular projects flat on the plate I don't see any of this...just did some patterns this morning and they are fine.   Any wisdom?  Painted with a couple coats of Tamiya Primer covers it generally but in the correct light you still see some roughness.  I guess I am at a loss why this happens in the same spot all the time...

Thanks in advance.

Joe

[Sokramiketes]

Interesting.  Is this visible before curing, or just after?

[John]

Those look like harpoon shipping containers

Whenever I get this -- It's because I didn't clean the print well enough ...

[Chris333]

Yeah the only time I seen this is when people post their wargame figures on Facebook

[narrowminded]

Now that I spent 9 hours today trying to figure out how to post a picture....lol...anyway.  as you can see I'm getting a frosting line on my prints.  I have a Photon Mono, printing at 2.5 per layer and .05 layer height.
Joe

I have one that's fairly new to me so have run only 20 or so prints maximum.  BUT, I suspect your normal time might be a little high.  I have successfully run as few as 4 bottom layers at 40 seconds and then as little as 1.65 seconds normal time and not more than 2 seconds, all at .05 thick layers.  That's with a variety of resins including Anycubic and Sirya-Tech Fast.  With Sirya-Tech Tenacious added to Fast, up to 30%, I suspect that requires a little more time based on internet wisdom but I still have run that successfully at no more than 2 seconds.  I will try that with a lower setting in the future.

I'm not saying that these are an ultimate and I will be experimenting further but can say that I haven't lost a print yet with these settings.  Hope that helps.

[narrowminded]

A few more bits of info might be helpful for folks to get a clearer picture.  There is a lot of experience with these guys.

What resin and what washing medium and method?

[JoeD]

More info.  I have been using the Anycubic Grey, Black, White with the same results on all 5 machines.  The flesh color is UNIZ Beige which I really like for smaller parts.  I use Denatured Alcohol for cleaning and rinsing usually doing the first soak for 3 minutes, second soak about as long and then a final rinse and then blowing off the alcohol with compressed air.  If the part is fully flat I have a good clean, if its a bit shiny in crevice's then I run it through the final rinse again.  I let the parts air out for at least an hour before putting them under UV.   

When I pull the parts off the print platform, before a wash I can see some surface effect that becomes the chalking once washed.  It becomes evident as soon as I blow the parts off and they start to dry.  I am using new FEP and this happens on both my older machines and the one I just got. 

I put it under the scope and the surface looks pretty disrupted.  For these units, a little scotch bright and a few coats of Tamiya Primer and these are fine for my layout.  I'd like to try and solve the problem for work stuff when and if it occurs. 

So today I'll start working with print times etc and see if this clears up the problem.  Interesting it only happens on radius'. 

Thanks for the input and any other wisdom.   

Joe

[Sokramiketes]

It looks sorta like light refraction causing a crystallizing surface, rather than tight light pattern between the screen and resin. 

Can you think of anything that might be doing that?  Is the protective film still on the FEP sheets somehow?  Removed from both sides of the FEP?  You said the FEP is new, so it shouldn't be hazy or scratched. 

[JoeD]

It looks sorta like light refraction causing a crystallizing surface, rather than tight light pattern between the screen and resin. 

Can you think of anything that might be doing that?  Is the protective film still on the FEP sheets somehow?  Removed from both sides of the FEP?  You said the FEP is new, so it shouldn't be hazy or scratched.

I checked to be sure...not there, the film I use I get from McMaster Carr...it comes in rolls without the protective film you see on the sheets from Amazon and others..  But my new printer has the pre cut, pre installed film so I tried it on that as well.  Same results. 

I have it set up now on all 5 of my machines, with different settings.  I realize that all 5 have their own minor differences most likely but we'll see what happens.  Given my experience so far, I'm sure it's something I'm missing.

Thanks for your help.

Joe

[Chris333]

Only thing I see is you say "soak". I scrub the crap out of my prints with a chip brush in old alcohol and then blow dry. The print will still be shiney because the dirty alcohol will end up being sticky from resin in it. Then I do this all over again with clean alcohol, but this time when I blow it dry it will be bone dry. Sometimes a complicated part with nooks and crannies will need 2 or 3 scrubs in the clean alcohol.

And I really don't know if it helps, but been doing a final wash in Simple Green. I just slush this around, no scrubbing. Rinse with water and blow dry. Done.

[Sokramiketes]

Resin is newer I presume?  Not a bottle that's been previously opened and sitting on the shelf for awhile?

[timwatson]

I have seen this with IPA not drying and then the print is rinsed.

For anyone using Isopropyl alcohol ... switch to denatured alcohol (DA). Prints are cleaner and I rarely if ever see the residue that IPA leaves. It's also so much faster of a cleaning method. I don't even brush my prints anymore.
Also one more great thing - the resin separates out of the used DA so much more cleanly. It's easy to prop up a UV light over the DA let it cure and separate it out with a silicone spatula.

[JeffB]

I have seen this with IPA not drying and then the print is rinsed.

For anyone using Isopropyl alcohol ... switch to denatured alcohol (DA). Prints are cleaner and I rarely if ever see the residue that IPA leaves. It's also so much faster of a cleaning method. I don't even brush my prints anymore.
Also one more great thing - the resin separates out of the used DA so much more cleanly. It's easy to prop up a UV light over the DA let it cure and separate it out with a silicone spatula.

I switched to DA a while back and noticed how much better it cleans resin right off the bat...  Great for cleaning resin and it was available when IPA got scarce at the start of the Pandemic.

Just keep in mind a few things...  First, DA is much more flammable than IPA.  If your basement workshop is in the same space as your furnace (as is mine), it's advisable that you clean your prints with DA somewhere else (especially if it's winter and the furnace cycles regularly).  Second, it's quite a bit more toxic than IPA.  Read up on it prior to using it and make the decision to switch (or not) once you've educated yourself on the health risks.

While it is markedly better at cleaning prints of excess resin, I switched back to IPA now that it's available again.  I'm not overly paranoid about using chemicals (I use Acetone pretty regularly), I wanted to limit exposure to DA based on what I'd read about it. 

JB

[John]

Just keep in mind a few things...  First, DA is much more flammable than IPA.  If your basement workshop is in the same space as your furnace (as is mine), it's advisable that you clean your prints with DA somewhere else (especially if it's winter and the furnace cycles regularly).  Second, it's quite a bit more toxic than IPA.  Read up on it prior to using it and make the decision to switch (or not) once you've educated yourself on the health risks.

While it is markedly better at cleaning prints of excess resin, I switched back to IPA now that it's available again.  I'm not overly paranoid about using chemicals (I use Acetone pretty regularly), I wanted to limit exposure to DA based on what I'd read about it. 

I used DA for a while this summer -- but found the smell was causing me problems .. my printer is in the basement -- close to the furnace .. so I also switched back to IPA 91% .. it's pretty cheap at Walmart now ..   my wash regimen is pretty close to Chris' -- Clean pring in small bucket with Simple Green Concentrate diluted 50% -- scrub with my old tooth brush .. then drop into a bath of IPA - scrub some more lightly ..  also depending on the model, I will remove the supports by placing it into some warm water from the faucet .. then off to the cure ..

[Chris333]

I tried DA a bunch of times and it just seems to work faster. That slimy resin turns bone dry quick. In fact I just saw Menard's has a gallon of DA for $15. That is now cheaper than 4 quarts of 91% from Walmart. But there is nothing wrong with 91%.

I wish there was a real way to strain out the resin. All the tricks get rid of some of it, but you dip your gloved hand in it and it will be all slimy. I do decant it al lot to get rid of the particles that settle. But you can't use it forever.