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Some parts I've printed so far. |
I recently finally bit the bullet and got a resin 3D
printer, a Phrozen Sonic Mini.
https://amzn.to/3h76Pvw Three main things came
together that made me finally take the plunge: cheaper prices, water-washable
resin
https://amzn.to/2OxjEDq , and mono screens for faster printing. The mono
screen leading to faster prints is why I went with the Phrozen Sonic Mini.
The only thing I really don’t like about the Phrozen Sonic Mini so far is the
flat-backed build plate which is messy. But I remedied that somewhat by
printing out an angled back in PLA plastic using my FDM 3D printer.
Anyway here is everything I’ve learned so far.
Level the built plate to the FEP film https://amzn.to/3fMs3hW
with the vat on the machine instead of using paper. Also I give the FEP film a
coat of 3in1 PTFE lubricant https://amzn.to/30icoR5 whenever I clean out the
vat. https://youtu.be/NYK_8aEpUCY
I have my printer set up in my garage and that means when
the garage door is open plenty of light can get in. So, when the printer is not
in use but I know I’ll be using the machine again in a few days I’ve been
leaving the leftover resin in the vat and storing the vat and the build plate
in their own tin containers which keeps them totally free of light. Doing that
not only assures no light starts curing the resin but keeps me from having to
empty/clean the vat; it also eliminates any potential resin leaks onto the
screen. You do not want resin on the screen, especially since it can leak down
into the machine. When going to use the stored resin vat again, I carefully
stir up resin before starting a new print.
Use a 1 or 2 layer sheet file that fills up most of the build
plate on every print. It uses up very little resin, makes for more reliable
adhesion for all the parts on the build plate, makes clearing off the build
plate easier when the print is done, and better assures nothing sticks to the
FEP film instead of the build plate. So, for instance, I like to put a 0.05 mm
or 0.1 mm sheet down when printing with a layer height of 0.05. Printing objects directly to the build plate is often problematic due to the first several layers needing to be overexposed to assure the parts adhere to the build plate; that translates into the parts being too thick (over-sized) the first few layers.
Watch this video to see the
technique I used to figure out the best resin exposure settings for my printer.
https://youtu.be/r9GwPEJ8Lq8 My only
issue with this technique is that the stl file used has some details so fine
that they can cause floaters to break off into the resin until the settings are
dialed in just right.
I’ve only been using water washable resin (Phrozen Water-Washable Rapid Resin Gray), so I can’t compare
it to anything else. All I know is that it has worked well enough for me as long as the model is not hollow; hollow prints eventually crack; light has to be able to reach every surface for the final curing. Other
than water for cleaning the prints, I use Sprayway glass cleaner https://amzn.to/2CL0Bm4
for cleaning the vat and build plate.
And I also use Mean Green for cleaning, which can also be used as a substitute
for isopropyl alcohol (IPA) for alcohol wash resins. I use lots of paper towels and shop towels. And
I reuse lightly used paper towels and shop towels by setting them in the sun
for a few minutes to cure any resin they have on them. Gloves are needed but
you can often avoid using them if you set up a neat cleaning procedure. I use
needle nose pliers to touch the uncured resin, so I rarely need to put on
gloves. I grab a razor blade with needle nose pliers to get the prints to start
peeling away from the build plate. Then I hold the print with needle nose
pliers and spray the print down with compressed air. I use a compressor tank but
canned duster air works too. Then I swish the print around in a container of
water for a minute; I remove it, rinse it again in a cleaner tub of water,
remove it, spray with air again and let it dry. I mostly cure prints in the sun
but have an LED UV light https://amzn.to/3h5pFDl
for cloudy days and nights and for
getting into crevasses. Sometimes I cure the prints in a clear jar filled with
water to get better light refraction and spread.
I use 190 micron paper paint strainers https://amzn.to/2ZyNxJw
for pouring resin from the vat back into the resin bottle. I just strain the
resin from the vat to a temporary container if I’m just going to put it back in
the vat. I do a strain like that every time I know or suspect that a part broke
off while printing and is floating around somewhere in the vat. Floating cured
resin pieces are recipes for problems. The paint strainers can be used multiple
times. I just give the mesh section a quick swish in water and then set the
filter out in the sun for a few minutes to assure any remaining resin cures. That
starts to turn the paper strainers into plastic strainers.
Supports are tricky. You want your model well supported
but don’t want the model overwhelmed with leftover bumps from supports. Angling
models on both the X/Y and Z axes at 30-45 degrees usually reduces the need for
supports, especially on rectangular objects. But the smoothest edges come from
flat planes perpendicular to the screen. The curing screen is made of pixels
and straight lines only come at 90 degree angles. That means that if you are
printing a freight car with flat sides, you’d want to keep those sides un-angled
and at 90 degrees to the screen, parallel to the screen’s pixels. Otherwise,
the pixels create a fine grain texture on the model; the texture can be easy to
sand down though so it isn’t always an issue. I use the free program Chitubox
for making supports but also sometimes design my own supports into models for
more exact supports. You don’t want islands and long unsupported layers. To
learn more about making supports that won’t result in failed prints and
floating parts in your resin vat, I recommend this video. https://youtu.be/sBAlZwZtiEQ
Overall, you won’t be able to avoid a certain amount of
trial and error before you get well versed in resin 3D printing. I’ve found
dimensional accuracy is hit and miss, so don’t expect parts to fit tightly
together perfectly without tinkering. If you don’t print a lot and don’t do
your own designs, Shapeways is still way easier, even with the less than ideal
price structure, waxy detail plastic (the wax supports are actually great
compared to resin supports and cleaning resin in my opinion), and shipping
costs. Overall, home resin printing is useful but it is nowhere near as great as I was hoping.
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