Looking good David. I've been having some laser "fun" of my own. One of my electronics projects is going to need a case, and it's a bit big to 3D print...plus I want something really finished looking. So I decided to get the k40 going and see if I can't cut it out of black acrylic.
I should probably update my laser thread with the details...maybe I'll do that tonight. But short version - I had to finally remove the exhaust duct so I could fit 12"x12" stock in there. Which meant having to remove the laser tube itself because one of the bolts that holds one of it's mounts was in the way. And that in turn means now I get to have the fun of re-aligning the tube and the mirrors. Which...is proving to be just as tedious and annoying as I had expected it to be. But - it also gave me an excuse to install the upgraded mirrors I had bought and never installed because I didn't want to deal with laser alignment. And I installed a power pot finally so I can test fire it at very low power. Oh, and I designed and 3d printed some risers to hold the expanded metal bed finally. So it's close to usable again...just...need to finish this annoying alignment procedure.
The same project also got me to dive into a new form of 3D printing. I decided to try SLS resin printing. I almost went with the Anycubic photon zero since at just $170 it's dirt cheap and had decent reviews. But the more I watched/read the reviews the more I realized what most of the reviewers really liked was the wash/cure station that was released along with it. It actaully has noticably lower resolution than other SLS printers - and the whole reason I want it is to print small functional parts like knobs and buttons that are too small to do to my liking on my FDM printers. Yeah...I can print them on FDM...but they're so small they just don't look right with the layer lines even printed at 0.10mm. I even tried printing them in ABS and vapor smoothing them...but they just don't look consistent enough then.
FWIW - buying these knobs isn't really an option. They're for special fancy dual rotary encoders (i.e. one encoder but with nested shafts so they can act as two separate encoders) and no stores that sell to consumers sell them in quantities of less than 1,000. I only need 4 so that would just be silly.
I've actually wanted to try SLS printing since before I even got my first FDM printer...so this was really just an excuse to finally try it
I did some research on other <$300 SLS printers and decided that the Phrozen Sonic Mini sounded like the one I'd be happiest with. It got really good reviews from a bunch of places and is apparently way faster than most others because it uses a monochrome LCD for it's mask that lets more UV light through. Most printers in this range do layers in 5-8 seconds. The Sonic mini does them in 2-4 so that makes it significantly faster. It did have a few flaws when first released but the biggest (a weak plastic resin vat) has been upgraded to an aluminum one. The other big flaw is the stock build plate is rather poorly designed and hard to clean after printing...but there's a replacement available now with a slanted back that solves that. Unfortunately it was out of stock on Amazon so I wound up ordering from a distributor who claimed 2 day fed-ex shipping and that they shipped out products in 3-6 days.
First bummer was having to actually pay for shipping. That bumped the price up $60. But they sold the upgraded build plate for half the cost it sells for on Amazon and it was also out of stock on Amazon as well - so that saves $20 which helped offset the bummer about shipping price. The next issue was they took longer than the 3-6 days to ship. Apparently the "distributor" I bought from doesn't actually maintain inventory - they just drop-ship direct from the manufacturer. And the manufacturer closed their shop for a week for a dragon boat festival the day after I ordered. Great. I e-mailed the distributor asking when I could expect shipping...and when I hadn't heard back in 24 hours got ready to dispute the charges with paypal and/or my credit card company and put plan B into action.
I ordered an Elegoo Mars Pro off of Amazon. The Mars Pro was about the same price as the Sonic...and has an upgraded UV lamp that makes it slower than the Sonic but still faster than other <$300 printers. It was also in stock with prime delivery in 3 days. The day after Amazon shipped the Mars pro I finally got a shipping notice on the Sonic - and sure enough it was 2 day shipping from Taiwan.
The mars pro arrived yesterday. Setup took all of 10 minutes. But my first two test prints failed:
The prints were sticking to the FEP film at the bottom of the vat instead of the build plate. Still the part that did print showed enough detail to get me excited.
I wasn't sure if the problem was the white resin I was using (since this is a light based process color of resin can make a BIG difference in settings) since the stock test print was apparently prepared for grey resin...or if I had just done a poor job of leveling the build plate. So...I tossed caution to the wind and changed multiple variables. I re-leveled the bed and decided to try printing my knobs instead of the pre-sliced test file.
It worked!
It's hard to get a photo that shows the detail and finish on these but they're amazing! More like cast parts than printed parts! And while resin is brittle it's also very tough. I put one of these in my dremel hobby vise and wasn't able to break it in any orientation! They were also accurate enough to fit the encoders first try.
They aren't perfect. You'll notice there's some major elephant foot going on which caused issues for the top knobs. Also I want them in black not white (I have black resin but didn't want to clean the vat and switch resins yet) and the top knob is a tiny bit looser than I'd like and the lower one is a tiny bit tighter than I'd like. But for a first "real" try with my own sliced parts...huge success.
One thing to note. Since SLA printers do a whole layer at once it's kind of neat that I can put as many of these on the build plate as I can fit and it takes just as long as printing one. Which is nice when you want to do a lot of parts at once. But is a bit of a bummer that just printing one isn't any faster when you want to iterate a design or do a quick test of a setting change.
In fact - I didn't mention it but the test part was a 3 hour print but I couldn't even see if it was working or not until over 2 hours in because it was still down in the vat. So you have to let a print run for at least 2 hours before you can even get a hint of if it's working or not.
After the success with my knobs I tried the test file again. I overrode the exposure in the printer to lower it from 7 seconds per layer to 5 to compensate for the white resin but suspect it was really just re-leveling the print bed that got me success this time:
Note - this was still a bit wet from post processing. The detail on the words on top is astounding. I've seen photos of this test piece before but they don't do it justice. It's so detailed and so fine! There are no visible or noticeable layer lines of any kind. And the fine details that show through...just astounding!
Now note - I would still say a FDM printer is more useful and functional by far. It's also much more pleasant to use. The resin STINKS, but while printing with the cover on the smell isn't that bad (the mars pro even has a charcoal filter which seems to help) But cleaning the prints after is messy and annoying. The resin in addition to smelling bad can cause chemical burns so you have to wear nitrile gloves and wash the finished parts in isopropyl or denatured alcohol....both of which are almost impossible to find right now thanks to COVID. A popular alternative is a cleaner called "mean green" but I can't find any locally which leaves me with the next most popular option - Simple Green. I HATE the smell of simple green
The smell of the simple green bothers me WAY more. And once washed parts need to be final cured under UV light. I can just stick them outside but I also got a little UV spot light for $20 off Amazon which I can stick in a foil lined boxed to take care of that in just a few minutes.
Standard resin is also very brittle. It's very hard...but not very tough. So ok for things like busts in models but not great for functional parts. But there are also "ABS Like" tough resins that cost a bit more but are supposedly less brittle. There's also a few flexible resins and you can blend them - people add the flexible to regular resin to make the regular resin less brittle. I picked up some of the flexible to try but haven't had a chance to give it a go yet.
And after last nights success...the printer I originally ordered showed up today.
First print on it is running now. Overall first impression the mars pro is a more refined package that impresses me more. But the sonic seems to have a few nice things in it's favor in addition to it's speed.
So I'm going to have a hard time deciding which one to sell. I don't really have room for both (not sure I even have room for one!) so I shouldn't keep both. But I'll give them a workout for a week or so before I decide.