Hello all thought I update my 3D printing experience.
After a couple months I found that I really liked the Orange 10, but for it's smallish build capacity (98 x 55 x 140 mm). So I bought an Elegoo Mars device (120 x 68 x 170 mm). Out of the box the maximum Z-axis capacity is 155 mm, however the firmware and build platform clamp screw can be easily modified to get 170 mm travel. Operationally they are very similar, arguably identical. I still have the Longer having not worked up the ambition to list it for sale anywhere (this may be a "first love" inhibition thing, IDK).
What I Have Learned About 3D Resin Printing (in n o special order):
- The cheap "rapid" resins (anything < $50/kilogram)--and any advertised as "ABS like"--are worthless, too brittle to be of any use for any working components (I don't do "dolls" so I don't know about that;
- Most resins state using Isopropyl Alcohol ("rubbing" alcohol in 70 or 90% concentrations) as a "post-printing" rinse (30 seconds or so). However as a result of the COVID-19 scare that is in short supply. I have been using KLeen-Strip's alcohol "fuel" (50-60% methanol, 50-60% ethanol, $17 a gallon at Home Depot) as an alternative--it works quite a bit better, requiring less to rinse the models, I have also skipped the alcohol and used a 75/25 mix of tap water and Mean Green degreasing cleanser. It works well also--I suspect Purple Power, Mr. Clean, Fabuloso, or whatever your favourite might be will work just as well;
- After the rinse I give then a final scrubbing with hot water, a soft brush, an a squirt bottle of full strength Mean Green (dry with compressed air). This is essential if you plan on painting the component;
- For most flat or "flatter" models you will need to angle the object and use supports, the resin will puddle on any horizontal flat surfaces and look like "puddled resin" on the final print;
A makeup paddle thingy for SWMBO
- Post printing/cleaning final curing is necessary. This can be done in seconds/minutes using artificial UV light, or hours of exposure to sunlight.
- The best resins are those labeled as being "engineering", "flexible/flex", etc. They are typically urethane based and have post-cure "elongation at break" specs of 25% or better (stay away from the cheap "11 to 20%" rated crap. Expect to pay $60+ per kilogram.
Being by nature an impatient sort, not wild about being dependent on the whims of Mother Nature, I originally purchased an inexpensive 6 W UV flood lamp and cheap little plastic jewelry "display" turntable from Amazon. Using these and a foil lined cardboard shroud I could properly post cure a print in 5 to 10 minutes.
But, seeking something automated and faster it occurred to me that a small microwave oven, gutted of the MW stuff, had what I needed--a nice chamber, turntable and timer. I found a nice 0.7 ft³ unit on Craigslist for $10, and replaced the magnetron, HV transformer and ballast capacitor/diode with a 30 W UV LED (of precisely 405 nm wavelength as needed by the resin) and a constant current 900 ma/33 V power supply. Wiring that up to the microwave's timer/control relay gave ne just what I needed:
The finished product:
The UV LED was mounted (w/ heat sink compound) to an old CPU heat sink, that assembly then mounted in an enlarged hole where the magnetron and it's waveguide had been in the side of the oven. There was plenty of room in the oven's side compartment for the LED, heat sink and LED power supply. There are two screws mechanically fastening the heat sink to the wall, I used metallic duct tape to seal and "pretty" it all up.
The microwave's active cross flow cooling, designed for a 700 W device, is entirely adequate to the 30 W LED's cooling needs.
I also used a couple of strips of the tape o the oven's door, as the 30W lED is very bright (10-20 seconds will cure anything, were I doing this again I might use a 10 W LED).
Here's a link to
the LED on Amazon ($16.29);
And the
constant current power supply ($10.92);
Here are some photos of the finished project;
just a plain 'ol microwaveUV LED mounted on an old CPU heat sink and installed in place of the magnetron--the "bump" above the LED is left over waveguide I did not remove. (I see I need yet to clean up some of the grinding dust from enlarging the hole):
Chrome duct tape on window in m-wave door--I had considered lining the entire interior with foil, however with the 30 W LED the gloss white seems to relect the UV quite well...
LED ON room lights on
LED ON, room lights off
OEM schematic of m-waveAs modified schematic of m-waveFun stuff I've made:
2020 Participation TrophyF-Bomb -- Do not drop; dropping the "F-Bomb" is bad...