Longer Orange 10 3D resin printer $165.20 on Amazon

[reboots]

Maybe keep the small one going for a while, to see how it holds up. The fundamental design issue with these low-cost resin printers seems to be that the LCD gets damaged by the UV irradiation; they use plain old display LCDs which were never meant to see intense UV. But reports on how long that takes before it affects functionality vary a lot.

Longer offers a replacement LCD for 30USD, which does suggest that it's a wear item:

https://www.amazon.com/dp/B07TK96KS7

[artag]

Is there a good place where the operation and design of these printers is discussed ? I can find generic forums for FDM printers but SLAs seem to be siloed by manufacturer - there is little DIY or development discussion.

This was not always the case : there was a good forum on DIY DLP printers on google plus, I believe. Unfortunately it disappeared when that closed.

Good finish is certainly not a strong point for any sort of 3D printer. However, the best use I have seen them put to was on the development of a knitting  machine. The parts didn't look pretty but a new mounting bracket or spacing piece could be spun out much more quickly than even in a well-equipped workshop - especially if several had to be made. That experience convinced me they had uses even if if wasn't to make beautifully finished products.
 

[beanflying]

Robust and rapid tooling is one of the great uses for 3D printing be it filament or resin. In my day job I needed some bits for overhauling Lever Espresso machines. The pin spanner is available ex Italy for a lot of $$ so I rolled my own. It gets used with a 2' wrench and the spring compressor gets used with two adjustable clamps. While not in daily use the sub $20 worth of filament and hardware beats importing or likely paying someone else $2-300 to make them.

The right most part was the first pin spanner but it couldn't be used for reassembly so I rolled the vertical pinned one which does both.

[cliffyk]

Guess it won't like my linux machines. Run on WINE? Do you have to join facecloth for support? Just jumped in her, will research.

I am running all I need on Linux Mint 18.3, native mode; I use ChitUBox 1.6.1 for minor editing  and slicing (With a ChitUBOx plug-in provided by Longer).

For original design work and intensive editing I use FreeCAD 0.18. It's a great application, but at version 0.18 it can at times be a bit flaky.

[jh15]

thanks!

[cliffyk]

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 microwave


UV 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-wave


As modified schematic of m-wave


Fun stuff I've made:

2020 Participation Trophy


F-Bomb -- Do not drop; dropping the "F-Bomb" is bad...

[coppercone2]

I printed a battery holder with 8 second exposure time on ABS like resin and it broke when I dropped it on ceramic tile, like obsidian. maybe it will do better on the recommended 10-14 second exposure time.

[cliffyk]

All of the "ABS like" resins I  have used have been brittle as Heck--the worse was Elegoo's water washable garbage; scary brittle and quite worthless--I wrote an unflattering review on Amazon and Elegoo contacted me offering a free liter of any resin they offered as compensation--indicating to me they know it's crap.

One of the better reasonably priced ($54  per kg) resins I've used was Phrozen Functional Beige Flex--however i have not been able to get it for the last 6 months or so. I found that mixing it 50/50 with the "ABS-like" stuff greater improved the impact resistance of the latter.

I have heard good things about the Siraya Tech Tenacious resin ($65 / kg from Amazon), with reports that mixing it with the cheap crap improves resilience as well. Once my wallet recovers from the "season" I am going to get some ...

[wraper]

I printed a battery holder with 8 second exposure time on ABS like resin and it broke when I dropped it on ceramic tile, like obsidian. maybe it will do better on the recommended 10-14 second exposure time.

Why would it matter when you are supposed to additionally UV cure it afterwards?

[cliffyk]

The recommended post curing makes the cheap "ABS-like" resins even more brittle. To use a seasonal metaphor they snap like a well-cured wishbone.

To be frank l I had become disillusioned with the utility of LCD shutter based SLA printing until I moved up to the Phrozen Beige Flex resin (35% to 45% elongation at break)--I've gone through 5 kg of it since April; but it has not been available on Amazon since mid-August--just used the last of my store today in fact, mixed with some gray "ABS-like" crap-- maybe I used it all up?.

The $30/kg "ABS-like" stuff rated to have 7% to 10% elongation at break is a complete waste of money; usable only for items that will not have to endure any load and never be "dropped" like my F-bomb:

[james_s]

That F-bomb is way funnier than it ought to be, I smirk every time I see that picture.

[coppercone2]

I think its alright so long you make the parts thick. I printed some other stuff with flaws (vortex tube) and it required a hammer and some force to take apart.

Things like the seek thermal camera bracket are fine. I don't think your FBOMB will break if you drop it. I think the 'sandie' pen is decently strong also. The SD card holders are made are very strong I think, but that is all thick stuff.

I did notice a great strength increase at 14 seconds.

I think you just need to be mindful of the design you use, there is stuff that does not seem executable with certain resins. I think calling the resin 'useless' is jumping a gun but I don't like hyper engineered mechanical design with plastic in general.

I printed maybe a gallon worth of things and the only stuff that gave me problems is like thin stuff with sharp edges (i.e. thin box lids, thin housings). Mainly stuff I look at that makes me think 'this guy was only thinking about weight'. I think it comes with trying to clone polyethylene injection mold designs in plastics that are way less flexible. Usually even in the natural form those designs make me think 'cheap bs'.

[cliffyk]

That F-bomb is way funnier than it ought to be, I smirk every time I see that picture.

Do you recognize the base model?  It's "Fat Man"...

[cliffyk]

I think its alright so long you make the parts thick. I printed some other stuff with flaws (vortex tube) and it required a hammer and some force to take apart.

Things like the seek thermal camera bracket are fine. I don't think your FBOMB will break if you drop it. I think the 'sandie' pen is decently strong also. The SD card holders are made are very strong I think, but that is all thick stuff.

I did notice a great strength increase at 14 seconds.

I think you just need to be mindful of the design you use, there is stuff that does not seem executable with certain resins. I think calling the resin 'useless' is jumping a gun but I don't like hyper engineered mechanical design with plastic in general.

I printed maybe a gallon worth of things and the only stuff that gave me problems is like thin stuff with sharp edges (i.e. thin box lids, thin housings). Mainly stuff I look at that makes me think 'this guy was only thinking about weight'. I think it comes with trying to clone polyethylene injection mold designs in plastics that are way less flexible. Usually even in the natural form those designs make me think 'cheap bs'.

That is the core of engineering, knowing the characteristics of your materials and designing accordingly..

A professor many years back (most likely John Heywood, he was my favourite) perfectly defined engineering as "Making what you want from what you have." 

[coppercone2]

part of the appeal of a 3d printer for me was that I could go quickly print a bunch of stuff that is already designed to help 'pay it off' a little while learning by using thingiverse and such.

Now with the cost of resin its a far cry to pay it off but I accumulated a few missing knob repair jobs, brackets, stuff for thermal camera.. I would say I maybe broke even, even with having to buy more FEP film. Some weird stuff like thermal SMD microscope that actually works proper with adjustments.. stuff I could have made the old fashioned way but given the effort required to do the design, thingverse was useful. When parts look like too much shit its often easier to use epoxy putty and paint on them afterwards when you are playing with it to see if it is weak anywhere.

Also,  keep in mind the 3d printer is not only for functional parts, but if you do casting.. its invaluable even with the weakest non realistic garbage parts since the material changes. Total game changer there..

My favorite thing is make the complex portion of it out of 3d print then just bend metal and glue it to make a respectable hybrid. You just need to get glues right.

The problem is that those websites don't give you much detail on the parts.. so you pretty much need to print a variety to see what the fails are, if you are a hands on learner. now I got a bit of a feel for what looks like BS. Sometimes its probobly cheaper to put a metal back plane or something on some parts then to try to figure out how thick to make it.


Also I found that for threads and whatnot, using automotive paint correction chemicals to wet-fit parts is excellent to reduce friction.

[ralphrmartin]

Just ordered myself one of these for a mere £85 off eBay UK as "Open box / New", which is just amazing. I remember that the first SLA printer i saw cost a 6 figure sum.

Cliff, is there anything you can share with us now, that you wish you had known when you started out, apart from your comments above? And while you say to avoid cheap resin, can you tell us which one(s) you feel to be the best trade off between durability of finished item and price - and the settings you use for that resin?

Thanks!

Ralph