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Any body using a 3D resin printer?

Started by TimB, Dec 26, 2021, 04:38 PM

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TimB

Hi all

I now have a Elegoo mars 2 pro printer and having issues. Before I go off searching other forums I'm asking here as you people have a shed load of experience in all kinds of stuff.

It's a question about supports.

Thanks

Tim

trastikata

Hi Tim, I am using LONGER Orange 30. What are you interested in exactly?

TimB

Thanks

I'm trying to print these parts. Had zero success due to either the parts not sticking to the top plate or it starts to stick then fails.

I started out getting it to do the supports, and that was useless. Then I posted here. Then I tried it as per the image below. I think this is way better than the one with the supports and it started to work then failed to adhere about 1mm out.

I'm at a loss. The resin makes a MESS and having damp alcoholed paper towels stuffed in the bin worries me (I put the bin outside now)

Re-leveled the bed 4 x. Applied PTFE spray to plastic in the tray (and polished it in).

It's doing my nut in. The old FDM printer worked great but was porous and to rough for seals, getting 3D printed SLS parts is expensive and time consuming. Just trying to get this to work.


supports.png

top204

I've taken a look around, and most sites are saying, pretty much, the same thing. But this site was a bit better.

https://www.instructables.com/Troubleshooting-Prints-Arent-Sticking-to-the-Build/

Also, this guy seems to know a bit, and is saying what others are saying:

https://www.youtube.com/watch?v=c_RoA-11MWU

As soon as I get my workshop back in our new home, later this year, I am going to try and get a resin printer, because they look excellent, and I have a lot of projects in mind for nice smooth 3D prints. :-)

trastikata

Tim, I can't see the model inside but here are some things I noticed and keep in mind when I orient the parts for printing:

- First few layers need some extra exposure time to stick better
- I see some of the details inside are in the air - so they won't print correctly or not at all! Think of it when printing a new layer it has to adhere to some extend to the previous layer and if there is no bond to support it, it will fall off and each consecutive layer will fail too.
- So considering the previous note - you need either to orient the detail in this way or to add internal supports so that no layer starts into the resin only. In your picture I indicated such an example - when the platform is in the resin and the layer, where those indicated parts start, is cured - it will be very thin strip. Now when the platform starts moving upwards, because of the high viscosity of the resin, that thin layer in the beginning of the shape will be broken and that will happen with each consecutive layer that forms this shape.
- Another point to consider is that resin get stuck inside cavities. So any cavity inside the detail which doesn't have enough time or enough space to drain out the resin trapped in it, will tend to create some hydraulic pressure on the detail when the platform moves into the resin. Much like a piston and trapped air in front of the oil gets compressed which could push out the detail or damage thin layers. For this you need to optimize the design and/or slow down the plunge speeds.
- With regards with the previous problem - sometimes that trapped resin cures from the constant UV exposure and creates thicker surfaces than actual design.
- Another issue I noticed is warping - if details are not additionally cured with strong UV lamps or under the sun right after printing, they have very low strength and undergo plastic deformation even under its own weight if left for few hours to rest.

Overall 3D SLS printers (at least the cheap ones) are not what I would have expected and while the quality on simple shapes is much better, then for complex shapes they are not that great as advertised. Much thought has to be given for orientation and design with respect the previously mentioned problems in order to achieve successful printing.   

 

TimB


Thanks

I have a feeling temperature may be my biggest issue. It's in my workshop and I have turned the temp up to a balmy 19oC which if great for me but not the resin. It's very thick so will need to make a tent for it to keep it all warm.

The first layers are 35-40 seconds and matches the recommended. The first 20-30 are fine so think it could be again the temperature and the tick resin.

When I started out I though long and hard about the support, when I get it to add them it will not support the sections you highlighted. But to be sure next test I will put supports into the design as peeling the very small start to the radiuses will be an issue when pulling the part off.

There ends up only being a small section that has a cavity. I may add a drain I can plug later.

It's not as easy and fun as with my dirt cheap FDM printer. As you say it's not as "magical" as people make out. Perhaps I can dip the FDM part in the resin then UV it to get the finish and water sealing I desire. I will proceed as I keep thinking now of all the little custom parts I can make with it.

Thanks Tim

JONW

Hi Tim

I have the same printers and don't seem to have too many issues but my parts are fairly simple..   I have set it up once with a4 sheet of paper and use he ABS like resin with no issues. You need the baseplate to have some texture so it sticks, if it sticks to the FEP sheet try modifying the  initial exposure time and renew the FEP sheet or try a raft and rotate the part on supports. Thin the resin for the start process by putting the bottle in warm water, it also releases any air easier.  Also filter the resin when warm, if you have any small cured resin in the bath it created voids and can fail.  If you look through the part layer by layer in Chitubox you can see the unsupported sections where you need supports.

You will have issues printing the horizontal tubes without supports and as mentioned they are not great for complex shapes with voids and you will need to spin the piece and use a large raft with internal supports.

Feel your pain Tim, if I have a complex part that fails multiple times it goes out for manufacture in a heartbeat now.   

TimB


Thanks JONW

I heated my workshop up to 22C today, I also warmed the printer. The first print today failed. Half was on the build plate and half on the FEP. I found out by pausing it at around 16%. I did that at the beginning and wondering if that might be causing it. Its layer separation that is my issue now.
Leveled many times using A4. This time I leveled it in the tray. One thing is I am not hearing it peel off the FEP.

This part is really not that hard and there are no islands. I added supports even though it should not need any. My resin is transparent as I want to watch fluid flows. But that should not affect anything.

If I get it to work I will report back.

Tim

Tenaja

Even 22 is very cold for resin. I used to use a Form 1, and it would work best when heated far above room temperature. We tried a heating blanket, and that helped (must pre-heat long enough) and then a heater enclosure.

But, if you cannot get the first few layers to stick, that is moot. Figure out why the base is not bonding, because everything follows that.

TimB


I kind of got it to work, then gave up.

The issue was that after a few layers it delaminated and did not stick. The printer is a new mono LCD and the software  automatically sets the cure time to 2.5 seconds. The bottle says 8 seconds which is common for colour LCD's.

So I changed the time to 6 seconds as well as the angle it was printed at and added loads of supports.
It produced one part that did not fall apart. But it was distorted.

The issue is that it's a part that even when angled produces slices that are large. This is an issue for releasing it of the FEP film. So when I tried again the part was ripped of the supports.

End result is I gave up. Dug out my trusty mini FDM printer and made my parts using that. My last print took 25+ hours but it worked and ended up with a usable part.

I went for SLA as the parts need to be waterproof. The FDM are not without post processing, but that just requires a spray with lacquer.

 
Tim

towlerg

@Tim FWIW some people claim to have reduced porosity and increasing inter layer strength by annealing. There is also a technique of filling and surrounding the object in sand and heating way up. Some filaments (those with a relatively non toxic solvent) can be vapor smoothed is ABS and Acetone.

TimB

Hi towlerg

I think I will give solvent a go as I want to smooth some surfaces anycase. More Youtubing.....

joesaliba

@TimB

I think this is one of the best methods for annealing PLA or PETG: -

https://youtu.be/nRLJ4ylGTFc

Regards

Joe

towlerg

BTW if you don't fancy ABS, ASA will work just as well, doesn't smell so bad and is easier to print.

Also if you don't fancy Acetone smoothing, PVB (similar to PLA) will smooth in isopropyl alcohol.

Stephen Moss

Depending on what you are doing it maybe cost prohibitive but try taking a look at https://hubs.com (formerly 3D Hubs), they do all kinds of 3D printing as well as CNC milling and sheet metal fabrication.

As I recall for 3D printing you just upload your STL file, it gets checked for errors and if error free an instant quote is provided.

TimB

Hi

Like the others I have used the price gets prohibitive. One part was £84. It uses about £3.50 worth of resin so you can see a few £80 parts would add up to a 3d printer.

Now if only I could make it work....

Tim

towlerg

80 quid, that sounds outrageous. Hard to believe anybody would use such a service.