A Venture Into The Unknown - Elegoo Mars 3D Resin Printer

[richbrummitt]

That's what I thought, since how do people get these lovely fine details and definitions on prints. The cover was left on after the print - I literally started it and left it to finish and then left it a while longer before I got around to taking the plate off and cleaning up. Will the cover let UV light in? My assumption was that the colour was chosen deliberately to filter most visible light out. 

 

This milk churn load is easier to remove from the build plate than the rooks were. I had a real fight with those! I went looking for a box of razor blades because I know I had some around 9 years ago but I do not know which box in what room they are in. $60 for a pair of flexible build plates seems a better option to me. Hopefully I can just leave the head on the Z axis and change the plates in and out.

 

The whole print is 54x15x5.5mm and that volume is less than 50% filled so it is not using much resin. I am therefore not putting much resin in the machine. I am printing standard settings - 0.05mm layers. I think it is 2.5s/layer after the base layers at 35s. 

 

The problem is not uniform or consistent across the print. Yesterday I printed another from the same .ctb file (madness, I know) and resolved to clean it straight after it finished. It does seem I have a problem with the draining resin curing because I again had the problem of a very thin film of resin curing on the build plate before I had got the print off the plate. I did manage to clean it off with alcohol and scraping this time because it was a bit thinner. Does the standard grey resin really start to cure in room/daylight after only a few minutes? The part is better but still has significant areas of globs. There are some areas that have come out exactly as they should have, but not many. 

 

One thing I did manage to do was cure the part with far less warping. It will always warp some because of the geometry but I'm happy with how flat I did manage to get this time. 

 

Some really helpful pointers there @njee20. Any tips for how to get rid of the bubbles in the resin? It does seem good at holding bubbles and I think that might be a contributing factor. Some of the affected areas are not at the base but a non-planar film further up the cones.

 

 

 

 

Edited November 11, 2020 by richbrummitt
insert images.

[njee20]

Weird. I’ve never had bubbles like that. I wonder if that’s the retract speed being too high - so it’s slapping back into the resin, and generating bubbles in the stuff that hasn’t cleared from the base of the churns.

 

If you want to keep trying that file (nothing wrong with that), then I’d definitely start tweaking the lift/retract settings. Ideally change one at a time, so you know what’s fixed it! Try lift speed at something like 60mm/min.

 

edit: I wonder if more resin would actually help. Personally unless I’m mixing resins I just pour a load into the vat, I never measure it. I wonder if bubbles are more likely because there’s not much in there. 

Edited November 11, 2020 by njee20

[Adam FW]

that's really strange, I've never had an issue like it

 

I have done a quick google search for bad resin symptoms and came across this from formlabs

 

https://support.formlabs.com/s/article/Ragging?language=en_US

 

looks to be a very similar problem they call 'ragging', it has a number of causes including out of date resin and densely packed parts, hopefully the article helps or at least knowing a potential name for the problem may lead to a solution.

 

I do think something is wrong with the resin but I'd be surprised if it had 'gone off' as there was such a shortage earlier in the year that most stock should be very new.

[njee20]

Densely packed parts tallies with my thought, the resin can’t drip out easily. Worse at the moment with lower temperatures and more viscous resin. 

[monkeysarefun]

I'd say the same- resin is not clearing from between the churns before it gets dunked back into the vat and hit with the lights.  The waviness implies that in any particular cycle it has  drained more from between some churns than others. That tightly packed the resin is going to run down the sides of the churns rather than drip directly off of the build plate. Is it overly cold there right now? If so heat the resin vat with a hairdryer or similar before setting it off.

[richbrummitt]

It’s meant to be a full load of churns and they went 15x4 in a slat sides van. I could split them into individual rows of else fails. 
 

The resin has 7 months left on it according to the bottle and the thermostat is at 19-20 Celsius when I’ve been printing. Humidity is ?? and I don’t have a measuring tool for that to hand. 
 

How much shaking to mix does the resin need before pouring? Perhaps I am being overly vigorous. 

[monkeysarefun]

1 hour ago, richbrummitt said:

How much shaking to mix does the resin need before pouring? Perhaps I am being overly vigorous. 

Not much if the fact that I'll have some sitting in the vat for a  couple of weeks and just give it a quick swish with the spatula before setting off a print is anything to go by. 

[55020]

I wouldn't "shake" a bottle of resin at all. 

 

monkeysarefun's "swish" is a much better description of how to mix the resin, whether in or out of the bottle.

 

 

 

Steve

[richbrummitt]

Yesterday I had a more successful print. I tried a few things on the one build:

 

- lift speed reduced from 90 to 60mm/min

- a single row of churns flat on the plate

- the current 15x4 array of churns flat on the plate 

- inclination of the array above on supports

- array parallel to the build plate but lifted 5mm with a skate raft. 
 

The skate raft made the print easy to remove from the plate but this last print did not survive. I had my first stuck to FEP print with this one. Unsurprising that the build tore apart at the support/part interface even with 90% support density and medium weight supports. 
 

Watching the print drain after finishing shows that the array really can hold a good amount of uncured resin. The inclined array drained a little better but there was still a good amount of liquid resin suspended between the churns at the lowest point. 
 

When I removed the plate with the parts on I used a thin plastic scraper to move the resin from between all the parts and dabbed them off with a paper towel. This released a fair amount of resin back to the vat. 
 

I proceeded to separate and wash as per usual. Here the prints that survived. 
 

 

 

 

That last shows some warping. I believe this will be the supports not being of sufficient density. I had to add all the supports individually on this one because the auto generated ones were looking awful. 
 

Short version is that none exhibited the phenomenon encountered previously.
 

There is another variable that I’ve thought of this morning. Does anyone else have LED down lighters in the room with their printer? I’m sure I had the lights off yesterday and they could have been on previously. 
 

There are many variables in my ‘test’ of yesterday (it’s not a good test) so I will print the original file again today and see what happens this time. 

[njee20]

Looking much better! LED lights shouldn't make too much difference, unless you've got a spotlight right on the cover. I've seen people who have their printer in a bright window getting some "skin" on the vat, but artificial light should be ok.

[richbrummitt]

Dredging this thread rather than keep starting new ones. 
 

Thanks to help received up thread I’ve been much more successful. One big change was getting a wash station (Anycubic wash and cure). I would say that it is essential to my workflow and that people getting a resin printer budget for this or something similar. 
 

I recently updated to chitubox 1.8.1 from 1.6.5 (I think) but I wrote down all my settings first and set up a new profile with those. A couple of defaults have changed and some new settings. Light delay 7/8s where I previously had 0. I know what it is but not how it affects prints. Also: Anti aliasing by default is now 4 and motion blur 2. Again I’m unsure what effect these would have. I was happy with my prints before. I changed with an expectation of better auto supports but I don’t see them. 
 

Since, I’ve been trying to print a cattle van. I have some effects that I’ve been working to eliminate. The main problem is to keep the solebar straight.
 

 

The view from the other side if the same model is not the same. 

 

 

I added a plinth several mm deep but that seems to have it’s own issues, which is weird because a van with a similar structure prints okay. The van is inverted so the curve of the roof means that the layer transition is not supports to everything at once. Even so the distortion seems to be more pronounced here than I think it should be. 

 

 

Another view shows the plinth details. The bracing would improve stability during cure. 

[drduncan]

Rich, 

 

I wonder if the curve is due to the supports breaking off - you can see some in the bottom image. As you are using a plinth maybe go for heavy supports the don’t taper to a point?

Duncan

[Quarryscapes]

I'd try printing straight on the bed without the supports under the sacrificial bit. 

[jdb82]

I think I'd be tempted to tilt it 45 degrees on both the x and y axes - that should help

[monkeysarefun]

Missed the early bird special on the Mars 3 but put one on preorder.  Ultra 4K screen, build plate a bit larger than the Mars 2 (but not Saturn size) and a few other nice-to-haves, plus a free copy of Chitubox Pro.

 

$300US with free delivery to downunda.

 

The question is, did I beat njee20....?

 

 

Edited June 21, 2021 by monkeysarefun

[richbrummitt]

On 26/05/2021 at 00:24, richbrummitt said:

Dredging this thread rather than keep starting new ones. 
 

Thanks to help received up thread I’ve been much more successful. One big change was getting a wash station (Anycubic wash and cure). I would say that it is essential to my workflow and that people getting a resin printer budget for this or something similar. 
 

I recently updated to chitubox 1.8.1 from 1.6.5 (I think) but I wrote down all my settings first and set up a new profile with those. A couple of defaults have changed and some new settings. Light delay 7/8s where I previously had 0. I know what it is but not how it affects prints. Also: Anti aliasing by default is now 4 and motion blur 2. Again I’m unsure what effect these would have. I was happy with my prints before. I changed with an expectation of better auto supports but I don’t see them. 
 

Since, I’ve been trying to print a cattle van. I have some effects that I’ve been working to eliminate. The main problem is to keep the solebar straight.
 

 

The view from the other side if the same model is not the same. 

 

 

I added a plinth several mm deep but that seems to have it’s own issues, which is weird because a van with a similar structure prints okay. The van is inverted so the curve of the roof means that the layer transition is not supports to everything at once. Even so the distortion seems to be more pronounced here than I think it should be. 

 

 

Another view shows the plinth details. The bracing would improve stability during cure. 

 

An update on this:

 

One super helpful forum member (they know who they are) contacted me by PM and really helped me focus with the troubleshooting with some great suggestions and support. They also went to the trouble of test prints on their printer, which proved that it was possible. 

 

My first problem was that my settings did not copy over from Chitubox 1.6.5 to 1.8.1 successfully and I needed to reduce my lift speed. That stopped the model separating from the supports where they were adequate. Previously sliced files printed okay so it was hard to suspect the printer but I dutifully checked everything with that. 

 

It turns out that the sacrificial parts are not required. More supports, particularly at the corners, made all the difference. I have still not got a perfect result but I have got to something that I am going to accept. I still get some distortion when removing these prints from the build plate whatever I do with the bottom layers so the 'silver bullet' is to cure the model on the build plate sufficient to separate it from the supports without flex, before removing the raft and leftover support structure. The horizontals are then horizontal rather than slightly banana-esque when viewed along.

 

I damaged the most recent prints removing them from the supports in this way (so no pictures because they went in the bin already) but with more care I know it is possible to do.

 

[richbrummitt]

Now for pictures. 
 

 

 

the sides bow out a little sometimes, see around the top of the drop flap, and the top of the ends are a bit wibbly. Printing with an inclination on the long axis may or may not fix the ends but the sides might still bow out. (I think the latter is happening when I de-sprue the top of the sides - above the windows - which I’m doing on the green part.) It’s something that I will need to look into for the future for coach bodies but more trial and error there to use thinner layers &c. &c. 

[njee20]

On 21/06/2021 at 01:06, monkeysarefun said:

Missed the early bird special on the Mars 3 but put one on preorder.  Ultra 4K screen, build plate a bit larger than the Mars 2 (but not Saturn size) and a few other nice-to-haves, plus a free copy of Chitubox Pro.

 

$300US with free delivery to downunda.

 

The question is, did I beat njee20....?

 

Haha, missed this! I wasn't fussed by the Mars 3 - fills a niche I didn't need. The bump in build volume is useful, but I'm not worried about the increased detail. I do have a Sonic Mega on order though!

 

I have bought a mono upgrade kit for my original Mars, it was only £5 more than the standard LCD, see how it works out.

[Tricky-CRS]

I have an Mars 3 on pre order missed the early bird but I think that was only 100 units. I am only interested in the increased detail so will see if it is any better.

[monkeysarefun]

I bought the Mars 3 after thinking of getting my original Anycubic Photon working again. The issue seems to be motherboard related but at $131US for the motherboard plus $45 delivery for a 'might fix it' I though $300 for a spanking new upgrade in the form of Mars 3   was a much better use of the cash. 

[njee20]

Absolutely! My Photon is virtually dead now; hideous z-wobble on anything more than about 15mm high, the LCD is dying, but it’s so much more faff to change than the Mars I just can’t be bothered! I ought try and resolve both at the same time!

[monkeysarefun]

If you have a corner of your layout going spare and have a larger printer, why not put in the Albert memorial? It's free to download, the guy who posted it has many other London landmarks posted that could make cute little desk ornaments or whatever...

https://www.myminifactory.com/object/3d-print-the-albert-memorial-157887

 

 

 

 

 

 

[monkeysarefun]

Well this was pretty cool. Back in June I paid $300USD for a pre-order Mars 3  with free delivery and 12 months subscription  to Chitubox Pro.

 

I've had the printer a couple of weeks and today I got a paypal notification that I'd got a $45USD refund! Not sure what its for since I've not had any info about it from Elegoo. I might email them asking what its all about but am concerned they'll realise its a mistake and take it away again so I might just sit quietly on it.! 

 

So, all up a Mars 3 delivered with 12 months of Chitubox Pro cost me $255USD, or about 187 GBP..