Resin printing problems, what am I doing wrong?

[ikcdab]

After a lot of thought we bought a elegoo Saturn printer last May. We are using it with elegoo water washable resin and the chitubox (or sometimes lychee) slicer.

 

But it is problematic. Certainly not "out of the box". At the moment I am using it for functional items such as servo mounts and internal fittings in my  block bells, but i plan to move to scenic features such as girders, signal lamps, canopies etc.

 

So far it has been a hit and miss affair. sometimes prints work, other times they fail for no apparent reason. This is incredibly frustrating and I am on the verge of chucking it away -  but I keep coming back for more. So I have tried to list the variables below and where I am with them. I am grateful for all comments.

 

1. build plate levelling. This was not a problem, but after a recent failed print I spotted that the build plate had lifted 0.5mm on one side. i corrected this and the subsequent print was good. So now i feel i need to check the build plate before every print. Is this what other do?

 

2. FEP film: the very first print I did failed and I had model stuck to the FEP. In my ignorance I was too vigorous with cleaning it and I damaged the film. I replaced it and then had to replace again. My current film has visible marks but no holes. I clearly cannot replace the FEP after every print, but how do you know when it needs replacing? I think I have the tension right as i have had some successful prints, yet others that have failed on the same film.

 

3. settings: After the first initial fails, I changed the settings and had some successes. these are as follows:

 

I have not changed these settings since i started and, as I said, sometimes they work, other times it doesnt.

 

4. supports: this seems a bit of a black art and I cannot find absolute rules. i tried to print some signal lamps and these failed completely. As the component was so small, i thought it good to switch to "light" supports as opposed to "medium". The light ones have a smaller contact area and I now think that these werent strong enough and pulled away from the model. Is I type, I have switched back to "medium" and we will see what happens. What I don't know is how much support is needed for the inital bit of the component. With my servo mounts, the printer has to "draw" a horizontal line across as the first part of the component and then  build subsequent layers on top of that. So now i try and cram in lots of supports on this intial piece. What i don't know is how far a 0.05mm layer of resin can span between supports. The image below shows what I mean - The thin black line is the first layer of the component. How best to support this?

 

 

5. pausing. I get anxious and so i occasionally pause the print to see what is happening. I have now read that this can cause problems with failed prints. But I have always done this and sometimes it works and sometimes it doesnt - so I'm not sure if this is a problem or not.

 

6, temperature - as it has been cold out in the shed, I have brought the printer into the house so it is at normal household temperatures - I live in Somerset. The resin is also in the house and I shake it before pouring into the vat.

 

7. other things: because of the number of failed prints, I have got into the habit of filtering the resin before each print. I empty the vat, clean it out, polish the glass and refill the resin. Absolute pain to do every time. 

 

8. Too much on the build plate: I have crammed on a lot of things onto the build plate and now i am wondering if cramming things in might cause problems, though I dont see how. In theory I could build one large component the extent of the plate and it should work - so what is the difference with doing lots of smaller ones? After today's failed print I am now trying again with the components thinned out - but they also now have medium density supports, so if it works I won't know which one solved the problem.

 

I cannot think of any more variables for now. So all advice gratefully received. i really want this to work properly but at the moment I am pretty sick and tired of it.

 

Ian

[ChrisH-UK]

I use an Elegoo Mars 2 Pro and was pleasantly surprised how well it worked out of the box. I've attempted to answer each og your points below based solely on my own experience.

 

1. I check my build plate regularly but not every time I print and so far (3 months) I've only had to adjust it twice.

2. My fep has a few marks but still works ok, for best results I should replace it but I'm still happy with what I'm producing at this stage

3. I've mostly used the default settings for the printer and the resin. Obviously the manufacturer's recommended settings are very conservative and trusted Youtubers can suggest how to improve on them and YMMV.

4. Supports certainly is a black art. I've printed some things directly on the build plate, those with a small support footprints snap off cleanly, larger pieces do not. I'm still learning what makes the best supports including building my own into the design. I plan to invest in a magnetic build plate.

To troubleshoot further you would need to show more of the item being printed, personally I wouldn't trust a single horizontal line as the first layer of actual part, regardless of the supports around it.

5. I've only paused under exceptional circumstances for fear of sabotaging the print.

6. Have always printed at normal household temps, I know others have had issues with cold temps and draughts.

7. I only filter the resin at the end of a session when I empty the vat or if I can tell there is debris in the vat

8. I have printed multiple things but try hard not to cram the build plate full. 

 

[GWR57xx]

Santa very kindly delivered a Mars 3 Pro for Christmas 2022 (my first 3D printer), which I am just getting to grips with.

After reading everything I could find about setting it up I went ahead and ran my first print. It failed - stuck to the FEP.

Cleaned everything out and re-levelled the build plate, using the four bits of paper method (one per corner of the build plate to make sure it's exactly level.

Also read a whole load more stuff on'tinternet and came across a very useful tool called UVtools. It's a free download and will analyse your ctb file (Chitubox slicer output file) for any issues.

Equally usefully, it allows you to fine-tune parameters for the bottom layers, especially the initial "Rest Time After Retract". Apparently the printers ignore this delay for the first exposure, which is when it is most critical.

The build plate has just compressed the resin to within 0.05mm of the FEP, and resin is rushing out of the way when the first exposure happens. 

Using UVtools I've added a 20 second delay for the base layers, to allow the resin time to settle. So far, so good (tempting fate I expect).

Also, your bottom exposure time of 50s looks a bit high - I'm now using 20s but I realise this varies by printer, resin, temperature etc...

So far I've only used Elegoo Standard Grey resin - lots still to learn. Not least getting to grips with 3D modelling, which is all new to me too.

What fun!!
 

[stevel]

can you show a screen capture of the item that failed, from the slicer program, it may need to be at an angle to the plate. i have attached an example of a wagon print.

I have found that temperature can make a huge difference, and keep my printers under the cardboard box they came in, with a 16w reptile heater underneath, this has almost eliminated failures.

I also turn on the printer some 30 minutes before printing to allow everything to warm up.

the only time you need to empty the vat is when something is stuck to the FEP, you can test this using the small plastic scraper, by gently stirring the resin across the Fep, you will feel if you hit stuck resin.

if something is stuck to the FEP, a gentle push from underneath should release it.

[drduncan]

I agree that temperature is likely to be an issue. Check you resin bottles and see if they have a optimal temperature. I have reptile heat pads (£16 from Amazon) stuck to the inside of my Anycubic photon Mono Perspex and using a temperature control box that came  with them the temperature is kept between 25 and 30 degrees during printing. My printer lives in the attic and it gets cold up there! In fact in the last cold snap I had to add a second heat pad.

 

Duncan

[drduncan]

Just to emphasise Steve’s point about turning on and letting things warm up. This morning the temp inside my printer was 21.9 with the printer off. Turning in and leaving it for just over 30 mins saw the temp rise to 23.9.

 

Duncan

[The Fatadder]

Cold is certainly an issue at this time of year, I have completely stopped printing after having a couple of failures around the time of Warley last year once the temperature dropped.  We dont have the heating on constantly so there is quite a lot of temperature variation through the night when I do most of my printing.   Think I will go and have a look at those reptile heat pads as that sounds a good solution for getting the printer up and running again, particularly a I am now building up something of a backlog! 

 

In terms of the build plate I have only ever checked mine when ive moved the printer, though I will probably check it again when I start using it after a couple of month brake over the winter.  I tend to leave the resin in the tank when I am not using it rather than continusly draining and refilling, but again drain it when its planned to be out of use for a while.

 

I will often put a lot on the build plate at the same time, although I do try and avoid having lots of small parts combined with a large item that comprises many more layers.  One thing I have found is that if you print the same thing in the same location on the build plate (particularly if it is not angled) it damages the FEP due to the pull pressure being applied to the same location over and over again.  The solution seems to be moving the part around on the plate for repeat prints (rather than just leaving it dead centre).   As for when it needs replacing, I tend to replace once I start having failures.  I do keep meaning to buy a second tank so that I can switch between two, the logic being that often due to the previously described issue I have areas on my FEP that are not useable, however a lot of the screen is still good.  My thinking is that I would like to make use of the life remaining in the good areas of the FEP for smaller prints, but have an alternative option when I am doing something like a full wagon.

[drduncan]

My set up. You can see the black heat pads abs the thermometer below the left hand one - it’s lift by the vast securing knob.

Duncan

[PhilH]

32 minutes ago, drduncan said:

My set up. You can see the black heat pads abs the thermometer below the left hand one - it’s lift by the vast securing knob.

Duncan

Interesting…I too have experienced failures on my Mono x during the cold weather, not so much on my Mars 2 pro. I wonder if it is that being bigger it’s a colder space, I don’t know. Which wattage pads do you use, seems to be a lot of different ones on Amazon,, better still can you post a link to yours please?

 

 

[drduncan]

My photon mono has 2x16watt heat pads. https://www.amazon.co.uk/AIICIOO-Lizard-Vivarium-Tank-Warmer/dp/B086SL7MYX?pd_rd_w=MIVZX&content-id=amzn1.sym.28ecf3c0-e35d-463b-8f69-d55af961869c&pf_rd_p=28ecf3c0-e35d-463b-8f69-d55af961869c&pf_rd_r=42FFCWVHN676J7Y43AZP&pd_rd_wg=JKFAo&pd_rd_r=a0f4e8af-d8df-46e6-a2a2-094cb31f243b&psc=1&ref_=pd_bap_m_grid_rp_0_0_sa&th=1

Edited January 18, 2023 by drduncan

[Giles]

I find that my Mars 2 Pro runs reasonably warm - warmer than the ambient temperature - which is extremely useful from this perspective.  I operate it in an unheated room in the house, so this is beneficial. I have a very low rate of failed prints.

[PhilH]

After reading up on heating the printing space/ resin I’ve decided to go with a temp controlled fermentation belt, usually used in homemade beer making etc. Apparently you wind it round the resin vat and it keeps the resin at workable temps, being as both the machines have metal vats I’m hoping it will work well.

 

We will see if it’s as good as people say or just another rabbit hole to pour cash down.

 

[ikcdab]

So a further question. Supports.

In the attached image, you will see the first part of the print appearing as a black line spanning the supports. My question is, how far can resin span in this situation? Bearing in mind its only 50 microns thick at the start, there must be a lot of strain when the build plate tugs it away from the FEP. Up until now I have crammed in as many supports in this situation as I can, but i am now wondering if that is the right thing?

 

[PhilH]

I’m by no means an expert but if I have to print anything with a horizontal surface I incline them, min 15 deg, 30 better. As I understand it that reduces the pull of the Fep as only part of that surface is in contact with the Fep. Hopefully others will come on with better solutions but that usually works for me.

[ikcdab]

1 minute ago, PhilH said:

I’m by no means an expert but if I have to print anything with a horizontal surface I incline them, min 15 deg, 30 better. As I understand it that reduces the pull of the Fep as only part of that surface is in contact with the Fep. Hopefully others will come on with better solutions but that usually works for me.

Thanks, yes i do that. In this case i have inclined things 45 degrees for just that reason. Its a longitudinal girder.

[Quarryscapes]

This is exactly why you incline stuff, so the contact area with the FEP is reduced as small as possible. That will print but you will have a wibbly wobbly edge, imagine the underside of fishbelly rail and your supports are the chairs. 

[ikcdab]

3 hours ago, Quarryscapes said:

This is exactly why you incline stuff, so the contact area with the FEP is reduced as small as possible. That will print but you will have a wibbly wobbly edge, imagine the underside of fishbelly rail and your supports are the chairs. 

Yes I know about inclining stuff and that's what I do.  But however you incline it, you still have to start the print somewhere, hence my question about how far the first layer of the print can span between supports.

I have done two print runs today.  The first one had a few gaps in three print, luckily on the hidden side.  I immediately ran the print again with the identical print file and that one went perfectly.  The only difference would be thatv the second print was after the printer has thoroughly warmed up.... Though it is situated in a normally central heated house.

 

[PhilH]

On 19/01/2023 at 12:59, PhilH said:

After reading up on heating the printing space/ resin I’ve decided to go with a temp controlled fermentation belt, usually used in homemade beer making etc. Apparently you wind it round the resin vat and it keeps the resin at workable temps, being as both the machines have metal vats I’m hoping it will work well.

 

We will see if it’s as good as people say or just another rabbit hole to pour cash down.

 

Sitrep…I’ve managed a couple of successful prints using this thing, of course there’s nothing to say that they wouldn’t have been successful anyway. However, it has acted as a confidence booster and added to the hope that I can actually print in a cold house. One caveat, because I had to feed the plug cord into the printer I had to angle the lid slightly meaning that it wasn’t completely sealed during printing. Fortunately I have a couple of the Elegoo mini activated charcoal air purifiers which, to my mind anyway, do help to mitigate the fume smell somewhat.

 

Some stats..the belt is rated at 35 watts so is frugal to run. It is long enough to completely wrap round the Mono X vat. The start temp of the resin in the vat was 14 deg, after just over an hour on max when I started the print it was 25.5deg. Average ambient temp in room was 16.5deg.

 

Obviously one, or even two swallows don’t make a summer, but I am cautiously optimistic that this could help with the problem of printing in low temps.

 

[PhilH]

I am actually very pleased with the item described above as it seems to be the answer to printing in a cold house. I have quite a big order from a family member for objects to be used in a training situation for the Army so had to find a solution really. I used both printers and both worked so, as I say, either it would have worked anyway or the belt is the solution.The first bits off…

 

Edited January 27, 2023 by PhilH

[MikeTrice]

I have used a paint stripper heat gun to warm the resin and build plate before starting a print. Once the print has started the machine generates enough heat to keep the process working.

[chb2488]

On 26/01/2023 at 13:44, Quarryscapes said:

This is exactly why you incline stuff, so the contact area with the FEP is reduced as small as possible. That will print but you will have a wibbly wobbly edge, imagine the underside of fishbelly rail and your supports are the chairs. 

Very enlightening so far! On the prints I had done, I noticed the resulting wobbly edge. Are there any common design tricks around this? If e.g. you print the body of a covered goods van, could you extend one side slightly and then remove that section?

[stevel]

12 hours ago, chb2488 said:

Very enlightening so far! On the prints I had done, I noticed the resulting wobbly edge. Are there any common design tricks around this? If e.g. you print the body of a covered goods van, could you extend one side slightly and then remove that section?

I use a sacrificial strip along straight edges, an idea borrowed from someone on this forum, and it has proved successful.

these two prints show how the strip has warped but not the actual model and some of the supports have even broken away without affecting the print.

[The Fatadder]

9 hours ago, stevel said:

I use a sacrificial strip along straight edges, an idea borrowed from someone on this forum, and it has proved successful.

these two prints show how the strip has warped but not the actual model and some of the supports have even broken away without affecting the print.

Interesting how you e done it with just small

1mm? Square blocks between the sacrificial strip And the body.  I’ve been using a V joint along the whole edge, I hadn’t thought about reducing the contact area further still

[stevel]

10 hours ago, The Fatadder said:

Interesting how you e done it with just small

1mm? Square blocks between the sacrificial strip And the body.  I’ve been using a V joint along the whole edge, I hadn’t thought about reducing the contact area further still

here are the dimensions I use for the breakaway strips.

 

this is the slot openings, in the connecting strip

[Quarryscapes]

I find knife edge supports very useful, you'll have to do them at the design stage though. These are how my FR axleboxes are printed.