Horizontal lines in resin print and other niggles

[The Great Bear]

Hi there

 

On many of my prints I get random hoziontal lines aligned with the layers, varying in spacing and severity.

 

 

Some prints are ok, but many aren't with similar print orientation and support density. I can't pin down why some are afflicted and some aren't. In hindsight keeping a systematic record of variable like resin, exposure, print orientation etc would have helped! I don't think it's a temperature issue as the resin was warmed prior to the print and the printer enclosure has a heater in it.

 

My printer is 5 years old, Phrozen Shuffle XL and is rather battered as it's been taked apart several times recently replacing the stepper motor as original one got jammed from a resin spill and then lcd replacement. I recalibrated the z axis after fitting the new lcd. The FEP is only a couple of prints old.

 

Any suggestions as to the cause and solution would be much appreciated as I've got a growing pile of nearly there but not quite prints.

Edited July 27 by The Great Bear

[stevel]

I had  a similar issue, mostly resolved by making sure the Z axis threaded rod, was well greased. 

 

Stephen 

[Quarryscapes]

This is caused by having an uneven cross section. Hard to judge on that model, but if you imagine a simple cylinder being printed on end it would all come out perfect, but if you were to add say a dome on one side in the middle that wasn't hollowed out, then when you examine that section of the print you will see that the cylinder diameter has increased in the section with the dome and gone back to normal when it goes back to plain cylinder again. The extra cross section means those layers do not shrink back a much between layers, so you get the stepping effect. 

 

You can get similar random effects though from having an insecure build plate. 

[The Fatadder]

13 hours ago, stevel said:

I had  a similar issue, mostly resolved by making sure the Z axis threaded rod, was well greased. 

 

Stephen 

What grease did you use to prepare it?

 

I have had similar issues in the past and had this suggested as a solution.  I think I have also had similar issues casued by pressure buildup in the print which was resolved by adding (hidden) holes for the resin to escape while printing.

 

Speaking of printing, its been 3 days of warm weather and I havent switched the printer on yet.  Think I need to resolve that and get printing over the weekend!

 

 

[billbedford]

43 minutes ago, The Fatadder said:

What grease did you use to prepare it?

 

Lithium grease

[The Fatadder]

8 minutes ago, billbedford said:

 

Lithium grease

Thanks, have got some ordered.   Will only be running small prints tonight so hopefully will be ok, will hold fire on bigger jobs until I have sorted it

[The Great Bear]

The distortion as in my first post has gone away, went back to using the resin I was using before with a longer exposure time. For good measure I applied some lubricant to the z axis.

 

To answer a point made earlier, given the nature of the model changes in cross-section there lots of and some will of necsssity be abrupt. Not sure what I can do.

 

The last couple of prints (only) have now got a new issue: a noticeable step in the model.

 

I

 

It's done it for two pints in a row using the same sliced file, with different exposure settings same resin. Other prints with same model and similar arrangement of supports didn't have this. What could have caused this step?

 

Another niggle is smaller banding on the print, in line with the layers. I tried changing the print orientation reducing the angle from horiztonal down to 30 degrees from 35 and keeping the same 15 degree twist. Is this a print orientation thing? I tried shorter exposure which possbly helped

 

Final issue is shrinkage of the print. Some earlier prints (with same resin) it was negilible but recent prints it's been a bit more, still not a lot 2mm over a 140mm model so not a lot around 2%. But, when trying to get model aligned with the RTR chassis I'm using for this bodged Saint and fixing scews it starts being a problem. How can I correct for this? (I am using Chitubox.)

 

Earlier prints didn't have these problems and I don't know why. My frustration compounded by that on my ancient printer each print takes 12 hours.

 

 

[heraldcoupe]

What resin are you using? I've stuck with Siraya Tech Build for my bodies, it's been very good for the (quite similar in concept) work I'm doing, no significant issues with shrinkage.

One thing I have found is that curing under UV brings a lot of issues with distortion where multiple cross section thicknesses are at play - might your shrinkage issues be related? I've taken to let my prints cure in ambient light. There is some reports mileage in curing at elevated temperature rather than under UV, but I've not experimented for myself in that area. Having worked with casting Polurethane and silicone resins for the past 20 years, the difference in curing with those media can be significant.

Secondly, are you working with a print angle calculated from pixel size and layer heights, ie arctan(layer/pixel)?

 

 

For transitions in cross section, I try as far as possible to adjust the inside faces where the external ones are fixed. There are still many frustrations though.

 

I believe the printer you are using is an older 2K design (do correct me if I'm worong on this). My Elegoo Saturn 2s aren't state of the art (8K), but are a significant upgrade in terms of layer visibility over my (now retired) 2K Longer printer. The differences was dramatic from the very first print.

 

Cheers

Bill.

Edited May 30 by heraldcoupe

[billbedford]

4 hours ago, The Great Bear said:

 

It's done it for two pints in a row using the same sliced file, with different exposure settings same resin. Other prints with same model and similar arrangement of supports didn't have this. What could have caused this step?

 

 

I would suggest it was something on the leadscrew, maybe dried on resin?

[The Great Bear]

6 hours ago, heraldcoupe said:

What resin are you using? I've stuck with Siraya Tech Build for my bodies, it's been very good for the (quite similar in concept) work I'm doing, no significant issues with shrinkage.

One thing I have found is that curing under UV brings a lot of issues with distortion where multiple cross section thicknesses are at play - might your shrinkage issues be related? I've taken to let my prints cure in ambient light. There is some reports mileage in curing at elevated temperature rather than under UV, but I've not experimented for myself in that area. Having worked with casting Polurethane and silicone resins for the past 20 years, the difference in curing with those media can be significant.

Secondly, are you working with a print angle calculated from pixel size and layer heights, ie arctan(layer/pixel)?

 

 

For transitions in cross section, I try as far as possible to adjust the inside faces where the external ones are fixed. There are still many frustrations though.

 

I believe the printer you are using is an older 2K design (do correct me if I'm worong on this). My Elegoo Saturn 2s aren't state of the art (8K), but are a significant upgrade in terms of layer visibility over my (now retired) 2K Longer printer. The differences was dramatic from the very first print.

 

Cheers

Bill.

Firstly, Bill, I must say I've been very impressed with your printing work, the various Bulldogs. The resin I'm using is Sunlu water washable dark grey. I use water washable resin because I had very bad skin reacation to IPA some years ago as a result of poor precautions when cleaning prints and now get skin irritation if I come in contact with it. I prefer the dark grey, I tried white but didn't get as good results. It had been working well until last few prints, including less shrinkage. When I've cured under UV distortion has been limited on the dropped section at front of running plate warping upward. Curing in small goes flipping model over seems to have helped with that.

 

Print angle, I tried printing at 33.69 degrees (arctan 50/75), not too bad but some horizontal layer lines on the buffer beam and stepping on the splashers where the print angle led to it being locally a flat surface. Twisting the model a bit removed some of that, the stepping on the splashers of that and reducing the inclination to 30 degrees also helped reduce prominance of marks on the buffer beam and smokebox front flat bits. I may try the arctan angle once again.

 

Some of the lines/stepping I'm sure my ancient printer doesn't help with. You'e right it's nearly 6 years old 2k one with colour lcd, Phrozen Shuffle XL. It's been taken apart several times to replace cracked LCD screen and a bunged up stepper motor. The last time it broke I was secretly hoping I couldn't fix it! Because it is old it is sturdily built, metal case and it has a hinged lid which most new printers don't have but I need due to the printer's location.

 

3 hours ago, billbedford said:

 

I would suggest it was something on the leadscrew, maybe dried on resin?

Thanks, I'm giving that a go. No obvious debris on it, but giving it a clean and new dose of lubricant. Fingers crossed that works.

 

 

[heraldcoupe]

3 hours ago, The Great Bear said:

Firstly, Bill, I must say I've been very impressed with your printing work, the various Bulldogs. The resin I'm using is Sunlu water washable dark grey. I use water washable resin because I had very bad skin reacation to IPA some years ago as a result of poor precautions when cleaning prints and now get skin irritation if I come in contact with it. I prefer the dark grey, I tried white but didn't get as good results. It had been working well until last few prints, including less shrinkage. When I've cured under UV distortion has been limited on the dropped section at front of running plate warping upward. Curing in small goes flipping model over seems to have helped with that.

 

I would certainly look at brands other than Sunlu, most brands have water washable options. Sunlu's reputation is not good, though I've no direct personal experience. I was looking closely at them as an alternative source when having problems with my preferred Siraya Build resin, but they really had nothing to offer that came close. User feedback was very poor.

That one issues I had with Siraya resins was down to an out of date batch, they have since tightened up their batch IDs and no subsequent issues.

 

While I've only trialled a few domestic (Anycubic) water washable resins, I did find their performance less impressive than the regular versions from the same brand. I too have suffered skin issues which I at least partialy blame on the printing, but haven't positively identified what aspect. Knowing about the IPA issue, Methylated Spirit has been recommended as better than IPA, though quite a bit more expensive. It's something I intend to explore, at least experimentally...

 

Cheers

Bill.

 

[billbedford]

One thing to remember with water-washable resins is that the contaminated water used for cleaning should not be poured down the drain. It should be saved and sent to a chemical recycler. 

[njee20]

FWIW I rate Sunlu resin. Specifically their ABS-like. Siraya Fast is marginally better, but it’s double the price. 
 

I clean in acetone, far better than IPA IME, perhaps worth exploring. 
 

Totally agree with Bill on water washable resins. A lot of people assume they’re good to just clean under running water or whatever. In reality it’s no less toxic than ordinary resin. 

[F2Andy]

On 30/05/2024 at 21:26, The Great Bear said:

... I use water washable resin because I had very bad skin reacation to IPA some years ago as a result of poor precautions when cleaning prints and now get skin irritation if I come in contact with it....

Likely a reaction to the resin, not the IPA. Water-washable is a different chemical, so you can be sensitive to one and not the other.

 

This is important because IPA is used in other application. I had a blood test Monday, and it was an IPA-impregnated wipe that the nurse wiped my skin with to disinfect it, so skin reaction to IPA is pretty unlikely. But if you really are allergic to IPA, you need that on your medical record, so nurses, etc. can act accordingly.

Edited June 5 by F2Andy

[ianmaccormac]

A freind also had a very bad reaction to IPA - he now uses Meths and finds it works out cheaper, dries more quickly and doesn't seem to have the problem of becoming saturated and needing replacing regularly. I have started to use it also and am finding the same. He is  still very sensitive to IPA but now has no issues when cleaning.

[The Great Bear]

After a frustrating few days, back making progress. Gave the z axis another clean and also realised that the coupling on the between the stepper motor spindle and screw the grub screw had come loose, which I think was cause of the issues seen in last couple of prints. Following the suggestion, I thought I would give the Siraya Build resin a go and be extra careful noting my previous issues. Initial impression is positve, it seems to have solved shrinkage issue (though that could also have been the z axis thing), perhaps less prone to warping and less brittle when cured.

[LMSfan72]

13 hours ago, F2Andy said:

Likely a reaction to the resin, not the IPA. Water-washable is a different chemical, so you can be sensitive to one and not the other.

 

This is important because IPA is used in other application. I had a blood test Monday, and it was an IPA-impregnated wipe that the nurse wiped my skin with to disinfect it, so skin reaction to IPA is pretty unlikely. But if you really are allergic to IPA, you need that on your medical record, so nurses, etc. can act accordingly.

I believe surgical spirit can be either IPA or ethanol so it is important to be on allergy/reaction record as stated.

[LMSfan72]

4 hours ago, ianmaccormac said:

A freind also had a very bad reaction to IPA - he now uses Meths and finds it works out cheaper, dries more quickly and doesn't seem to have the problem of becoming saturated and needing replacing regularly. I have started to use it also and am finding the same. He is  still very sensitive to IPA but now has no issues when cleaning.

We are talking the purple died Meths, correct? I’m interested if it doesn’t get saturated, but, in that case where does all the resin residue go?

[ianmaccormac]

6 hours ago, LMSfan72 said:

We are talking the purple died Meths, correct? I’m interested if it doesn’t get saturated, but, in that case where does all the resin residue go?

Yes. Don't know!

 

[Trainshed]

Hi, Just something else to try... make sure that the Z-axis stepper motor (servo?) rotates freely. turn it with your hand.

I had never ending trouble with my prints and it turned out that some resin had found it's way into the stepper bearing and gummed it up. took out the stepper and replaced both bearings and all was good again.

Since then, I have printed a little collar (from Thingiverse) that fills some of the gap between the Z-axis lead screw and the housing.

Happy printing

TrainShed.

[The Great Bear]

Well the old printer finally died so got a new a Uniformation GKTwo. Reason I went for that was the good reviews, build volume, the built in heater (as my printer is in an outbuilding) and hinged lid (the printer is under part of the layout so no space for a lift off lid). I'm having some teetihing troubles, though.

 

One of which is build plate adestion. At the moment I'm continuing to try Siraya Build as recommended earlier in this thread, I'm finding that prints (on both this new and the old printer) are struggling to adhere to the build plate. I've checked the levelling of the build plate and that is ok. I've tried increasing exposure setting for the base layer from that in the Sirarya profile for this resin, but still having issues.

@heraldcoupe wondering if you had this issue at all with this resin? The Sunlu water washable resin I was using before the build plate adhestion was very good. On my old printer I resorted to sanding the build plate but don't want to jump straight to that on the new one.

Edited June 24 by The Great Bear

[Harlequin]

I have the exact opposite problem with Siraya Tech Build resin!

 

It sticks to the build plate so strongly that I sometimes break the raft when getting prints off and remaining fragments have to be chipped away.

 

My build plate is laser-etched, I think.

 

Edited June 24 by Harlequin

[chuffinghell]

I found reducing the lifting speed helps to reduce layer lines, I found a noticeable difference between 60 seconds and 50 seconds

 

Reducing the lift speed reduces the peel forces

 

As for plate adhesion, my previous printer build plate had a 'shot blast' finish, after a while it started to loose adhesion. I sanded the build plate by putting a sheet on sand paper on a flat surface and gentle sanding the build plate but you shouldn't have to do this with a new printer

 

Is it a new bottle of resin? it may be past its used by date or be contaminated?

 

 

 

Edited June 24 by chuffinghell

[The Great Bear]

The resin is new bottles purchased within last month from Amazon. The build plate on the new printer is not engraved with any kind of pattern, nor was the old one.

 

Below are the settings I'm using for the new printer, the profile is as downloaded from the Siraya website for this resin and printer.

 

To try and solve bed adhesion I increased the bottom exposure 5 seconds from the default one. The normal exposure I increased slightly, a simple exposure text suggested 1.9s was better than default 1.8s and then added a little more due to larger models I print. I haven't changed any of the speeds, timings or lift distances yet.

[Harlequin]

I use very similar settings for the base layers but my exposure time for normal layers is longer (2.5s) for 25um layer height and there are a number of other differences: