Horizontal lines in resin print and other niggles

[chuffinghell]

I have my bottom lift speed the same as my normal lift speed, reducing the lift speed to the same as the bottom lift speed (50sec) might help to reduce layer lines?

 

Still don’t know what to suggest for not sticking other than increasing the base layers to 35 seconds

 

I have an Elegoo Saturn 3 Ultra and use Anycubic HD water wash resin so my speeds and exposure times are completely different and wouldn’t be of any use to you

 

Really wish I could be more helpful 😕
 

Edited June 24 by chuffinghell
About as useful as an ashtray on a motorbike

[heraldcoupe]

On 24/06/2024 at 10:25, The Great Bear said:

@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.

 

By the time I started using the Siraya resins, I'd had adhesion problems with others and routinely key the plates before use. Having said that, when I bought my second and third Saturn 2s, I noted the surface finish form the factory was effectilvely pre-keyed, so I did nothing to that and found adhesion good from the first go. 

 

I use the standard Siraya parameters, with only exposure time tweaked for my favoured .040 layer height.

 

I've recently been looking at upgrades and dipped my toe in the water of full professional printing equipment. In the first instance, it's startling how much you can pay for resin!
The big takeaway for me though was the move to 'soft' release, ie a more flexible film than what I have been used to. Speaking to manufacturers and distributors, this is being credited with reduced visibility of layer lines, which makes sense. This seems to be reflected in the latest generation of domestic printers with changes to the film materials.

Edited June 26 by heraldcoupe

[heraldcoupe]

This is my setup on the Saturn 2 in case that's any help. The only variation from stock Siraya profile is the 2.5 second exposure time to align with .040 layer height.

[The Great Bear]

1 hour ago, heraldcoupe said:

This is my setup on the Saturn 2 in case that's any help. The only variation from stock Siraya profile is the 2.5 second exposure time to align with .040 layer height.

Thank you for supplying this, Bill and also @Harlequin previously I will compare with what I'm now trying.  I think similar but a couple of differences:

 

Large difference is the exposure time. The downloaded profile from the Siraya website had 1.8s exposure for 50 micron layer. Yours for 40 micron and Harlequin's is quite a bit longer. I did some exposure tests for 50 micron using XP2 validation matrix test and it was showing 1.9s was best. I know the printers are different but the basic technology is the same I think so a bit suprised, I guess my one must have a stronger light source?I Nonetheless, I should try some more (larger) tests to double check.

 

Rest time after retract - I have less. I can see logic in a longer one to make sure things are settled (for want of better word) in the vat once the build plate has lowered before actually starting the print.

 

Another thing I'm realising is that even with a short exposure times prints take a good while, due to the lifting / retract times and various pauses. Slowing down the print process reduces failures I'm reading and learning. Patience, of course, is a virtue!

[Harlequin]

I am wondering if 2.5s exposure time is too long for my 25 micron layers and maybe I should have made more adjustments when I set the layer height. (My machine is a Phrozen Sonic Mini 8KS with 25 micron XY resolution, hence the 25 micron Z.)

 

However, I am getting really good, high detail prints out of it quite reliably so I don't really feel the need to change anything!

 

I read a tip somewhere (can't find the reference now) that suggested not cleaning the build plate between prints and even to wipe some resin onto it before printing. I used to assiduously wipe off excess resin but now I just make sure there's nothing solid attached and put the plate back in the machine. I think the idea is that the plate is "pre-wetted" so that resin flows over the whole surface more easily the next time it enters the vat.

 

Edited June 26 by Harlequin

[heraldcoupe]

On 26/06/2024 at 12:31, Harlequin said:

I read a tip somewhere (can't find the reference now) that suggested not cleaning the build plate between prints and even to wipe some resin onto it before printing. I used to assiduously wipe off excess resin but now I just make sure there's nothing solid attached and put the plate back in the machine. I think the idea is that the plate is "pre-wetted" so that resin flows over the whole surface more easily the next time it enters the vat.

 

 

I give the plate a rudimentary wipe over, but I don't obsess on it. Similarly, the tank is rarely drained. Even with failures, a tank clean cycle is enough to remove any detritus.

 

On 26/06/2024 at 11:53, The Great Bear said:

 

Large difference is the exposure time. The downloaded profile from the Siraya website had 1.8s exposure for 50 micron layer. Yours for 40 micron and Harlequin's is quite a bit longer.

 

I'm not familiar with your printer, mine uses a PFA film and this will be quite a factor in determining exposure. As I toy with getting high-end kit, I am also looking at the Saturn 4, which is two generations ahead of the Saturn 2s I currently use. The new films reduce exposure time significantly.

[The Great Bear]

Something that's been frustrating me with one particular print (of a tender) is an unwanted area of different texture on the print. It happens in the same place, where the back of the coal space is and in the print as below also eminating from the rear of the tender. If I change the angle of the print it still occurs it's size changes. Grey primer paint doesn't hide it. Printing in different parts of build plate doesn't change it. I am assuming it something to do with the model and orientation as I haven't seen it on other prints but don't understand why a different texture results. I never saw anything like this on my old printer. If I greatly reduce the angle of the print down to 15 degrees so so from the horizontal it is reduced / almost gone but that lower angle makes some other bits of the print harder, the thin edges at the bottom of the tender sides harder to keep straight, need a lot of light supports with then more risk of damage in removing them, filing smooth. I've just about got one not perfect but I can live with. But I'd welcome any thoughts on what's gone wrong here / clues as to how to avoid in future.

Edited July 27 by The Great Bear

[Harlequin]

Both marks correspond to places where the print forms a sealed "roof" above the film. So when the print lifts there's a lot of suction, not just the normal thing of the print sticking to the film. The suction will pull in the resin close to the film first, which is usually where the white pigment seems to settle.

 

When the print finally lifts one wall of the "roof" clear of the film the suction stops, the resin flows in normally and the white mark stops.

 

You can simply make sure the resin is really well mixed before printing but the suction would still happen and that could cause other problems. So a better solution might be to make some holes in the model at the "apex" of the "roof"s.

 

[The Great Bear]

12 minutes ago, Harlequin said:

 So a better solution might be to make some holes in the model at the "apex" of the "roof"s.

 

 

Thank you, Phil. What kind of gap, a few layers (so barely noticeable to the eye) or something more substantial? (The layer height is 50mm)

 

 

[Harlequin]

5 minutes ago, The Great Bear said:

 

Thank you, Phil. What kind of gap, a few layers (so barely noticeable to the eye) or something more substantial? (The layer height is 50mm)

 

 

 

I'm afraid you might have to experiment a bit. I suggest starting with a 2mm square or 2mm diameter hole. It has to go right through the top of the tank.

 

[The Great Bear]

Not the clearest of photos but a few 1mm holes resolved this - 3 in the back wall of the coal space and 4 close to the back of the tender

 

 

Thank you for you help, Phil @Harlequin

 

[Harlequin]

44 minutes ago, The Great Bear said:

Not the clearest of photos but a few 1mm holes resolved this - 3 in the back wall of the coal space and 4 close to the back of the tender

 

 

Thank you for you help, Phil @Harlequin

 

 

Great! The print is looking really good.

 

[The Great Bear]

Marks like these are a z axis issue aren't they? Only appeared on last couple of prints I think.

I managed to sand them away so that not noticeable after a couple of coats of spray primer.

 

Clean and lubricate the z axis I guess is the answer? I have some spray lithium grease, is that the right stuff? Spray onto a rag and wipe that on the thread?