3D prints

[carlislecitadel2]

Hi Paul,
I have heard filament can get moisture logged. To be honest the quality has not changed using new filament of the same type so I don’t think that is it. I have a Comcrow enclosure and printer running most of the day so it’s quite warm, no drafts and it’s warm in the toy room, as SWMBO refers to the railway area. There are several silicon sachets in the enclosure which have not showed any sign of changing colour. It’s always possible but I’m leaning more toward different filaments and their properties and/or slicer settings as the more likely culprits.
The first filament I used was Techbears white and it yielded a great finish. However, it did not normally print well defined rivets. These prints were done using the Creality slicer. Strangely it missed elements of some prints out completely, like consistently not printing one of the 4 vents on one of Sascha’s containers or the supporting stunts on one side of a hopper wagon. I switched to the Cura slicer, which the Creality one is based on, and the missing elements issue disappeared. All prints had all elements printed and to the same quality.
When the Techbears white PLA ran out I tried Esun ePLA gloss grey as my dad complained he could not see the detail on white prints. Initially those prints were very stringy but the appearance of layer lines was very visibly reduced and rivet detail was clearer. Both PLAs had adhesion issues with prints detaching mid print so I started using rafts. Much more plastic is required but at least prints stick 98% of the time. I altered temperature and retraction settings to reduce stringing and was getting nice prints seen early in in this thread.
Irritatingly Amazon no longer stock either of these filaments now so I have been trying others. I also had to move my printer and change the nozzle after a couple of issues with one particular .stl print coming off the raft and me returning to find 6 hours of congealed plastic round the nozzle. It was easy enough to replace the nozzle but it took a long time to get the z off set sorted after that to get rafts to stay on the bed and even though I got that fixed after a week my prints have never been to the same quality again. The Sunlu grey filament doesn’t seem to give me great results but if fairness I had deleted my originally slicer profile so that may be as much the reason for the filament it giving great detail. Esun PLA gloss black and changed slicer settings returned some of the detail but prints were the stringiest I had done. I am also trying Esun ePLA matte white and getting the results posted this week. Not as stringy on the bodies but inclined to blob a lot around rivet detail such as corner plates. It really a case of adjusting one or two parameters at a time and reprinting the same file over again to play spot the difference. I am using Andrew Grand’s 2mm LNER wooden bolster wagon scaled to 4mm as the test bed at present and have reduced the blobbing a bit by increasing retraction and dropping back to 20mm sec print speed with a wipe after each layer. I am doing that as it’s a smaller print compared to Phil’s vans and I had promised a trio to the owner of a lovely little NER layout which is on the N.Ireland exhibition circuit and which I hope is at the Bangor show this weekend.

I also get some .stls which curl up at the corners as they print while others do not. One 10mm print for a reverse Stanier brake does it every time. I am increasing the initial layer height and the fan speed on lower layers to see if that helps. I will try and remember to take photos of each print at different settings to illustrate the impact or not of any setting changes. It’s a bit sickening that the initial standard settings before I understood anything about slicer settings turned out such nice prints compared to the tweaked ones. I did go back to Cura’s basic 0.08 and 0.12 settings a couple of weeks ago and only changed them to include a raft and supports touching base plate but results were poor which makes me think the PLA type is maybe as important as the settings.

[john coffin]

Interesting reply, and obviously you have tried many things.

One thing I would say, is that it often seems to me that when you fiddle with your 3D printer it gets worse.
Strange that many of the videos you watch seem to make it really easy, and yet when you fiddle it becomes
really complex.

I too had some problems with raft moving, but unlike you, my machine is not running so often, and thus I bought
a new bed, etc, but updating the slicer to the latest Creality one was a big move. Strangely I found the Cura
"industry Standard" was not to successful. Makes you wonder.

I wonder if there are steps too far in some cases?

Paul

[carlislecitadel2]

Hi John,
I fully agree - it’s very easy to mess up your printing and the more you change the worse you seem to make. It’s not as simple as it’s made out to me.
That said, at the First Bangor show last night, Derek, a fellow UMRC club member who has both a resin printer and an Ender 5 max, brought his friend down to chat to me. His mate Alan had introduced Derek to 3D printing and Derek had showed him my photos. Derek too had thought moisture might be an issue. Alan took a look at the first print I handed him of one of Phil’s vans and immediately said he could tell from the rafts initial layer that my Z-offset was too high. Then he looked at 5he side and said the detail was there ok but my flow rate and temperature migh5 be out. He asked what my retraction settings were at and advised dropping it to 0.8 and increasing print speed from 20 to 45. I had read to turn the speed down and increase retraction to about 2 to deal with stringing. I ran off a few 1/72 ammo boxes for a military friend at the show early this morning using Alan’s suggestions for the new settings and lo and behold no stringing at all and sharp prints at a faster rate. Trying the same settings out now on Sascha’s LNER D25 FM container. I have never got a decent quality print of it yet so if this works I will be very happy. Fingers crossed.