Dodgy resin 3D print

[Dan Randall]

I recently had a go at printing some BR Mk1 coach ends in 7mm scale as an experiment, but they could have been better….

I printed the ends  vertically on my Elegoo Mars2 Pro, using Elegoo’s ABS-Like Photopolymer Resin and they had printed as well as I’d hoped for, until the very top of the gangway opening was reached, at which point, they took on the appearance of having shifted outboard by about a millimeter!

 

I was wondering if it was a support (or lack of), issue as the slicer (Chitubox), only placed 6 supports in the gangway opening, so I tried it using Lychee slicer instead.  This only put in one support and produced much the same result, but with some additional distortions on the way up….

I was only trialling it on the Elegoo, with a view to farming the job out to a professional 3D print outfit if I need any more ends.  The question is, will any of the prints they produce in say SLA, or SLS, suffer from the same distortions?  Any thoughts please?

 

 

Regards

 

Dan

[stevel]

Dan I'm thinking this may be a sticky Z axis screw, try spreading the lubrication, on the screw and then run the print bed up and down about 100mm.

[Dan Randall]

1 hour ago, stevel said:

Dan I'm thinking this may be a sticky Z axis screw, try spreading the lubrication, on the screw and then run the print bed up and down about 100mm.

Thanks Steve - I’ll give that a try at some point and report back, but it probably won’t be for a little while. 🙂

 

 

Regards

 

Dan

[LMSfan72]

Looking at how the shift occurs at the top of the opening I think it’s the change in area across the top of the corridor that changes the sticking forces considerably at that layer. I would add supports and try a different orientation

[JimFin]

Printing vertically like that will always pose a risk of a wobble, orientating the job with supports behind will be more reliable and may give a better finish. This you tube explains - 

 

[PhilH]

Try printing at 20 deg to horizontal,  also Lychee gives you plenty of options re supports, light, medium, heavy, tip shape and diameter etc., so try playing with them.(Having said that I choose tip dia depending on job then choose auto placement, either light, medium or heavy depending on size of job) I always move my objects 5mm off build plate too.

I have to say I find the basic Lychee to be about the best slicer I've tried.

 

Edited October 12, 2023 by PhilH

[Dan Randall]

Thanks for the additional suggestions guys - I shall experiment in due course.

 

 

Regards

 

Dan

[stevel]

On 11/10/2023 at 17:40, Dan Randall said:

Thanks Steve - I’ll give that a try at some point and report back, but it probably won’t be for a little while. 🙂

 

 

Regards

 

Dan

I had another thought on this, also try raising the model higher with longer supports, if the mishape is in the same place then it is not the Z-axis, but if it moves down the model, it is.

[billbedford]

On 11/10/2023 at 22:52, Dan Randall said:

I printed the ends  vertically on my Elegoo Mars2 Pro, using Elegoo’s ABS-Like Photopolymer Resin and they had printed as well as I’d hoped for, until the very top of the gangway opening was reached, at which point, they took on the appearance of having shifted outboard by about a millimeter!

 

This looks like the build plate is moving horizontally relative to the vat. I've seen something similar when I've not screwed the build plate to its support tight enough. 

 

[Blefuscu]

Lots of good advice here. I would add that if you are farming that out to professional SLS printing then they should support and clean the model, and as long as it meets their design criteria it should be fine. I used to use https://jlcpcb.com/ for my prints before I had a printer.