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How would you print this threaded Rod ? (Image)
Posted: Sun Jan 03, 2016 3:24 pm
by RomeFallsAgain
What is the best way to print something like this?
Should I add a raft and print it vertically?
It didn't do so well horizontally.
The problem with printing it vertically is it will break much easier than if it had printed horizontally
Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 7:08 am
by CompoundCarl
Yup, I would print it vertically, but no raft. The raft isn't needed, just use a brim if you're having trouble with adhesion.
Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 7:30 am
by dkightley
And if you get issues with stability, try the technique as described here:
viewtopic.php?f=23&t=4150
Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 8:01 am
by RomeFallsAgain
Thanks! Excellent information.
It's a shame that long thin towers can't be printed horizontally.
(I think plain cylinders and squares can, but not the threaded rod I'm doing or tall thin complex objects?)
In all honesty I used a small raft and it did work perfectly. But this part is only 4" tall.
If it had been taller maybe it would not have?
The advantages (I think) would be much stronger parts and much faster prints.
That due to the direction of the layers and less direction changes for the head.
Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 8:09 am
by dkightley
The one problem with printing your threaded rod is actually the thread!. The quality and completeness of the printing of the thread this way is dependant on the nozzle width and the pitch of the thread. A 0.2mm nozzle and a very coarse thread might print okay.....but a file thread would fail on wall thickness.
I have successfully printed long thin cylinders lying down.....the upright tubes in the second photo down in this thread on TalkingTGauge:
http://www.talkingtgauge.net/viewtopic.php?f=8&t=123 The important thing is that there was no features that would fail due to thin walls.
Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 8:33 am
by RomeFallsAgain
dkightley wrote:The one problem with printing your threaded rod is actually the thread!. The quality and completeness of the printing of the thread this way is dependant on the nozzle width and the pitch of the thread. A 0.2mm nozzle and a very coarse thread might print okay.....but a file thread would fail on wall thickness.
I have successfully printed long thin cylinders lying down.....the upright tubes in the second photo down in this thread on TalkingTGauge:
http://www.talkingtgauge.net/viewtopic.php?f=8&t=123 The important thing is that there was no features that would fail due to thin walls.
Agreed. Just out of curiosity I went ahead and printed the rod and also a block that had been created with inside thread matching the thread on the rod by subtracting the threaded part of the rod from the block. Surprisingly, the threads on both printed accurately and better yet they worked!
A seemingly impossible task but somehow it worked. Visually, the threads appear precise. But like you said, they probably are very weak.
I'm not even sure how it could have printed the threads because I believe the thread edges are less than .4mm.
In this test I hand tightened the threaded object and it got too tight for me to turn it further with no indication it would fail, so I gripped the rod with pliers and tightened some more. It got VERY tight to the point the pliers started to slip on the plastic rod. Nothing broke! So at least this time it worked well. Again, i even wonder how it worked. One thing I did was print at a slow speed.
This was with the rod printed vertically. But the block with the inside thread was printed horizontally.
You can get an idea how fine these threads are by comparing them to the ruled paper the object is laying on.

Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 3:58 pm
by billyd
I find if you want to use threads in your printed designs it's best to make up your own, extremely course ones rather than standard real machine threads. This is because small details really cause problems. So for example instead of drawing a 3/8-16 unc thread, I would make up one like a 3/8-4 thread. It still will thread, but it will be much easier to print and likely a lot stronger.
Re: How would you print this threaded Rod ? (Image)
Posted: Mon Jan 04, 2016 4:17 pm
by RomeFallsAgain
billyd wrote:I find if you want to use threads in your printed designs it's best to make up your own, extremely course ones rather than standard real machine threads. This is because small details really cause problems. So for example instead of drawing a 3/8-16 unc thread, I would make up one like a 3/8-4 thread. It still will thread, but it will be much easier to print and likely a lot stronger.
Good idea. Not sure what I was thinking to make the threads so small.
I think making them larger and coarser will work better.
Re: How would you print this threaded Rod ? (Image)
Posted: Tue Jan 05, 2016 8:00 pm
by RomeFallsAgain
The recurring problem I'm having with vertically printed cylindrical objects is they are inherently weak due to the layers being laid out inline with the forces applied to the rod rather than lengthwise as would be the case if they were printed horizontally.
But there appears to be no way to print a threaded rod horizontally.
I may try printing at a higher temp to see if that bonds the layers better.