Printed rod Strength

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airscapes
Posts: 557
Joined: Wed Jan 31, 2018 11:36 pm

Printed rod Strength

Post by airscapes » Mon Apr 25, 2022 4:28 pm

I have never read about anyone doing this, so I figure I would share.
I was designing a new spool mount for my M2 that would use bearings. There are lots of spool center deigns on the web but I needed the mount. After reinventing the spool center, as I wanted to design it myself, I was going to buy a 1/2 aluminum rod, drill and tap the end and mount it using the center unthread hole in the M2 frame, where the existing mount is.
Before I went in search of said rod, I make a plastic mount that would bolt up where the original one is using the same 4 screws. Now an 80mm long 1/2 printed rod, even at 100% infill (PETG) is not going to be all that strong and could get snapped off.
My fix was to add the proper sized hole with counter sink to accept a 2 1/2" decking screw, which made this plastic shaft really stiff and strong. I did not try and break it, but I am guessing it will not snap even if I tried. Like rebar after the fact..
Hope someone finds this idea helpful, I know I will be far more willing to print rods if I can make the strong enough for the job at hand.
Doug

Phil
Posts: 210
Joined: Mon Sep 19, 2016 7:49 pm

Re: Printed rod Strength

Post by Phil » Wed May 04, 2022 4:49 pm

Excellent idea! Another possibility is the orientation of the rod while printing. Does it really need to be round? Or will a hexagon or octagon work?

airscapes
Posts: 557
Joined: Wed Jan 31, 2018 11:36 pm

Re: Printed rod Strength

Post by airscapes » Wed May 04, 2022 9:26 pm

This was to replace the stock spool holder on my M2 with a 2 part bearing setup.. Bearing is 1/2" ID so rod needed to be 1/2 and round.
Rod and bearing insert.jpg
spool on the holder.jpg

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