Stackable, printed extrusions that can be filled with resin

I have published a design on thingiverse that are stackable extrusions that you can print out at 0% infill, and fill the cavity with resin.

It's a work in progress, but it's nearly finished after going through a few revisions.

The thingiverse has a detailed description.

[www.thingiverse.com]

Thank you for reading and taking a look

Edited 1 time(s). Last edit at 04/26/2018 08:50PM by klcjr89.

Are you going to print them and try injecting them with foam?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Why not just print 100mm high extrusions? I have successfully done this before using the CAD files supplied by openbuilds. I used them to make a 3D scanner I designed before buying the correct lengths of extrusion.

EDIT: a better idea would be to remove the locating pins and instead design long strips that slide into the channels. The diameter of the center hole can then be larger to accommodate more foam.

Edited 1 time(s). Last edit at 04/26/2018 03:33PM by Origamib.

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the_digital_dentist
Are you going to print them and try injecting them with foam?

Yes, I already have yesterday as a curiosity.

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Origamib
Why not just print 100mm high extrusions? I have successfully done this before using the CAD files supplied by openbuilds. I used them to make a 3D scanner I designed before buying the correct lengths of extrusion.

EDIT: a better idea would be to remove the locating pins and instead design long strips that slide into the channels. The diameter of the center hole can then be larger to accommodate more foam.

Firstly, the center hole is not for filling of foam, please read the thingiverse entirely. Hint: threaded rod.

There is a reason why I arrived at the design that I currently have. I wanted the T slots totally unobstructed to mount linear guides and other items on. I don't suggest using V wheels for precision linear movement, but people are welcome to try it and report back on their findings.

Edited 3 time(s). Last edit at 04/26/2018 06:44PM by klcjr89.

The foam doesn't expand so much that it breaks the plastic?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
The foam doesn't expand so much that it breaks the plastic?

This was my thought too, and with one perimeter it definitely could. I recommend four perimeters.

Edited 1 time(s). Last edit at 04/26/2018 06:43PM by klcjr89.

I made up a quick mockup of the stack and I think the method should work well. These are the 30x30s and I didn't feel with this size that it was necessary to fill with foam or resin.

I have removed the foam filling from the description, as I found the foam doesn't cure in the relatively air-tight cavity, as the foam cures in the presence of moisture. Since the foam blocks the filling hole, very little moisture can enter the cavity. I discovered this by cracking open one face of the extrusion on purpose and viewing that there was almost no foam at all in the inside; all of it pretty much oozed out.

I have since changed the description to only mention filling with resin.

This was a 60x60 extrusion with spray foam:



Edited 4 time(s). Last edit at 04/26/2018 11:00PM by klcjr89.

Have you calculated the cost of this "extrusion" compared to aluminum?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
Have you calculated the cost of this "extrusion" compared to aluminum?

On the basis of the 60x60 extrusion I planned to purchase from Misumi, it costs less for me to print the extrusions and that is with high-quality pricier filament than the bargain bin no name filaments. For smaller extrusion sizes, it may or may not be worthwhile; I did not calculate the price difference.

I'm not doing it on the basis of cost, but rather to make something unique. The idea started for building a printed pink panther printer for cancer awareness.

The filament is UV sensitive metallic sparkle pink and it looks amazing under a blacklight:



Edited 1 time(s). Last edit at 04/26/2018 09:06PM by klcjr89.

That does look nice! Who makes the filament?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
That does look nice! Who makes the filament?

Thanks! 3DXTech is the manufacturer (all USA based, thankfully.)

I was thinking about modeling a channel into the extrusion so I could put high intensity UV leds hidden inside the extrusion, but am not sure how well the light would be diffused. Would also be interesting to see if resin would help diffuse the light. I would probably design a PCB and place the UV leds on it that way it can be more easily inserted into the extrusions. I would probably get the PCBs made through OSHPark.



Edited 4 time(s). Last edit at 04/26/2018 09:27PM by klcjr89.

I've put UV LEDs inside fluorescent plastic parts before and it was very disappointing. The UV makes the surface it hits glow, but it doesn't penetrate the plastic, so the effect is very weak.

I print using fluorescent filament at Maker Faires and have about 20W of UV LEDs installed in my printer. I like to use FoxSmart Screamin' Green TPU but that pink stuff looks really nice, too. I'll have to get some.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
I've put UV LEDs inside fluorescent plastic parts before and it was very disappointing. The UV makes the surface it hits glow, but it doesn't penetrate the plastic, so the effect is very weak.

I print using fluorescent filament at Maker Faires and have about 20W of UV LEDs installed in my printer. I like to use FoxSmart Screamin' Green TPU but that pink stuff looks really nice, too. I'll have to get some.

I was thinking of just aiming a high power blacklight at the printer, but that would probably not be allowed at a convention/festival if I were to bring the printer there.

I'm trying to persuade 3DXtech to make the same as the pink, but in a blue color. No word on that yet.

Edited 1 time(s). Last edit at 04/26/2018 10:28PM by klcjr89.

I bought a bunch of 1W UV LEDs (get the cheap ones- 400 nm- the 360 nm cost a LOT more and don't cause any brighter fluorescence), a couple strip type PCBs, and then mounted them on aluminum angle stock to direct the light and dissipate heat. I power them with a $8 dc-dc converter set for about 19V out which puts about 20W into the 30 LEDs so they'll live a long, happy life. See [drmrehorst.blogspot.com] I put a few in the top of the machine pointing down on the bed and then two long vertical strips on either side of the clear PC front panel. The way I have arranged the lights you can't see them directly when you look into the front of the printer, but they reflect off the walls very nicely and give a nice effect in photos.

This pictures is with the original UV LED strips I used which were not bright enough, and before I added light to the top of the printer.



I have about 18W of white LEDs arranged on the top and alongside the vertical UV lights in the front of the machine.



Edited 2 time(s). Last edit at 04/26/2018 11:18PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
I bought a bunch of 1W UV LEDs (get the cheap ones- 400 nm- the 360 nm cost a LOT more and don't cause any brighter fluorescence), a couple strip type PCBs, and then mounted them on aluminum angle stock to direct the light and dissipate heat. I power them with a $8 dc-dc converter set for about 19V out which puts about 20W into the 30 LEDs so they'll live a long, happy life. See [drmrehorst.blogspot.com] I put a few in the top of the machine pointing down on the bed and then two long vertical strips on either side of the clear PC front panel. The way I have arranged the lights you can't see them directly when you look into the front of the printer, but they reflect off the walls very nicely and give a nice effect in photos.

This pictures is with the original UV LED strips I used which were not bright enough, and before I added light to the top of the printer.

I have about 18W of white LEDs arranged on the top and alongside the vertical UV lights in the front of the machine.

Thanks for the info, do you think I could use such 400nm UV LEDs to directly light up the extrusions if I place them within the extrusions?

Edited 2 time(s). Last edit at 04/26/2018 11:26PM by klcjr89.

On a side note, I'm pleased to be able to find 6 and even 10ft. lengths of #8-32 threaded rod. I could not find M4 threaded rod greater than 1 meter easily. A 6 ft. length of #8-32 threaded rod only costs $2.32.

Edited 2 time(s). Last edit at 04/26/2018 11:36PM by klcjr89.

When I use foam for a close gap, I use a mist water sprayer before I inject the foam.

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o_lampe
When I use foam for a close gap, I use a mist water sprayer before I inject the foam.

I might try this, as the casting resin is very expensive and the volume required to fill the cavity would be astronomical.

Calculations show that it is alot cheaper to buy aluminum compared to the filament on the basis of 30x30 extrusions. However, with the 60x60 extrusions, it is cheaper to print them (probably not in the long run, see below). Initially, I was going to buy 60x60 aluminum ones from Misumi but after seeing the price, I came up with this idea.

Time and electricity is another thing; to print a printer of the_digital_dentist's style that is 1800mm tall and 894mm wide (size that I was planning to build), I calculated it to take at least 713 hours, or 29.7 days non-stop! And that assumes no failures of any kind. These calculations didn't include the time to print the Z axis extrusions either, only the four vertical posts and twelve horizontal extrusions. These calculations were done for the 30x30 size of extrusion.

I think the idea is still valid for smaller projects, provided you want something in a unique color.

Edited 4 time(s). Last edit at 04/27/2018 03:07AM by klcjr89.

I've printed the 30x30 and filled it with foam and as a test I printed it again with 5% infill as a test and its seems just as strong.

Edited 1 time(s). Last edit at 04/27/2018 03:11AM by mars on the rocks.

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mars on the rocks
I've printed the 30x30 and filled it with foam and as a test I printed it again with 5% infill and its seems just as strong.

Did the foam actually cure without voids or did it turn out like the 60x60 extrusion I posted earlier in this thread? Photo is in that post.

Edited 1 time(s). Last edit at 04/27/2018 03:10AM by klcjr89.

I got it to cure but it didn't have a top I still got voids though I think this technique might better suit thinner walled objects as far as strength goes but between 3 and 5% infill with 4 shells should be strong enough for a 3d printer and wouldn't use to much more filament

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mars on the rocks
I got it to cure but it didn't have a top I still got voids though I think this technique might better suit thinner walled objects as far as strength goes but between 3 and 5% infill with 4 shells should be strong enough for a 3d printer and wouldn't use to much more filament

Good to know, thanks for trying it. If you see the post I made before your first post, you will see my thoughts on this idea based on calculations I made.

I have another idea though if you cut a square out of the middle of it you could print the outer part with 4 shells in the good filament and the a center square out of cheaper filament but lay it on its side. so the outer part wil print standing up and the inner part side ways. this would have the layer lines cross each other making it super strong

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klcjr89

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o_lampe
When I use foam for a close gap, I use a mist water sprayer before I inject the foam.

I might try this, as the casting resin is very expensive and the volume required to fill the cavity would be astronomical.

Have you considered using mineral fillers in your resin? Calcite is very cheap!

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klcjr89
Thanks for the info, do you think I could use such 400nm UV LEDs to directly light up the extrusions if I place them within the extrusions?

There's a couple problems with putting LEDs inside the plastic. First and foremost, it won't make the plastic light up like it does when you shine a UV light from outside. The UV doesn't penetrate the plastic to any depth- it makes the surface it hits glow, which would be inside the prints. The light that filters through to the outside will be relatively dim and it won't glow like it's being lit with a black light. The other problem is that the LED's get warm and it will be hard to get the heat out of the plastic (which is a thermal insulator).

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

... a relative simple solution for this "UV penetration problem" is to use clear or translucent materials, which won't block the UV light (e.g. 405nm or 396nm diodes) -- and then paint the surface with the luminescent colour

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Viktor
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I'm so tempted to build a printer with this idea, I just need to pick a smaller build volume size to make it more feasible.

Edited 1 time(s). Last edit at 04/27/2018 05:23PM by klcjr89.

The black linear guides I want to use look so good paired with the UV pink extrusions



Edited 1 time(s). Last edit at 04/27/2018 06:18PM by klcjr89.