# 5 axis 3D printing?

#### strantor

Joined Oct 3, 2010
6,112
I can't believe the idea never crossed my mind. Even more unbelievable that it took me this long to hear someone else put those 4 words together. I rushed straight here after running across it on YouTube so I'm not familiar with what's out there for the hobbyist yet. Just curious if anyone here is "in the know" about hobbyist 5 axis 3D printing and wants to talk about what they know.

I largely gave up on 3D printing years ago when I found that no matter what material I printed with, it would always be weak in one axis because of the "wood grain" aspect. With a 5-axis machine you could build a solid part from the center outwards, with each layer having an opposing "grain," making this a moot point.

#### shortbus

Joined Sep 30, 2009
9,647
How would you make the base plate for doing this? Don't 3-D printers have to have a heated base plate? I don't know because I don't do this but why can't the "grain" thing be overcome by changing the direction of the printing path on every pass. It is my understanding that the weakness from 3-D printing comes from the passes being to long, where the part cools down before the next pass is applied and it not sticking.

#### strantor

Joined Oct 3, 2010
6,112
How would you make the base plate for doing this? Don't 3-D printers have to have a heated base plate? I don't know because I don't do this but why can't the "grain" thing be overcome by changing the direction of the printing path on every pass. It is my understanding that the weakness from 3-D printing comes from the passes being to long, where the part cools down before the next pass is applied and it not sticking.
Imagine you want to print a filled sphere. On a traditional 3D printer, this sphere will be built from the bottom up, starting with a small disc, then a slightly larger disc, then a slightly larger one, and so on, until half-way, then the discs start getting smaller again. You can print each disc in a different direction, but still at the end what you get is a sphere-shaped stack of discs. Sure, the discs are melted together but they aren't bonded like a sphere cut out of a solid piece of plastic would be. Put too much force on it, and it will split between the layers (discs).

We print the same sphere on a 5-axis machine. The build platform can be a lollipop stick and we start building out on the very end of it. Now we can make this part like a ball of yarn instead of a stack of discs. The layers can be alternating directions as before, but instead of in flat, easily separated layers, they are wrapped circumferentially from the inside out like an onion. It would be a much stronger sphere I think.

You are right about the heat being a problem for traditional 3D printing. You get much better layer adhesion on small parts where the next layer is applied on top of the previous one that is still hot. In this scenario you also get deformation because you're trying to stack jelly. The vast majority of parts (at least the ones I would want to make) are too big to be able to print on top of a layer that's still hot, so the layer separation is something that has to be lived with. I think a 5-axis machine would make this issue almost entirely moot.

#### eetech00

Joined Jun 8, 2013
3,418
3D printers must have come a long way in a short time since then.
I’ve had a few project enclosures printed recently that came out awesome. There weren’t any weak spots I could find.

#### strantor

Joined Oct 3, 2010
6,112
3D printers must have come a long way in a short time since then.
I’ve had a few project enclosures printed recently that came out awesome. There weren’t any weak spots I could find.
1. "had a few printed" is potentially very different than "printed a few." If you farmed out to a professional printing shop, chances are they were using professional equipment, not hobbyist stuff, big difference.

2. Did you try standing on your enclosures and bouncing up/down a few times? Project enclosures are a good candidate for 3D printing (even hobbyist grade) as all they have to do is keep dust out. When I was 3D printing I was trying to make a prosthetic hand you can slam in a car door without destroying.

#### shortbus

Joined Sep 30, 2009
9,647
I watch both Joe Martin and Dave Kindig on Motortrend TV, the only two shows that know what they are doing when it comes to building a car. One of them, think it's Kindig, has a 3-D printer that uses a carbon fiber filled nylon material. Those parts from what they show are very strong. But then again their machine isn't a hobby level one.

#### eetech00

Joined Jun 8, 2013
3,418
1. "had a few printed" is potentially very different than "printed a few." If you farmed out to a professional printing shop, chances are they were using professional equipment, not hobbyist stuff, big difference.
Yes..I did.

2. Did you try standing on your enclosures and bouncing up/down a few times?
No…not designed for that.

Project enclosures are a good candidate for 3D printing (even hobbyist grade) as all they have to do is keep dust out.
worked great for me…

When I was 3D printing I was trying to make a prosthetic hand you can slam in a car door without destroying.
wow.
Materials you never thought of are being used for 3D printing like Houses, Cars, Buildings, Rockets….

#### BobTPH

Joined Jun 5, 2013
5,801
Don’t know if this is correct or not, but a heated cabinet might help with inter-layer strength by keeping the layers from cooling toi much before the next layer is printed.

Bob

#### MrSalts

Joined Apr 2, 2020
2,378
1. "had a few printed" is potentially very different than "printed a few." If you farmed out to a professional printing shop, chances are they were using professional equipment, not hobbyist stuff, big difference.

2. Did you try standing on your enclosures and bouncing up/down a few times? Project enclosures are a good candidate for 3D printing (even hobbyist grade) as all they have to do is keep dust out. When I was 3D printing I was trying to make a prosthetic hand you can slam in a car door without destroying.
Amazing that you stopped working on a prosthetic hand project because the material wasn't able to withstand being slammed in a car door. Maybe you should have told the person you were trying to help that you decided to make the project fail by setting unreasonable expectations on the material before you ever started. What non-3D printed material and manufacturing process would have passed the slammed car door test - even if price wasn't an issue?

#### djsfantasi

Joined Apr 11, 2010
8,579
Don’t know if this is correct or not, but a heated cabinet might help with inter-layer strength by keeping the layers from cooling toi much before the next layer is printed.

Bob
I was wondering that myself…?

#### MrSalts

Joined Apr 2, 2020
2,378
Don’t know if this is correct or not, but a heated cabinet might help with inter-layer strength by keeping the layers from cooling toi much before the next layer is printed.

Bob
You can heat it in a box and one 3D printing company had a patent on the idea for a while but, you only get so much benefit. If the box is hot enough to actually retain "tack" and allow the next layer to form an "inter penetrating layer" of polymer (the new chain actually entangles with the previous layer's polymer chains), the. The material is so warm it has virtually no strength and the pressure from the print head pressing the next new layer into place will collapse the structure. In other words, the heated box has almost no effect on a polymer unless it has a wide softening temp vs glass-transistion temp (Tg). Common polymers with good structural properties (engineering polymers) do not have such a broad temp between softening and Tg.

#### MrSalts

Joined Apr 2, 2020
2,378
If you want a plastic part with good appearance and physical properties. Look into SLS Nylon. The previous layer is heated and next layer is nylons powder that is fused to the growing part - the part is built in a bed of powdered nylon. . You can also build steel parts this way.

#### djsfantasi

Joined Apr 11, 2010
8,579
You can heat it in a box and one 3D printing company had a patent on the idea for a while but, you only get so much benefit. If the box is hot enough to actually retain "tack" and allow the next layer to form an "inter penetrating layer" of polymer (the new chain actually entangles with the previous layer's polymer chains), the. The material is so warm it has virtually no strength and the pressure from the print head pressing the next new layer into place will collapse the structure. In other words, the heated box has almost no effect on a polymer unless it has a wide softening temp vs glass-transistion temp (Tg). Common polymers with good structural properties (engineering polymers) do not have such a broad temp between softening and Tg.
I’m sure that if this worked, it would have been done. But, the data is there to aim a laser To locally heat the previous layer of the print. No worries about “squishing” the previous print. Energy efficient as you’re only heating a thin layer of printed material.

#### Sensacell

Joined Jun 19, 2012
3,069
Consider the mechanical difficulties of adding another axis, not to mention the software complexities. Now consider the benefits.

It seems barely worth the trouble.
I often design parts from two pieces that get glued together to achieve a composite with multiple "grain orientations" - much easier than adding another axis of motion.

#### strantor

Joined Oct 3, 2010
6,112
I watch both Joe Martin and Dave Kindig on Motortrend TV, the only two shows that know what they are doing when it comes to building a car. One of them, think it's Kindig, has a 3-D printer that uses a carbon fiber filled nylon material. Those parts from what they show are very strong. But then again their machine isn't a hobby level one.
Yes that stuff can be very strong, and you can print it with a hobby machine. It is great for things that only need strength in two axes.
Amazing that you stopped working on a prosthetic hand project because the material wasn't able to withstand being slammed in a car door. Maybe you should have told the person you were trying to help that you decided to make the project fail by setting unreasonable expectations on the material before you ever started. What non-3D printed material and manufacturing process would have passed the slammed car door test - even if price wasn't an issue?
Amazing that YOU wrote the final chapter of MY story all by yourself without asking for even a single detail. Very impressive.

I said I gave up on 3D printing, not on the project. The shortcomings of 3D printing drove me in the direction of CNC machining and I now have a large CNC mill (not a hobbyist machine) sitting in my garage, representing a rather large investment of time and money.

A number of materials and processes could pass the test. Carbon fiber, nylon and many other plastics, either cast or machined, etc.

The slammed door test is not unreasonable. These kinds of things often happen to prosthetics as people can't feel them, forget they're there. The last prosthetic my father used cost \$50k and he destroyed it in a similar way.

Anything else you want to know, feel free to ask. But that's the last time you write my bio and then attack me on its contents.

#### strantor

Joined Oct 3, 2010
6,112
Consider the mechanical difficulties of adding another axis, not to mention the software complexities. Now consider the benefits.

It seems barely worth the trouble.
It's not that difficult mechanically; at least not that complicated to turn a 3 axis mill into a 5 axis mill. Just bolt a tilt/turn table to the mill table. Software for 5 axis subtractive machining already exists and I assume it could be used, either as-is or as a starting point for 5-axis 3D printing. I'm probably grossly oversimplifying the problem, I often do that. Your point is taken; it wouldn't be a walk in the park. But I think it would be very doable, and I think it will be a game changer for the 3D printing community. At least the small corner of that community which is interested in making functional parts instead of toys and ornaments.

#### MrSalts

Joined Apr 2, 2020
2,378
In the example above, How do you avoid hitting the stick of the lollipop as you build the sphere. The extruded would have to be infinitely thin to print next to the stick and you would need a long stick printed for every part to allow clearance of the print head to access the bottom of the part. Selective laser sintering seems much easier for a DIy 3D printer if you also consider a 5-axis contraption a DIY printer.

#### shortbus

Joined Sep 30, 2009
9,647
@strantor Again I might be totally wrong about this, but wasn't one of the big selling points of 3-D printing that it could make things to simulate castings, but from plastic. By that statement many(most?) cast parts a hollow inside, like an engine block or cylinder head with their water passages. What I imagine your 5 axis part to be would be more of a solid part?

#### strantor

Joined Oct 3, 2010
6,112
In the example above, How do you avoid hitting the stick of the lollipop as you build the sphere.
Two ways I can think of, I'm sure there are more.

See around 0:27, imagine the stick is there.

See around 0:48:

I can't find any good examples of 5 axis 3D printing being done the way I would like to do it (think "ball of yarn"). The part in that 2nd video would be just as weak as one made on a 3-axis machine.

The extruded would have to be infinitely thin to print next to the stick
No it wouldn't. Just make a longer stick.
and you would need a long stick printed for every part to allow clearance of the print head to access the bottom of the part.
ok? What's the problem? The stick is a support structure. Support structures are common concepts in 3D printing. I'd wager that this stick represents a lot less support structure than most printed with 3 axis machines. On top of that, consider the stick could be part of the machine; a tiny build platform sticking up from a tilt/turn table. Then no support structures would be required at all.
Selective laser sintering seems much easier for a DIy 3D printer if you also consider a 5-axis contraption a DIY printer.
You're right, this 5-axis business is silly. We should just start laser sintering plastics.