3D Printing Weight of 3D Printed Body Tubes

[BigMacDaddy]

In one of the other threads the conversation turned to (touched on) fully 3D printed rockets. I have always avoided printing body tubes whenever possible and instead prefer to print parts that fit on standard Estes cardboard body tubes. Someone posted that they have 3D printed lots of complete rockets and that "I do not think that they are that much heavier" so I was curious about what the difference in weight is.

Quick table below -- for the purpose of this quick analysis I basically selected the stock Estes body tube and trusted the thickness and weight that was presented in OpenRocket for the stock Estes cardboard tube (with the exception of the BT-80 which is obviously incorrect so I weighed a couple of those). Then I switched the material to "Printed PLA" and changed the Wall Thickness to either .8mm or 1.2mm (representing 2x or 3x .4mm layers). Obviously weighing everything would be more accurate but I was just trying to get a rough approximation for the increased weight. These are all 18" long tubes except the BT-80 which is the stock 14.25". The weights listed are in grams with the multiplier indicating the ratio of the 3D printed weight to the cardboard tube weight.



So the printed body tubes range from 2.4x to 7.1x as heavy as the cardboard tubes with total weight increases of a range of 20g to 80g. Obviously, whether the 3D printed body tube is "too heavy" is going to depend on your design, purpose, how large an engine you want to use, etc... I would also point out (for anyone that happens to come across this that is new to rockets) that often increasing weight in the rear of the rocket forces us to offset that with more weight in the nose to create similar stability. Generally speaking a fully 3D printed rocket shifts weight backward as compared to a rocket with a plastic nose cone, cardboard body tube, balsa fins, and cardboard engine mount. Given this, some designs will see the increased weight being further compounded if nose weight is needed to stabilize the rocket.

What the heck I will look at the weight of fins also... This analysis is simply looking at 4x flat fins that are 5cmx5cm in size (obviously the real benefit in 3D printed fins is in the cool shapes you can print but I was just curious about weight). This also assumes a solid print which would be the case if you just printed a flat fin that is not too thick.



Not as much of an increase as I would have guessed (at least not over plywood that I usually use). Balsa is still the king when it comes to light fins but I still think that 1.5-2mm plywood is a good balance of strength, finishing, weight, etc...

 

[cwbullet]

Great info. I think the key with 3D printing is similar to using metal or fiberglass. If you plan to fly light, use as little as possible.

 

[Kelly]

It would be interesting to see such a comparison done using paper (or any other material) vs printed plastic on an equal strength basis. That is, compare a paper body tube to a PLA body tube that is printed with whatever thickness assures that the two are equivalent in strength. Or, if we're comparing fins, look at parts with equivalent stiffness.

 

[BigMacDaddy]

It would be interesting to see such a comparison done using paper (or any other material) vs printed plastic on an equal strength basis. That is, compare a paper body tube to a PLA body tube that is printed with whatever thickness assures that the two are equivalent in strength. Or, if we're comparing fins, look at parts with equivalent stiffness.

I agree -- I have often thought about this with fins...

However, the idea of "strength" is actually pretty complicated (especially w/ 3D printed parts and designs). For example, a 3D printed body tube is relatively strong to vertical compression but not particularly strong along Z-axis for sideways stress (especially w/ only 2 perimeters).

 

[lowga]

This is a great thread on a number of levels. My preference is to use 3D printed parts with cardboard tubes...but sometimes I will "kit bash" to achieve the desired result. For instance, I am currently working on an Estes 7240 Honest John. The fin can is 3D printed from Boyce Aerospace, the nose cone is plastic from the 7240 kit. the body tube is Mach 1 BT-60 thin-wall fiberglass.

The specs for the build are to create a park-flyer version of the Honest John variant called "Father John." Boyce Aerospace was nice enough to design and print the air brakes, which will be fly away on launch but look great on display.

I wanted something that would be rugged, easy to fly, and be large enough to use a Jolly Logic Chute Release to keep the rocket close to the pad. The other option is a nose cone deploy altimeter.

Waiting for a warm day to spray primer, and then on to finishing. Certainly the thin wall fiberglass it heavier than cardboard, but not so much as a 3-D printed tube would be--and much stronger in all axis.

I may try a go at having the motor band and some (prototype) launch lugs made for the rocket. That would add more scale realism.

 

[dr wogz]

That has always been one of my argument. 3D printing isn't a replacement, it's an alternative. And I feel a few (a lot?!) seem to think the strength / robustness is equal to or only slightly inferior to the traditional materials; paper, wood, etc.. it's not. (And we've all seen how susceptible it it to heat & UV..) Many will also print to make it easy / quick to print, and that can create a weak part (3D printed parts are weakest parallel to the layers, as with the wood grain) Or try to print the part in one shot.. Breaking the part into multiple pieces, orienting them accordingly on the bed, then making an assembly will yield a stronger part. but that takes time & effort. 3D printing is supposed to be quick.. (or so it's believed..)

But then again, I've never understood someone who prints a part such as a tube, when tubes are readily available (and stronger / lighter). 3D printing is great a really complex shapes & geometries.. Why use it as a substitute?

 

[vcp]

The models I built for NARAM60 were wholly or largely 3D printed with the following considerations:

• ABS printed single-layer vase mode, ~0.4mm walls.
• print striations were not filled, but rather sanded smooth and wax-finished.
• sanding reduced the single-layer weight by ~15 percent.
• fin fillets were integrated, and perfect.
• all shapes were blended aerodynamically.
• fin alignment was 'perfect'.
• bright plastic colors eliminated paint.

https://www.thingiverse.com/thing:3056609

 

[BigMacDaddy]

I had a few shipping and other heavier tubes so wanted to see how these compared to the equivalent 3D printed tubes. The results were surprising to me - at least for the heavier duty shipping tube.

I weighed three of the tubes I had (circled or with arrow pointing to them in picture below) and then modeled a tube with same OD and 1.2mm thick sides to see how much it would weigh (I just used Prusa Slicer estimates for grams of filament used).



Right Bottom Tube: 283x78.7mm (Cardboard: 57.3g / ABS Print: 86.04g 10h17m)
Middle White Tube: 483x80mm (Cardboard: 162g / ABS Print: 149.43 17h55m)
Partial Section of HiC Container: 112.5x103mm (Cardboard: 33g / ABS Print: 45g 5h20m)

So the white heavy duty shipping tube weighs 9% more than the 3D print would weigh. The other two cardboard tubes weigh less - 27% and 34%. I think that all these tubes are stronger than a 1.2mm printed tube -- at least against cracks on Z-direction but maybe not against dings. The white shipping tube is really heavy duty -- may need to make a static model out of that one. Big advantage in print speed and small cost savings since these tubes were all free.

 

[OzHybrid]

I print exclusively in ABS. This is because it can be dissolved in acetone and the slush can be used for bonding. Others like other filament choices, that's theirs, this is mine.
Recently fully printed a Minie Magg with GF cloth/ABS slush covering on the body tube and internally GF cloth lined nosecone.
Standard nosecone blown PVC 280gm, printed ABS GF reinforced190gm
Standard without motor 1500gm ..Printed, Finished with G64 1200gm. The disadvantage of printing is that it's layers. The GF reinforcement allows you to add a lot of strength and non layer dependant strength. You can add density adjustment blocks in CURA to increase the fill in local spots where you need additional strength. With normal construction, the material you are using would be homogeneous. More strength would be a tube that's stronger and heavier overall.
So short version is that for a MPR rocket, I reckon I can make something for the same purpose 25-30% lighter in ABS. That does take a bit of effort elsewhere.

 

[OzHybrid]

That has always been one of my argument. 3D printing isn't a replacement, it's an alternative. And I feel a few (a lot?!) seem to think the strength / robustness is equal to or only slightly inferior to the traditional materials; paper, wood, etc.. it's not. (And we've all seen how susceptible it it to heat & UV..) Many will also print to make it easy / quick to print, and that can create a weak part (3D printed parts are weakest parallel to the layers, as with the wood grain) Or try to print the part in one shot.. Breaking the part into multiple pieces, orienting them accordingly on the bed, then making an assembly will yield a stronger part. but that takes time & effort. 3D printing is supposed to be quick.. (or so it's believed..)

But then again, I've never understood someone who prints a part such as a tube, when tubes are readily available (and stronger / lighter). 3D printing is great a really complex shapes & geometries.. Why use it as a substitute?

Why print a tube?
I cannot even buy a full length of 29mm motor mount cardboard tube here in Australia. When I tried to buy some in US and ship here, it was 120 US$ for shipping alone. That forces me to look at alternatives. Including printing tubes. If I have to do that, I'll make the best tube I can. Once that methodology is done, I can create any tube I want. I'm nearly there.
Also as things change, the change accelerates.
Here's a link to the latest CURA profiles.
Wowsers is all I've got, having just tested it......
Minie Magg nosecone was 24hr print before (and I was printing it quick) down to 13Hrs 35Mins

 

[BigMacDaddy]

Why print a tube?
I cannot even buy a full length of 29mm motor mount cardboard tube here in Australia. When I tried to buy some in US and ship here, it was 120 US$ for shipping alone. That forces me to look at alternatives. Including printing tubes. If I have to do that, I'll make the best tube I can. Once that methodology is done, I can create any tube I want. I'm nearly there.
Also as things change, the change accelerates.
Here's a link to the latest CURA profiles.
Wowsers is all I've got, having just tested it......
Minie Magg nosecone was 24hr print before (and I was printing it quick) down to 13Hrs 35Mins

For sure if I lived in many other countries where parts are less available that would dramatically change the value proposition for fully 3D printed rockets. Although I would still see how much it was to ship a large shipment of body tubes, plywood sheets, Kevlar line, etc... before I shipped a bunch of kits.

 

[jweger77]

I really like the flexibility that comes from printing tubes. You're not held to standard sizes and can fine tune thickness to offset the weight differential. Then again, I print just about anything I can. I replaced the drive gear in my garage door opener three years ago with an abs printed one and it still works.

 

[BigMacDaddy]

I really like the flexibility that comes from printing tubes. You're not held to standard sizes and can fine tune thickness to offset the weight differential. Then again, I print just about anything I can. I replaced the drive gear in my garage door opener three years ago with an abs printed one and it still works.

Whether or not the shape of a rocket or plane lines up with standard body tubes sizes is a factor in me considering to make a model or not. I can make any model so I select those where the ratios of the major body components can be replaced with standard body tubes without destroying the look of the plane or rocket. Occasionally I will take on a unique challenge that will wind up being almost all 3D printed but usually I can make a much more impressive model if I make some components out of lighter materials.



Some that are fully or almost fully 3D printed...

 

[jweger77]

Whether or not the shape of a rocket or plane lines up with standard body tubes sizes is a factor in me considering to make a model or not. I can make any model so I select those where the ratios of the major body components can be replaced with standard body tubes without destroying the look of the plane or rocket. Occasionally I will take on a unique challenge that will wind up being almost all 3D printed but usually I can make a much more impressive model if I make some components out of lighter materials.

View attachment 553724 View attachment 553723 View attachment 553725View attachment 553728

Some that are fully or almost fully 3D printed...
View attachment 553729View attachment 553730 View attachment 553731 View attachment 553732

That's truly an awesome collection of designs and builds! Fantastic!

 

[BigMacDaddy]

That's truly an awesome collection of designs and builds! Fantastic!

Thank you...

 

[SolarYellow]

Why print a tube?
I cannot even buy a full length of 29mm motor mount cardboard tube here in Australia. When I tried to buy some in US and ship here, it was 120 US$ for shipping alone. That forces me to look at alternatives. Including printing tubes. If I have to do that, I'll make the best tube I can. Once that methodology is done, I can create any tube I want. I'm nearly there.

With the weight differences noted in the OP, I'd be learning to wrap my own tube and buying a roll of virgin craft paper rather than 3D printing them. Or maybe get one of the AliExpress carbon tube makers to make me some ultralight tubes.

 

[OzHybrid]

With the weight differences noted in the OP, I'd be learning to wrap my own tube and buying a roll of virgin craft paper rather than 3D printing them. Or maybe get one of the AliExpress carbon tube makers to make me some ultralight tubes.

I've just made a 160mm tube using 8 wraps of 50mm wide water activated glue white paper tape. Came out OK. I've scrapped the idea of a fully printed tube in ABS for flight but would use it as a former. The tubes I printed and wrapped with fiberglass cloth and ABS slush, suffered from distortion over time. This might be rectifiable with experimentation, but the paper tubes work better.
Norm

 

[Rustie0125]

In one of the other threads the conversation turned to (touched on) fully 3D printed rockets. I have always avoided printing body tubes whenever possible and instead prefer to print parts that fit on standard Estes cardboard body tubes. Someone posted that they have 3D printed lots of complete rockets and that "I do not think that they are that much heavier" so I was curious about what the difference in weight is.

Quick table below -- for the purpose of this quick analysis I basically selected the stock Estes body tube and trusted the thickness and weight that was presented in OpenRocket for the stock Estes cardboard tube (with the exception of the BT-80 which is obviously incorrect so I weighed a couple of those). Then I switched the material to "Printed PLA" and changed the Wall Thickness to either .8mm or 1.2mm (representing 2x or 3x .4mm layers). Obviously weighing everything would be more accurate but I was just trying to get a rough approximation for the increased weight. These are all 18" long tubes except the BT-80 which is the stock 14.25". The weights listed are in grams with the multiplier indicating the ratio of the 3D printed weight to the cardboard tube weight.

View attachment 514493

So the printed body tubes range from 2.4x to 7.1x as heavy as the cardboard tubes with total weight increases of a range of 20g to 80g. Obviously, whether the 3D printed body tube is "too heavy" is going to depend on your design, purpose, how large an engine you want to use, etc... I would also point out (for anyone that happens to come across this that is new to rockets) that often increasing weight in the rear of the rocket forces us to offset that with more weight in the nose to create similar stability. Generally speaking a fully 3D printed rocket shifts weight backward as compared to a rocket with a plastic nose cone, cardboard body tube, balsa fins, and cardboard engine mount. Given this, some designs will see the increased weight being further compounded if nose weight is needed to stabilize the rocket.

What the heck I will look at the weight of fins also... This analysis is simply looking at 4x flat fins that are 5cmx5cm in size (obviously the real benefit in 3D printed fins is in the cool shapes you can print but I was just curious about weight). This also assumes a solid print which would be the case if you just printed a flat fin that is not too thick.

View attachment 514490

Not as much of an increase as I would have guessed (at least not over plywood that I usually use). Balsa is still the king when it comes to light fins but I still think that 1.5-2mm plywood is a good balance of strength, finishing, weight, etc...

Awesome info indeed. I Suspect not all options was considered. I have been on similar path and have managed to print parts comparable to cardboard. Here is one example. The cardboard here was thicker stock. But the lightest version is 1:1 ratio with LPR BT60

 

[BigMacDaddy]

Awesome info indeed. I Suspect not all options was considered. I have been on similar path and have managed to print parts comparable to cardboard. Here is one example. The cardboard here was thicker stock. But the lightest version is 1:1 ratio with LPR BT60

Curious about how thick your printed tubes are and what BT-60 tube you are comparing to?

I have not done too many experiments with larger diameter nozzles and spiral printing or anything like that. In this case I just used OR to compute weight so pretty rudimentary.

Also I definitely found that the weight difference was not as substantial with really thick mailing tubes.

 

[Rustie0125]

Curious about how thick your printed tubes are and what BT-60 tube you are comparing to?

I have not done too many experiments with larger diameter nozzles and spiral printing or anything like that. In this case I just used OR to compute weight so pretty rudimentary.

Also I definitely found that the weight difference was not as substantial with really thick mailing tubes.

Printing with 0.4mm nozzle, I use open rocket library of BT tubes change the lenght and look at the mass. The BT-60 I'm comparing to is 12.3g per 200mm all available in the library seems to be around that mark.

With regards to the wall thickness, it depends in the material used. PLA+ is 0.6mm with 1mm bead spire running clock and anticlockwise.

For LW-PLA two approaches was tested and tried. One is 0.8mm wall with sub surface grid 1mm to provide some lateral structure. This grid forms about 25mm square pattern inside the tube.

And second approach is 3mm thick walls by design but the slicer settings creates cavities inside the walls. This approach is alot more sturdy. But does weigh more. More material more weight regardless of design.

Hope that helps.

 

[JohnCoker]

I don't see the benefit of 3D printing body tubes when the standard materials are stronger, lighter and have a better surface finish. (I can see if you're making a non-cylindrical rocket, but not to replace regular tubes.)

I am working on proper testing of things which need to be fabricated anyway and so are a better candidate, such as CRs, bulkheads and fins. I expect 3D printed parts to be a lot weaker for the same shape, but we have the option of printing complex shapes (ribs, varying thickness, truss structures, etc) and I hope to make up the difference that way.

Maybe someday instead of cutting plywood with a CNC router I'll be printing everything. Don't get me wrong; quality plywood is an amazing material, but additive manufacturing is much more flexible and cleaner.

 

[Rustie0125]

Ya the point is here not to replace the cardboard tubes mearly to show its not the only option. And does not cost more.

My project will have custom shapes pretty much the entire rocket body hence the reason for doing all the testing.

 

[KenECoyote]

To me, the big benefit of printing a body tube is for those rockets with curved bodies (ex. X-1, BSG Colonial Viper).

 

[OzHybrid]

I don't see the benefit of 3D printing body tubes when the standard materials are stronger, lighter and have a better surface finish. (I can see if you're making a non-cylindrical rocket, but not to replace regular tubes.)

I am working on proper testing of things which need to be fabricated anyway and so are a better candidate, such as CRs, bulkheads and fins. I expect 3D printed parts to be a lot weaker for the same shape, but we have the option of printing complex shapes (ribs, varying thickness, truss structures, etc) and I hope to make up the difference that way.

Maybe someday instead of cutting plywood with a CNC router I'll be printing everything. Don't get me wrong; quality plywood is an amazing material, but additive manufacturing is much more flexible and cleaner.

Thats a very US centric reply. Not everyone has access to the materials you can take as readily available by next day delivery. Shipping costs from the US can be prohibitive.

You do these things to see if we can develop new techniques. Along the way something new and exciting might come out. The result only has to be acceptable for it to be worthy of use. Best practice depends on what's available to you.

 

[Rustie0125]

To me, the big benefit of printing a body tube is for those rockets with curved bodies (ex. X-1, BSG Colonial Viper).

Makes perfect sense yes. I'm looking at the body as more of a skeleton or spine and will be creating the cavities and bays in different places inside the tubes accessible from outside. If I had todo this in carboard I'd be cutting and glueing forever and then I would be able access it again. One area that I'm growing very interested in printing is Airfoil fins to impart spin

 

[BigMacDaddy]

Printing with 0.4mm nozzle, I use open rocket library of BT tubes change the lenght and look at the mass. The BT-60 I'm comparing to is 12.3g per 200mm all available in the library seems to be around that mark.

With regards to the wall thickness, it depends in the material used. PLA+ is 0.6mm with 1mm bead spire running clock and anticlockwise.

For LW-PLA two approaches was tested and tried. One is 0.8mm wall with sub surface grid 1mm to provide some lateral structure. This grid forms about 25mm square pattern inside the tube.

And second approach is 3mm thick walls by design but the slicer settings creates cavities inside the walls. This approach is alot more sturdy. But does weigh more. More material more weight regardless of design.

Hope that helps.

That is interesting... It would be cool to compare strength vs. weight vs. print time (vs. quality) for a variety of printing techniques for a few common shaped airframes. Some examples:

• Simple Cylinder
• Simple Cone
• Cigar Shape (Ogive to Ogive cones)
• ????
• ????

In addition, some possible print approaches:

• Single wall
• Double wall
• Adding low % infill
• Adding vertical bracing
• Gluing in separate bracing elements
• ????
• ????

I don't necessarily think we need to be completely scientific about this -- just need to experiment till we find what works for us.

One example: I found when printing my JB-3 Tiamat that I could print with a single wall w/ .6mm nozzle and 2 walls with .4mm nozzle and the build felt quite strong (due to the complex geometry in large part). I planned a couple of frame parts as inserts as well as a motor mount tube so it should be very strong once complete (I don't feel the need to always print everything as a single part). Unfortunately, I seem to always get at least 1 layer shift when printing this with a single wall .6mm nozzle so could not rely on that approach.

 

[OzHybrid]

When comparing the strength of printed components it's tricky. With 3D printing, you get the option to create significant strength from structure. If I was printing a centering ring, it wouldn't just be a disc. It would have structure. Might also have some threaded insert pads. This also holds for tubes. It would be double walled with a honeycomb spacer if printed, not just extruded as a coil of hot plastic on top of the next stacked up ring of plastic. That would be a bad design for that construction methodology. Might even have a super light glass epoxy cover. So comparing a badly designed bit of wood that was used simply because it exists as a poorly laminated sheet to a disc of plastic printed to look like the badly designed disc, is irrelevant. ish....

 

[Rustie0125]

That is interesting... It would be cool to compare strength vs. weight vs. print time (vs. quality) for a variety of printing techniques for a few common shaped airframes. Some examples:

• Simple Cylinder
• Simple Cone
• Cigar Shape (Ogive to Ogive cones)
• ????
• ????

In addition, some possible print approaches:

• Single wall
• Double wall
• Adding low % infill
• Adding vertical bracing
• Gluing in separate bracing elements
• ????
• ????

I don't necessarily think we need to be completely scientific about this -- just need to experiment till we find what works for us.

One example: I found when printing my JB-3 Tiamat that I could print with a single wall w/ .6mm nozzle and 2 walls with .4mm nozzle and the build felt quite strong (due to the complex geometry in large part). I planned a couple of frame parts as inserts as well as a motor mount tube so it should be very strong once complete (I don't feel the need to always print everything as a single part). Unfortunately, I seem to always get at least 1 layer shift when printing this with a single wall .6mm nozzle so could not rely on that approach.

View attachment 581626

Indeed all of these is yet to be tested, I just had to first test and proof to myself that it's viable as a alternative. I did post a update on my progress here Thread 'STEM 3D printed rocket project update- ongoing' https://www.rocketryforum.com/threads/stem-3d-printed-rocket-project-update-ongoing.180027/

I suspect having a 3D printer with a dual extruder is becoming a valuable addition because if you could print PLA+ as core structure and LW-PLA as skin. It would allow for some very flexibility.

 

[JohnCoker]

When comparing the strength of printed components it's tricky. With 3D printing, you get the option to create significant strength from structure.

Yep, that's where I plan to make up the expected strength gap. (But first I want to test things everything to get a baseline.)

 

[JohnCoker]

Thats a very US centric reply. Not everyone has access to the materials you can take as readily available by next day delivery. Shipping costs from the US can be prohibitive.

Apologies; I did not consider cost (just time and mechanical properties). To be fair, the OP is listed as being in the US (New Jersey).

You do these things to see if we can develop new techniques. Along the way something new and exciting might come out. The result only has to be acceptable for it to be worthy of use. Best practice depends on what's available to you.

That I can understand fully! It'll be interesting to see what comes of these tests.