3D printing for HPR

[cwbullet]

It's easier to 3D print parts them cut them from plywood. (I expect many more people have 3D printers than CNC routers.)

I concur. Ease of printing vs cutting and routing is key, but it is also cleaner. No sawdust to clean up. Then again, you do waste a lot of filament getting it perfect,

 

[OzHybrid]

I concur. Ease of printing vs cutting and routing is key, but it is also cleaner. No sawdust to clean up. Then again, you do waste a lot of filament getting it perfect,

Use the best method from everything YOU have available. While it's possible to completely print a rocket, and I've done it, you can achieve better performance and lighter weight by not restricting yourself to a single construction methodology.
Printed components can suffer from delamination after heavy landings. There is no easy way to identify the start of any cracks.
With conventional materials the failure modes are known. You can cut centering rings with a jigsaw, or 2 holesaws or a pair of scissors if you're using 1/16 ply. There is no necessity for a cnc router and I've used all those methods.

Lastly there is no point in printing a centering ring in some exotic material when the cost of that is excessive. So those results while interesting, are not practical for those who cannot afford those exotics by the cost of either the printer required or the ongoing exotics cost.
The majority of people will be printing in PLA, +, PETG or ABS.

 

[Rschub]

I concur. Ease of printing vs cutting and routing is key, but it is also cleaner. No sawdust to clean up. Then again, you do waste a lot of filament getting it perfect,

I am more than happy to support people like Dragon Rocketry that provide laser cutting services, I understand the thinking behind trying to do everything in house, but I am wary of rabbit holes from long experience.

 

[boatgeek]

In the long run, something that would be very helpful would be a matrix of an object’s strength vs. printed wall thickness and infill percentage. Like it would be nice to know that a 1-layer wall with 30% infill is 90% of the strength of a 2-layer wall with 50% infill.

Thank you for doing this work!

 

[Chad]

I do a lot of 3dprinting for ebay components and also for jigs like for fins and things. It's been a game changer for me, if something doesn't turn out right then make an adjustment and re-print. Let the printer do the hard work.

 

[kramer714]

I do a lot of 3dprinting for ebay components and also for jigs like for fins and things. It's been a game changer for me, if something doesn't turn out right then make an adjustment and re-print. Let the printer do the hard work.

I agree with you, recently made a few nosecone / av bays using up some 38mm leftover fiberglass tubes. Different vintages and different suppliers / wall thickness on the fiberglass tubes. Each had a slightly different I.D. I ended up making slight changes to the OD of the shoulders, 'customizing them' so they each fit a particular tube perfectly. Easy to do on a 3d printer. Just minor 'tweeks' of the two index features on the nosecone cup (light green part) to make it custom.
Mike K

 

[JohnCoker]

You can cut centering rings with a jigsaw, or 2 holesaws or a pair of scissors if you're using 1/16 ply. There is no necessity for a cnc router and I've used all those methods.

Jigsaw and hole saws are much more work and produce poorly-fitting parts. (I've used these and other methods in the past.) Without CNC routing, I think 3D printing is the best hope for home-made components in the long term.

Lastly there is no point in printing a centering ring in some exotic material when the cost of that is excessive. So those results while interesting, are not practical for those who cannot afford those exotics by the cost of either the printer required or the ongoing exotics cost.
The majority of people will be printing in PLA, +, PETG or ABS.

I was curious about the range of printers I had access to (including through services). I will focus next on adjusting settings to print with the X1C in ABS, PETG and PLA. (There is no PLA in this first set because it's low Tg rules it out for use in CRs, but I am including PLA in the bulkhead samples.)

 

[JohnCoker]

In the long run, something that would be very helpful would be a matrix of an object’s strength vs. printed wall thickness and infill percentage. Like it would be nice to know that a 1-layer wall with 30% infill is 90% of the strength of a 2-layer wall with 50% infill.

Agreed. It's quite expensive to get the testing done, but I will try to quantify some of these dimensions.

 

[SolarYellow]

... I am wary of rabbit holes from long experience.

That's what this whole rocketry thing is, right?

 

[SolarYellow]

Jigsaw and hole saws are much more work and produce poorly-fitting parts. (I've used these and other methods in the past.) Without CNC routing, I think 3D printing is the best hope for home-made components in the long term.

Agree that jigsaw and hole saws are limited. And you're super-lucky if you happen to find two hole saws that make the precise ID and OD you need for centering rings. Even one is pretty unusual.

CNC routing at the low end can be cheaper than printing, but it doesn't have the versatility. On the other hand, I think it's way superior for things that can be built up out of flat stock. And it can be used for balsa, bass, plywood, composites, foam, even light aluminum work. It's kinda nice to be able to choose your material and make it into the shape you want, rather than trying to find a filament or resin with appropriate characteristics and then working to find all the settings to make it functional.

A proper shop should have both.

 

[thzero]

Another thought. Printing rings and bulkheads at 45 degree angle. Both FDM and resin.

 

[atestani]

I've been printing centering "rings" like this for my interchangeable motor mount system. The main benefit is everything is concentric and perpendicular, i.e. not tilted. The round indentations are to clear rail button rivet nuts and the slots are for clearing the fin tabs. These are printed with very low infill so they are very light.


I forgot to mention I have a laser cutter, metal lathe, CNC milling machine but 3D printing is my preference for making parts.

 

[JohnCoker]

OK, I've got the first batch of numbers back comparing printer settings (all printing ABS on the Bambu X1C). I want to do a couple more batches with higher number of wall loops to find the fall-off point, then I will publish a more complete update. I'm also curious whether the pattern comparison would change at 50% density.

 

[JohnCoker]

I posted additional test results, trying to refine the best FDM print settings:
https://www.jcrocket.com/printed-components.shtml#hypothesis3settings

 

[2-0turbo]

I posted additional test results, trying to refine the best FDM print settings:
https://www.jcrocket.com/printed-components.shtml#hypothesis3settings

Very interesting results, John. Thank you for all the time you’re putting into this and for sharing your data!!

 

[cwbullet]

Very good results. Although I have not tested it to this degree, this is what I am seeing on the field. Then again, I probably would not fly 3D printed rockets and parts with most Warp 9 motors.

 

[Sooner Boomer]

Very good results. Although I have not tested it to this degree, this is what I am seeing on the field. Then again, I probably would not fly 3D printed rockets and parts with most Warp 9 motors.

I will. Send me one w/a 38mm motor mount. Your choice of an H999 or an I1299.
Watch the very end of this (after the still shots)