3D Printing Nose Cones

Anybody had good luck printing larger nose cones? The one I'm building is for a 3.5" shipping tube.

I use Simplify3D for slicing. My first attempt was to use just three outer walls. (Due to complications and poor layer bonding, it broke before flight). Now I am pondering using both an inner wall and outer shell with some kind of fill pattern. This has exponentially increased the simulated print time as expected, yet I am not sure if there is a good benefit.

https://a360.co/2H7JI3T (Link to the Fusion 360 File)

William

Wschmiedlin said:

Anybody had good luck printing larger nose cones? The one I'm building is for a 3.5" shipping tube.

I use Simplify3D for slicing. My first attempt was to use just three outer walls. (Due to complications and poor layer bonding, it broke before flight). Now I am pondering using both an inner wall and outer shell with some kind of fill pattern. This has exponentially increased the simulated print time as expected, yet I am not sure if there is a good benefit.

https://a360.co/2H7JI3T (Link to the Fusion 360 File)

William

Click to expand...

What size nozzle are you using? If it's .2mm then it's not ideal to have three walls. If it's .4mm then it should be quite strong with three walls. More likely than not if you fix your printers layer issues, there should be no problem using three walls (assuming it's not a hpr).

I can help fix your bonding issues if you don't know where to start.

I thought about using a bigger nozzle but have not played with that yet. And, I think I corrected my bonding issues... new extruder and hot end.

William,

I currently use a CR-10S printer. I've created many 4" PLA nose cones that have survived L2 & L3 flights using a .4mm nozzle.

I also use and inner wall of about .080" thick with 20% infill. The photo below shows a conical nose cone for a 4" project. Stiff as a board. Maximum height for my printer is 500mm so the nose cone is 2 pieces.

You are right as far as printing. Just the lower portion took 30 hrs at .1mm height. Just over two days to completely build, but it looks great.

Keith

Eric Jimenez said:

I can help fix your bonding issues if you don't know where to start.

Click to expand...

...but doesn't the layer to layer bond remain the weak point regardless?

shonc182, you are correct. In my original post, I complained about the long process time to print. Eric suggested using a larger nozzle, which lays down a larger amount of plastic with each pass (needing fewer walls / passes) but remember with the increased diameter the contact area of each bead / pass is increased. This allows for a greater bond area.

With my current design, I may have to keep the two walls up to the shoulder of the nose cone because of some threaded geometry, then switch process techniques to only print the outer shell.

shonc182 said:

...but doesn't the layer to layer bond remain the weak point regardless?

Click to expand...

Yes in general. But if you have your settings dialed in correctly, a good print won't fail at the layer lines. You can get it to where the material itself fractures and not have it fail at the layer lines.

I have printed two 3in nosecone in PETG. They are rock solid and have held up extremely well up to an J motor so far. I believe I printed with 4 walls as additional noseweight just adds stability and requires less epoxy and BBs to move the CG forward. For PETG, the trick is to print slow (40-60mm/s) and at a high temperature (250C for me) in order to get excellent layer adhesion.

Photos are of my new 3D printed rocket and my 3D printed L2 project.

Big nozzles help increase the layer bonding heat tremendously. I use a .6mm for the Fly away guides and fincans.

Landru said:

Big nozzles help increase the layer bonding heat tremendously. I use a .6mm for the Fly away guides and fincans.

Click to expand...

Also cuts down on the print time tremendously. Win win.

I have printed a 4" and 3" for my Nike Apache in ABS. https://forum.ausrocketry.com/viewtopic.php?f=6&t=5019
for details.
Last flight had the 3" at Mach 2.14.
Feel free to steal any ideas in the design.

OverTheTop said:

I have printed a 4" and 3" for my Nike Apache in ABS. https://forum.ausrocketry.com/viewtopic.php?f=6&t=5019
for details.
Last flight had the 3" at Mach 2.14.
Feel free to steal any ideas in the design.

Click to expand...

The design page is awesome. I keep going back to it every time I sit down at my desk.

I like the use of ribs between the walls of the NC. Thinking about a corkscrew rib inside my own design, vs. letting the slicer use a default fill pattern.

Glad you like it. The way I think about the design is to design the features I want in the part, and then finally add any features needed to make it all stay together. Try to be minimalist with what you add if you are aiming for a good mass fraction in the rocket. If mass fraction is a "don't care" then use whatever method to join the features that you want. Keep thinking and evolving your skills. Additive manufacturing is a completely different mindset to the traditional subtractive.

BTW, don't forget a conical (countersunk feature) for where the thread goes through the top of the nosecone, inside. Makes assembly easier .