3d FDM Print vs Resin Print

[coryhenry]

Got another chunk of work done on the FDM hull. The upper is almost complete with the retract mechanism custom made in Bob's design. I also got the connection complete around the missile tubes and the drive train is almost complete.


The retract mechanism was a bear to design and create but it works!

[coryhenry]

Got some more work done on the FDM hull. The MSD is just about the right size. I thought I was going to have tons of room in this cylinder but the missiles cut that prospect short! The battery will be in the bow and two servos will also be run wet in the bow. The FDM hull is proving easier to work on and less brittle. For scale the ballast tank is 10inches long.

[coryhenry]

I use Prusa Slicer and it is a great slicer, but is really tuned to Prusa printers. I have found tolerances pretty close to the model but have had to make minor adjustments to scale.

[Henk Freubelaer]

And that should be shrink, not schrimp *facepalm*

[biggsgolf]

Great info guys! Thanks

[Henk Freubelaer]

I do the same as Coryhenry, if I need to scale for my model than I do it in my design program.
For that I use Fusion 360.

But as a quick solution I did scale some models in my slicer, some that I found on thingiverse.
As a slicer I use Cura.

I am not a big fan of it but it is possible.
But keep in mind that your print might schrimp when it cools off.
So you might print your model a little bigger than desingned.

[biggsgolf]

Thanks, I am just starting using Tinkercad & Photon Workspace mostly.

[CC Clarke]

What is the best way to change a STL Files scale? If the the original scale is 1/72 how best to change to 1/96 for example. Would “Meshmix” “uniform scaling” be a good solution?

It would help to know:

1. What 3D modeling app you're using.
2. What slicer you're using.

Slicer's typically have a scaling tool that uses a bounding box to display the "as-is" three dimensional measurements of the part to be printed. You can take the ratio (1/72:1/96) and enter one measurement, and the other two should update globally. This is easily performed in ideaMaker.

Free from Raise3D: Powerful 3D Slicer Software: IdeaMaker by Raise3D

CCC

[biggsgolf]

Thanks, its a lot to learn at first!

[coryhenry]

I haven't gotten deep in the digital modeling side of things. If its minor scale changes I can do it in my slicer software but that is a bandaid approach. If I developed them model I go into FreeCad and change the scale there.

[biggsgolf]

What is the best way to change a STL Files scale? If the the original scale is 1/72 how best to change to 1/96 for example. Would “Meshmix” “uniform scaling” be a good solution?

[coryhenry]

Just pop a battery connector in the front and run a waterproof NiMh battery pack in the wet.

Bob

Great Idea Bob, for some reason I always forget Batteries can run in the wet.

[Henk Freubelaer]

Great project.

Maybe something usefull for a future project, I treat my printed parts with resin from my other printer and cure it under UV light.
It makes the PLA much stronger and it fills in most of the printlines, this saves a lot of time when it comes to use filler.
And I find sanding the resin top layer gives a smoother result than sanding the PLA, PLA alway's sands a bit rough.

[RCSubGuy]

Don't be afraid to get creative here, Cory.

The only purpose of the forward battery compartment is to... house the battery. Power can be provided from any number of external sources (though the MSD makes it very convenient). You could pop off the forward battery section, cut it really short (just enough to basically hold the forward servos) and reinstall. Now you have a truncated cylinder with the forward section of your boat completely open for missiles. Just pop a battery connector in the front and run a waterproof NiMh battery pack in the wet.

The beauty of the MSD design is that if you want to transfer the cylinder to a different boat, just get another section of tubing and pop it on. It would literally take 15 seconds to do.

Bob

[Subculture]

Ballast tank is difficult to estimate as many factors dictate its size. As yours is a 3d print though you should be able to use the STL file split it in cad at the desired waterline and let the software provide you with a very accurate figure for displacement. Make sure you use volume and not weight.

I think you will need some means of compensating for a shift in charge cg and cb with those missiles being toward of the boats centre of lift.