Firstly, thanks to Selwyn, Bill and (unknowingly to him) Brian Dill. I have been on the 3dprintedradioyachts site on countless occasions and have been inspired (basically stolen lol) ideas from the layouts and angles used on the decks etc.
And with regards to Selwyn in particular - I have been as blunt as “I have this problem. Have you figured it out so I don’t have to waste my time trying to re-invent the wheel?” and he has been on point with the answer.
There are also some guys who have done some crazy CAD stuff on Facebook RG65 group.
EDIT - Forgot to thank Claudio for the design/rig plan!!!
I thought I’d start loading some pics of my progress so far.
Everything is going well in terms of weight and strength. My method seems to be rather complicated compared to some others but I’ve been having a blast
I’ve got a hull done and floated it without any keelfin and it’s sitting really well in the water already.
Keelfin is made and the bulb and rudder are in CAD almost ready to go.
My main considerations while designing the files for print were to maintain the alignment of the mast, keelfin and rudder.
So the hull and internals for it would ideally be printed as a single piece - this would mean that I cannot use “Vase mode”
I’m using Marlin firmware with Slic3r Prusa Edition for slicing the CAD file.
Behold the outcome in all its glory… not.
This was one of my first attempts on my new printer.
The finish was terrible as I hadn’t calibrated my extruder and setup my firmware correctly at this point - but I just couldn’t wait.
There was horrible over extrusion but it proved that I could get an actual section printed!
This test also showed up some issues with my design…
I was attempting to get a rounded profile to make printing easier. When I used fillet on the CAD file I didn’t pay attention to that section which lies horizontal to the horizon when printing. The printer didn’t stand a chance.
It also showed up the following issue which bothered me. It’s an artefact of from printing a single wall hull and internal structure at the same time.
What’s happening is two issues.
If I was using a solid body and using “vase mode” in the Slicer program, the printer would do a continual loop one layer wide around the hull shape. I can’t do this as I want an internal structure.
So it prints the main hullshape and then stops, makes a small blob and goes to the internal structure. It’s not that bad and could be sanded but it kind of defeats the point.
2.If you look carefully there are holes in the hull, right next to the rudder trunk, top right. I believe that this was down to getting the extrusion width wrong on my Slic3r settings (It’s actually quite illogical but worked). I’ll go into this later as it has an incredible impact on the print.
I decided that I should go back to the “Vase Mode” as described by Selwyn etc. and just keep going.
I calibrated my extruder (this makes sure that it puts out the correct amount of plastic) and attempted my first real go in the only colour I could get - My Eyes are Burning Orange
I unfortunately don’t have any pics, but the long and the short of it is that I had a flat deck and very sharply angled sheerline. This gave me a wonderful curved hull section but an incredibly warped deck.
Bill had mentioned it before but it never sank in so I got hold of Selwyn and two thundering great chunks of knowledge were dropped.
Thin and flat is crap. I’m paraphrasing - He is much more polite than that. Put angles in which apply tension on the cooling filament and it holds its shape.
Print cold. It’s incredible. I’m not sure if my thermistor just reads high, but my filament states that it’s minimum temp is 180. I’m at 175 and it’s so much better than when I was at 195. This could be specifically to do with the thin walls we are printing, I don’t know.
I made dimples and a foil shape in CAD to align the seperate keeltrunk/mastwell and rudder trunk.
I exported the hull as a single solid thing from CAD and told Slic3r to cut and print a single outer layer.
You can see here how I have adapted the failed section from before with a straight, 45 angle that printed very well.
Here is the mastwell/keel trunk and rudder trunk
And here you can see the joining rings as per Selwyn’s recommendation on the site and the keel trunk section sitting in loosely.
It was a great accomplishment, but it felt very thin. I cant explain it, but I would have been worried about the thing breaking in the water.
So it was time to start putting it together and the amount of play bugged me, and I was still a bit annoyed that I have to manually align the rudder/keel fin - All my attempts at doing this on wooden yachts have been terrible.
So it sat on the back-burner for a week until I suddenly realized that I was missing a trick in in Slic3r. You can print parts with different materials coming out of two or more nozzles, or with different colours etc.
If you can specify a section to be printed in different ways, I must be able to get the hull done as one pass and the internal as a seperate section (this sounds misleading - I am still printing both bits at the same layer height, but it does the hull piece first, then the internals)
So without further ado… Where I’m at.
It’s incredibly strong and note that the picture on the scale is the hull including the mast/keeltrunk and rudder trunk.
It has a thicker layer for the hull than previously (now 0.6mm instead of 0.4mm) which is due to the weird thing about extrusion widths I mentioned earlier. I’ll clarify later.
Here is a pic of the pieces joined with my rings (I love these pics - the rings remind me of the frames in wooden hulls)
The rings can probably be lightened by putting more holes in them to drop weight.
And here is my method of joining sections.
Each hull section is printed with an internal ring on the Printer’s build plate.
It has 3 alignment holes int this.
I then print a matching ring with a lip that sticks out. This is shaped to fit the curve of the next section.
The ring is 0.6mm high and the raised portion was originally another 0.6mm above that. I did a test where the raised lip was 1mm high and it was a much easier fit and gave a great alignment.
hull section
The section facing us is the bit that was on the build plate whilst printing.
Joining ring
Using Cyano Acrylic to join the ring to the hull bit. Toothpicks are awesome
Note the little ledge sticking up. This collar aligns the next hull section and the whole assembly strengthens hull from bending laterally.
Floating in the pool with no keelfin or anything
I have the keelfin done and have started the rig building.
Nice Job Andrew !
The total weight is nevertheless higher than the design budget of 73g (Hull + Deck + Trunk). 53% excess weight .The 39g additional weight should be compensated by accepting 1.2mm sinking at water level. There is some margin for that.
Cheers
Claudio
Thanks, I’m really enjoying the project
With keel-fin and the rg65 rudder I made I’m sitting at 149g.
I need to weigh my servo and winch, and I have no clue how much a swing rig weighs.
We shall see. What I can say is that it’s sitting in the pool and there is no leaking after 3 hours.
So that’s another bonus/ tick
Andrew, this is an impressive result! You have accelerated up the learning curve very quickly. I dare say Selwyn may be calling you about some of your techniques.
It sure would be fun to race your new boat against Selwyn’s in a battle of the 3D stars
Congratulations…Bill
p.s. Our friend, Craig Smith, has seriously joined our team. He brings great design experience and unbelievable Solidworks skills. Craig has put his CAD skills to work to develop all of the internal bits to work toward our goal of printing an IOM hull with integral internals…no construction required. Initial tests are very promising, but there’s lots of challenges, as you would understand. Cross your fingers.
For me personally, getting the internals printed at the same time is the holy-grail, and it would seem to be completely do-able.
I need to figure out why i had to print with such a thick hull. I started laying out an RG65 off plan and it’s fine at 0.4mm. This HAD to get done at 6mm or it would print massive holes… very confusing but much to learn.
I have hit a bit of an issue though… my drum winch doesn’t fit in the hull So I’ll get onto organizing an arm etc. but that one really caught me off gaurd.
This project is cursed…
Re-did the cad for a swing arm. Happily toddled off to get some 6mm carbon rods for the rig.
Supplier has none and reckons it will be a while before more come in. The joys of not living in the US or Europe.
So untill further notice the n-Arrow3b is the centre of focus for the 3d printing endeavour as I can get away with some of my 340spine arrow shafts as masts and booms.
Woot woot
So I’ll get onto organizing an arm etc. but that one really caught me off gaurd.