Marui Samurai 4WD - Another SilverTriple's journey...

[silvertriple]

My brother is printing with an Ender 3 converted direct drive with the original extruder on top of the hot end at 60 to 80 mm/s. On my side, I've not even played much with the speed of the printer yet. In theory, it should be able of much more than what I do right now... I had a lot of discussions with my brother, and I may look at the Biqu H2, which seems to be a good compromise in terms of weight. I've looked in thingiverse, there is already some options for mounting it on an Ender 5 plus, which could be a good start. That being said, I may have to digg into firmware topics (which is another learning curve by itself )...

[Dadio]

If the 5+ has the same control board as the 5 then I'd recommend going from an 8 bit to a 32 bit board , the Big Tree Tech 32 bit SKR boards are cheap , I've got one in my Ender 3 , if your looking at having to play with the firmware for a good direct drive extruder anyway then I'd ditch the old board and do the firmware on that instead . TH3D does a drop in board for the Ender series , it's more expensive but they have a configuration setup wizard on their web site that's so easy to use , I've got their board in my Ender 5 and I love it , it's so easy to set up compared to normal , worth the money to me .

[silvertriple]

The only thing I'm totally not sure about is the touch screen of the Ender 5 plus : it does have a separate firmware, and while I could find easily some elements for the mainboard, it's not the same thing for the touchscreen... I will need to find out anyway...

[silvertriple]

Was thinking tires again...
There is some STLs for the tires in Thingiverse. And yesterday I come across an interesting post on one Facebook group about tires printed with Varioshore foaming TPU. It's a TPU with foaming agent inside, and it results in different density depending on the temperature you print it. And it have some advantages compared to standard TPU: in particular, it could be printed with a bowden extruder. Another one is that you could potentially target the right shore for tires including (and that what's interesting) infill which would remove a lot of the support issues... I may want to try that for Samurai tires. I'll probably have to order some Colorfabb Black Varioshore Foaming TPU at some point within the next months...

[Dadio]

I wonder if the foaming would offer more chemical grip , I've never been sure about TPU or TPE for tires as they both tend to be quite a low friction plastic , fine for dirt or sand where mechanical grip is all you really need but if it's on road or carpet I'm not sure they would work well , maybe the foaming will offer more in this respect .

[silvertriple]

I wonder if the foaming would offer more chemical grip , I've never been sure about TPU or TPE for tires as they both tend to be quite a low friction plastic , fine for dirt or sand where mechanical grip is all you really need but if it's on road or carpet I'm not sure they would work well , maybe the foaming will offer more in this respect .

A standard tire is about 60A shore. The target is this or slightly lower. The grip is a combination of two things : the grip of the material and its ability to deform itself to maintain contact with the road...
Ultimately, there is only one way to know, it is trying

[silvertriple]

Another learning about parametric design...
Anything involved in a parametric sketched must be fully defined, otherwise the design is degenerative when you hit some limits... That is very obvious once you understood that there was a missing constraint, but until that it was not clear... So first thing to check is that the sketch defining the extrusion is made of black lines and not of blue lines (Yes, I know, I feel like a noob, now )

[Dadio]

If you totally want to experience confusion try a 3d sketch , that becomes bonkers .

[silvertriple]

If you totally want to experience confusion try a 3d sketch , that becomes bonkers .

It's totally on my plans ... I'm quite sure I'll need this to deal with the roll cage of the Nichimo (and if not for the Nichimo, it maybe of use if I try to design a JavHunter Rollcage)...

[silvertriple]

If the 5+ has the same control board as the 5 then I'd recommend going from an 8 bit to a 32 bit board , the Big Tree Tech 32 bit SKR boards are cheap , I've got one in my Ender 3 , if your looking at having to play with the firmware for a good direct drive extruder anyway then I'd ditch the old board and do the firmware on that instead . TH3D does a drop in board for the Ender series , it's more expensive but they have a configuration setup wizard on their web site that's so easy to use , I've got their board in my Ender 5 and I love it , it's so easy to set up compared to normal , worth the money to me .

I've looked at the details, and apparently, on the Ender 5 Plus, it requires as well a replacement of the touchscreen with one compatible with the mainboard. All things in, that bumps the cost slightly, considering that I also want to move to linear rails... Quite a good bunch of thinking is required ahead...

Back on the topic, I launched a final printing for my Samurai wheels. I've opted for on set of oval blocks at the moment (I could always change my mind if I find something better later). I did a few change in my cura settings :
- Infill 30%, Grid (which I think should be ok, as some are using Lunchbox with printed wheels and an infill at 20%)
- Monotonic Top and bottom
- Ironing, concentric
- Support in tree mode, everywhere
- Layers of 0.12 at the exception of the first one. The wheels are grown up from their rear face.

For a set of 2 rear and 2 front in 50mm diameters, it is going for about 23-24 hours print. The current progress is about 61%. And the result in terms of quality appeared to be promising as per what I can see already on the spokes of the front wheels (and yes, there could be always ways to have better quality, but this will be probably good enough).

[silvertriple]

Here are the new printed rims. The quality is really better than previous set.


I may want to adjust the retractation as there traces of under extrusion in the areas post a move, but beside this it is quite good.

I will try with tires on a Samurai next

[Dadio]

Those looks really good , a couple of coats of clear lacquer and they will look ace ! I'd print them one at a time because the time is the same but you cut a lot of travel artefacts and if one fails you don't loose all 4 , just my feelings plus you can look at the first and twerk the settings .

[silvertriple]

Four wheels, oval blocks




Two minor details to review in my stl and they are good to go...

[silvertriple]

Those looks really good , a couple of coats of clear lacquer and they will look ace ! I'd print them one at a time because the time is the same but you cut a lot of travel artefacts and if one fails you don't loose all 4 , just my feelings plus you can look at the first and twerk the settings .

Well, yeah, could have done this way... I thought it was not needed following what I've done previous week with this filament, and if I've done that, I would have 4 different quality of wheels... I could continue tweaking this forever . And for the travel artefacts, I do not have much, and they almost appear only on the part which is going to be covered by the tires anyway, so it's ok...


And by the way, tree support is working perfectly, and they are very easy to remove...

[silvertriple]

This got me thinking the whole night. It's good, but it doesn't respect one thing of the Samurai design. Something disturbs me when I look at those pics.
The rim diameter size difference of the original wheels is about 4mm. Front tires are lower profile than rear ones. That gives a very specific look to the buggy (it would be the same with a Kyosho Progress, I believe).
4mm is nothing and a lot, ultimately.
Yes I could choose original diameter and squeeze smaller tires on both Front and Rear (aka @Dadio's method... But I won't be able to do that with the oval blocks which are the closer in spirit from the Marui Hyper Traction tires I can find... I can't do that but what about adding a millimeter to the external ring of the front rim so it looks bigger?

Let's see... I still have the front wheel originally printed. it has a bigger external diameter, but I found it too big, so I reduced it for the second set... I took them in pictures, and here is:


I think I got my perfect solution, now