Bruder 320 conversion with 3d printed parts
 

After recently completing my little bruder bulldozer conversion I decided to next have a try at making an excavator. I began with a Bruder 320 and began cutting plastic. I will post pictures below as I make progress. I am teaching myself how to 3d model using Fusion 360 (free) and then printing the parts on my 3d printer. I will be using modified servo motors for the tracks as well as for slewing. I ordered a magom hydraulic pump and I am going to attempt to make my own cylinders and valves when I get that far.

Mount for track motor. http://i951.photobucket.com/albums/a...otorcover2.jpg
http://i951.photobucket.com/albums/a...or%20cover.jpg
Hub Adapter
http://i951.photobucket.com/albums/a...%20adapter.jpg
All Glued together
http://i951.photobucket.com/albums/a...r%20covers.jpg

Re: Bruder 320 conversion with 3d printed parts
 

Paintedhttp://i951.photobucket.com/albums/a...otorCovers.jpg

Center pivot and gear.
http://i951.photobucket.com/albums/a...nd%20print.jpg
http://i951.photobucket.com/albums/a...ower%20ger.jpg
Top Pivot
http://i951.photobucket.com/albums/a...upperPivot.jpg
Assembledhttp://i951.photobucket.com/albums/a...hine/Pivot.jpg
http://i951.photobucket.com/albums/a...in%20place.jpg

Pinion gear
http://i951.photobucket.com/albums/a...ine/Pinion.jpg

Re: Bruder 320 conversion with 3d printed parts
 

Bearing Holderhttp://i951.photobucket.com/albums/a...ng%20Mount.jpg
There is as slip ring in there but I forgot to take pictures of it.
http://i951.photobucket.com/albums/a...d%20pinion.jpg
http://i951.photobucket.com/albums/a...hine/Gears.jpg
http://i951.photobucket.com/albums/a...hine/Gears.jpg
http://i951.photobucket.com/albums/a...chine/Test.png

Re: Bruder 320 conversion with 3d printed parts
 

Wow, that is slickon owl-stuff!

Re: Bruder 320 conversion with 3d printed parts
 

nice build ! you have good idea for that build ! keep up good work !

Re: Bruder 320 conversion with 3d printed parts
 

wow thats amazing work . i cant wait to see it all complete .
you might have to print me those files... my printer is down at this time

Re: Bruder 320 conversion with 3d printed parts
 

Thanks for the kind comments, it is coming together ok as time allows. My pump and valve body arrived from Magom in Spain yesterday, what little pieces of art those are. I am currently working on attempting to build my own cylinders that hopefully wont spew oil all over the place :)

Re: Bruder 320 conversion with 3d printed parts
 

Nice work! I love that turn table with a bearing and everything. Now time to try some 3d printed hydraulic cylinders?

Re: Bruder 320 conversion with 3d printed parts
 

The cylinders are proving to be difficult to construct. There is a fine balance between too tight/won't move, and too loose/leak all over. Unfortunately though the printer is of no help there since the parts need to be machined and very smooth, and to pretty accurate size. I will post a pic if I can get a cylinder working later.

Re: Bruder 320 conversion with 3d printed parts
 

yeah I would imagine you would have to machine everything just like you would with metal. I would think doing a acetone smoothing that would create almost a hardened shell around the outside of a abs part and then machine that. Everytime I try to get a good finish on this thermoplastic it ends up melting and I havent been able to get a real good surface finish, but I havent invested too much time trying either.

Re: Bruder 320 conversion with 3d printed parts
 

Here are some pics of a couple of the cylinders I made. 1 of the three I made is perfectly leak free, the other two ....not so much! Nothing horrible but they are dripping around the gland where the shaft leaves the end of the cylinder. It looks like I need to re invent my seals somehow. It was pretty neat to see them moving though, and even with the pump just barely turning they are quite powerful.

http://i951.photobucket.com/albums/a...214170915a.jpg

http://i951.photobucket.com/albums/a...0214170915.jpg

Re: Bruder 320 conversion with 3d printed parts
 

Very nice work on the 3D printed parts and custom cylinders.

Re: Bruder 320 conversion with 3d printed parts
 

Wow those cylinders look absolutely superb.
Please could you publish drawings/details of them?
Have you used lost wax castings for some of the parts?
I would like to be machining these out of barstock

5

Re: Bruder 320 conversion with 3d printed parts
 

Thanks for the compliments. The cylinders are simple in theory but I am finding that having the gland end seal without leaks is easier said than done. I made 4 cylinders. 2 are great while the other 2 leak so my design of using o rings as a seal may not prove to be workable in the end. No casting is involved, all lathe work. the barrels are just 1/2" copper pipe which happens to already pretty much have a mirror finish inside (I assume from the drawing process) and the end caps are machined from brass stock. the internals of the cylinders consist of aluminum pistons with steel shafts. No drawings, but if you look on the MagomHRC website you will see that they have very good exploded drawings. Honestly for about 50 bucks a cylinder it is probably best to just buy the cylinders from them, but where is the fun in that!

Re: Bruder 320 conversion with 3d printed parts
 

You are doing some nice work here. Guess you are finding the cylinders a bit tricky to make. Keep at it- you can make it work. Good Luck

Re: Bruder 320 conversion with 3d printed parts
 

If you are going with Magom cylinders this french forum has a guy who modified his Magom cylinders to be more reliable as far as leaks.

http://camions-rc.fr/forum/viewtopic...4474&start=240

He might also have more information on what he did in this build thread, I'm not really sure where.
http://camions-rc.fr/forum/viewtopic...2937&start=360

I use Google translate to read his stuff.

Re: Bruder 320 conversion with 3d printed parts
 

Thanks for those details, MagomHRC do have some nice detail drawings. My experience with "O" rings is limited to fire service breathing apparatus pressure reducing valves. These had a hollow piston about 1/4" diameter sealed in a cylinder with static "O" ring the pressure on one side was 3000psi the pressure on the other side 125psi. It was sometimes found that the pressure on the low pressure side increased. On close inspection it was often down to scratches on the piston or poor "O" rings. The remedy was to polish the piston to remove longitudinal scratches and check the "O" rings discarding any that showed damage or moulding flash etc. Crikey I do seem to go on:D

Re: Bruder 320 conversion with 3d printed parts
 

It has proven to be a bit more difficult than I thought it would be to eliminate the leaks around the shaft of the cylinder. I haven't done anything with them for a couple weeks but I will get back to them soon, in the meantime I will follow the links posted above to see what I can learn. Thanks!

Re: Bruder 320 conversion with 3d printed parts
 

nice

Re: Bruder 320 conversion with 3d printed parts
 

Me likes it a LOT