Bobs 1st 3D Project

[BobZilla]

Hello Group,
I have been working on a new machine design in Fusion360 and I thought I would start a thread for this project.

This will be a nine pole mechanical setup. The coils are about 2 inches tall, it's a pretty small machine. Each frame upright accommodates 9 coils so the initial design can have up to 18 coils and then I could build it back with more uprights and a longer axle but I'm not sure if that will be necessary. The magnets are going to be in super-pole configuration on the front and maybe a genny setup on the back with wider magnets, haven't decided on it yet. I will most likely use SSR and reeds for the switching.


I have never used a 3D printer before so I am hoping I have not gone too overboard with the design. I plan to do it in ABS filament and use nylon bolts everywhere possible. My printer was supposed to already be ready but they sent me a kit instead of the assembled model I paid for so I had to send it back and they are shipping me the correct one Which should arrive sometime next week.

Here are some pictures from the design software:









The last one is what I came up with for coil mounts, this was probably the hardest part to get right.

Well that's it for now, I will update as I make progress.

[BobZilla]

I discovered when I did a full mock up that a few things needed adjustment.

Here is how it should basically look with all the parts.





And I had to rework the spool holder

[Tom C]

that is going to be fantastic Bob!! let me knw if you wan help printing some stuff out I can do so and mail them to you. just send me the STL my Robo has an 8 x 9 bed so I can do some pretty big rotor diameters, and my flashforges do nice detail work.

because of the way the software slices, all 3D printers print in segments not true arcs. I always print some test pieces when doing circles so I can make the part actually fit the piece I want. for example if I want a .500 hole to slide an axle thru and I am printing on my flashforge I need the diameter called out on the part to be .550 so fifty thou larger it ends up being around .505..... this is the same for cavities for roller bearings, etc. it does not seem to matter for shapes like hexagons for nuts etc, since they are just pure angles and printers love those.

even so I would do a few test pieces for fit before I committed to a full part run. I did that once and it was a 36 hour print and 1/2 a spool of filament, its a big plastic paperweight.

Tom C

[Gary Hammond]

Hi Bob,

That looks like a pretty neat design!

My only suggestion would be a small change to the spool holder by making it in two pieces rather than three. The base and one side could be made in one piece which might make it stronger, and the other side would be the other piece. So instead of bolting three pieces together you would only have to bolt two pieces together.

[BobZilla]

Thanks for the feedback guys!

Tom I had thought about that issue with the holes, I figure I will do as you said and print a test piece first. I had the same issue on the first few parts I had machined from my own drawings but I was able to ream the holes a little with a file since it was aluminum. I had a question on material while were at it. I know ABS is tougher so I will use that for the wheel and main uprights for sure but looking at these plans do you think I could print say the spools and the feet from PLA instead? I have two rolls of white ABS and I will have two rolls of PLA when my printer arrives so I could use either. I guess I will know more after I get to work with this stuff. Anything else besides ABS that is recommended for mechanical parts? I saw PET after I had already ordered my ABS but it is described as being a tough material with low warping so maybe that would have been a better choice, just curious what you guys think for materials.

Gary I think your right on that spool mount. I am going to try making a simplified 2 piece version. I had concerns about it's strength when I was looking at it too, Funny how our brains work sometimes, as soon as I figured out that "mirror" tool I was committed to what I came up with. I think I was just stuck on the idea of the same part just flipped over but DUH,, 2 pieces is a great idea. I'm also not sure on the spool core size, I might widen that up a bit but it's going to take some tinkering once I have at least a single coil machine from these plans up and running.

[BobZilla]

New version of the spool holder after Gary's suggestion.





Those bolt holes are basically for 1/4inch nylon bolts and nuts. I keep looking at them and wondering if maybe it would be better to use some smaller brass screws like M4 with a flange washer. I could see either working nicely but it's getting to be decision time because I need to order all the parts soon like bearings screws and such.

[Gary Hammond]

Hi Bob,

That looks a little stronger to me. For the screws you could use nylon, brass, or stainless. And you would only need one screw at each location if you printed in some locking tabs and slots for alignment as well.

[BobZilla]

Hi Bob,

That looks a little stronger to me. For the screws you could use nylon, brass, or stainless. And you would only need one screw at each location if you printed in some locking tabs and slots for alignment as well.

Maybe I should call this Gary's machine ,, Just kidding. I really appreciate your input Gary! You are right once again. I think I will try like built in pegs on the top piece that slide down into the bottom with a bolt through the middle, or maybe like a dimple kind of thing. I get what your saying though.

I know why I am not seeing some of these design modifications on my own. I have to change my thinking. I have designed a lot of stuff, way more than the finished products you guys have seen in the past that I had fabricated, but it was always with plate metal in mind. Basically pick the thickness and add holes and bends and cuts. This extrusion element really brings out so many more possibilities than I had with the machine shop plans. I mean yes it was possible to make parts more 3D but the cost would always be way too much. Like starting with a 1/2 inch thick material and removing 1/4 inch of most of it just to make a post at a 90 degree from the finished surface. With this 3D printing your not removing all of that material but just building it up where you want, I'm not used to thinking that way.

I will keep tinkering with these plans, really Gary thanks a lot for your insight.

Once I get this thing finalized and built I will release the plans and a parts list for the group. I need to make sure everything prints and fits together correctly and that the machines performance is worth building it first though.

[BobZilla]

Good news,
I have my printer up and running now and I just printed a 1st try spool holder. I am letting the bed cool right now so I have not even tried inspecting it really. I am hoping these supports come off because if not it's all for nothing lol. I can already see that I need to play with the slicer program and try to get better definition. This was basically a "normal" setting that I tweaked only a few things on, like the wall thicknesses I set to 5 instead of default 3. It's ABS filament and the temp was 255 on head and 100 on bed.

I'm going to clean it up tomorrow and test the bolt holes for fit and if it's good then I will start cranking out the rest of them.

[Brian McNece]

Good news,
I have my printer up and running now and I just printed a 1st try spool holder. I am letting the bed cool right now so I have not even tried inspecting it really. I am hoping these supports come off because if not it's all for nothing lol. I can already see that I need to play with the slicer program and try to get better definition. This was basically a "normal" setting that I tweaked only a few things on, like the wall thicknesses I set to 5 instead of default 3. It's ABS filament and the temp was 255 on head and 100 on bed.

I'm going to clean it up tomorrow and test the bolt holes for fit and if it's good then I will start cranking out the rest of them.

[ATTACH=CONFIG]6236[/ATTACH]

[ATTACH=CONFIG]6237[/ATTACH]

[ATTACH=CONFIG]6238[/ATTACH]

Very Nice Bob
Did you get your printer already assembled?

[Tom C]

Bob,

ABS really likes an enclosure, even just a cardboard box. check your slicer thickness, for small parts .2 MM is what I like, you can also increase the number of shells (that is the number of walls on the inner and outer surface of the parts befre it starts generating infill. let me know if you have specific questions.

Tom C

[BobZilla]

Hey Brian,
Yes I did. Originally they sent me a kit by mistake so I had to go through a return process which is why I said finally got it up and running. Not because I was working on it but it was a long wait. It was on back order for a few months to begin with. Prusa is just swamped with orders.

It's worth noting that although I had some issues initially with them, I would still say that their customer support is TOP notch and a great company. I was a little concerned about it because they are in Czech Republic and I thought their could be problems with returns or getting help but it is quite opposite.

The spool holder came out decent after I cleaned it up but not perfect by any means. As I said I know there are settings I can play with to change the results but I am re-printing one right now with the same settings but I flipped the parts 90 degrees to see if they do better that way. I will show another picture when that is done and we can see the difference. Over all I am very happy with the results even as they are. It might not be perfect looking but it will perform it's function no problem.

[BobZilla]

Bob,

ABS really likes an enclosure, even just a cardboard box. check your slicer thickness, for small parts .2 MM is what I like, you can also increase the number of shells (that is the number of walls on the inner and outer surface of the parts befre it starts generating infill. let me know if you have specific questions.

Tom C

Hi Tom,
You were typing your message at same time I was answering Brian... I did increase the shell from 3 to 5 on these. I didn't have any problem with warping and it stuck to the bed nicely. As I said to Brian I am trying it again with it flipped 90 degrees. I think the big circle's will like that orientation better than having to sort of bridge the whole thing together.

I am contemplating purchasing simplify3D for my slicer. I have seen a lot of video's and some look like it is way better but others show prints where free software beat the pants off of it so it's hard to decide if it's worth it. These were sliced with a Prusa edition of Slic3r, they did some tweaks to it to make it their own release. I might try Cura just to see how that does too.

[Tom C]

I have simplify 3D and it is very handy.... CURA does a few things better, but the fact that S3D has your printer already configured in its settings helps a bunch.

Tom C

[John_Koorn]

Looking good Bob

John K.