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JB's 3D CAD & Printing bench


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I'm relatively new to Fusion 360, and am self taught through various YouTube tutorials. I understand the basics of the 3D design process, but come unstuck when things 'don't work'. Many hours are spent trawling the internet and watching semi-relevant videos, only for me to end up not much further on than when I started. So, I'm turning to the wealth of skill, knowledge and expertise we have here.

 

I am about to delve into the world of 3D printing and want to create a few things to adorn a Manning Wardle Old Class I. So far, I have knocked up a wheel centre, chimney and the later version of the safety valve cover. Nothing too complex (though the wheel centre took me an age), but I'm happy with them nonetheless.

 376865322_Latersafetyvalvecover.png.eee03334051291ae61762bdea9e0498e.png  1333409239_Chimeyrender.png.af4ad87369893d57884b70195a8e5c64.png  1425671310_Wheelcentre.png.987cfc6553b602e518ab5cbbde63d7b5.png

However, it's the older earlier version with the flutings that I'm struggling with. It's meant to look something like this:

post-6979-0-72760600-1514720917.jpg.72887592430532b0b708a0eada6e33f9.jpg (apologies that's rather small)

It's the flutings that are causing me the problems. I have the basic shape of the cover sorted (I know, I still need to sort the top surface out and the fluting itself is not yet quite the right shape), and I can 'cut' the fluting into the main body of the cover. However, when I try to repeat this by using the 'pattern' feature (to get 12 of them, evenly spaced around the surface), I get an error:

314082243_Screenshot2019-12-31at21_19_00.png.1f22c736e16b45c909f7544ca5f52d60.png    1997670943_Screenshot2019-12-31at21_21_00.png.dac86ef0a64fffb3c40b7816f16a7bd4.png

 

I think it has something to do with the fact the main body of the valve cover is tapered, getting narrower the further up you go. I tried repeating the same process with a parallel sided version and it worked no problem at all. It's driving me slowly mad, so if anyone has any ideas, I'd love to hear them. Just keep any replies in layman's terms, as anything too complex will fly right over my head!

 

Oh, and once we've found a solution to this, I have another problem too (my wife tells me I have many problems) regarding the smokebox door.......

 

Edited by jdb82
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Hi,

It seems from your post that you are moderately experienced with fusion 360, and as you have identified a fluting shape which works, and one which doesn't, it looks very much like a bug in the software. I would report it on their forum, I don't think they are prejudiced against "hobby" users as long as you are asking sensible questions.

Rgds John

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15 hours ago, JohnGi said:

Hi,

It seems from your post that you are moderately experienced with fusion 360, and as you have identified a fluting shape which works, and one which doesn't, it looks very much like a bug in the software. I would report it on their forum, I don't think they are prejudiced against "hobby" users as long as you are asking sensible questions.

Rgds John

 

Sounds like a plan - I'll see what they say.

 

Rather than it being the shape of the fluting itself that are tapered (although they are), I was referring to the main body of the valve cover being tapered. But now that you mention it, this could potentially be the cause - I will alter the shape of the flutings so they have parallel sides and see if that makes a difference, so thanks!

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Its a great piece of work but before you over invest your effort, maybe check that that level of detail is capable of being printed. I suspect it is getting towards in 7mm (beyond in 4mm?) the limit of resolution of even a resin printer.

Edited by JimFin
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10 minutes ago, JimFin said:

Its a great piece of work but before you over invest your effort, maybe check that that level of detail is capable of being printed. I suspect it is getting towards in 7mm (beyond in 4mm?) the limit of resolution of even a resin printer.

 

It's certainly beyond an FDM printer - I'm hopeful of experimenting on a friend's resin printer before forking out for one myself. I've had Shapeways print the chimney and the wheel centre and they turned out great, however the safety valve has some pretty thin parts, so we'll have to see.

Oh and yes, this is in 7mm

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Problem solved :-)
705520543_Screenshot2020-01-01at22_15_28.png.70c864f80806b2b5aab805598c8bafa3.png   455528860_Earlierdomefiddlingv3.png.d3393ee67e1c8a1793547f9b94963f92.png
Thanks to a very helpful chap over on WT who gave a perfect set of step by step instructions. I think I'd gone wrong because I did the sketch of the fluting on an offset plane which I then projected onto the 'cone' of the valve cover, rather than creating a tangent plane and doing the sketch from there. 

Now all I need is a 3D printer.....
My next challenge, which I have yet to find a solution to, is creating the semi-circular dished smokebox door. Tried a few methods already, however I thought of a potential solution whilst in the shower this morning...I'll see what I can come up with.

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27 minutes ago, andrewnummelin said:

Very pleased to note that you solved your problems. The ones I had on a similar project are detailed at:

https://www.scalefour.org/forum/viewtopic.php?f=7&t=4936#p46444

and

https://www.scalefour.org/forum/viewtopic.php?f=100&t=4826#p46375

 

 

That's both a very nice piece of 3D CAD work, and a lovely model to boot :-) How you do such things in 4mm scale is beyond me. Did you get anywhere with the etch artwork in the end? I'm part way through drawing mine, but have stalled a bit due to a lack of time, as well as a nagging thought that the software I'm using for it really isn't designed for this purpose. In the absence of enough money to afford Auto/Turbo/Corel CAD, I must teach myself something like Qcad instead.....

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10 hours ago, jdb82 said:

 

That's both a very nice piece of 3D CAD work, and a lovely model to boot :-) How you do such things in 4mm scale is beyond me. Did you get anywhere with the etch artwork in the end? I'm part way through drawing mine, but have stalled a bit due to a lack of time, as well as a nagging thought that the software I'm using for it really isn't designed for this purpose. In the absence of enough money to afford Auto/Turbo/Corel CAD, I must teach myself something like Qcad instead.....

Fusion 360 is available free for home/hobby use.

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2 hours ago, rab said:

Fusion 360 is available free for home/hobby use.


Can you use Fusion to do 2D work as well? I just use it for the 3D building of the ‘castings’, but I’ve never tried using it for producing etch artwork. I’ll have a look and try it out sometime.

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Yes, you can produce 2D work. The sheet metal tools are really useful if considering etched parts.

 

The more I use Fusion the more useful I find it, particularly expressions, where if used you can change the thickness of material in one setting and all tabs and cut-outs will be amended.

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On 03/01/2020 at 10:32, jdb82 said:

 

... Did you get anywhere with the etch artwork in the end? ..

For this loco the answer is no. The only etch artwork I've done is the valve gear for a completely different project - it has been etched but I've yet to start the loco so I've no idea yet whether I've done OK or made terrible mistakes!

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Had the safety valve cover above printed for me from Shapeways in their fine-detail plastic, and I was pleasantly surprised by the detail. The top end of the flutings are only a fraction of a millimetre deep, and this detail has been retained. 

Apologies for the grainy photo......average camera-phone and poor lighting hasn't done the part any favours, so you'll have to take it from me that the quality of the print is good.

IMG_1540.JPG.dbdaddda4d39df3d7631490b95c1d290.JPG

 

By way of comparison, and purely for interest value, I also ordered one from Xometry.com which hasn't arrived yet. They don't offer the same material as the Shapeways printed one (fine detail plastic), so I chose something that's hopefully similar. I added the plinth to the 3D model before ordering from Xometry - I realised I'd left it off the Shapeways order. I'll post a piccy of that when it arrives. 

 

As previously mentioned, I want to cast these in brass, however I don't want to pay the exorbitant prices for one of the above companies to do that for me! Plans are afoot to construct a home 'foundry', where I can print in castable resin, and then cast in a suitable metal (brass or otherwise). I find a model far more satisfying if it's all metal, rather than having lots of plastic/resin glued to it. Nothing wrong with those that do make use of plastic parts.....just personal preference :-) 

Edited by jdb82
The bloody annoying auto-correct
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I had to do some similar modelling in Fusion360 for a recent project, and I remember the valve cover being a complete pain to do. I like the software in general, but it does seem fairly buggy - I've had a lot of issues mirroring fillets and doing patterns. Usually some fiddling with the feature settings will solve it, or of not there's always multiple ways to draw things in CAD.

 

For printing, have you tried 3Dhubs? They do resin printing. They got too expensive for me as I tend to print whole locos, but smaller parts should be a lot cheaper.

 

IMG_20191103_165044.jpg.2130abdd121fbbdb32b14cc0b21c7429.jpg

Edited by TurboSnail
Tpyo
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12 hours ago, TurboSnail said:

 

For printing, have you tried 3Dhubs? They do resin printing. They got too expensive for me as I tend to print whole locos, but smaller parts should be a lot cheaper.

 

 

 

Haven't come across them - I'll look them up. Thanks!

I'm currently trying to get to grips with making the raised/domed smokebox door. The only way I can think of describing it is a semi-circular, domed door. Tried loads of different ways in Fusion but haven't found one which is quite right yet....

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  • jdb82 changed the title to JB's 3D CAD & Printing bench

Resurrecting this thread now I actually have a 3D printer of my own. A while ago, (see first post) I had a play with Fusion 360 to model a few bits for a Manning Wardle Old Class i. After a few pieces of helpful advice, I got them looking like they should and had them printed in different materials by Shapeways & Xometry.

Now I've got my own printer - an Elegoo Mars Pro - I've printed them myself. Just though I'd post them here for interest sake  Apologies for the poor lighting on the photos.....a light box is next on my list of things to make.IMG_4967.JPG.0f5a950cd47f714eab86f4117ac66de3.JPG

IMG_4968.JPG.faef6e4d717d05013127f81cb9083b8d.JPG

IMG_4970.JPG.e829f87eb8d6442f343af3f5ef5d2298.JPG

IMG_4971.JPG.6fe389bef34a9b6e8a206ee46310f786.JPG

 

 

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  • 1 month later...

No more printing just yet.....I'm awaiting delivery of a new FEP, after I got a bit over-enthusiastic whilst trying to remove a failed print.

I have been doing the 3D modelling of a few other parts for the MW Old Class i, ready to go when the FEPs arrive. 

Buffer Body & Head: These will be a self contained sprung buffer, so the hole in the top surface is for a retaining wire to prevent the buffer head from falling out.

627866130_BufferBodyHead.png.899d90add0436ff848a59d8c95c36a4c.png

Coupling chain bracket: The prototype I'm working from uses an eye bracket instead of a hook, bolted on to the buffer beam.

956009077_couplingbracket.png.2fc4d6fd85610e07ddb3a49b4ddf4d55.png

 

Blowdown Valve: I don't have any information about what the valve on the prototype would have looked like, but looking online, they all look to be quite similar, so this is my best guess. This will be pretty small (no more than 3mm from back to front), so I'm hoping it will print OK.

405539189_blowdownvalve.png.0605066e27853db2e1b22d55c4e84d65.png

Smokebox Door: Not finished yet.....still battling with the hinges. For someone well-versed in Fusion360, this is probably quite straight forwards, but for me it's taken an awful lot of trawling through videos and forums to get to this point! Creating the domed shape, and then to get the hinges to follow the contours of the domed shape, ended up being quite straight forwards however there just didn't seem to be any info out there about how to do it! Got there in the end.

923304347_Smokeboxdoor-development.png.0bbd63fe22ca8bc3d035b63bffb0c8c6.png

 

 

Edited by jdb82
typo
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Here are the prints of the renders in my previous post - pretty much straight off the printer with minimal cleaning up. 

 

Talk about cruel closeups....The layer lines are barely visible with the naked eye. I'm going to try a couple of things. Firstly just paint it and see if the paint smooths the steps, and secondly reduce the layer height from 5 microns to 3 microns. Maybe unnecessary, particularly as these will eventually be cast, but we'll see. For scale, this is just under 2cm wide.

IMG_2762.JPG.f95b0c35e7e7c29dec2443a0b16d587e.JPG

The springs need a bit of remodelling in Fusion to make the join between each leaf a little more distinct.

IMG_2763.JPG.a20f524b64a948df69e3bb1370f12c33.JPG

Coupling hook - perhaps half a mill of so too long, but printed really well

 IMG_2765.JPG.6aeadb4a0baa6988d925711cf4ff2da8.JPG

Blowdown valve - needs a dusting but at 2.8mm long (including the spigot at the top) this is the smallest thing I've tried printing. My poor photography equipment (skills?) doesn't do the detail justice.

IMG_3706.PNG.9637722b31f60c5acdaa3a4ab137adad.PNG

The buffer body and heads printed well. These are 2 separate components, which once cast will have a self contained spring - the wire, which prevents the buffer head from falling out will be trimmed back, soldered in and filed smooth. I need to alter the 3D model a bit though as it's a bit of a tight fit at the moment.

IMG_2768.JPG.3c0568fff247460e4371bfd068718b43.JPG

IMG_2769.JPG.6fea33ce257d9b7abd17dd420497f518.JPG

IMG_2770.JPG.37bbc63807147d8a04179083cfa2d0f3.JPG

 

 

Edited by jdb82
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  • 2 weeks later...

Nice work. I have my eye on a H class once I have finished the AB tanks I'm working on. This is going to sound like a silly question. The only thing I'm struggling with on my Saturn is printing buffers. How did you get yours to print?

 

Marc

 

 

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10 hours ago, Furness Wagon said:

Nice work. I have my eye on a H class once I have finished the AB tanks I'm working on. This is going to sound like a silly question. The only thing I'm struggling with on my Saturn is printing buffers. How did you get yours to print?

 

Marc

 

 

 

I was playing about with what worked best, so I printed one vertically, and one at 45 degrees. Both printed fine, although the bottom curved edge of the tilted one was slightly less defined than the one printed vertically. As you can see, I've gone a bit overboard with the supports. This probably helped, but I think the key is making sure the supports (think I used medium in the end) are right up to the very edge of the buffer head. The down side to printing vertically is that there are some tiny layer lines. They sand down with 2000 grit paper easily enough, but I'd rather they weren't there to start with. I 'm going to try reducing the layer height and see if that helps, but now the Christmas holidays are gone it's just finding time!

2120676846_Screenshot2021-01-11at06_22_35.png.d1aa9c9a51bb55127992e468348064e2.png

 

24324481_Screenshot2021-01-11at06_21_12.png.b6014133c36b52c222b56b2d2d842158.png

 

I can send you all the support/pring settings if you'd like, although I'm using a pro, not a Saturn.

Edited by jdb82
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Thanks for that. I was trying to print with the head down. Thinking about it printing with the base down makes more sense. 

If I get time time I will have a go tonight.

Marc

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