Dabbling in Fusion 360

Discussion in '3D Modeling Projects' started by Rob Pulham, Jun 25, 2021.

  1. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    You may have seen elsewhere that coming up I have a test build for an LNER D2. The first build is to be a BR period build and I have a J6 chimney casting from Gladiator for it. However once the etches are proved I plan to build a second D2 for myself which I wish to finish as it was in it's early life with the LNER in lined green.

    This means that it will need the original chimney so I need to turn one/have one 3D printed or something.
    Those who are Gauge O Guild members my be aware that following on from the success of the virtual shows the Guild has been hosting some special interest session in various subjects one of them being 3D CAD/Printing. I missed the initial session a few weeks ago but caught up with it via the YouTube channel and then joined last nights session.

    Prior to joining the Zoom session I downloaded and installed Fusion360 which is the software at the centre of the 3D CAD element of the sessions.

    This morning I had a play and following a demo video done by a fellow GOG member last year I managed to draw a chimney.
    Having completed it I shared the image below with the gent who ad created the artwork for the D2 etches and he commented that the smokebox looked a bit narrow. Then it dawned on me that I had used the figure for the radius taken from the drawing and hadn't doubled it to enter the diameter. Apparently you can enter a radius figure but I haven't worked out how yet.

    So this afternoon I attempted to redraw it using the correct smokebox size.

    1624621578411.png
    You will note in the image above that there are orange coloured squares. These are offset planes that I used to apply the dimensions from my chimney drawing. I managed to miss out one of the planes (for the bottom of the chimney rim) and try as I might I couldn't manage to draw any lines between the planes like I had this morning. in frustration I deleted all but the base, saved it and went and had my dinner.

    This evening I worked out how to import a drawing, resize it and then draw over it as I would in Inkscape or QCAD.

    Below are a couple of views of the revised drawing.

    upload_2021-6-25_21-10-33.png

    upload_2021-6-25_21-20-49.png

    I am now a happy bunny. I haven't got anywhere near the skills of our very own Andy or Paul but it's a start.
     
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  2. paul_l

    paul_l Staff Member Administrator

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    When you're ready Rob, you know where to email the STL file for a test print to.

    Suggest you add a central spigot to locate the chimney - you can always drill it out once the glue has set, or used as sprue if you send them to be cast via lost wax casting.

    Paul
     
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  3. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Thanks Paul,

    Personally I prefer them without a spigot but I hear what you are saying and add one. Albeit I will probably add a tube as I would like the chimney to be hollow.
    That is when I work out how to do that of course
    :scratchchin:
     
  4. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Following Paul's advice, more work on the D2 chimney today has got me a tube sticking out of the bottom to help with location and the rivets around the base.

    D2 Chimney III.JPG

    D2 Chimney IV.JPG

    D2 Chimney V.JPG
     
  5. paul_l

    paul_l Staff Member Administrator

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    Hi Rob

    If you wish to have the chimney hollow, create a circle sketch aligned on center, the diameter of the hole. Then extrude the sketch and delete it from the chimney model.

    Following on from the STL you sent me to test, I have loaded it in to Chitubox (available free of charge from Chitubox Download )

    Supports added, I have copied the model and turned it upside down. Supports were added.

    upload_2021-6-26_23-13-13.png

    The job was then sliced with a layer height of 0.05mm

    Transferred to the printer and a 2h10m wait until we find out how well they turned out

    Paul
     
  6. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Brilliant thanks Paul,

    I have another chimney to draw for a friend so I will have a go at making that one hollow.
     
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  7. paul_l

    paul_l Staff Member Administrator

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    Prints removed from build plate and rinsed to remove uncured resin, then popped into the ultrasonic bath for 5 min - I used AnyCubic's Eco resin. Another rinse in water .. and

    :drums: :drums:


    Unless there is a risk of warping, I remove the supports before curing - tends to cause less damage as they are still soft.


    Now a final wash in IPA, dry off and then cure and were done.

    Paul
     
  8. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    They look excellent, I can feel my chest swelling:p
     
  9. paul_l

    paul_l Staff Member Administrator

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    Just for info

    The supports we're added manually, and were a combination of Light , Medium and Heavy

    upload_2021-6-27_10-54-17.png

    Viewed from the underside the two central squares are the heavy supports, preferrably this would be the lowest point. As these are both hidden and will provide the anchor to the build plate.

    Because the Heavy supports wont make contact with the model until later, I used medium supports around the locating ring Rob designed, these will easily cope with the peeling forces for the start of the base.
    Like wise the light supports will cope with the start of the build, by the time peel forces start to get larger the medium and heavy supported areas will have all merged together.

    My preferred spigot design is as below

    upload_2021-6-27_11-17-37.png

    The central spigot is approx 6mm (or larger) dia and the lowest point of the model.
    This allows several heavy supports to be placed on the spigot, light supports on the outer rim, and add a few medium supports between 1/3rd & half way from the rim to the spigot to help the light supports until the whole model is supported via the heavies.

    I know Rob prefers a hollow chimney so I'd do that as follows

    upload_2021-6-27_11-27-38.png

    Once the model is printed &/or fitted the hollowed can be drilled out (hand drill, broach or reamer only as these are rather brittle). For a bigger hole increase the size of the spigot at the design stage.

    Note the intersection between the chinmey base and the spigot, I have applied a fillet to strengthen the base area, especially as this would be drilled out.

    If you are sending these as masters to a caster, they will thank you for a longer spigot as it gives them something to attach to the moulds.

    Paul
     
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  10. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    I've just finished watching the 2 Ian McCormack O Gauge videos mentioned by Rob, at least now I understand the processes and a bit more of the jargon.
    Having read all the discussions between Paul and Andy on Paul Highland 0-4-4 build, the only bit I didn't really get was what is the function of the FEP plate and why it's tension matters so much. Other than that the print, wash cure process seems pretty simple, the key to any successful job is the design bit.

    None of which is going to persuade me into the 3d printing world even if the process and results I find fascinating.

    Mossy
     
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  11. paul_l

    paul_l Staff Member Administrator

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    Hi Mossy

    The way the FEP works, 2 main functions, 1. to hold the resin into the vat, 2. let the UV light through it to cure next layer of resin to the previous layer or to the build plate for the first layer.
    Tensioning the FEP is required to both seal the vat, but also to provide a flat surface. The FEP also needs to be flexible enough to start a peeling action as the build plate rises after each exposure. The resin after exposure is still fairly flexible, so too slack a FEP sheet may allow the FEP + print to move with the build plate and prevent separation, with repeated exposures the print will stick to the FEP rather than the build plate. On the other hand too tight and the FEP can't flex as much so the whole print will release at once giving a Ping sound, but the amount of force required may prevent the release or even the supports to fail.

    Once tightened you can't slacken it off as the FEP has been stretched. However if you slow the lift speed and raise the lift height you can compensate for it being too tight.
    Another disadvantage of over tightening, is the FEP will stretch over time, if you fully tightened it at the start, then you have no adjustment after the FEP strectes, so you end up replacing the FEP earlier.

    Another word on FEP's, any sign of dings in the surface I'd recommend replacing it, a FEP is far cheaper than a new LCD screen after resin seeped through a small hole in the FEP and cures to the screen. I've had this happen once on my Photon and fortunately managed to remove the cured on resin from the screen surface with IPA, Acetone and a scalpel blade. Not a procedure I wish to repeat.

    As Sean Connery once said - "Never say Never" it may bite later. :avatar:


    Paul
     
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  12. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Thanks for the explanation Paul, fundamentally I'm just a noise bugger and like to know the answers.
    What film was Sean Connery in when he said Never say never. Isn't it a long after Sean Bond film title?

    Mossy
     
  13. paul_l

    paul_l Staff Member Administrator

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    That's the movie, he'd said to his wife he'd never play Bond again, so when he played the part in movie Never say Never again, his wife reminded him, and they used it for the movie title.

    Paul
     
  14. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    you learn something all the time!
     
  15. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Frustratingly it has taken me two days and much head scratching and muttering to get a second chimney drawn.

    This one is for a C12/J52 that wasn't fitted with condensing gear (those that were, had a shorter chimney fitted).
    Despite the frustrations I have learned much from my battle and I feel that this is a much finer and more accurate rendition than the D2 one that I did a couple of days ago. I may revisit the drawing and see if I can refine it.

    C12-J52 Chimney 1.JPG

    C12-J52 Chimney 2.JPG

    C12-J52 Chimney 3.JPG
     
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  16. paul_l

    paul_l Staff Member Administrator

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    pt 2 continues

    The STL file from Rob was loaded into Chitubox

    upload_2021-6-30_0-6-36.png

    and again a copy turned upside down and supports added

    upload_2021-6-30_0-4-36.png

    Transferred to the printer for printing - estimated for 2h 7m

    Back soon

    Paul
     
  17. paul_l

    paul_l Staff Member Administrator

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    And as if by magic


    The prints have only been washed and then the supports removed.

    Some may have wondered why I print a copy upside down, as the base of this model is finer, removing the supports can cause damage the fine edge
    as can be seen on the photo below


    So in this case I would print further prints upside down, as its easier to file down the pips on top of the chimney, than try and rebuild the flange rim.

    Rob - hopefully I'll get to the post office tommorow and send you the prints.

    Paul
     
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  18. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Thanks Paul,

    It's much appreciated.
     
  19. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    At the risk of boring people with my new found skill I have drawn up a couple more items yesterday.

    First was a much simpler task than the chimneys that I have drawn so far, this time a dome for the D2.

    D2 Dome 1.JPG

    D2 Dome 2.JPG

    D2 Dome 3.JPG

    Then at a friend's suggestion I had a go at the GNR version of the Ramsbottom safety valves.

    Ramsbottom 1.JPG

    Ramsbottom 2.JPG Ramsbottom 3.JPG
    I had got this far when Chris looked over my shoulder and said "it looks good but it doesn't look right" she was of course correct the springs should be on the lever that I hadn't drawn yet not the valve stems...

    To be continued...
     
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  20. paul_l

    paul_l Staff Member Administrator

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    Hi Rob

    If you continue the springs higher - 1 turn beyond the height of the center stem, you can then use a plane to slice through the spring level with the top, don't ask me how to do it in Fusion I've not got far - yet, but is how I would do it in 123D.

    Chimneys in the post

    Paul
     
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