FreeCAD and my model

Discussion in 'General Engine Discussion' started by lee webster, Oct 12, 2019 at 4:40 PM.

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  1. Oct 12, 2019 at 4:40 PM #1

    lee webster

    lee webster

    lee webster

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    Hi all,
    I hope to be starting my 1/3rd scale model of a 1930 Austin Seven engine soon......
    Step 1. I am now fairly proficient at using the cad programme FreeCAD. It has annoyed the socks off me on dozens of occasions, but I couldn't stop using it even though I have a new copy of Solidworks, I still prefer to use FreeCAD. I have now designed the block and the head, I hope to attach images, if I get them in the correct order the first image will be of the block with a white outline at the front. The outline is the sketch I use to "cut" into the block to show the internals. Other images are sections of the block. The last two images show the inlet and exhaust ports moulds. They will need to be lengthened to give more material on the valve face and the ports face. My explanations are poor, forgive me! One of the ports images has a great deal of lines on it, this is the file that could be sent to a 3D printer. block cut 2.PNG block cut 3.PNG block cut.PNG block.PNG ports bottom mesh.PNG ports bottom.PNG ports top.PNG
    Step 2. 3D printing of the moulds. If I cast the parts in aluminium then I can 3D print the block as it appears and use investment plaster to produce the mould. The 3D printed part is the melted out and metal poured in. If I have to pour in aluminium, very likely, what type of finish would be suitable? I would prefer it to look like cast iron, perhaps a matt black would give it a display model look that would be OK. Your advice and oppinions requested please.
    I will stop here as there are more steps for another day.
    Lee
     
  2. Oct 12, 2019 at 4:42 PM #2

    lee webster

    lee webster

    lee webster

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    Idiot, you didn't tell them about the dimensions of the block.
    Width 44.666mm
    Length 79.666mm
    Height 40.333mm
     
  3. Oct 12, 2019 at 5:22 PM #3

    TSutrina

    TSutrina

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    I assume you know that there is a wax for 3D printing of investment castings, moldlay by Lay filaments. I would go to the jewelry investment youtube posts to find comparable wax, Paul Manler: make a vacuum chamber by V0g

    PLA and other 3D print material leave a film.
     
  4. Oct 12, 2019 at 5:35 PM #4

    TSutrina

    TSutrina

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    I have been using freeCAD for years now. On grabCAD I have posted a model of may atlas Lathe all built on freeCAD The difficult part was to find an open source program that would let me bring in Step files on individual parts so that I could output an assembly Step file. As I see your using the latest issue of freeCAD 18 I still have 15 on my computer since it has a tech drawing bench.
     
  5. Oct 12, 2019 at 7:10 PM #5

    lee webster

    lee webster

    lee webster

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    Thanks TSutrina, that's the sort of information I need. I'll watch the videos on youtube now. I have heard of grabCAD, I'll have a look.
    Lee
     
  6. Oct 17, 2019 at 11:21 PM #6

    lee webster

    lee webster

    lee webster

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    Hi TSutrina, Those video's certainly gave me something to think about. I thought I would use lost pla and investment plaster, but I think it could be better to use 3D printed parts to produce the sand moulds for casting metal, either iron or aluminium. Thanks agian.
    I had a look at your lathe design, now thats the type of lathe I would like to buy! There is an old Boxford lathe at a local market. It is quite an old lathe, but it just looks so good. It has a metal cabinet, several chucks and a great assortment of gears, cutters, tooling. Everything. The price is under £700 but without knowing more about lathes, that could be £700 for scrap iron. I have now ordered my 3D printer so I can at least print out the parts I have drawn to see what a scale model looks like before I attempt to build it.
    Lee
     

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