Tuesday, August 27, 2013

More 3D Prints and a first attempt at a casting


When I came home last night, I was happy to find a box from Shapeways on my doorstep.  I was excited to see how well, another USA based 3D Printing service had done, so I quickly opened the box.  I was very happy with the detail and the price was much cheaper than the previous two “high detail” prints I have received. 



 

The 3 prints I have received have all used a resin that is cured by UV Light.  So perhaps it should not be surprising at all that they are remarkably similar in quality.  I do have some prints incoming made of different (and cheaper) materials and when they arrive, I will give you a comparison between them.   I would like to do a post just on the 3d Printing technologies with links to videos for each type.  Today I’ll just link you to this one which is the type used to make the Sculpteo, Ponoko and Shapeways pylons.

 
 
The resin casting has been a limited success.  It took 5 casts for me to get one of high enough quality that I’m happy with it.  The Alumilite High Strength II mold is holding up well, and is quite flexible compared to the standard silicone mold that comes with the kit.  There are a few flaws in the mold, but it captured the detail quite well. 
I opted for a single mold, but am thinking about trying a two piece mold to reduce the strain on the details, especially the panel indentations, as I remove the casts.  I've found that Isopropyl Alcohol helps as a lubricant and evaporates quickly once the cast has been removed.  The small volume of the pylon makes it more difficult to get the exact ratio, and the fourth cast broke on removal because it was quite brittle.

 
 
Thanks again for dropping by and reading this far.  I welcome your comments and if you have questions, feel free to ask away.
 

7 comments:

  1. If you are in Canada or the States try this product from Smooth-On:

    http://www.smooth-on.com/Release-Agents-for/c1123_1226/index.html

    Silicone release agents are fantastic. I'm a professional sculptor/caster and its what I use.

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    1. Thanks, I'll look into it. The fine details in the mold are getting damaged as I pull the bigger top through the narrow neck. I'm going to try a 2 piece mold next.

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  2. Sorry if you already know this, I'm not sure what your experience level is with casting;

    If you do a two part mold try moving up to a silicone rubber with a higher SHORE hardness (firmness), since you have basically no undercuts to have to worry about (I'm assuming you'll do two sideways pieces) the higher hardness lets you 'clamp' the pieces together (I use rubber bands, 5 or 6, on molds that small) with minimal to no deformation, which drastically reduces the size of your mold-lines.

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    1. THat was supposed to be a reply to your reply, oops.

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    2. I'm certainly no expert, but I've made enough mistakes to know that I need to do something different. I am going to try to use my CAD file to generate a negative that I can then make into a 2 piece mold and have it 3D printed. If that becomes to difficult, I will likely use the silicone mold rubber that comes with the standard kit by Alumilite. It is significantly stiffer than the high strength II silicone, which is counter-intuitive but makes sense when you think about it for a bit.

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  3. If you keep having problems feel free to pop me an e-mail at jesse.l.sinclair@gmail.com.

    I've been doing this for years so I don't mind helping if I can. I've cast everything from miniatures to costumes to vehicle parts for mesuem replicas (I once had to cast 5 foot long incendiary bombs for a Lancaster replica at 85% of life scale, that was a nightmare, the molds weighed 25lbs each).

    I'm not sure why you'll need to 3D print negatives to make the 2-part mold?

    Check out this video if you need help; http://www.youtube.com/watch?v=FQ1A7ZjTsx8

    The only difference I would do on yours is have the base of the pylons directly against the mold box, that way it doubles as your pour hole.

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  4. Thanks for the tips and links.

    I was successful in making a two piece mold, and my first casts were pretty good, although I have to be careful to avoid trapped air.

    In my CAD program, I was able to use the original part remove that material from a block in order to form a mold. Unfortunately, printing the mold was a bit too expensive for me to attempt. Although I was able to reduce the price by half by removing excess material it was still over $100 to make a two piece mold that would allow me to cast 4 pieces at a time.

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