Patterns for Aluminium Sand Casting

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Daws
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Location: Qld, Australia

Re: Patterns for Aluminium Sand Casting

Postby Daws » Wed Dec 13, 2017 6:49 am

I'm using my first post on this forum to tell you how great this project is! The quality of the prints and the castings are amazing. I'm from a design engineering background and it's great to see the printer being used to create engineered parts and supplement traditional industry.

I recently ordered my N2 and am looking forward to doing some real engineering once it arrives :)

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Vicky@Raise3D
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Re: Patterns for Aluminium Sand Casting

Postby Vicky@Raise3D » Wed Dec 13, 2017 10:07 am

Daws wrote:I'm using my first post on this forum to tell you how great this project is! The quality of the prints and the castings are amazing. I'm from a design engineering background and it's great to see the printer being used to create engineered parts and supplement traditional industry.

I recently ordered my N2 and am looking forward to doing some real engineering once it arrives :)


Welcome to join the Raiser family! :D

StickShifter
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Joined: Thu Dec 14, 2017 1:47 pm

Re: Patterns for Aluminium Sand Casting

Postby StickShifter » Thu Dec 14, 2017 1:56 pm

Thanks for your time to post the pictures and related info!!!! This is exactly one of the reasons I bought my printer, to make aluminum casting faster and simpler. I just received my N2 this week and can see many projects in my future. I have made my own foundry oven and have done some castings the old fashion way. But this will move me into the 21st century.
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caxton3d
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Re: Patterns for Aluminium Sand Casting

Postby caxton3d » Sun Dec 17, 2017 9:26 pm

Stickshifter and Daws, GOOD! More converts to printing patterns for metal casting! I would love to see your results so don't forget to post some pictures. The main thing which I think is essential is that after the pattern is printed you should give it a couple of coats of 'Pattern Coat' which is an epoxy based resin type paint. It is easy to rub down, so all the printing layers vanish into a beautiful smooth surface which makes the pattern pull out of the sand easily. If you try and use a 'raw' printed pattern the sand will just stick to it.

Image
Pattern making for the restoration of vintage Dennis Fire Engines

StickShifter
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Joined: Thu Dec 14, 2017 1:47 pm

Re: Patterns for Aluminium Sand Casting

Postby StickShifter » Thu Dec 21, 2017 2:06 pm

Thanks for the info on the Pattern Coat.

Slightly different topic but I am also using my printer to create prototype models for things I will be machining on my CNC mills. This is a single cylinder of the cylinder heads I plan to make for my race car. This print was 65 hours and it came out great considering it was only my third print. LOL I was surprised at how hard it can be to remove the support material. Live and learn.
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Casale8
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Joined: Fri Oct 20, 2017 5:17 pm
Location: The Real Upstate New York

Re: Patterns for Aluminium Sand Casting

Postby Casale8 » Thu Dec 21, 2017 4:39 pm

caxton3d wrote: It is unfortunate that the real world engineering advantages of 3D printers is overshadowed by the perception that they are only used for the printing of cartoon novelties.


Agreed. I'm printing for Aerospace applications.

This is a fantastic thread Caxton3d!
Thank you for sharing.
-SCC
“One man's "magic" is another man's engineering. "Supernatural" is a null word.” -R.A.Heinlein

StickShifter
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Re: Patterns for Aluminium Sand Casting

Postby StickShifter » Thu Dec 21, 2017 6:44 pm

Thanks Caxton3d for the info. This may be of interest to people in the US. This is about the same thing and can be found in most automotive body repair supply shops. It's also called "Bondo in a can" I use it as my first step when laying up fiberglass parts.

http://www.evercoat.com/product-detail/ ... 100708/us/

caxton3d
Posts: 44
Joined: Tue Dec 27, 2016 1:59 pm

Re: Patterns for Aluminium Sand Casting

Postby caxton3d » Tue Dec 26, 2017 9:31 am

StickShifter, I love the look of your cylinder head,. It will be no mean feat to machine it from solid. Do you have a 5 axis mill to get into the ports?

I agree with you about the problems of removing the support material and the quality of the surface finish once the support is removed. I have a crankcase for a classic racing two stroke motor cycle printing at the moment which needs quite extensive support. When it comes off the printer I will post some pictures of the supported surfaces and the settings which I used.

With best wishes from England for an enjoyable Christmas.
Pattern making for the restoration of vintage Dennis Fire Engines

caxton3d
Posts: 44
Joined: Tue Dec 27, 2016 1:59 pm

Re: Patterns for Aluminium Sand Casting

Postby caxton3d » Tue Dec 26, 2017 9:59 pm

This is a 1970 vintage Greeves Oulton 350cc two stroke racing motorcycle.
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These are the crankcases. There is a weakness around the top flange where the cylinder barrel bolts on. I need to cast new crankcases with a stronger flange.

Image

The first thing to do was to reverse engineer the original cases, this was done using Solidworks.

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The first case half was then printed to see how it lined up with the original opposite half. These are the printer settings that I used for the support structure.

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This is what the support looked like.

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All the support broke away relatively easily leaving a relatively smooth face.

Image

However, there was one section of support around the curved section of the top of the crankcase where the support was virtually impossible to remove. Can anyone suggest a change to the support parameters which might alleviate this problem?
Pattern making for the restoration of vintage Dennis Fire Engines

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Vicky@Raise3D
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Re: Patterns for Aluminium Sand Casting

Postby Vicky@Raise3D » Wed Dec 27, 2017 2:27 am

Have you ever tried with Line infill type for support structure? Is it strong enough to support your model?
Or what about dense layer for your support structure? Which will generate some support layers approaching to the model with high infill density.

caxton3d
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Re: Patterns for Aluminium Sand Casting

Postby caxton3d » Wed Dec 27, 2017 9:32 am

Vicky,
If you take a look at the screen shot of my settings you will se that I do have dense support turned on. Rather than have line infill I usually run with the cross hatch infill as this is stronger. Along with many other people I find that the line support is easily damaged as the print nozzle often hits it during traversing. I know that the Z-HOP adjustment is meant to fix this bit I am not totally convinced.

As the picture shows the dense suppport came away perfectly cleanly when it was supporting a flat ‘roof’ but stuck when it was supporting a curved surface.

In the support parameter page can you explain the purpose of the ‘Vertical offset top layers’ and ‘vertical offset down layers’ parameters. Thanks, Barry.
Pattern making for the restoration of vintage Dennis Fire Engines

zemlin
Posts: 365
Joined: Sat Oct 21, 2017 2:02 pm

Re: Patterns for Aluminium Sand Casting

Postby zemlin » Wed Dec 27, 2017 1:33 pm

In my testing, the key variable I've found that makes the biggest difference in both the quality of a supported build and ease of support removal is layer thickness of the build. In general I start at .5x nozzle diameter and tweak from there - assuming one layer separation. If your support is too difficult to remove, increase your build layer thickness.

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Vicky@Raise3D
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Re: Patterns for Aluminium Sand Casting

Postby Vicky@Raise3D » Thu Dec 28, 2017 5:02 am

caxton3d wrote:Vicky,
If you take a look at the screen shot of my settings you will se that I do have dense support turned on. Rather than have line infill I usually run with the cross hatch infill as this is stronger. Along with many other people I find that the line support is easily damaged as the print nozzle often hits it during traversing. I know that the Z-HOP adjustment is meant to fix this bit I am not totally convinced.

As the picture shows the dense suppport came away perfectly cleanly when it was supporting a flat ‘roof’ but stuck when it was supporting a curved surface.

In the support parameter page can you explain the purpose of the ‘Vertical offset top layers’ and ‘vertical offset down layers’ parameters. Thanks, Barry.


The vertical offset refers to the gap which calculated by layer between the ends of support and surface of the model. Top layer refers to the first layer of model after support. Down layer refers to the last layer of model before support.
May I ask the .gcode and .data files of this model to check how the dense layer and vertical offset work at the curved section.

Daws
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Joined: Wed Dec 13, 2017 6:41 am
Location: Qld, Australia

Re: Patterns for Aluminium Sand Casting

Postby Daws » Mon Jan 01, 2018 12:27 am

caxton3d wrote:As the picture shows the dense suppport came away perfectly cleanly when it was supporting a flat ‘roof’ but stuck when it was supporting a curved surface.


I have only recently started with my N2 and found the same thing, I printed some motorcycle handlebar switch mounts and found that supports under the arch of the clamp part were very hard to remove and required some action with a Dremel. I am using normal support and grid type but dense support is turned off, these are small parts so the layer height is set at 0.1 which probably doesn't help.

Great projects all, it's good to see the printers being put to use as an engineering tool and the Greeves is now my favourite project :)

caxton3d
Posts: 44
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Re: Patterns for Aluminium Sand Casting

Postby caxton3d » Wed Jan 03, 2018 11:48 am

Daws, after the crankcases comes the really interesting bit - A new cylinder barrel with four side transfer ports rather than the standard two side ports. That should test the printer!

I am posting a link for Vicky with the .STL and .gcode for the crankcase if you want to have a look at it a bit more closely.

Please post some pictures of your switch mounts, it is always interesting to see other peoples work of parts with an engineered purpose.
Pattern making for the restoration of vintage Dennis Fire Engines

caxton3d
Posts: 44
Joined: Tue Dec 27, 2016 1:59 pm

Re: Patterns for Aluminium Sand Casting

Postby caxton3d » Wed Jan 03, 2018 12:07 pm

Vicky, here are links so that you can download load the .STL and .gcode files for the crankcase. (If anyone else would like to look at these files, feel free to do so).

http://www.dennisfire.co.uk/timing%20side.zip

If you look at the post from Daws on this thread I am not alone in finding difficulty in removing support from under curved surfaces.
Pattern making for the restoration of vintage Dennis Fire Engines

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Vicky@Raise3D
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Re: Patterns for Aluminium Sand Casting

Postby Vicky@Raise3D » Thu Jan 04, 2018 8:13 am

Checked with your gcode preview, the last two layers of the end of the curved surface have no dense layer generated which means there have two overhang layers without support after the end of the support structure. I will recommend you to give Pillar type or Manual Support which also uses Pillar type support structure a try. I tried with Pillar type support with 2mm Pillar Size. The dense layer will not be generated until the last layer of the curved surface.


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