3D printing of 5″ loco wheel patterns for the foundry

This topic has 5 replies, 5 voices, and was last updated 16 March 2018 at 12:23 by Adam Cro.

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15 March 2018 at 15:08 #9135
David Leahy 1
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@davidleahy1
3D printing of loco wheel patterns for the foundry
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15 March 2018 at 15:08 #346236
David Leahy 1
Participant
@davidleahy1
Dear all,

Do any members to these forums have any experience of making foundry patterns from 3D printed materials? I am wanting to make a set of wheels for a loco I am currently working on and have read to a small degree the ability of 3D printing to make patterns that can be used in sand casting. I assume that the CAD files of the wheels can be sent to a 3D printer of the suitable size and a filament chosen that will be correct for this application?

Any pointers here will be much appreciated.

Best regards,

David.
15 March 2018 at 15:32 #346241
Neil Wyatt
Moderator
@neilwyatt
Speak to your foundry – they may have certain requirements with respect to surface finish and material, but it should be straight forward enough.

Follow all the same rules for draft angles, section sizes etc. that you would for a conventional pattern.

You may want to consider either very low layer height or specialist processes/treatment to get a smooth surface finish.

A single sided pattern should be straight forward, but if you want things like spokes tapered on both sides beware of creating a pattern you can print but can't cast.

The pattern will be reusable for one loco's worth of castings.

If wanting repeat use I would suggest printing oversize and getting an aluminium master pattern cast.

Neil
15 March 2018 at 15:37 #346244
JasonB
Moderator
@jasonb
Have a look at Myfordboy on Youtube he has started to print patterns though he only casts in Ali and brass.

Easy enough to print two half patterns to get detail on the back of the wheel.

We did have a member how posted about using a CNC router to make his wheel patterns which also works well. Look through his postings here to find the wheel ones, also some printed pattern work there too.

Edited By JasonB on 15/03/2018 15:38:52

Edited By JasonB on 15/03/2018 15:41:24
15 March 2018 at 16:33 #346253
Martin Johnson 1
Participant
@martinjohnson1
If you don't mind joining tractiontalkforum.com, there is some interesting work going on there on 3D pattern printing for models and full size.

Martin
16 March 2018 at 12:23 #346348
Adam Cro
Participant
@adamcro58170
David,

What gauge are you looking at? What is the loco?

My advice, much like Neils, would be to find a local foundry or one someone can recommend that are happy to work with 3D printed patterns. Take along a sketch or drawing and show them what you have in mind and take on board their advice.

The main things they will advise on is how the pattern needs to be made, whether its a 2 part pattern if you have tapered spokes both sides or single piece on a simpler pattern and what sort of shrinkage is required and lastly where they would want to add their runners too. Don't forget your own machining allowances too!

With regards to having a pattern made for sand casting I have found a place in London called 3D print UK to be very good. They use Nylon and offer a free polishing surface to give a great surface finish.

If you are looking at small gauge locos, for one offs 3D wax printing and investment cast iron could be a better route/cost effective route and experience in this so far has had brilliant results on cast iron wheels.

Hope that helps,

Adam
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