3d Printed Patterns or Wood?

Hi guys:
I am an entire newbie trying to get started making some patterns. I have been trying to determine, what exactly is the benefit of 3d printed patterns versus wood patterns? What are all the pros and cons of each?
Its not like I would be doing any amount of production, so how well they hold up over the years really does not matter as this will probably be a once and done casting. By the way, the cheapest method is the most appealing to me.
Any tips or advice would be appreciated.

 

those are not your 0nly options what are you making

 

Hi Andy,
If you don't have a 3d printer already as well as an up to date computer to run it, the answer might be right there. Of course it also depends on what your trying to make. Another option is a CNC router, but that can get just as costly if not more-so. Plus then you have to learn how to use the darned things. Patternmakers got along for a long time with neither, but in all seriousness it depends on what you want to make. I have to say, those 3d printers look like witchcraft to me!

Pete

 

Please see the attached picture.
It is a replacement gearbox part that is obsolete.

I have a nearby foundry that will do a sand casting for me, since I don't have the proper tools yet.
I realize that I could be using aluminum for the pattern, but what are the other options?

 

I have the computer, but not the printer. I also have a subscription to Fusion 360.

 

One and done would be ideal with lost foam, which can be cut by any number of tools including a coping saw to simple hot wire all the way up to CNC. If you can break your part down into basic rings and triangles with machining allowances that may be the way to go.

Wood is fiddly but very satisfying once done.

Both wood and lost foam you have to add the shrink into the pattern while building.

3D printing is slick because you can design 1:1, add in shrink at the slicing stage, start the printer and walk away...

My latest pattern was a hybrid, a 3D printed feature glued to a wooden base and coated in epoxy.

 

So as far as pricing goes, which is usually better; wood or 3d printing? I quoted the photo I posted above with a local woodshop and it would cost me right around a thousand dollars.
Is it ok with most foundries to use standard PLA? How much surface finishing does it take after printing a part?

Thank you.
Best Regards,

 

I get acceptable as-cast surface finish by coating the .16mm layer height PLA printed parts in epoxy ( bulk 2:1 or 4:1 with some working time, not the 5-minute small tube stuff) and casting in Petrobond.

How big is your part? Have you calculated a parting line and draft and machining allowances or is that to be done yet?

The time to make the pattern wood versus PLA can be similar except most of the time with PLA I am doing something else during the print wheras with wood it is hands-on the whole way.

 

The largest diameter on that photo is actually 16 inches. At this point I am thinking that I will have the parting line where I drew the red line in the photo.
As far as allowance for shrinkage, I am not certain quite how much to allow. Is roughly 3 percent enough?

Thank you.
Best Regards,

 

I am thinking I might try the 3d printer route. Does anyone have advice on which make or model to try and which to avoid?

 

16 inches is not trivial to print, for most home systems that means sectioning and printing for days.
What material are you looking to have cast?
CNC lost foam may be the way to go to, since it's meant to be a one-off.
Know anyone with a 24" CNC router?

 

Yes, it would be around a thousand dollars for wood pattern created with a CNC.
I think I may want to have a pattern I can keep just in case I want to cast it again sometime.
Since I am new to 3d printing, I was wondering how it compares and wanted your opinions.

Thanks!

 

I think I like that idea. How much does aluminum shrink? Or why would you need 2x shrink factor?
I am going to try and find someone near me that could let me do a test run on a 3d printer.

 

Yes, of course. I wasn't thinking.

As far as the draft, I have only drawn a preliminary CAD model that is exactly like the original. I am planning to add 2 degrees of draft. Is that roughly correct or should it be more?
Should all surfaces have draft or do small surfaces not need it?

 

I make the bulk of my pattens on a 3d printer. I do mostly 1 off's or very limited numbers. If I got into a place where I was doing so many that I was killing the pattern you can always print a replacement. Or Like Dave says print a 2x shrink and cast the pattern.

 

@AndyOverPartsPro do you have a section and/or other views of the design so far?