3d Printed Patterns or Wood?

Discussion in 'Pattern making' started by AndyOverPartsPro, Mar 18, 2024.

  1. 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.
  2. HT1

    HT1 Gold Banner Member

    those are not your 0nly options what are you making
  3. Petee716

    Petee716 Gold Banner Member

    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!

  4. 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    It is a replacement gearbox part that is obsolete.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?

    Attached Files:

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

    Tops Silver Banner Member

    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.
  7. Tobho Mott

    Tobho Mott Administrator Staff Member Banner Member

    I've glued 3D printed details onto handmade patterns before too. In a limited sense a cheap 3D printer could replace a whole wood shop in a much smaller footprint. But the printed patterns probably won't be as nice to make molds with. For me learning how to make wood patterns is fun while learning CAD and frigging around with a temperamental printer is not. But my printer has certainly come in handy a few times when a 3D pattern file has been provided or already existed on ie. thingiverse or the like... Glad I have some ability to use both ways.

  8. 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,
  9. Tops

    Tops Silver Banner Member

    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.
  10. 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,

    Attached Files:

  11. 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?
  12. Tops

    Tops Silver Banner Member

    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?
  13. 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.

  14. DavidF

    DavidF Administrator Staff Member Banner Member

    3d printing is great for making patterns on the cheap. The down side is that the patterns will distort over time especially if not mounted to a match plate, and hot molding sand will kill them in minutes.
    You could print the piece with 2x the shrink factored in and then cast an aluminum master pattern if you think you'll be needing it for the next 100 years, or if you plan on making hundreds of them.
  15. 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.
  16. DavidF

    DavidF Administrator Staff Member Banner Member

    356 shrinks 1.3- 1.4%
    If you cast an aluminum master to use for the pattern you need to double up your shrink factor...
    First cast shrinks 1.3% to create your master pattern, then when you go to cast the actual part it shrinks 1.3% again...
    Did you add draft to your cad model ??
  17. 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?
  18. crazybillybob

    crazybillybob Silver Banner Member

    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.
  19. DavidF

    DavidF Administrator Staff Member Banner Member

    2 degrees on the outside is fine, but I would go a bit more on the ID and also allow a bit for machining tolerance..
    Tobho Mott likes this.
  20. Tops

    Tops Silver Banner Member

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

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