Skip to content

How To; 3D printing & bronze casting

August 21, 2013

For the Velocette Rally, I volunteered to make the trophies for the various classes of bikes at the Concours d’ Oilegance, our not-at-all-formal gathering on the Saturday afternoon where we push all the bikes into a pile and gaze at the oil leaks, broken mufflers and occasional shiny bits.

Velocette Naked Lady

Step one was to get a good digital file of the logo that the Veloce factory put on the headstock of the motorbikes.  It is often referred to as The Naked Lady, although she isn’t showing all that she could.

 veloce logo casting

I scanned that image into Solidworks, then built a CAD part with the various lines lifted up into a relief.  This was all very simple, but it took about 5-6 hours to get all the little lines traced and sketched, then extruded to a depth and 3 degrees of draft added for the sand casting process.

 P1060541

The CAD file was exported to a 3D printing machine that a friend has.  This machine was an “affordable” type that costs around $2,000.   Others are available for $500. 

 

3D printing is a fairly new technology that has a lot of press lately.  It can be used to make patterns like this, or to make up finished plastic or even metal parts.   Some printers can even use materials like rubber or similar to ceramics.

 

It may be difficult to imagine how the machine works, so I’ll explain it a bit.  Imagine your typical office printer on your desk.  It feeds the paper in one direction, and the printer head moves back and forth across the paper, dropping little drops of ink in specific places.  The paper feeds in a little more, and the printer head moves across again, dropping drops.  Eventually the head has passed over every square inch or square millimeter of the paper, and it either drops ink or leaves that spot empty.  The drops add up to form words or images.  A 3D printer does the same method.  But the paper is replaced by a flat plate of aluminum or hard plastic.  And the printer head moves front to back as well as side to side.  The printer head drops a little bit of melted plastic instead of ink.  Once the head has travelled over the full area of the base plate, a motor lowers the plate a small amount, say .007”.  The printer head then travels back and forth all over again.  Then the plate lowers .007” again, and it repeats.  Eventually the little dots of melted plastic form layers of a solid part, with each layer being that .007” dimension.

3D printing the Veloce trophy pattern

 2013-06-10 11.42.34

 

Check on the internet, there are a number of these 3D printers now available.  But the quality of the small features will vary for different machines.  (mostly due to the size of the dot of melted plastic, and how small was each step movement of the head).  For medium sized parts or medium features, the only concern will be the waviness of the surfaces due to the layer height of .003” or .007” or .020”, etc, and these surfaces can often be sanded smooth as needed.

 

Or don’t buy a machine, just pay somebody to make your parts.  At my day job I’ve used these guys before, and there are many more out there.

 

P1060529That green part didn’t have enough resolution on the small ribs of the relief, so I had another friend make up two on his 3D printer machine.  That machine uses a better process with more accuracy, but has a $100,000 price.

 

The parts were glued onto an old board, and gates and runners were installed.  You might recall this stuff from the How To: Spark Plug Holder article.

P1060531Here is the backside of the plate.  It was then placed into a box of sand to produce a negative gap with the specified shape.  Another box of sand was used to form the backside surfaces.  Then the board was removed and the two boxes were placed together.  The empty hollow spaces in-between the two sand boxes were filled with molten red brass to make two trophies.  Here is a link showing more info on sandcasting.

 

P1050731 

Occhio Lungo

The kids and I spray painted the castings, then wiped off the high edges with a rag soaked in paint thinner.  A quick drill and tap operation made threads, and another volunteer made up oak bases and brought some screws and spacers to the rally.  K ordered some lettered plaques from a local trophy shop, and we were ready for some cold beverages.

 

trophies

I’d like to give special thanks to Terminal Brass and Foundry for their work on the wood plates and the castings.  And to Derek at Moss Machine for the super fine 3D prints.

If you liked this one, there are a lot more How To articles on Occhio Lungo here or here.

9 Comments leave one →
  1. Tim Yeatman permalink
    August 21, 2013 1:36 pm

    Waiting for my printer now, sometime in Sept.

    • Anonymous permalink
      August 22, 2013 4:42 am

      Hi Pete
      Fantastic process!
      I have done quite a bit of lost wax or “investment” casting using silicone moulds. The main advantage is that the detail and finish you can get is phenominal. I have actually copied and cast fine splines very accurately.
      Looking at what is possible with the 3D printer the mind boggles at what could be achieved
      Regards
      Antony

      • August 22, 2013 12:18 pm

        I’d love to try investment casting, but so far I’ve only done sand casting. I did play around with some plaster molds in the kitchen one time with the kids, and melted some solder in a frying pan to fill them up. That was fun.

    • August 22, 2013 12:20 pm

      Neat. What will you be making?

      • August 22, 2013 1:47 pm

        Pete, I’ve still got a sandcast aluminum pipe holding ashtray I did in tech college in 64. We had a lot of fun in that class.
        The printer will start by doing some stuff for my HO train layout and we’ll see from there.

  2. August 21, 2013 11:39 pm

    Years ago I remember seeing articles on 3D printing and even video clips of pieces being produced and thinking to myself that this must be an Aprils fool.

    hands up!, technologies have now left me on the side line with the ‘wheezy boys’ and matron; a mere observer 8-(.

    • August 22, 2013 12:19 pm

      Oh yeah. The technology just keeps moving forward. Some of it is dull (cell phone apps) but others can be very useful to an oldbike guy. Have fun.

  3. tp@dpchd.com permalink
    August 22, 2013 11:56 am

    I’ve got to say, I’ve never had a dull minute reading or viewing your posts. It is a very pleasant respite from the daily grind of a Harley shop.

    Thomas Perkins

    Dudley Perkins Company

    Harley-Davidson & Buell

    333 Corey Way

    South San Francisco, CA 94080

    650.737.5467 http://www.dpchd.com

    Est. 1914 – A family tradition of

    four generations.

    _____

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: