Archive for the 3DP Materials Category

Lecture at National Conference for Cast Iron Art

Posted in 3DP Materials, metal casting, rp/am sculpture, Uncategorized with tags , , , , , , , , , , , on May 3, 2011 by skaad

Recently I attended the National Conference on Cast Iron Art held at the historical Sloss iron foundry in Birmingham, Alabama.  I was lucky enough to present a lecture on my recent research into the application of Additive Manufacturing technologies to the process of Metal Casting.   What follows are the first 22 slides.  The next post will contain the final images.

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Requested resources

Posted in 3DP Materials, rp/am sculpture, Uncategorized with tags , , , , , , , , on May 3, 2011 by skaad

I have just returned from giving a lecture at the 2011 National Conference on Cast Iron Art.  I am still working on uploading the full powerpoint presentation from the lecture, but as a teaser here is the reference list that was most requested:

We are getting ready for an iron pour and finals are coming so look for the images from the powerpoint after May 15th.

Introducing Glypsum (glazed gypsum plaster)

Posted in 3DP Materials on December 21, 2010 by 3dpglass

At Solheim Lab in Washington, we have been printing many, many molds and having great fun casting glass (more posts on that subject later).   It seems that our kilns have been going non-stop over the past week (what an exciting time in our lab).

Today’s post is a new development that came as a result  of observing  the glass molds after the casting process.    The molds were quite robust after firing.   We tested fired PVOH (hydroperm) past 2200 F (1200 C) succesfully.  Thus it seemed that PVOH might be able to take glaze!  Wow!

We test fired a few bars with glaze and the results were positive (although they were very porous).    Laura West suggested showing something cool (not just your standard test bars).

[showtime]

We present a simple bowl with glaze and and some dark blue crystal glaze sprinkles.     We took care of the porosity issue by infusing with colloidal silica before glazing.

With all of our excitement, we sent an email to Michael Eden in England with a simple question “Hey Michael, have you ever heard of anyone glazing plaster?”.  The answer “Yes, me!”

{Copyright Michael Eden}

“I infused one of the commercial printing plasters with a proprietary refractory infiltrate (from Axiatec) that allows it to be heated to 1500C (2730F). The material is too absorbent for glaze, so I coated with vitreous slip, fired it to 1000 C, then dipped it into our lovely lead glaze, stained with copper oxide. Then fired to 1085 (1985F)

Definitely a case of the pre-industrial meeting the post-industrial!”
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Great fun to find other minds that ask the same questions “What if you did …  OR Could we do that…?”

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Glass Casting in Printed Molds: Part I

Posted in 3DP Materials, glass casting, Uncategorized with tags , , , , , , , , on November 28, 2010 by chwyman

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My name is Charlie Wyman and I am currently a graduate student at the University of Washington in Mechanical Engineering.  Prior to beginning my studies at the University of Washington, I received my B.A. in Applied Mathematics from Whitman College, and upon graduating I spent several months designing and fabricating metal sculptures from copper and steel.  This quarter I have been fortunate to have the opportunity to work in the Solheim RP Lab under the guidance of Prof. Mark Ganter.

Recently, under the direction of Prof. Ganter and Prof. Laura West, I have been experimenting with “kiln casting glass” directly into printed molds.  The primary material that has been used thus far is hydroperm, a material that is ready to use out of the bag.  For the first few tests, I used a standard glass firing schedule and System 96 glass, which is more viscous that typical casting glass. I also used an open-faced mold of a mask I designed as the test mold.

Preliminary results have shown promise, but we still have some details to work out.  We initially had some problems with mold burn-in and devitrification, but I believe this was due to discrepancies in the firing schedule.   These issues have been significantly reduced.

Future tests will include varying the firing schedule and temperatures to minimize the frosty surface, spots, and devitrification, and to determine at what point mold burn-in occurs. I will also experiment with different types of glass and mixing other materials with the hydroperm.

Plaster Powder VOHP (Version “Out of the bag” HydroPerm)

Posted in 3DP Materials, rp/am sculpture, Uncategorized with tags , , , , , , , , , on November 6, 2010 by 3dpglass

by  Laura West and Mark Ganter

As a result of the collaboration between artist (and  a bit engineer) Laura West and engineer (and more than part – artist) Mark Ganter, we are making great strides in the Fresno City College Sculpture Lab and the UW Solheim RP Lab  for the past few weeks.  This went into high gear when Laura West came up to Seattle last week for Ars Mathematica and to finalize some research on the cemetenous material (see posts).  As you may have noticed, Mark made and amazing discovery and found a printing fluid (rice wine) that works straight out of the bottle.  A few days later, Laura began testing a type of gypsum cement straight out of the bag and Mark joined the party/followed suit/something like that literally within hours.

We have been both testing a number of different high strength specialty plasters and have found several to be amazingly successful. We are presenting last week’s winner.

The recipe is “There is no recipe“.   You simple purchase HydroPerm, cut open bag, and pour into machine.

It has good damp strength, great green strength, and air drying seems the best (although we have been known to bake a few).   The best part of VOHP parts is you can spray them with water OR gently wash them in water (and the parts get stronger)!  You can even use water based paints, stains, and varnishes.   The VOHP parts open up a new frontier in post processing options.

“Around midnight before Laura West was to leave her very productive visit at Solheim RP, she ran a test of a USG material called Hydroperm that is often used in metal casting.  It printed beautifully.  Good strength and very little binder migration (we call this “bloom”).  She then decided to run a small test mold and a few small sculptures.  Within two hours of starting the print, Laura took the test mold over to the metal casting lab and discovered that it does indeed hold up very well to cast metal.  This material is potentially even better than the cementenous formula.”

We have had successful results with a variety out-of-the-bag printing materials since we began our collaboration.   Some of them have potential for metalcasting (We would recommend waiting until we get past preliminary testing to try this – we promise to get you results soon).   As we test these and other new materials we will keep you posted on this site and open3dp.

"MesoBio" printed in Hydroperm by Duane Storti

 

 


Mark has been printing up a series of sculptures in Hydroperm for an exhibition in the ArtSpace Gallery at Fresno City College titled “Rapid Premonitions”  They are printing amazingly well. . .

"Moai Bowling" printed in Hydroperm by Mark Ganter

 

We think this is the best powder that we have found to date.   It works for part printing and it works for mold printing!!

Mold form featured on Thingaverse!

Posted in 3DP Materials, metal casting, rp/am sculpture, Uncategorized with tags , , , on November 3, 2010 by skaad

The stl that I created this weekend as a template for metal casting that I posted caught the eyes of the folks over at Thingaverse (where you can download it).  This is a place to share digital designs that can be made into real, physical objects.  Their motto is: “Let’s create a better universe, together!”  There is a wonderful collection of bizarre and useful objects that can be downloaded and printed.  It is worth checking out.

Rendering of Basic Mold form with Keys

Formula form Cementenous Metal Casting Molds

Posted in 3DP Materials, rp/am sculpture on October 31, 2010 by skaad

Printing cementenous mold at Solheim Lab

Our presentation ( Laura West and Mark Ganter) at Ars Mathematica in Paris was a great success and as promised we are jointly releasing our cemetenous metal casting formula for you to play with. What follows is a series of tips along with the formula.  Of course we found that it also works quite nicely for sculptural forms and has the unique quality of not needing an infiltration.

The formula simply is:

1000 parts VersaBond Cement
250 parts Maltodextrin
250 parts PVA powder

These molds should be approached much like sand molds.  They will have similar surfaces and strengths, you will also need to think of venting them in a similar way.  For smaller molds, you should not let the thickness get less than 1/2″ and for larger molds you should increase it to 1″ or more.  You will either need to build them as open face molds or as 2 part molds to get the powder out of the center.  As time goes I will post more mold making tips on this blog as well as open3dp.

You will find that you need to print adjust your powder setting to be fairly wet, but not so wet that the part pulls away from its surroundings.  The first few layers may tend to slide, so you should orient your part to account for that (put the bottom of your mold on the bottom of the build) and put it at least 1/4″ up into the build.  Placing a few test bars below your build is also a good idea.  Creating your patterns on a textured build plate also seems to help.  You may find that you need to adjust the anisotropic scaling on x-plane in your print program, which is easy enough to do.  Baking the mold on warm (do not go above 125 degrees F or the sugars will start melting) will help with de-powdering.  The only “infiltrant” you may want is a light spraying of alcohol.  This will make the surface of the print hard enough to file your nails – seriously I have filed several broken nails in the lab with this material!

For a finer surface on your cast you may want to paint a thin layer of mold wash on the surface.  You can buy a commercially available recipe (Porter Warner) or you can create a mixture 50/50% zircon flour and graphite stirred into either alcohol or naptha.  Fused silica flour can also work as part of the recipe.  A mold wash, depending on the pattern, can allow for a second pour if it is an open face mold.  If you have a two part mold, you will need to join the two sides.  Any 5 minute epoxy will work for small molds.  For larger molds you should use a professional grade core paste and/or mold weights/metal clamps to hold the mold together.

A good resource for sand casting  techniques is “The Complete Book of Sand Casting” by C. W. Ammen. It can be found on Amazon for less than $15 and should be in every metal caster’s library.  Although I will eventually post tips and rules for gates (the channels to get the metal to the pattern) and vents (the pathways for air to escape from the mold) as well as things like metal temperatures and types, this book is an old classic and  will give you a head start.

I have attached a Rhino 3d and a stl file which you can use as a base for a mold.  You can take a stl and “cut” or “Boolean” it from the form just below the tapered hole to create a negative space to pour into.  If you are having difficulty with your cut in Rhino, use the “analyze” tab and check your direction.  Often this is the cause of the problem.  If you have a choice you should place thicker forms over thin ones and you may need to add vents – which you could cut by hand.  You should note that this is a two part keyed mold form, even though it appears to be a single object. Link to file download.

I (Laura West) was lucky enough to return as a visiting artist again at Solheim lab for the last week.  During the last few weeks first at my lab in Fresno and then especially at UW some significant break throughs have been made, which we will be discussing soon.  There is a great deal to be said for artist/scientist/engineer collaborations (expect some posts soon from both of us).  One of the most amazing things that was accomplished was printing a mold and pouring it within 3 hours – one hour before I left for Fresno.  I am leaving you with teaser shot of some these new materials below: