Acrylic cube

Hallo,

every die maker in the die casting industry can machine a acrylic box.

To find more information contact the North American Die Casting Association. Members of NADCA did similar things you are planning.

www.diecasting.org

regards

Y

The email alert say the high informative comment above was from Stirling Stan ?

Can you use two halves of your cube with half of the shape machined in each part then glue/screw the two parts back together?

Hi carlosalejandro:

Contact a plastics company such as P&A Plastics explain what you need and I am sure they will be able to assist you with this project.

mechtech

SolidConcepts in California (http://www.solidconcepts.com/) can do things like that very well and very quickly. Most other rapid prototype shops should be able to do this as well. I haven't used them for anything clear, but they use several materials, including acrylic, that I think would work for you. I have worked with their engineers to figure out how to manufacture things before and they are very good.

First of all, your wanting to use this "cube" as a mold for casting other materials sounds like you should be using a silicone rubber, or 2 k polyurethane. Secondly, if you want to cast acrylic, you need to select the specific acrylic monomer(s) that you want to use for hardness and physicals. For example, will you need to invert or deform the acrylic in order to remove the cast part? Then you need to make a pre-polymer of, for example, methyl methacrylate with, again for example, benzoyl peroxide, to form a viscous pre-polymer. If you polymerize monomer to cast the cube, you'll have a lot of shrinkage, plus bubbles. Degas the viscous prepol, catalyze it and cast your cube. Keep the temperature down during curing. You should have just enough shrinkage to be able to remove the acrylic cube from its mold.

I think what Carlos is trying to do is to create a hollow shape inside the acrylic so that he can pump some liquid through this void & observe the pattern of the flow.

Depending on your budget and the complexity of your design, you might want to look into an SLA (Stereolithography) printer using WaterClear Ultra resin. The printers are quite expensive but there are several businesses who have purchased them and offer their services like http://www.3dproto.com/. The advantage is the designs could be easily repeated and could be modified easily, verses sculpting a new wax sculpture every time. I think WaterClear Ultra® resin is as clear as acrylic. Other resins may be cloudy or colored in comparison. By the way, PIV means Particle Image Velocimetry.

Ah ha! I think you are right. My earlier reply was based on the reverse -- making solid objects, and observing flow around them. On reading with your interpretation, it makes more sense.

Bobguz

Your lost wax process is the perfect answer but I think Carlos should use the water soluble plaster as the heat from the reaction of the acrylic may melt the wax.

Dociron

It sounds like you are building something like a water tunnel.

The box part could be easily built like an aquarium. I don't think you'd want to cast that part, because it would be more work, and difficult to achieve the flatness of sheet materials.

The models could be cast of one of several water-clear resins (many large hobby shops and art supply houses have all the materials for doing exactly this).

Sources for clear resins:

http://www.emsdiasum.com/microscopy/products/embedding/resins.aspx#24210

I don't know that you could get close enough to the working fluid's refractive index to be able to analyze flow on the far side of an object: I'd think there'd be too much lensing effect. (I'm just guessing here -- I haven't looked up the indices, nor do I know what your working fluid will be.)

If you don't need the model itself to be transparent, then plaster is certainly easy to work with, and can be lacquered to protect if from the fluid. Some epoxy resins are essentially water clear, and are not as unpleasant to work with (nor as carcinogenic) as polyesters. They can, however, exotherm in a large mass, leaving your cast piece frothy, and probably destroying the mold too.

Create your virtual waste object with Geomagic Studio 10, or scan as built prototype with Faro Platinum Laser. Output to 3D printer in micro-crystalline plastic (lost wax medium) Shrinkage and expansion are very predictable, both when tooling and when eliminating (wax) patterns from mold cavities. 'Rcast' from Reynolds Polymer Technologies [may be a one-stop shop for your project] - supplier for submersibles, aquariums among other clarity-sensitive applications. Does your void preclude the use of internal optical sensors, or could you eliminate the refraction index requirement? We use all of the above in my studio.

it would be neat to etch each side with images, patterns, or symbols.