Molding and Casting¶
Tasks¶
Group: - Review the safety data sheets for each of your molding and casting materials. Then make and compare test casts with each of them. Compare mold-making processes
Individual assignment:
- Design a mold around the process you’ll be using, produce it with a smooth surface finish that does not show the production process, and use it to cast parts.
Group¶
For this weeks group assignments, I was tasked with reading the data sheet for the materials we used and testing the different types of mold. Here is the link to our group website.
Data Sheet¶
Smooth on: Mold Star¶
Mold Star™ 30 is a platinum-cure silicone rubber designed for mold making, featuring an easy 1A:1B mix ratio by volume or 100A:96B by weight. It cures at room temperature with no need for vacuum degassing due to its low viscosity. Mold Star™ 30 is suitable for casting wax, gypsum, resins, and low-melt metal alloys. The rubber has a pot life of about 45 minutes and cures in approximately 6 hours. It cures to a blue, medium-firm rubber (Shore 30A). Users should thoroughly mix both parts before combining and avoid surfaces containing sulfur, which can inhibit curing. Vinyl gloves are recommended, as latex can interfere with the curing process.
Key Properties:¶
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Pot Life: Approximately 45 minutes
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Cure Time: Around 6 hours at room temperature (73°F / 23°C)
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Shore Hardness: 30A
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Color: Blue
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Mixed Viscosity: 12,500 cps
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Heat Resistance: Up to 450°F (232°C)
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Shrinkage: Less than 0.001 in./in
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RationL 1:1
XTC-3D¶
XTC-3D™ is a protective coating designed to smooth and finish 3D printed parts. It is a two-part epoxy system that should be mixed and applied with a brush. It self-levels to eliminate visible print lines without leaving brush strokes. It has a pot life of approximately 10 minutes and a cure time of about 4 hours,. XTC-3D forms a hard, impact-resistant surface that can be sanded, primed, and painted. It is compatible with many 3D printing materials, including PLA, ABS, PETG, and powder-printed parts, as well as other substrates like foam, wood, plaster, and paper. The coating can be colored using UVO or IGNITE colorants and enhanced with fillers such as metal powders or glow additives. To extend working time and prevent excessive heat buildup, it is recommended to pour the mixed resin into a flat tray to reduce mass. XTC-3D is VOC-free and offers a good solution for getting a smooth, high-gloss finish on 3D printed objects.
Molds¶
The first mold we made was a 3D printed mold. We designed it in fusion 360. This allowed us to quickly prototype and make adjustments as needed. While it was fast and convenient, the surface finish had small visible layer lines, so we had to add a layer of XTC-3D to smoothen the layer.
The second mold we made was milled from a block of machinable wax using the CNC machine. This process took more time compared to 3D printing, especially when setting up the tool paths and ensuring the correct milling depth, but it resulted in a much smoother and more precise mold with a high-quality surface finish.
Since the molds we made were hard, we needed the cast to be flexible and soft. We measured out equal parts of A and B and poured them into a mixing container. Then we stirred the mixture thoroughly until it was fully blended and uniform in color, making sure to scrape the sides and bottom to avoid any unmixed material that could affect the curing process.
Once it was mixed, we poured the silicone into both molds, the milled wax mold and the 3D printed mold. The low viscosity of it made it easy to fill in all the details of each mold. We made sure to pour slowly and evenly to avoid trapping air bubbles and to ensure the silicone reached all areas of the mold.
We then left the molds to cure overnight, allowing the silicone to fully solidify. This makes sure that the material reached its final hardness and was safe to de-mold without tearing or warping.
Individual¶
For my indivdiual assignment, I made my mold using a 3D printer. The first step was to create the mold in fusion 360. I picked an image from google and imported it into fusion. I then used the line tool in sketch to trace out the entire shape.
Once the image was traced I created a base for it and printed it with the 3D printer.
The mold had a bit of layer lines on it so I added a small layer of XTC-3D.
Reflection¶
This week’s molding and casting assignment was a valuable hands-on experience that taught me the importance of understanding material properties, safety guidelines, and how different fabrication methods impact final results. Through our group work, I reviewed the safety data sheets for Mold Star 30 and XTC-3D. I learned about their working times, compatibility, and handling precautions. Comparing the 3D printed and CNC milled molds highlighted trade-offs between speed, and surface finish. 3D printing was quick prototyping but visible layer lines, and CNC milling delivering a much smoother finish. For my individual project, I designed a mold in Fusion 360 by tracing an image, 3D printed it, and applied XTC-3D to improve the surface before casting with Mold Star 30. This process taught me the importance of careful mixing, slow pouring to avoid air bubbles, and consistent post-processing. Overall, this week strengthened my skills in digital design, material handling, and the practical nuances of mold-making and casting.
Here are the fusion files for this week.