Fab Lab UL - Molding and Casting

Assignments

Ernesto: My contribution to the group project included testing different materials such as a composite made from plaster and cement, and experimenting with chocolate casting. Additionally, I used food-safe silicone RTV for molding.
Jorge: I analyzed RTV PLATINUM 1510 Silicone Rubber, Mold Release Wax, Polyurethane Rubber, as well as castings such as Glycerin Soap with Chlorhexidine, Chocolate, and Ceramic Plaster.
Marcela: My contribution to the group work was to review the datasheets of the materials and extract the most important points.

Manufacturer: MEGATIENDAS
Composition and Ingredients:
CNot classified as hazardous according to Regulation (EC) No 1272/2008.
May cause slight skin and eye irritation.
May cause respiratory irritation if inhaled.
Natural or synthetic waxes
Petroleum distillates
Additives
Hazards Identification:
In case of inhalation, remove to fresh air. If experiencing respiratory discomfort, seek medical attention.
In case of eye contact, rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
n case of ingestion, rinse mouth. Do not induce vomiting. Seek medical attention if symptoms occur..

Manufacturer: Glici
Composition and Ingredients:
Glycerin
Chlorhexidine
Hazards Identification:
Eye Irritation: May cause moderate irritation upon contact with eyes
Skin Sensitization: May cause allergic reactions in sensitive individuals.
Acute Toxicity: Low risk of acute toxicity from accidental ingestion in small amounts.

Manufacturer: Donofrio
Composition and Ingredients:
Cocoa Mass/Cocoa Solids
Sugar
Cocoa Butter
Milk Solids
Emulsifiers
Flavorings
Hazards Identification:
Allergies: Chocolate contains ingredients such as milk, nuts, and soy, which can trigger allergies in susceptible individuals.

Manufacturer: Martell
Composition:
Not classified as hazardous according to Regulation (EC) No 1272/2008
calcium sulfate hemihydrate
additives for setting and processing
In case of inhalation, remove to fresh air. If experiencing respiratory discomfort, seek medical attention.
In case of skin contact, wash off immediately with plenty of water.
In case of eye contact, rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
Hazards Identification:
Not classified as hazardous.

For the group part we did different mold and casting tests
Using SLA resin technology, we designed and manufactured the pieces for which we wanted to make the molds.
We had already tested and tested this print in week 5: 3D printing, so we already knew that it had a much superior finish compared to other printing technologies.
With these designs, we proceeded to generate the molds with food grade RTV silicone rubber.
In addition, we use a wax mold to compare different experiments.

After having the molds, we did several tests of different types of materials.
This took us longer than expected because in some cases, such as the plaster, the finished piece broke because we thought it had already dried.

Finally, we did the test with wax and the results were very similar to those obtained with molds made of SLA printed parts.

Initial cost of a 3D printer can be lower than CNC milling machines, especially for entry-level models.
Material costs vary but can be high depending on the type of filament or resin used.
Minimal wastage as only the required material is used.
Generally lower labor costs as the process can be more automated.

CNC milling machines can have a higher initial cost and are much mor bigger.
Material costs can be lower as milling typically uses more common materials like metals and plastics.

Can be faster for creating large molds, especially with high-speed CNC machines.
Suitable for mass production once the setup is complete. You manufacture one and the rest can use that model.
Often requires less post-processing compared to 3D printing. Only cleaning.

Limited to materials that can be extruded or cured in layers, such as various plastics, resins, and some metals.
Mechanical properties can vary widely and may not be suitable for high-stress applications.
Newer materials and technologies (e.g., metal 3D printing) are expanding capabilities.

Can work with a wide range of materials, including metals, plastics, and composites.
Produces parts with excellent mechanical properties suitable for high-stress and high-temperature applications.
Material properties are consistent and well-understood.

Precision depends on the printer resolution and the material.
Typically, lower surface finish quality compared to milling, may require additional finishing steps.
Tolerances are generally less tight compared to milling, especially in complex geometries.

High precision and excellent surface finish, especially with modern CNC machines, better for the SLA 3d printer.
Capable of producing tight tolerances.