For the group assignment, we met to organize ourselves and review the progress each member has made so far. Below is the information related to the group project.
An important aspect to consider when doing this assignment is the use of personal protective equipment, since it involves working with materials that contain chemicals potentially harmful to health. The smell of the catalyst, both in silicone and resin, is quite strong. Even though silicone smells somewhat like rubber, it can still pose health risks if inhaled for extended periods. Therefore, it's essential to protect yourself by using a mask, latex gloves, and safety glasses.
For this assignment, molding and casting materials will be used, excluding F-20 Plus silicone and polyester resin, each with its respective catalyst.
| Silicone Type: RTV (Room Temperature Vulcanizing) | |
|---|---|
| Vulcanizes at room temperature. Suitable for use as a flexible mold. | |
| Features | |
| Medium hardness and viscosity | Makes it versatile for various applications in industry and art. |
| High tear resistance | Durable for repeated use and fine detail capturing. |
| Suitable for casting and brush-on techniques | Can be applied by pouring or with a brush, depending on the need. |
| Available Sizes | |
| 1 kg container | Small projects and testing purposes. |
| 5 kg bucket | Medium-scale productions. |
| 20 kg bucket | Large-scale or industrial applications. |
I will be using this material primarily to create a negative, as it will serve as a flexible mold. Below, I will provide a general data sheet for the product, since there is no detailed information available online, either from the brand or in general.
This type of silicone is specially designed for creating high-quality molds of all kinds, as it is a general-purpose silicone. It is suitable for reproducing pieces in resin, plaster, polyurethanes, waxes, costume jewelry, cold ceramics, etc.
| Product Description | |
|---|---|
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The F-Plus Catalyst is an additive specifically formulated for the vulcanization of RTV (Room Temperature Vulcanizing) silicones. It is used in combination with F-Plus silicone to create high-quality flexible molds, suitable for various applications in industry and the arts. |
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| Key Features | |
| Mixing Ratio | 2% - 3% catalyst by weight of silicone |
| Form | Transparent or slightly opaque liquid |
| Curing Time | Depending on the amount of catalyst used, curing can range from 30 minutes to 24 hours |
| Ease of Use | Easy to dose with a syringe for accurate measurement |
| Instructions for Use | |
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| Catalyst Properties | |
| Adjustable curing speed | Using more catalyst will speed up curing, while using less will slow down the curing time. |
| Versatility | Suitable for all types of molds, including those used for casting pieces in resin, plaster, polyurethane, wax, jewelry, ceramics, and more. |
| Compatibility | Compatible with other F-Plus silicones and similar-quality RTV products. |
| Usage Precautions | |
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| Benefits | |
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| Available Sizes | |
| 100 ml container | For small projects |
| 500 ml container | For medium-sized projects |
| 1 liter container | For larger projects or industrial use |
It is recommended to use a scale to weigh the silicone and a syringe to measure the catalyst in order to ensure precise mixing.
The resin will be used for casting applications.(This information was sourced from ChatGPT.)
| Product Description | |
|---|---|
| Silikast-Pro is a high-quality unsaturated polyester resin designed for general molding, laminating, and other applications that require good mechanical and thermal resistance. It is ideal for mold manufacturing, automotive parts, repairs, and various applications in industrial and artistic fields. | |
| Key Features | |
| Type | Unsaturated Polyester Resin |
| Color | Transparent or slightly yellowish |
| Composition | Polyester base + Styrene monomer |
| Working Time (Pot Life) | 15–30 minutes, depending on ambient temperature and catalyst amount |
| Curing Time | 30 minutes to 1 hour (full curing may take up to 24 hours depending on the thickness of the piece) |
| Density | 1.1 – 1.2 g/cm³ |
| Viscosity | 2000 – 3000 cps (depending on temperature and formulation) |
| Curing Properties | Requires a catalyst (Methyl Ethyl Ketone Peroxide, MEKP) to initiate the curing process |
| Instructions for Use | |
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| Mechanical Properties | |
| Tensile Strength | 60 – 80 MPa |
| Flexural Strength | 85 – 95 MPa |
| Impact Resistance | 10 – 15 kJ/m² |
| Modulus of Elasticity | 3.5 – 4.5 GPa |
| Thermal Properties | |
| Heat Distortion Temperature | 80 – 90°C |
| Coefficient of Thermal Expansion | 50 – 60 x 10^-6 /°C |
| Applications | |
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| Usage Precautions | |
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| Available Sizes | |
| 1 kg container | Ideal for small projects |
| 5 kg container | For medium-sized projects |
| 20 kg container | For industrial use or large-scale projects |
The characteristics of the resin may vary depending on the type of catalyst and mixing conditions. It is recommended to conduct tests before large-scale production.
| Product Description | |
|---|---|
| The Polyester Resin Catalyst is a compound that, when mixed with the resin, initiates the curing (vulcanization) process of the polyester resin. This catalyst is essential for ensuring that the resin hardens and acquires the desired mechanical and thermal properties. | |
| Catalyst Usage Method | |
| Mixing Ratio | Add between 1.5% and 2% catalyst to the total amount of resin, or 10 to 20 drops per 100 grams of Silikast-Pro resin. |
| Mixing | After adding the catalyst to the resin, mix thoroughly for at least 1 minute to ensure the mixture is homogeneous. |
| Instructions for Use | |
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| Usage Precautions | |
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| Available Sizes | |
| 50 ml bottles | Ideal for small projects |
| 100 ml bottles | For medium-sized projects |
For this assignment, I created a mold using 3D printing, which will be one of the test molds. For the second mold, I made a positive design, from which I will obtain the negative part using silicone.
| Feature | 3D Printed Mold | Silicone Mold |
|---|---|---|
| Detail Precision | High | High |
| Mold Surface | Smooth | Variable |
| Fabrication Time | Long | Moderate |
| Reusability | Low | High |
| Cost | Moderate | Low |
| Ease of Demolding | High | High |
Both molding methods have advantages and disadvantages depending on the type of project and the resources available. The 3D printed mold is ideal for quick prototypes and complex designs, while the silicone mold offers flexibility and durability for longer production runs. The choice between one or the other will depend on factors such as available time, budget, and the nature of the final product.
The following table provides a comparison between the molding methods using 3D printing and CNC milling, based on the process, production time, cost, precision, and recommended applications.
| Aspect | 3D Printing | CNC Milling |
|---|---|---|
| Manufacturing Process | Uses a 3D printer to create the mold from an STL file. Direct process without additional tools. | Uses a CNC machine to mill the mold from a material block. Requires programming and tool selection. |
| Production Time | The estimated time for printing is approximately 4 hours and 56 minutes. | Time varies depending on design complexity, but is generally longer due to the machining process. |
| Cost | Low initial costs, ideal for prototypes and small-scale productions. | Higher initial costs due to the need for specialized tools. More cost-effective for mass production. |
| Precision and Surface Finish | May show visible layer lines affecting the surface finish, but post-processing can smooth the mold. | Offers a smoother and more precise surface finish, especially with materials like aluminum. |
| Design Flexibility | Allows for complex geometries and customized designs without significant limitations. | Limited by tools and material geometry, which can restrict complex designs. |
| Recommended Applications | Ideal for rapid prototyping, low-volume productions, and custom designs. | Best suited for mass production, durable molds, and when high precision is required. |
Conclusion:
The choice between 3D printing and CNC milling depends on the specific needs of the project. 3D printing is ideal for rapid prototyping and small-scale productions, while CNC milling is better for large-scale productions requiring high precision and durability.