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Molding an casting

Week 12

Group assignment:

  • Review the safety data sheets for each of your molding and casting materials, then make and compare test casts with each of them
  • Compare printing vs machining molds

Group 1

  • Hans Moncca
  • Maryori Vásquez
  • Jose Alberto Rodriguez
  • Cristian Loayza
  • Silvana Espinoza
  • Maria Angela Mejia
  • Jesus Lucero

    • Group 2

  • Renson Samaniego
  • Wilber Giron
  • Ronal Vilca

    • Group 3

  • Grace Schwan
  • Jorge Pazos

    • Group 1:

    Hans Moncca Contribution

    REVIEW THE SAFETY DATA SHEETS FOR MATERIALS


    SILICON F10 PLUS

    The following RTV F-10 silicone is a flexible silicone that is for creating elastic moles. It is resistant to breakage and is suitable for producing molds for wax, soap and candles. Here is the data sheet that the supplier gave us and a summary table of it.

    CARACTERISTIC INSPECTION METHOD VALUE
    MIX RATIO A:B 100:3
    COLOR - White
    POT LIFE 25°C 40-50 mins
    Demold time 27° C 8-12h
    Storage Store covered, in a dry and cool place. -
    Shelf life - 12 months with original unopened package

  • After understanding the curing time and the proportion that we have to take into account so that the silicone can become a mold, we will proceed to perform the test in a glass similar to the previous ones to know the consistency and curing time.
  • We began to make the exact measurements for the test and have the exact proportions and have a perfect mold. In this case we use water first to obtain the weight of how much silicone we are going to use.
  • After obtaining the indicated weights and the appropriate portions for the test, we begin to make the silicone in our glass and then the catalyst; the proportion according to the data sheet is 100 to 1, that is, for 100 ml of silicone, 3 ml of catalyst.

    • Finally, after carrying out the entire mixing process, we waited for the curing and after 24 hours we were able to obtain the following result.

    COMPARATION AND CONCLUSION FOR SILICON TEST

    After carrying out all the tests on the silicones that we were able to obtain in Lima, Peru together with my colleagues. I can leave these 3 conclusions that I think are important in the following table:

    CHARACTERISTICS RTV 20 PLATINIUM RTV EXTRAFLEX F10 PLUS CONCLUSION
    DEMOLD TIME 8-12h 5-12h 4-8h 8-12h Regarding time, I consider that Platinium silicone and Extraflex have a shorter curing time and the product is ready to use.
    DESMOLDING Little difficult Difficult Easy Easy Regarding demolding, I would recommend using the EXTRAFLEX and the F10 PLUS because being more flexible than the other two, we can obtain better molding.
    DETAILS little detail detailed Very detailed Very detailed According to the details, I consider that the F10, Platinium and Extraflex silicones present better detail of the mold we want to make.
    FLEXIBILITY flexible not very flexible very flexible Very flexible I consider that flexibility is important when making molds to be able to remove them and we only had complications with the PLATINIUM silicone

    COMPARATION PRINTING VS MACHINING MOLDS

    To compare printing and machining molds, I think we have to see the process of each of them. 3D printing molds are faster to make and have a very detailed finish for casting. I consider that due to time and finish it is a good option to use. Compared to machine molds, we have to carry out a more laborious process of configurations and milling but it is not left behind in terms of finishes. Both have characteristics that distinguish them.

    After seeing the molds of each process, I would choose the 3D printing mold because of the speed and detail we can achieve. I liked how to make molds with a machine and wax, but in my case, I suffered a lot in the machine configuration and finishing stage because I felt that the machine was uneven or the wax was not finishing in some areas of my model. I consider that the 3D mold obtains more detail from the model unlike the machine mold.

    Group 2:

    - Cristian Loayza

    - Silvana Espinoza

    - Maria Angela Mejia

    - Jesus Lucero

    Safety and Test Cast

    To use the router machine for milling the wax block mold -as a team- we went to the Universidad Cientifica del Sur Fab Lab which is located in the Architecture Faculty of the university, in Chorrillos district, in the city of Lima, Peru.

    Safety Considerations

    When working with materials for mold-making, prioritizing safety is paramount. It is essential to equip oneself with protective gear, including safety glasses to shield the eyes from potential splashes or spills. Additionally, wearing long sleeves and gloves serves to minimize skin exposure to the material, reducing the risk of irritation or allergic reactions. Furthermore, a face mask should be worn to prevent inhalation of any airborne particles or fumes emitted during the molding process. By adhering to these safety precautions, one can ensure a safer and more secure working environment while engaging in mold-making activities.

    Safety Data Sheets of Molding Material: Silicones

    For this task, we tested two kinds of silicone: Silicon RTV F20 Plus and Platinum Silicon RTV A30. In Peru, Silicon Peru is the local seller.

  • It is worth mentioning that we had an initial problem with the OOMMOO silicone. Because it had not been used for more than a year after purchase, one of the components was completely dry. Reading the data sheet, we discovered that its shelf life is only about 6 to 9 months. This material is very scarce in Peru (only one store sells it). We immediately contacted the supplier, but they did not have that silicone in stock. As a team, we look for alternatives and get other more accessible materials in the country.
  • The first material we tested was the Silicon RTV F20 Plus. It is a liquid mold making silicone rubber that comprises two components: a white liquid serving as the silicone itself (component A) and the curing agent (component B). The mix ratio is: component B should be the 2%-3% of the amount of component A. The curing process typically takes from 4 to 8 hours. Noteworthy qualities include strong tear resistance and exceptional tolerance to high temperatures.

    • Following the review of the datasheet, we proceed to utilize the material, mixing it in accordance with the specified proportions and values outlined within the documentation.

  • Once the two materials are merged, we commence the process of stirring the mixture for one minute until it achieves a homogeneous liquid state, thus facilitating the silicone test to yield the desired outcome. When the mixture hardened, we obtained a whitish and flexible material.
  • The second material we tested was the Platinum Silicon RTV A30. It is a food-grade silicone that comprises two components: a translucent liquid serving as the base (component A) and the curing agent (component B). The mix ratio is 1:1. The curing process typically takes from 5 to 12 hours. This food-grade silicone is environmentally friendly, odorless, and non-toxic, ensuring safety for various applications such as makin food molds. With its remarkable resistance to high temperatures and aging, it can withstand temperatures ranging from -60°C to 200°C. Moreover, its exceptional tear resistance makes it highly durable for a wide range of uses.

    • Upon reviewing the data sheets, we conducted our test using the specified proportions and mixed the materials accordingly to achieve the desired outcome.

  • Once the two materials are merged, we must adhere to the recommended mixing time of 3 to 5 minutes at most before pouring the mixture into our mold. When the mixture hardened, we obtained a translucent and flexible material.
    • Safety Data Sheet of Casting Material: Polyurethane Resin

    For this task, we tested Polyurethane Resin. In Peru, Silicon Peru is the local seller. It is an MDI polyether based polyurethane elast omer. This is a two part polyurethane casting system with a mix ratio of 1:1 and cures at room temperature after 5 minutes.

  • After consulting the datasheet, we move forward with the application of the material, ensuring that we mix it according to the specified proportions and values provided in the documentation.
  • Upon combining the two components, we initiate the stirring process for approximately 30 seconds until the mixture achieves a uniform liquid consistency. This step ensures that the resin test results in the desired outcome by facilitating optimal homogeneity. When the mixture hardened, we obtained a light beige hard material.

    • Conclusions

    Molding materials such as silicone offers a versatile and essential material for mold-making. Its flexibility makes it very easy to remove from the mold, a feature that can be useful for complex molds.

    Casting material like polyurethane resin provides versatile solutions based on their rapid curing, strength, and detail replication, they offer cost-effective and efficient options for manufacturing prototypes, models, and functional components.

    Teamwork and quick action in unexpected situations allowed us to obtain the results for this assignment.

    Group 3:

    Ronal Vilca Apolin Contribution

    For group work, we met through Google Meet with colleagues Wilber and Renso, who are in the city of Pasco. We carry out tests using materials such as wax with the CNC Router and latex for modeling, in order to obtain better results in later stages.SORTA-Clear.

    Alginate Impression Material

    Imagen

    Specifications



    Blue Machinable Wax-1Lb

    Ferris File-A-Wax Blue is a softer wax formulated for excellent flexibility strength. The blue colored wax can be carved in the finest of sections, still retaining excellent details. Good for rounded corners and less intricate designs. Due to the low ash content, this product is ideal for the investment casting process.

    Imagen

    Specifications

    Viscosity at various temperatures

    Imagen

    Physical Properties

    Preparing the 3D design

    In this collaborative project, we used machinable wax to prepare the mold for the positive part, which allowed us to carry out tests with our materials.

    Imagen

    While carrying out some tests, we faced difficulties at first, since it was our first time working with these materials

    imagen
    imagen

    Finding the right consistency turned out to be the most challenging, but we managed to compare results.

    Imagen

    Team testing was necessary and very helpful in finding the right consistency with the SORTA CLEAR material. I will take this into account to carry out the next experiments and works individually.