For the group assignment, with Michel and Jonas, we chose three different materials from Smooth-On, each with different characteristics to see the difference. The group assignment can be found here.

To create a mold, I'll try two different techniques, the first one is using a FormBox and the second one using a 3D piece.

1. FormBox

   The FormBox by Mayku is a machine that will suck the air of a hot plastic sheet to create a mold of a model really easily.

   

   The machine has a hole at its base where a vacuum cleaner is connected and will suck the air out of.

   

   The mold is made of a simple plastic sheet by the same manufacturer of the FormBox, its parameters and instructions at the back are important to configure the FormBox.

   
   

   I first place the sheet on the first plate of the FormBox.

   

   Then pull down the second plate to lock the sheet on place and connect the two plates together.

   

   Then, I pull the two plates up so they are close to the warm parts of the FormBox (located on the top).

   

   Here, I configure the FormBox with the correct parameters, in this case, I put the heat to 6 and I don't need to touch the timer.

   

   Now, I just wait for the plastic sheet to be soft (becomes curved) like the instructions at the back of the plastic sheets box says.

   

   Finally, I can put my model at the base, turn the vacuum cleaner on and pull the two plates down to create the mold and wait a few seconds.

   

   (Assembly I found on Patrick's desk)

   

   Here's the final result :

   
   

2. 3D

   I'll make the 3D mold with autodesk Fusion and a model found online.

   The model I chose is from Thingiverse by Krashl, it comes from a video game I love called The Binding Of Isaac.

   To create the mold, I'll insert the model in Fusion, modify it, put it inside a square and do a difference to only have the square with a hole of the model inside and finally add a hole for the cast material to go through and split it in two to facilitate its removing.

   I first insert the STL model in Fusion : SOLID ➜ INSERT ➜ Insert Mesh.

   

   Since the original model is a bit too big, I'll scale it by half : MESH ➜ MODIFY ➜ Scale Mesh ➜ Scale Factor : 0.5.

   

   Since the original model also has too many faces, I'll reduce them : MESH ➜ MODIFY ➜ Reduce ➜ Face Count : 5000.

   

   I can now convert the mesh into something I can modify : MESH ➜ MODIFY ➜ Convert Mesh.

   
   

   Now, I draw a square around my model that will serve as a mold.

   

   I extrude the square above and under.

   

   I now do the difference to have a square with a hole of the model : SOLID ➜ MODIFY ➜ Combine ➜ Target Body : Square ➜ Tool Bodies : Model ➜ Operation : Cut.

   

   I do a hole on top where the cast material will be poured into.

   
   

   To split the model in two, I first have to create a plane in the middle of the square : SOLID ➜ CONSTRUCT ➜ Midplane ➜ Select parallel planes.

   

   Then, to split the model in two : SOLID ➜ MODIFY ➜ Split Body ➜ Body to Split : Square ➜ Splitting Tool(s) : Plane.

   

   I then modify the position of one of the bodies to show that we have two bodies now.

   

   Here's the result in Bambu Studio :

   

   Here's the result after printing :

   

I'll try 3 different materials to make casts.

1. Smooth-Cast 305 with FormBox mold

   Smooth-On is a manufacturer that proposes various molding and casting materials, each with different characteristics.

   I'll try their Smooth-Cast 305 material which is easy to mix, virtually bubble free and has a big hardness.

   Its datasheet contains more characteristics as well as recommendations for mixing, usage and safety.

   

   The package contain 2 bottles : Part A and Part B, I simply have to mix them together with the correct ratio and pour the solution in a mold.

   

   The first test will be made with the mold I made with the FormBox.

   

   To mix with the correct ratio, I use a measuring cup filled with water, the datasheet explains I need a ratio of 100A:90B.

   

   Here's a video of me mixing the bottles content together and pouring it into the mold :

   (Video speed : x2)

   Now that the solution is poured into the mold, the datasheet explains I have to wait 30 minutes for the cure to be done but just to be sure, I waited 1 hour before recovering the cast.

   
   

   I forgot to apply a release agent to facilitate demolding which took some time to remove the cast.

   

   The result is a hard cast with a look close to the original model :

   

2. Smooth-Cast 305 with 3D mold

   For this test, I'll try the same material but with the 3D mold I made.

   This time, I'll apply a release agent to easily remove the cast.

   
   
   

   Now, I find a way to fix my mold on the spot and pour the solution through the hole.

   

   At some point, my cast had a weird chemical reaction but nothing to worry about.

   

   After ~1 hour, I open the mold with a screwdriver and a hammer and it opens up really easily.

   

   The cast looks good but a bit weird and deteriorated, I'm not exactly sure why, maybe I should have waited for the release agent to dry a bit.

   
   

3. Plaster

   I'll try a different material and manufacturer this time, it is plaster by Gédéo and I'll use the 3D mold again.

   
   

   (Instructions)

   I use a spoon to fill the mold to know the quantity of plaster I need.

   

   Once everything is ready, I can mix, stir and pour.

   
   

   For this material, I had to wait 1 hour for the cure. The first mold piece was easy to take off but the second one slightly damaged the cast. Also, from the look of it, I didn't add enough plaster or my weighting was wrong.

   
   
   

4. SORTA-Clear 37 with 3D mold

   Let's go back to Smooth-On's products, this time, I'll try a more flexible and soft material, the SORTA-Clear 37 (datasheet).

   

   I know, due to our group assignment, that this material is transparent so I decided to add glitter to add a nice effect and coloring.

   

   Since the solution is more rubbery than the previous ones, pouring it through the hole was a bit hard and led to a messy workspace.

   

   For this material, I had to wait 4 hours for the cure to finish. It was really easy to remove the cast from the mold.

   
   

1. Smooth-Cast 305 material

   The datasheet explains I should use a release agent before pouring the solution to facilitate demolding, I forgot to apply it which took longer and a bit of pain to remove the cast.

   

   I struggled and used many tools to remove the cast from the mold, I even damaged the cast a bit but managed to take the rest of the plastic sheet that was stuck.

   

2. Solutions ratio

   For the tests with the plaster and the SORTA-Clear 37, the casts were missing their top which means I didn't add enough of the solution in the mold, probably a weighting error.

   

1. 3D mold (Autodesk Fusion)