Organization

Here is my organization to finish on time:

LINK TO THE ASSIGNMENT WEEK

Organization Of Week 11
Thursday 18st	Sketching the first drawings of the project to be developed.
Friday 19th	Modeling the project and defining in detail which parts should be shown, better understanding the CNC operation, recognition of components for the mold, etc.
Saturday 20th	Finishing cutting the mold and first impressions, sending it to be cut again!
Monday 22nd	First mold made and first wax test performed!
Tuesday 23th	Documentation and project completion day

WHAT I DEVELOPED IN THE GROUP ASSIGNMENT?

My contribution

Here I will explain my contribution to the group task, about the Data Sheets:

Data Sheets

SILICON OMMO 25 - SMOOTH ON

OOMOO 25 is an easy to use tin cure silicone rubber compound that features a convenient one-to-one by volume mix ratio (no scale necessary). It has a low viscosity for easy mixing and pouring . . . vacuum degassing is not necessary. This product cures at room temperature with negligible shrinkage. OOMOO™ 25 has a 15-minute pot life and 75-minute cure time.

We had a problem with this input, all the batches in our Fab Lab were dry.

SILICON RTV F20 PLUS

RTV silicone consists of a white liquid which is the silicone and the curing agent. The curing time is 4 to 8 hours. It has good tear strength and excellent temperature resistance.

After reading the technical data sheets, we use the material and mix according to the characteristics and values mentioned. Consider the mandatory personal protective equipment for the use of this material.

We proceed to perform the weighing according to the considerations, placing only a % of catalyst, we move and let dry for 8 hours, this is the result, we use as a mold the plastic cup.

The consistency is partially firm, the translucency is at least 80%.

PLATINUM RTV SILICONE HARDNESS 30-1 FOOD

The following silicone, similar to the previous one, also includes 2 mixtures. The main characteristic of silicone is that it is food grade, that is, we can use it to make molds for food, cakes or other types. It has high resistance to high temperatures and tearing.

After reading the data sheets we did our test with the proportion we provided and mixed to obtain the result. Let's remember that the curing time is 5 to 12 hours. In addition, we have to keep in mind that the mixing time is 3 to 5 minutes maximum and then pour into our mold.

First we started measuring the components on a scale to calculate the exact proportions. After waiting the hour recommended by the supplier for the curing time, we were able to get the result. It came out very good, resistant and with better molding compared to the previous one.

The consistency is stronger, heavier, solid and not very flexible, showing a good firmness.

RTV EXTRAFLEX SILICONE RUBBER

The following silicone has extra flexibility that facilitates the removal of the inner mold, it is specifically intended for soaps, candles, among others. It comprises 2 products, silicone and silicone catalyst, which only uses 2% of the total amount of silicone used.

After understanding the proportion of silicone and catalyst as well as other aspects such as the security that we must have. We will proceed to carry out the test in a glass.

First we start by weighing our container for the test and then we do simple calculations to obtain the amount we will need. We can use water to have better precision.

Then we start mixing and moving to have a uniform mixture so that it can be contained in the mold and can enter all the details of the glass on that occasion.

The consistency is flexible, a little softer than the previous one, but equally consistent.

SILICON F10 PLUS

The following RTV F-10 silicone is a flexible silicone used to create flexible molds. It is strong and suitable for making wax, soap and candle molds. Here is the data sheet given to us by the supplier and a summary table of it.

After knowing the curing time and the proportion we have to take into account for the silicone to 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.

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.

Consistency is flexible, with an opacity of 90%, quite firm as a whole.

I leave here the Data Sheets of the silicones used.

SILICON OMMO 25 - SMOOTH ON

SILICON RTV F20 PLUS

PLATINUM RTV SILICONE HARDNESS 30-1 FOOD

RTV EXTRAFLEX SILICONE RUBBER

SILICON F10 PLUS

COMPARATION AND CONCLUSION FOR SILICON TEST

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

WHICH IS WHAT I WILL DO

Part of my final project

As part of my final project I am interested in making a test of the exterior shape, of the ribbed shape, previously I had it already modeled, I leave here the file:

FUSION FINAL PROJECT FILE

3D Printing or Mold?

I started defining what kind of mold I would make, first to transfer from mold to filler, I decided to make one of them in CNC cutting and the other in 3D Printing, to verify differences and similarities and to determine the best result in both cases.

Designing my mold

To define the shape, I started by determining what I wanted to model, in this case the outer shape with holes, so I start modeling in Fusion 360.

First making the superposition of two conical bodies with the intention of STAMPING the holes in the new face and extrude out the final shape!

After that and once the holes have been extruded, I create a solid box that covers the whole body, so that I can then cut it to half the circumference of the body of my shape and extrude inside with solid margins to the sides.

After that we create an outer shape that is a square or cube and add inner offsets to provide the empty area

It got complex

Before arriving at this final shape, I had some difficulties in understanding how the mold worked, so in my first tests I made the mold directly in 3D Printing and in Wax in CNC, without realizing how the milling and 3D printing really worked to give me a non-rigid and easy to demold mold.

Here is the result of the 3D printing as well as the CNC milling result.

I thought that the milled or printed mold could receive the content directly, but that is not the case, thanks to my instructors they were able to help us with it.

Simplifying

Simplistically my model was very easy to model, resulting in no difficulties along the way, other than understanding the main idea of the mold and its contents.

STL FILE MOLD

Making it physical

3D Printing

The import on the printing table was done in STL, we modified the temperature of the nozzle and the base.

To start with 3D printing, I decided to first make a test of the final model, to get to know better the texture and shape of the mold.

I used PLA at 190°C and the model took about 12 hours.

This is the result

Then I print the mold

CNC cutting part 1

To mill my mold in wax, I first checked the inventory:

First, I found 1/8 "Spring Collet needed for the assembly.

Next, I went through all the end mills we have for developing the assigment, where I could see that we have 1/8", 3/32", 1/16" and 1/32" end mills which I thought were all going to be used for the assigment. Here is a picture of all the cutters, I finally used the 1/8" cutter.

CNC cutting part 2

SETUP FOR MILLING WITH CE MODS

To start milling my mold, first we have to make an excavation of our model. To do this we will use the 1/8" router shown in the previous section and here I will begin to show what the MODS.CE setup looks like.

First of all, I chose to use the SHOPBOT and that's why I use the MODS, for the ROUGH part, we choose the MILL 2.5D STL according to the picture.

Next, we load the STL FILE of our model. Click on SELECT STL FILE and open it.

First, in the MILL RASTER 2.5D window, we will change the MILL DIAMETER by the measurement we have in the milling cutter, in this case the 1/8" milling cutter to do the ROUGH work, so I change it to 3.175 which is the measurement in mm

Next we will change the MAX DEPTH setting, which is the maximum height at which MODS CE will remove the layers for cutting. In my case I increased it to 40 mm, but ideally I would like to have the models at less than 30 mm.

We deactivate the "DOWNLOAD" button.

STEPOVER point, the lower the value, the more detailed we will have our mold.

For my mold use the 0.1, in the DIRECTION section we will do it in two axes.

Then we deactivate the download button to have a preview, click on CALCULATE and wait.

Here is a screenshot with the detail at 0.1 with the 1/8" cutter. Patience with the loading of the image. Finally we must verify that the units of our file are compatible with the units of our SHOPBOT.

MILLING ROUG MY MOLD

To begin routing the wax I swapped out the SPRING COLLAR on the SHOPBOT for the 1/8" burs and attached the cutting bur to do the "RUDE" work.

Additionally, it is necessary to secure the wax block on the Shopbot.

Then the Z axis is calibrated and it is verified that the collet is correctly on the cutter.

For the first test, it was quite well detailed, so I started to leave it ready to start the silicone process.

With silicone

SILICON RTV EXTRAFLEX

First I prepared all the supplies I would need, such as the mold, silicone, catalyst, water, scale, and measuring cup.

- To calculate the amount of silicone to use, I did it based on the water in my mold to determine the quantities.

- After measuring them I did the same with the silicone, having a result of 50g.

- To know which catalyst to use, I had to make a formula, with the following result:

- For this case I am going to use 50g of silicone and according to the proportion suggested in the silicone technical sheet, 2%.

- After pouring the catalyst into the silicone, I mix without creating bubbles, slowly.

- Let's remember that we have a maximum of 3 minutes of mixture to pour into my mold

After mixing for the indicated time, I began to pour the wax into the mold, here is a video.

Finally, as a recommendation, you should compact the mixture to eliminate the bubbles generated in the silicone and let it cure.

After approximately 12 hours I unmolded the silicone and it looked very good, with no breakage problems and everything was fine, ready to receive different castings.

CASTING AND COMPARISONS

Here is a photo of two molds, one made with Wax and the other with 3D printing.

Here is a photo making the gelatin to test the mold.

Here is a comparison of both molds