Molding and casting.


link to design files.


and the link to the group assignment is: FabLabCDMX.


BRIEF

I want to make the Universidad Anáhuac Logo that is an "A" because i want to put it on my Final Project, so, I start looking for a Vectorized image of the "A" logo, but I can´t find it so I decide to retrace the "A" from the Radio Anáhuac Logo in Illustrator, after that I  opened it in Vectorworks to transform this 2D trace into a 3D , then I added it to a cube that will be the mold, the positive. Then I mill the wax cube in the Roland machine to obtain the mold of the A, then I cast silicone to obtain the negative silicon mold and then I cast clear crystal resin to obtain the final "A" logo.
Illustrator, Vectorworks, RhinoCam, silicone, clear crystal resine, catalyst, orange color aditive

I search for the A logo in the web
I download it and opened it in Illustrator
Then I retrace the logo with the line and pen tools.

I export the A as a DWG file and then i opened it in Vectorworks to made the 3D of it. Right now the size of the A doesn´t matter too much right now, later we will adjust that.

I clip the center of the "A" logo with the clip surface function.

Then I perform an extrusion of the "A" logo

This is the size of the available wax portion in the LAB, so I have to adapt my design to that size: 9.2x14.8x3.8 with a free depth of 2.12cm

Then I draw and extrude a square of the measures above in order to make the shape of the wax cube where I´m going to mill the mould of the A.

I scale and put the A inside the cube to see if fits correctly, the size and depth of the this mold is exactly dimensions of the available wax.


I made a fillet in all the edges of the mold including the A to avoid problems to demold the silicon.

Now we are going to open the 3D file into RhinoCam to do the setup before milling

Choosing what operation we are ging to do, in this case MILL

Placing the 3D object.

setting the size of the cube 90x90x38mm





In the MILL menu we choose parallel finish, this is the initial path that the tool will do



Choosing the tooling properties of a straight flute tooling

and setting the dia. of the tooling in 3.125mm.



Settings: rotation 18000RPM durection CW, PLUNGE 12000 mm/min, Approach 7000 mm/min, Engage 4000 mm/min, Cut 2000 mm/min, Retract 4000 mm/min, and Departure 12000mm /min.

the setup of the final finish, you can see here that the tool is going to move in the Z direction steps no more of the 50% of the tool diameter.

Generating the GCODE


Preparing the last settings to start the milling process



Here we need to establish the area and depth to prepare the surface to level it

Creating the path of the tool to follow

Everything ready

Checking the correct hold of the wax cube in to the Roland machine and being sure that is leveled

Starting the milling process
Milling the last details of the process

The milling process finished.

Now that I have my positive mold I need to pour silicon to made the negative mold,but, how silicon do I need to prepare? one option is to pour water into the cavity so I can see the exact amount of silicon I will need.

I´m going to use this Smooth-On urethane rubber to made the negative mold. We need to mix Part A with part B in a mix ratio of 2A:1B by Weight

Instructions and safety data sheet.

Here I mix and pour the urethane rubber into the mould and then we have to wait almost 16hours to cure

Here I mix and pour the urethane rubber into the mould and then we have to wait almost 16hours to cure





Just perfect.

And now it´s time to mix the cristal clear resine with orange color aditive and the catalyst. The amount of catalyst is 40drops for 100gr of resin PP cristal, this can vary depending of the size of the final piece, weather and aditive if you use it.

Mixing the crystal clear resin with orange aditive, check that the color is uniform, and without bubbles.

The resin waiting to cure in the urethan rubber mold, just wait, be patience, more less 72hrs before it´s completely cure.

The final piece, the A logo of the university.



the green spot

a place to re-connect