Molding & Casting

ASSIGNMENT

Individual Assignemnt

Design a 3D mold around the stock and tooling that you’ll be using, machine it, and use it to cast parts.

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.

Individual Assignement

WORK FLOW

The first operation, after the descriptive sketches of the idea to be developed, was the realization with Fusion 360 of the project: a medallion with a face in which is represented the upper part of a bison (symbol of my person and personality) and a face with the FLA logo (F for Fab, L for Lab, A for Academy) with the letters rotated to give more prominence.

SKETCH 1 SKETCH 2

3D Vision of The Project

Once the three-dimensional medallion has been reconstructed, first in positive and then in negative, and once the images are successful, it is necessary to move on to the phase of making the mould.

Draws by A.Fusion 360

I preferred to find a particular solution that required both the use of 3D printers and a more manual & complex work. First of all I printed the entire medallion on a filament printer, after the calibration operations. In order to prevent problems with the polyurethane resin, in 3D filament printing I left a support on one side, basically a cylinder with the function of a "pouring resin channel" and help in drowning the object in the silicone.

Studying The Product

The final product of the Medallion I preferred to make it all together from a resin printer by putting the ribbed medallion and providing some supports that will eventually be removed.

INFROMATION OF THE PROCESS

Once the moulds were finished and I noticed the success, I switched to the moulds with silicone and polyurethane resin. The actual mould will be made with Platinum Silicone because it is a non-toxic, hypoallergenic product (it can come into contact with skin and food), resistant to temperatures ranging from -50° to +400°, with fast hardening.

An Example Of a Result

As said above, to succeed in all the steps in 3D filament printing I created the cylindrical support. Platinum Silicone is a bicomponent: so I mixed about 100 grams of product A with 100 grams of B and mixed it well to amalgamate it. I prepared 2 containers. First container. I poured the silicone in a container not too big, in this liquid I drowned the PLA medal hanging from the top so that it would fall to plumb with the small cylinder that came out a little bit from the surface of the silicone where I put the cable hanging from the top (for safety I added some bolts to make a weight). Once the hardening was finished, I opened one side of the box containing the silicone and made a cut with a cutter to extract the medallion (without damaging the mold too much). Repositioned the mould with the help of scotch, I poured the polyurethane resin I had prepared (liquid prepared in equal parts with resin and hardener) through the casting channel.

EXAMPLE

Chocolate Mould

After 20 minutes, to be sure half an hour, I extracted the final product and removed the excess (cylinder). Second container: I repeated the operation with the second container in the same way as before until the silicone mould was filled. Instead of the polyurethane resin this time I poured some dark chocolate (the Platinum Silicone as said is non-toxic) obtaining a "nice and good" medallion .

SWEETY 1

SWEETY 2

REALIZATION

First Step

First of all I resized my locket using the "PRESS-PULL" function, then I turned one of the two faces so that it was straight when you turn the locket and then I joined them using the "COMBINE" function.
After that I built a square solid, I found the halves (the point of origin) of both the medallion and my solid and then I used the "COMBINE" function to integrate my medallion with the solid I built.
Once I did this I found the half of my solid and with the medallion inside it and I separated the two faces making them look like a "book".
When I did this I drew two arches from the middle of the medallion upwards so as to create space for the casting.

COMBINE MEDALLION STOCK

Second Step

360° view of the medallion embedded in the base

VISION 360°

Third Step

Tools measurement settings and first cut simulation: base, medallion perimeter and extruded elements (registration keys)
WHAT ARE THE REGISTRATION KEYS?
In a "double-sided" project, on one side there is an EXTRUSION and exactly in its opposite point there is a HOLE; in this way when we go to fit the two elements, they will fit perfectly. Once you have designed the registration keys you have to focus on the "faces" and drawings inside the medallion; to do this I insert the dimensions of my tool that I will measure through the gauge so that the software can make a "real visualization" simulation. After entering the various data, I start the simulation so that I can understand what the final result could be like.

FIRST CUT SIMULATION

Fourth Step

Now only the inner part remains, which is the drawing of the two faces. I will also go there to set all the parameters related to the tools I will have to use. I will do it, as before, measuring them with the gauge and inserting the measurements inside the software so that I can have a simulation as real as possible.

SETTING TOOLS MACHINE

Fifth Step

After having entered all the settings correctly I can and made a "generate" to apply the settings previously entered I can make a PREVIEW of my project so that I can see how it might look like once it is done.

BISON_PREVIEW

WRITTEN_PREVIEW

Visualization of the construction process of the medallion moulds with reference to the rounding of areas of the bas-relief: this is both for aesthetic reasons and for the need to strengthen the edges.

Once done "generate" I do a general check-up to see that v and to do so I do a "simulation" for each piece (bison and writing). If everything has been done in the correct way I have to EXPORT the files in nc.-Roland ISO format, format readable by the machine. I don't export the whole file for the part I have to mill but I export the files according to the "tool" I have to use that I have divided in T1 for the coarser parts and T3 for the smallerand more precise parts; so I export for all the files (BISON 1- BISON 2 / WRITE 1-WRITE 2).

TOOLS

BISON 1_EXPORT

BISON 2_EXPORT

Afterthe check-up and exported the files on a USB flash drive I get 1 block of wax that I will then cut in half and get two symmetrical parts that will be the basis of my cutting.

FULL WAX BLOCK

HALF BLOCK OF WAX

I screw my wax blocks on a wooden surface.

FULL WAX BLOCK

HALF BLOCK OF WAX

I Screw the wooden panel with the wax block screwed on top to the machine floor.

READY TO MILL

After preparing the material, I then open the milling program (Roland Vpanel) and change some settings: from "System Coordinates"to G54 and below, from "Set Origin Point" to G54 again.

SETTING THE MACHINE

I then have to set the X-Y axis and the Z axis from the machine based on where I placed them in my project. The X-Y axes I have positioned them in the center of my wax block, while the Z axis I first position it at the height of my wax block, then I position it lower because part of my block has already been cut.

SETTING X-Y-Z AXES

After that I'm going to take the files that I previously saved on my PC folder of the machine and start milling.

Since the cut surpluses remain on the wax block, every now and then I press the "VIEW" button from the machine to pause and remove the surpluses that could damage the engine.

"VIEW" BUTTON

CUT SURPLUSES

CLEANING THE WAX BLOCK

THE RESULT OF THE MACHINE PROCESSING?

The result are two simmetrical blocks of wax where on one side there is the bison and on the other the writing FLA (Fab-LabAcademy).

RESULT

Once I have the two perfect moulds, I proceed to pour the silicone rubber. The result will be a "reverse" mould compared to the wax moulds with which I will later make my medallion.

RESULT

GENERAL INFORMATION ON CASTING

When casting, the most important thing is to AVOID AIR BLOWERS. In order to avoid the formation of bubbles, every time you mix component B with component A, you must mix carefully and slowly, so as to avoid the entry of air into our mix of components (whatever they may be). after stirring carefully for 5-10 minutes, we have to pour our component inside the mould: to do this, we have to pour it in one single point and slowly so that it is distributed all over the mould in a uniform way and avoiding bubbles. This procedure is very important for this type of activity because it ensures that the result is as true and correct as possible.