12. Molding & Casting¶

Group Assignment ¶

This week we had to go to an iron foundry and so we decided to make a metal statue of the famous “Moai” stone statue from Easter Island.

And so, before continuing, I must say that before visiting the factory, our classmate Ashot, who owns this factory, gave a presentation on iron casting.

Thank him so much for everything.

So, to begin with, we 3D printed the sculpture. And since in the future we will pour hot metal onto it and with the help of high temperatures the plastic will completely burn out - for this we printed a model that is almost hollow and with thin walls, so that there are no problems in the future.

In general, this method of casting is not practiced at this plant, so how can one conduct an experiment? The method was that we had to make a cast of a complex sculpture with many internal corners and “locks”. And therefore, after pressing, it was impossible to remove the sand mold from the internal locks. And our experiment was like this - to do the pouring without removing pattern, directly onto the plastic - and we hoped that due to the high temperature, all the plastic would be burned and iron would be poured instead.

To my surprise, once removed from the sand the result was very good and all surfaces cast well except the bottom, but that’s how it should be since that was our pouring area.

Candlestick¶

So I thought for a long time what to do this week, since my original idea about the final project changed. But it so happened that one of my friends, who produces handmade candles, asked me to make a mold for a candlestick for her.

Design¶

And so I started designing, first I made a model of a candlestick,

then based on this I designed a silicone mold,

and since it was initially impossible to make it from silicone, I also designed a mold for silicone, which I will print on a 3D printer.

Mold’s 3D Printing¶

I then sliced it using the Cura slicer and printed it.The print came out good on the first try. So I have a 4 piece mold.

Casting of Silicone Mold¶

Then I started the process of casting the mold with silicone. For casting I used BEST MOLD 10 silicone with the highest elasticity So, to use this silicone, you need to mix component A with component B in a ratio of 100 to 2.

Safety¶

Before starting work, I read the instructions, unfortunately they are written in Russian, I will write a section about safety here for convenience.

Use personal protective equipment and gloves. Work with adequate ventilation. Wear safety glasses, vinyl gloves, long sleeves to minimize the risk of skin contact. Contact with skin and eyes may cause irritation. If in eyes rinse with water for 15 minutes and seek medical attention immediately. In case of contact with skin, remove material with a dry cloth, and then wash with soap and water. If irritated, seek medical attention. Eating is prohibited. Keep out of reach of children.

Conclusion¶

In general, you saw the result. It didn’t work out very well for me because this mold is intended for silicone of lower viscosity, you can pour liquid plastic into it and it will work perfectly. And with this material you need to either leave thicker walls with larger holes for pouring or use another technique for pouring, for example indentation. In the future, I will design a new mold more convenient for silicone.

Jewelry¶

Design¶

Mold Milling- from Wax¶

Toolpath Creating¶

I created the toolpaths in Fusion 360.

Rough Milling

FInal milling

In final cutting I used the 1/8” 4 Flute Solid Carbide Ball Nose Long for flat surfaces.

And for small rounded surfaces i use the 1/32” 2 Flute Solid Carbide Ball Nose

Mold’s Casting- from Silicone¶

So, we already have a wax mold and in order to fill it with silicone and not waste a lot of material, I decided to measure the volume using water. As you can see in this picture.

Once I knew how much material I needed to use, I used a scale and a syringe to measure the composition of the two-part silicone 100 to 2 and thoroughly mixed the two components.

As you can see in this picture I insert toothpicks into the mold before casting. Little bit about glaciers. At the design stage I realized that my part was very fragile and did not want to add glaciers. Because these glaciers would either spoil the appearance of the final product or were also very fragile and they would be breake during milling, and so I decided to use toothpicks as glaciers.

Final casting - From liquid plastic.¶

Safety¶

Before I started, I also read the instructions for the plastic, which is the same as for the silicone.

Use personal protective equipment and gloves. Work with adequate ventilation. Wear safety glasses, vinyl gloves, long sleeves to minimize the risk of skin contact. Contact with skin and eyes may cause irritation. If in the eyes rinse with water for 15 minutes and seek immediate medical attention. In case of contact with skin, remove material with a dry cloth, and then wash with soap and water. If irritation occurs, seek medical attention. Eating is prohibited. Keep out of the reach of children.

Casting - From Wax.¶

So this wax had a large shrinkage and this was visible with the first pour, about five percent. The second attempt was more successful because I not only put wax into it, but also pressed it with the second mold.