Danny Choo
The Making of Smart Doll
Soft Vinyl Mold Preparation
Continuing on from the previous section, now we look at how the molds are made for the soft vinyl outer shell.
1. Taking the 3D printouts of the body parts in the previous section, the next step is to make silicone molds which we will then use to make wax duplicates of the pieces. We then tie the two pieces of mold back together again and then pour in some hot wax.
2. Once the wax has cured, we can remove it from the silicon mold. Notice the wrist has a funnel attached - this is to enable us to pour in the soft vinyl when this eventually becomes a mold.
3. As soon as the wax copy is taken out of the silicone, the surfaces are rough and need to be polished down - if there are blemishes on the wax then it will end up being in the mold meaning anything made from the mold will also inherit blemishes.
4. Next up is preparing to make the wax copy into a mold and this is done in a process called Electroforming. Each part is first sprayed with graphite-based ink that makes it electrically conductive.
5. Each piece is has copper wire tied to it and hugh up to dry.
6. The wax copy is then dipped into an electrolytic bath. Deposits of copper then build up on the conductive surface to replicate the surface atom by atom.
7. Depending on the size of the wax piece, it can take a week for the copper to build up - this is the end result after the wax inside has been melted and poured away.
8. The copper molds are then welded on to a plate of metal called a "Frypan."
9. We currently only have one set of molds but discovered that we need to increase our mold count as we can't keep up with demands with this single set ><
10. The manufacturing process used to mold the body shell is called "Slush Casting." Here liquid vinyl is poured into one of the molds. The vinyl we use is the same material as other soft vinyl dolls on the market and does not pose any general risk to human health unless you eat or suck it - no sucking!
11. When the liquid vinyl is poured into the copper molds, air pockets get trapped in the liquid which must be removed - we do that by using a centrifugal separator which spins round for 30 seconds or so.
12. Even still, air pockets may be stubborn so they need to be removed using brute force - introducing a deaerator which removes all trace of oxygen from inside the chamber where the mold is placed.
13. The mold is the placed in a bath of oil which has been heated up to about 180 - 190 Celsius. The thickness of the doll piece is determined by how long you leave the mold in the oil. The heat penetrates through the mold and heats up the vinyl closest to the inner wall of the mold.
14. The copper mold is then placed into a cold water bath to cool down.
15. Next we need to pull the part out of the mold - pull to early and the part could end up being stretched - pull too late and it could be too hard to pull out or end up being damaged.
16. The mold has hoops attached - a slight change in the angle of the hoops affects the quality of the pull.
17. And this a hand freshly pulled from the mold - we then need to cut off the flash which is the funnel attached to it.
18. Together with the boss of mold maker Kamijo who have won awards for the quality of their molds.
19. This has nothing to do with soft vinyl but wanted to show you how we made the frame prototypes at one stage - we would use 3D printouts and copy them using silicone molds.
20. Some resin frame parts ready to be cut off the runners.
View more at www.dannychoo.com/en/post/27275/The+Making+of+Smart+Doll....
The Making of Smart Doll
Soft Vinyl Mold Preparation
Continuing on from the previous section, now we look at how the molds are made for the soft vinyl outer shell.
1. Taking the 3D printouts of the body parts in the previous section, the next step is to make silicone molds which we will then use to make wax duplicates of the pieces. We then tie the two pieces of mold back together again and then pour in some hot wax.
2. Once the wax has cured, we can remove it from the silicon mold. Notice the wrist has a funnel attached - this is to enable us to pour in the soft vinyl when this eventually becomes a mold.
3. As soon as the wax copy is taken out of the silicone, the surfaces are rough and need to be polished down - if there are blemishes on the wax then it will end up being in the mold meaning anything made from the mold will also inherit blemishes.
4. Next up is preparing to make the wax copy into a mold and this is done in a process called Electroforming. Each part is first sprayed with graphite-based ink that makes it electrically conductive.
5. Each piece is has copper wire tied to it and hugh up to dry.
6. The wax copy is then dipped into an electrolytic bath. Deposits of copper then build up on the conductive surface to replicate the surface atom by atom.
7. Depending on the size of the wax piece, it can take a week for the copper to build up - this is the end result after the wax inside has been melted and poured away.
8. The copper molds are then welded on to a plate of metal called a "Frypan."
9. We currently only have one set of molds but discovered that we need to increase our mold count as we can't keep up with demands with this single set ><
10. The manufacturing process used to mold the body shell is called "Slush Casting." Here liquid vinyl is poured into one of the molds. The vinyl we use is the same material as other soft vinyl dolls on the market and does not pose any general risk to human health unless you eat or suck it - no sucking!
11. When the liquid vinyl is poured into the copper molds, air pockets get trapped in the liquid which must be removed - we do that by using a centrifugal separator which spins round for 30 seconds or so.
12. Even still, air pockets may be stubborn so they need to be removed using brute force - introducing a deaerator which removes all trace of oxygen from inside the chamber where the mold is placed.
13. The mold is the placed in a bath of oil which has been heated up to about 180 - 190 Celsius. The thickness of the doll piece is determined by how long you leave the mold in the oil. The heat penetrates through the mold and heats up the vinyl closest to the inner wall of the mold.
14. The copper mold is then placed into a cold water bath to cool down.
15. Next we need to pull the part out of the mold - pull to early and the part could end up being stretched - pull too late and it could be too hard to pull out or end up being damaged.
16. The mold has hoops attached - a slight change in the angle of the hoops affects the quality of the pull.
17. And this a hand freshly pulled from the mold - we then need to cut off the flash which is the funnel attached to it.
18. Together with the boss of mold maker Kamijo who have won awards for the quality of their molds.
19. This has nothing to do with soft vinyl but wanted to show you how we made the frame prototypes at one stage - we would use 3D printouts and copy them using silicone molds.
20. Some resin frame parts ready to be cut off the runners.
View more at www.dannychoo.com/en/post/27275/The+Making+of+Smart+Doll....