12. Molding and casting¶
THIS WEEK CHECKLIST:¶
- [✓] Linked to the group assignment page
- [✓] Reviewed the safety data sheets for each of your molding and casting materials, then made and compared test casts with each of them
- [✓] Documented how you designed your 3D mould and created your rough and finish toolpaths for machining, including machine settings
- [✓] Shown how you made your mould and cast the parts
- [✓] Described problems and how you fixed them
- [✓] Included your design files and ‘hero shot’ of the mould and the final object
Group assignment¶
This time, I work with my groupmates together to review the safety data sheets for each of your molding and casting materials and make and compare test casts with each of them. CLICK HERE for the detailing of group assignment page.
Individual assignment¶
- Design a 3D mould around the stock and tooling that you’ll be using, mill it (rough cut + (at least) three-axis finish cut), and use it to cast parts.
Mold Design in Fusion360¶
This time, I sketch my one of my favourite cartoon in Fusion 360.
New CNC Machine Operation¶
This time, we used our new CNC machine for milling our mould. This is TigerCNC from China (Left Photo). For the right photo, it operated with mobile vacuum cleaner for clearning.
We decide to use Corn End mill for milling becuase it mill fine during the round edge.
Setting the origins basic on your CNC Machine setting. Since my CNC machine the origins position is left top concer, so I need to chage a setting in Fusion 360 either.
Setting for milling PCB will be different between milling 3D object, so I decide to mill in rigif Form first. After the testing mill result is good, it use machinable wax to mill it again.
Click Milling ->> Set Up –> Create NC Code for generating the file and before milling.
Each time click one tick on adaptive to generate the NC Code for milling. For using 3mm mill bit, it is for rough cut .For using 2mm mill bit, it is for finish cut.
Before milling your object, we should use the simulate function to check the milling route is that correct. You can click on Action –> simulate.
Since the first milling did not use the simulate function, so the last 5 minutes route is milling out the object eye and eyebrow suddenly. Therefore, it reminds me to check route before starting mill the object. For second milling, it keeps eye and eyebrow in the obejct. However, the eye and eyebrow seems too close. I go back to design and make more space between eye and eyebrow.
After having a test on Rigid Foam, it times to mill on machinable wax. Machinable wax is an extremely hard wax with a high melt point that has been formulated to deliver exceptional machining properties with high resolution detail.
For the first milling on machinable wax, the eye and eyebrow much more clear separation. However, I forgot to add holes in the corner for fastened 2 sides during casting process. Therefore, the second milling on machinable wax shows holes in the corner.
Molding¶
This time, I used AB Liquid Silicone for making the mold of my object.
Since I making the mold with Lydia together, so we decide to add more AB Liquid Silicone. But the most important part is he weight of Liquid Silicone A and B must be the same. We put 82g of Liquid Silicone A and B seperately. Also, each time need to use 3 different cups for measuring and mixing up.
These are the process after using needle to inject the mixing up Liquid Silicone ((Silicone A + B =C)). Normally, it takes 2 days for drying complately.
After 48 hours (2 days), the mold complately dry out and take it out. However, when I take out the mold, one of the air hole is broken and still connected to the mold. Next time, I need to add thicker to the air hole becuase it is too easy to broken during the taking out process.
Casting¶
During the casting process, I doing with Lydia and German. We are decide to do Hand made soap Thanks for Lydia to prepare all ingredients. There are some ingredients need to prepare, Sodium hydroxide, Calendula Oil and water. Using Calendula Oil is good for sensitive skin and most of the skin care product also using Calendula as a main ingredients.
Remember, waering glove during the whole process.
First, the scale of Sodium hydroxide and water is 2:1. During the mix up, they become hot, so we need to use paper cup of mixing up.
Second, the scale of water and Calendula Oil is 1:3.
Thrid, using needle to inject in the mold.
Fourth, using rubber band and acrylic to fasten steady during casting.
Here is the results of the casting. More drying time the result will much more better.
Here is my hero shot of the casting.
Next time, I prefer my molding can be deeper, so that the hand made soap outlook will be better.