X: Molding & Casting

I.Sewing&Ironning

Sewing

This is the first time I do something with doing because I used to think that all these jobs are replaced by the machine. Actually I saw my grandma sewing when I was a kid. The sewing machine is very similar but a little different. The most obvious difference is that for the machine we use in class, the needle will keep working up and down as long as your feet are on the paddle. But for the machine in my memory of my childhood, my grandma needed to keep flexing your feet to make the machine keep working, so it’s much more convenient right now. You can see my project of sewing. I want to make a actuator just what the lecturer did during the lecture. It’s not bad but not good as well. I should keep the needle on the trace and sew straight lines next time. They are “beatiful” curves this time.

Ironning

Just as sewing, I also never do ironning before since I have no need. I usually wear sports suit. And when I have need, my mom always help me handle it. There one thing you need to pay attention to is Don’t iron the material directly. I did so that my material just melted directly. Also, because the lab ran out of the material, I didn’t have enough material do make the gasbag. I can only choose to reuse the material that was used before. Because of this reason, I only have limited material so that my gasbag is not big enough to offer pressure to bend the actuator. You can first have a look of my ironning project.

The Actuator

After comining the sewng project and ironing project, I finish my actuator. From the picture below, you can see that it’s full of air but not full enough. As a result, the gasbag just expand the volumn of the actuator instead of bending the actuator. The reason is that normally the gasbag should be a little bigger than the sewing part so that enough gas will provide enough pressure to bend the actuator. But because of the limited resource I have, this is the best I can do. Another choice is that you can just sew again to make your sewing part smaller. I plan to do that at the end of the lab time but I don’t have enough time. It’s theoretical reasonable and correct.

II.Molding&Casting

I’m very interested in this part actually since this is the way to make the iron or bronze weapons in the ancient period. Another reason is that unlike 3D printing which can not do the delicate work like printing small scale of words, the project of molding and casting will retain almost every subtle feature of the object you use for.

Procedures:

1.Mix the silicone with the weighter

2.Suspend the object in cup(You’d better do this because I meet a problem without doing this)

3.Pour silicone in to the cup to make your object submerged, wait for curing, then remove it from the cup

4.Seperate two parts of mold by cutting and tearing

5.Mix and pour plaster casting material

6.Remove the plaster replica and clean it up a bit

O'Brien Cup

Because I want to mold something delicate to see if molding and casting can really retain the little feature, I find a 3D design of O’Brien Cup on the internet. There are a lot of greadt design on the website. Here is the LINK!

You can also just directly DOWNLOAD the file of the object.

I follow the instruction to mold my object. But there is a nuance between my operation and instruction. I don’t suspend the object in the cup! The thing I do is adding some clay to staiblize it. For some of you, it may be OK because your object is dense enough. But for me, I only chose to infull 20 percent when I printed it. As a result, my object is much less denser than the silicone so that it’s buoyant in the silicone. I used to think that it’s because I don’t add enough silicone in the cup. But when I fill the whole cup with the silicone and accidently touch the object with the stirrer, I find that the object is buoying actually. That’s why you can see an upheaval on the picture below. And my silicone doesn’t succeed curing even until finishing the lab time, so I cannot show my project.

The Mold

Summary

Everything I tried in this class were all unfamiliar for me. Some of them are memory for me, and some of them are strangers for me. What I did was to try my best to have a try of everything and know what are them. Although I had some failures in both parts of the class, I got precious experience form it and successfully found the potential solutions of them.

Besides, I made some progress for my final project during this lab time. I did it before so all things I did were successful: soldering of the Arduino NANO, buiding of the circuit for photo transistor, constructing the traffic light. I’ll do more things during next lab time and I’ll document what I did this time in the Final Project Part.