Some time ago, we were testing a STEM related product for kids at a low income school. The purpose of this project was to find out if kids could program using block programming. Another interest was to see how intuitive it was to use a plug and play hardware without much intervention.
The kids really did a good job at expressing their creativity by making fun projects! Due to the success, a newer version of the prototype was developed.
Water-jet machines are a special class of CNCs which use highly pressurized jets of a mixture of water and powdered abrasive, such as garnet. This can be assumed to be similar to Laser Cutters. They can only cut objects in 2 dimensions. However, unlike a laser cutter, the water-jet can cut through thick metals like steel, aluminum, and even carbon nano-fiber sheets!
Here is an example of a circular disc I cut from a steel slab for a funny little project, which uses the delrin from a previous post.
Here is another example of water-jet cutting to make a keychain.
Engraving on metallic surface doesn’t necessarily need an engraving tool. Depending upon the kind of application, the type of tool can be different. For example, when milling PCBs, a engraving tool can be substituted for a flat end mill tool for better accuracy when it comes to having very minute spaces between tracks, pads or holes.
It is not just the size of the tool that matters, but also the type of the tool used. In a previous post, I had used an engraving tool. Here is just an example of how different it looks when a different tool is used to engrave on a aluminum surface. I used a ball end mill, which is used to give effects of curving or filleting on the edges of the object. Spoiler alert: it did not turn out as I wanted it to.
Check out the video; the process is short and quick.
Printed circuit boards (PCB) are used in every electronic device. The PCBs, before they show the circuit itself on the board, they contain a layer of copper deposited on them. This is later removed – etched, to be exact – in the unwanted areas, and become the “connecting wires” within the electronic circuit. These days, milling machines are used to remove the copper accurately so that human errors are minimal.
Of course, if the design itself is flawed, no machine can compensate for that kind of human error.
Before milling machines were invented or, before it was affordable to use milling machines for PCB etching, the process was done using chemicals. It is still done in that way, but not extensively, as the process has a tendency to remove all of the copper if not done carefully.
The video below shows the simplest way to etch a PCB using household Muriatic acid, ferric chloride, and a clothes iron.
So, as previously shown, wood is an excellent material to machine into the desired form. It is possible to mill shapes using the tools of tiny sizes. In this case, a 1/32nd in. endmill. You simply need to be careful about the length of the flute of the tool.
Fusion 360 has a text feature in the model section. By selecting the desired font size, not too small for the endmill tool, and choosing the contour milling in the 2D section, it is possible to make appropriate alpha-numeric shapes onto almost any right kind of piece of material.
Ideally, I would have milled an actual cylindrical piece of object, but i found this weird wooden, plain looking keychain. Just so you know, the shape of the wooden part of the keychain is almost cylindrical. So it is better to select a cylindrical stock to make the CAM file.
Another reason why I milled this keychain was because we used to have an incredibly boring acrylic keychain, badly cut using a laser cutter (and not the one I had milled a while ago).
I’m really glad that I was able to fit the logo and all the letters on the keychain!
This was a bit advanced than the previous workshop. The kids used an integrated circuit, the 555 timer. They learnt to operate it in both monostable and astable mode. In the monostable mode, a push button was used to turn an LED on, where as in astable mode, the circuit operated on its own.
Further more, some of them modified the astable circuit to alternatively blink two LEDs. A short video summary of the workshop is below:
So, the second Project Spark workshop was on basic electronics. It was conducted on January 21st 2018. The kids learnt things such as Ohm’s law and it’s application in building simple circuits.
They also learnt about special types of resistors, such as light dependent resistor and potentiometer, and also about the bipolar junction transistor. They built a circuit to control the brightness of LEDs using these elements.
Although, it sounds like someone’s name, Delrin is actually the name of a plastic brand. The plastic itself is called polyoxymethylene, which happens to be a thermoplastic. It is relatively soft when you compare with metals and wood, however, tougher than ABS, making it an excellent machining material. Ever seen a white colored gear? It is made of delrin. The plastic can also be used to make other objects like handles, guitar plectrums, toys, machine parts etc.
I was working on a CNC based project, and has to mill parts for the final product. In this post, there are only two milled caps. I will make another post on the giant flower-shaped hole in the middle, and the completed project in the future. So, for now, there is this video with royalty free YouTube music and some background noise. The video below shows the milling of delrin, using the circular milling method.
Some time ago, we were testing the biggest laser cutter, the universal, which has a bed size of 2 ft. X 4 ft. We wanted to do an interactive project for little children to play at the New York Makerfaire.
A map of Downtown Brooklyn and Lower Manhattan with some of the most iconic buildings and monuments was decided to be the best choice. The children would press the monuments and a display would show the actual photo and a brief description of it.
But before making the actual prototype, we decided to test it out on a test piece of acrylic. It came out pretty good.
Here is the video of the test:
On November 5th, we had a Mars Lander developing workshop. Of course, we were not actually going to build a lander, but use the concepts to build something which can be dropped from the 4th floor (5th for the Americans) of a building. With 18 participating kids between the age of 10 and 13, grouped into 6 teams.
At the end of the workshop, the kids learned about using fundamental concepts of physics and creative thinking to develop a surround structure of a fragile payload. The payload was a light bulb wrapped inside a plastic covering. Each team had the opportunity to build a prototype which had to use at least two of these concepts:
Ultimately any combination of these had to be use, with making sure that the total weight of the prototype including the payload is the least. The kids were given only a selection of prototyping materials: masking tape, ice cream sticks, plastic straws, balloons, thread, plastic bags, papers, and barbecue skewers.
The great thing is that we had also built a structure. the tetrahedral pyramid using straws and showed the kids when we began testing all the
prototypes. All 6 prototypes were tested, and none of them broke when thrown from the height. Below are the 6 teams with the prototypes, and after that, the testing video.
