Every single mechanical engineer has to study a subject called mechanics. Some call it MOM, some call it SOM, some call it EM. But whatever you may call it, it's always there and it's always the same. This subject tells us how to decide whether our design will fail or not. And it is a very complex subject. And the bad news is, we only study this until we get familiar with the concept of Simulation. Once you start doing simulations, there is no going back. I had a glimpse of simulation very early in my college life, way before it would have according to my syllabus. And then I got myself involved in another project that made me understand simulation to a very great extend. This was the design and manufacturing of HAWT. Basically, we were trying to make a hybrid wind turbine that can produce electricity safely inside a crowded city. And the very first step included the Fluent based simulations. Actually, the first step was a literature review, but yeah you got the point. So, my s...
CNC machines are the most vital part of Mechanical Engineering. One way or another, we all end up using CNC machines in our projects. Let it be robotics, automobile, prototyping, additive manufacturing, CNC is used everywhere. My first experience with something similar to CNC was the 3D printer. We had an FDM based 3D printer in our college, which was majorly used for research purposes. We had worked on it for some time when we came up with the idea of making our own 3D printer.
We thought of making something less complex before making a 3D printer, something like a 2D printer. So, we decided of making the least complex 2D CNC machine: A Plotter. What it does is simply using a pen to plot whatever the file is provided with on a piece of paper. But making any CNC machine is very complicated. There are many things to take care of, the most important being vibrations. The body of a CNC machine needs to be stiff enough to ensure minimal vibrations. We achieved this by using layers of MDF sheets. Of course, it was not the stiffest structure, but it worked just fine. The whole design was made on Fusion 360 again and again till we reached a design that can be manufactured easily. To do so, we ensured that every single part of our assembly could be laser cut. This ensured very high precision.
Further, we didn't want to come up with a product that is already present in the market. So to ensure our machine was unique, every single component used was ensured to be open source and readily available. From the very micro-controller to motors to the software and the Gcode generator itself, everything was open source. Further, we tested our machine for hundreds of hours to ensure the best possible design. Since we were using laser cutter sheets to make our machine, every single part could be easily replaced with an upgraded design. Thus our design was modular. This modularity also helped us in testing and optimizing every single part of the machine.
Image: Rendered Assembly on Fusion 360.
This machine is the starting point of understanding robotics. Yes, this is not similar to traditional robots, but it works on very similar principles. Further, we have used the open-source software used for 3D printers to drive this machine. This not only helped us in understanding the details about CNC but also 3D printing. The hundreds of hours of testing involved helped us realize the problems associated with both 3D printers and CNC machining, which further helped us in optimizing this machine.
Here are some images of the initial prototype:
The initial prototypes were giving low quality results.
After doing some more iterations on the central assembly, and tweaking with the software, we were able to plot some very fine drawings.
At this point we considered our design to be complete. Installing a Laser would have cost us at least INR 10000 which was way beyond our budget. But after 6 months of Research and Development, we found this design to be very reliable and cost-effective.
Here are some images of the final machine.
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