Written by Tudor Dochia
Hello, my name is Tudor Dochia. I am a 17-year-old high school student from Romania, and I have a deep passion for mechanical and electrical engineering. I like participating in inventics competitions, where I represent my country at an international level and present my work.
I have made a lot of different projects for these kinds of competitions, but this year I invented a complete solution for PCB assembly, which combines the three main processes of assembling circuit boards into one device. Along with my team, we developed a prototype for a national competition, at which we won first place, giving us the opportunity to go to the biggest inventics competition in Europe, the EU Contest for Young Scientists (EUCYS).
Because of the scale of this competition, we needed to improve our prototype. One of our main goals with this project is to make it as affordable and compact as possible to lower the monetary barrier for start-ups that need to produce printed circuit boards. One of the most efficient ways of reducing costs is by having access to more diverse methods of manufacturing the parts required to build the project.
We have access to a 3D printer, but the speed of additive manufacturing is pretty slow compared to other processes, and we thought about CNC machining for some of the parts. This is where the kind people at Saintsmart sent us the 4040 RENO CNC for us to use. I had very limited experience in CNC machining before, having used a cheap no-name 3018 CNC before, and I was expecting to have a lot of difficulty machining the parts required.
After the machine came to my door, the unboxing experience was very pleasant. Everything was packed very well and arrived without any damage. The machine was split up into separate assemblies for all axis. The assembly manual that came in the box was very easy to understand, and it took me less than an hour to assemble the machine.
The final assembled machine
After assembly, I started tramming the spoilboard. I generated the gcode necessary using a program called KIRI:MOTO, a free web-based gcode generator, and used the program provided on the USB stick that came with the machine to send the commands to the machine. After tramming, I started testing. I ordered some cutting bits online, so before that, I engraved some plastic I had lying around using the provided engraving bits. I started engraving the Saintsmart logo, and the process generated a lot of chips, so I recommend having a vacuum cleaner or having a dust shoe on the machine to contain it. The engraving process worked great, and the final result was very precise and looked very smooth.
A snippet of the machining procces for the Saintsmart logo
After the cutting bits arrived, I started cutting some plates for the feeders that we use in our projects. This is one of the main reasons we wanted a CNC machine instead of using 3D printing. These plates are large flat objects that can take 1 and a half hours to make on a 3D printer but take 10 minutes to produce on a CNC machine. This is one of the most important aspects of our project: being able to produce the parts with less cost and quicker. We bought some semi-transparent cast acrylic for cutting and used a 2 flute 3.175mm bit at a 0.5mm depth per peass and 800mm/s feedrape at 10000 RPM. This time, we used Fusion 360 to make the programs because it offered us more options. One of the best aspects of this machine is its upgradability. The machine is built in such a way that swapping applications is very easy. We tried to swap the spindle that comes with the machine for a Dremel, and it fit perfectly in the holder that came with the machine. The cutting went smoothly, and no bits were broken. In the end, the cover fitted perfectly on the feeder, and it looked very good.
The full machining procces for the feeder cover
The final part mounted on the feeder
In conclusion, the 4040 RENO CNC is a perfect budget friendly CNC for beginners in the hobby and has helped us a lot in streamlining the production of our project, and will help us develop a lot in the future. This machine has also helped us better understand the processes involved in manufacturing commercial products and helped us improve our project.
