4. Electronics production¶
Group Assignment:
- [x] characterize the design rules for your in-house PCB production process
Individual assignment:
- [x] make and test a microcontroller development board
- [x] extra credit: personalize the board
- [x] extra credit: make it with another process
Group Assignment¶
This is the first time I have used a small CNC machine to make circuit boards. Although I understand the process of making PCB boards, it is the first time I make it myself, which makes me very excited.
Here is the destop CNC machine in our lab. Before start cutting something, we need to learn more fro the guide book about the cutting setting and knief selecting.
Here is machine website. http://www.jingyan-tech.com/en/html/product/10.html
Through the operation manual, we learned about the relevant parameters of the machine, especially a brief introduction to the subsequent tool selection and operation debugging.
Specification of the CNC destop machine¶
1. Brand Name: Jingyan
2. Machine Item: 3020-300/800W
3. Countertop Size: 240x440mm
4. Effective Stroke: 300x200x100mm
5. Overall Dimensions: 450x550x520mm
6. Spindle Power: air-cooled 300W/water-cooled 800W
7. Spindle Speed: 12000/24000RPM
8. Chuck Size: 1.5KW and below models are suitable for ER11 1-1MM clip
9. Stepper Motor: Type 57 3A
10. Sliding Unit: The X and Y axes use 16 chrome-plated optical axes, and the Z-axis uses 12 chrome-plated optical axes.
11. Transmission Unit: 1605 ball screw
12. Limit Switches: a total of 6 physical limit switches
13. Machine Accuracy: 0.02-0.05mm
14. Repeat Accuracy: 0.01-0.02mm
15. Processing Speed: 0-3500mm/min
16. Machine Weight: 38/43kg
Machine parts list¶
1. Frame part: work surface + moving processing parts.
2. Control box part: switch, emergency stop switch, indicator light, switching button.
3. Handwheel part: rotating handwheel with scale and damping, X, Y, Z axis buttons, digital buttons, start and stop buttons.
In addition, the entire machine requires a computer to be connected, and the MACH3 software is installed on the computer to set up the machine.
Tool selection and type¶
Finally, in the on-site workshop, we learned about different specifications of cutter heads and parameter setting methods.
There are differnt types of tools as well, including 1/64, 1/32 and V-bits that are mentioned in the class:
The tools that I will used are 0.4mm V-bit and right one is 0.8mm drill.
Traces and Outline cutting are use 0.4mm V-bit.
Drills cutting is use 0.8mm drill.
According to the group assignment requirements, we need to produce the following tool heads to test PCB circuit boards. Under the guidance of our teacher Salman, we used two tool heads for testing, one is a drilling tool head and the other is a milling tool head. , the completed results are as follows.
The following is a comparative test of different effects obtained by using V-bit and drill tools to process the same circuit board. Since the drill’s tools are relatively thin, the depth of processing will not be very deep, but the detail performance will be better.
Find the Zero point before cutting¶
This is the machine we are using and it can be controlled by the computer and a wired remote control:
We use this small nsure the board is been secured. This tool is to make sure the machine zeroing right. Becaus this tool have a sloid height and the machine can detect the tool when the tools is approaching it. The zero point of the X,Y axis will be easy to define. The most important is the Z axis, because it will influence the cutting effects.
Individual Assignment¶
Preparation of CNC cutting¶
Before starting to prepare the circuit board, I need to download the designed PCB files and GBR format production files from the assignment guide.
Then put it into the CopperCAM software. There is two files here for PCB manufacturing, one for layer tracing and one for edge cutting. Because the sample file do not need the drilling so that we dont need to change the knief.
We need to set up the GBR manufacturing file, set the cutter head type and number of contours/offset.
After setting up, input the G code of the manufacturing file into the operation interface of the CNC machine, and you can see that the machine’s travel route has been generated.
There are some parameters on the software:
The position of the cutting tools as it shown with X,Y,Z,A.
The reset posotion button is it shown on the left bottom corner with RED colord in emergency usage.
Start, hold, stop buttons as it shown on the left corner with green,yellow, red colored button.
The right three blanket will be Tool information， Tool cutting route， Main rotation details
There is also a route details shown on the upper right corner.
Making the board¶
After setting the parameters, we need to install and fix a blank PCB board on the machine tool of the CNC machine. Since I set the zero point of the machine manually, I used the machine’s operating rotating wheel to perform various debugging.
Throughout the entire production process, I experienced many failed production and processing results, mainly for the following two reasons:
1. Because the machine has no way to set the Z-axis zero point through the tool module at the end. I can only set the Z-axis zero point for machine processing by manually adjusting the roller and directly observing it with my eyes. This has a great impact on the later processing effect of the board.
2. Because the tool speed of drill cutting is not slowed down when generating NC files, the drill process often fails due to tool breakage.
After many failures with these two main reasons,I continued to debug and finally made it successfully.
Assembling the board¶
Next, I found the corresponding device according to the corresponding component list.
There is also a small episode here. I compared two different switches. Because due to the limitation of the soldering position, I finally chose the red switch for welding. The final product is as follows.
Soldering components has been a rewarding skill to develop. Starting with setting up a clean, well-ventilated workspace, I learned to gather the necessary tools: a soldering iron, solder wire, stand, and cleaning sponge. Heating the joint and applying solder became more intuitive with practice, focusing on creating smooth connections without excess solder.
One key technique I learned is to heat the joint with the soldering iron tip and apply solder to the joint directly, not to the iron itself. This ensures the solder flows evenly and forms a reliable connection. It’s important to avoid overheating components, especially sensitive ones like integrated circuits, by keeping the iron in contact for the shortest time necessary.
I found that practicing on scrap pieces helped build my confidence before tackling actual projects. Safety precautions, like wearing safety glasses and ensuring good ventilation, became second nature. After soldering each joint, I carefully inspected for any solder bridges (unintended connections between adjacent pads) or cold joints (dull or grainy solder joints) to ensure reliability.
Through this process, I’ve not only improved my soldering technique but also gained a deeper appreciation for the precision and patience required in electronics work. It’s a skill that continues to serve me well as I pursue various electronic projects
Tesing the board¶
For the final board, I first measured it with an electric meter to confirm that there was no short circuit on the board, and then connected it to the computer for a power-on test. When I saw the power light on, I burned the program and pressed the button to see that the indicator light changed.
