Electronics Production¶
WELCOME TO WEEK 8 ASSIGNMENT
In this week I learned how to produce a file that can be used in a PCB milling machine and learned how to mill and solder a PCB.
- The Machine: Roland MonoFab SRM20
- Design Software: Eagle
- NC Software: www.modsprojects.org
- Machine Software: Roland V panel for SRM20
- File Download: Schematic and Board design
After designing our circuit board on EAGLE (Follow assignment week 6 for details)
Step1: Draw a rectangle around your circuit board with the layer “48document”, rectangle must be at least .8mm wider than circuit.
Step2 Select all used layers and hide them except for Top Layer and Dimension Layer.
Step 3 File > Export > Image (Resolution:500, area: full, Monochrome) and save as: …_Traces.
Step 4 Unselect All Layers except for layer dimension, File > Export > Image (Save as:.._Cut)
Step 5 Open (Traces) image with gimp or photoshop, color black area with white.
Generating the PNG files to use them to calculate tool path for the milling machine. therefore we need two PNG files, one for the traces and another one for the cut files.
image No.4 is the traces file & image no.5 is the cut file.
modsprojetc.org¶
It is the program that calculates path of the machine (to provide the NC File - Numerical Control)
Step 6 Open www.modsproject.org > right click > programs > open program > Roland > SRM20 mill PCB. (check if dimensions from Eagle matching dimensions on modproject.org)
Step 7 Insert PNG file of traces and calculate path. I only changed few parameters which is Speed origin (changed from 4 to 3) and offset number (changed from 4 to 1) and chose the End-Mill 1/64in and change speed to 1mm/s.
Step 8 After pressing Calculate, a file with the extension .rml will be automatically save into your downloads folder. this is the file we need to use in the Machine software.
Step 9 Repeat same steps with the cut image file, but make sure to choose the end-mill 1/32in.
NOTE Do not change any of the default numbers in modsproject.org, I made a mistake in changing them the traces were too narrow and the speed was very low. The only numbers to change is the X,Y,Z Origion points to become 0,0,0
This is a preview of the file that was calculated through modprojects.org
Milling the PCB¶
NOTE never touch your board with your fingers, it will cause your board to oxidize with time. you can wash it with soap and water before starting your milling.
Step 1 Clean your machine and prepare your copper board by sticking double-sided tape equally and without any overlaps at the back of your copper board.
Step 2 Add the correct end-mill - insert it fully into the collet except for the brushed steel head which is the tiny pyramid part.
Step 3 We have to calibrate our X,Y,Z machine coordinates. X,Y coordinates can be determined according to where we placed our copper board visually. Z coordinate can be determined with the following steps: 1- bring your end mill as close as possible to the board 2- unscrew the collet while slightly holding your endmill and release it to fall on copper bed. 3- press Z on your software so that machine would know this is your Z coordinate.
Step 4 Press cut > add the right traces.rml file > ok. the machine will start milling the traces, aftr job is done replace the end-mill with the cut endmill following the previous steps and choose the cut.rml file.
Soldering my PCB¶
- Prepare all your soldering props on a clean surface.
- make sure your sponge is wet.
- Hang your PCB on the third arm (much easier) and turn on a light above, clean your solder iron through burning some wire and then wiping it with the sponge. we need a shiny tip!
- if your solder wire contains led (read on your datasheet) make sure you turn on the vacuum so you wouldn’t enhale all the toxic fumes.
- deposit small amount of solder on one copper pad, then weld the diagonal leg or the far one, then reheat the first solder and add an enough amount of solder.
- If you have excess amount of soldering, use soldering bread wire(copper wire) by pushing the bread wire into the pad while heating it, you will se the soldering will move to the copper wire.
- I found out that soldering in a diagonal position makes it much easier.
- I couldn’t get used to rotating my solder iron but it is the right way of soldering.
Coding¶
I programed my circuit read distance from distance sensor HC-SR04 Ultrasonic.
Board: DO IT ESP32 devkit
/* Example code for HC-SR04 ultrasonic distance sensor with Arduino. No library required. More info: https://www.makerguides.com */
// Define Trig and Echo pin:
#define trigPin 5
#define echoPin 18
// Define variables:
long duration;
int distance;
void setup() {
// Define inputs and outputs:
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
//Begin Serial communication at a baudrate of 9600:
Serial.begin(9600);
}
void loop() {
// Clear the trigPin by setting it LOW:
digitalWrite(trigPin, LOW);
delayMicroseconds(5);
// Trigger the sensor by setting the trigPin high for 10 microseconds:
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
// Read the echoPin, pulseIn() returns the duration (length of the pulse) in microseconds:
duration = pulseIn(echoPin, HIGH);
// Calculate the distance:
distance = duration * 0.034 / 2;
// Print the distance on the Serial Monitor (Ctrl+Shift+M):
Serial.print("Distance = ");
Serial.print(distance);
Serial.println(" cm");
delay(50);
}
Group ASSIGNMENT¶
For our group assignment we downloaded these files Cut File & Traces File, using modsprojects.org we generated path tool files and used them in the machine software to mill our test: we concluded that our sacrifice bed is inclide minimum -.06cm at the right side, therefore; Z axis should always be measured at the right side.
We also concluded that thickness on 0.016inch and up (0.4mm) is good milling thickness, and for higher current traces we can make bigger thickness.
Test # two by callibrating the Z axis correctly
