PCB Fabrication Using Mini CNC Milling with Step by Step Guide

PCB Fabrication Using CNC milling

 
Introduction

If you want to make PCB Fabrication yourself there are two ways to do it. The first method is the Etching method this process is laborious and involves messy chemicals and specially sensitized PCB’s. It is a bit difficult to use. But another method is easy to use. You can make many PCB once you have generated G Code in this method.

 We are using Mini CNC Milling. You can use any CNC router you want the CNC router. I have been using was Saint Smart CNC router. You can also buy CNC Router at Xbotics if you don’t have one for you. Click here to buy at Xbotics. To get more knowledge about PCB fabrication, you can also attend workshop at Avian Workshops

Hardware for PCB Fabrication

 

CNC Machine:

Due to technology improvement nowadays a bigger size CNC machine comes down to a smaller size machine. Also the price of the machine also comes down. I have given a link to one of the cheap CNC machines. Not only u can do PCB engraving in the machine, you can also use the machine to engrave Laser. Also it can also use to cut wood material. 

Tool Bit

The machine ready, we need to get the right tools for PCB Fabrication. The most important of these is the engraving bit. It is responsible for engraving all the actual traces onto the PCB. This bit needs to be sharp so it cuts as opposed to tearing the copper. Also it needs to be fine enough to mill any tiny footprints or traces.

With many experiments, we can use 0.1 mm v bit for milling the PCB. For drilling the holes in PCB, we need to use drilling bit. So you can use 0.8 – 1 mm drilling bit for drilling holes in PCB. To cut the outer layer of the board we are going to use the 1mm end milling bit. You can use same bit for drilling also that’s your choice. But don’t use drilling bit to cut the outer part it will break the bit.

PCB Copper Board

Now we are ready with the machine and drill bit. To engrave the PCB, now what we need is the board. Where we are going to do the engraving a single side copper clad PCB. I have bought it from Xbotics. Click here to buy PCB Copper board if you don’t have.

Spanner

After everything ready set we need tools to remove and attach the bit to the machine for that we need either plyer or spanner for that with that we have all the components

Software for PCB Fabrication

 

There are two software we need for PCB Fabrication. The first software is Flat Cam we are using this software to generate the G-code. We need it for the CNC machine. As you all know from the PCB design software we can only get the GERBER file. You can use any software to generate G-Code here we are using a flat cam to generate G-Code. Here the link you can download Flatcam software.

The next software we are going to need is a software to control the CNC machine. We are going to use Saint Smart own software. Click here to download software and drivers.

G code Generating

 

We are going to see how to convert Gerber file into CNC G-Code 

Steps:

  • First open flat cam software
  • Go to the bottom of the window were you can find a terminal kind of window there type the following command ”set_sys excellon_zeros T” and press enter. You can see in fig 2.1

Fig 2.1

  • Go to file and choose Gerber file and select the layer you want first bottom layer You can see in fig 2.2

Fig 2.2

  • Select the file and go to option change Application default to project option then change inch to mm. You can see in fig 2.3

Fig 2.3

  • Go to selected change appropriate value for Tool dia and width then generate geometry. You can see in fig 2.4

Fig 2.4

  • Select the new file that is generated and change cut Z, travel Z, Feed rate value accordingly for your machine requirement the click generate. You can see in fig 2.5

Fig 2.5

  • Select the new file generated click Export G-code. You can see in fig 2.6

Fig 2.6

  • The above step for top and bottom layer for drilling go to file choose excellon and select drill file
  • After opened the drill file if the hole does not match go to scale change .1 only if the value does not match You can see in fig 2.7

Fig 2.7

  • Then change Cut Z and travel Z value and click Generate You can see in fig 2.8

Fig 2.8

  • Go to the new file and click Export G-Code and save the file You can see in fig 2.9

Fig 2.9

Milling Operation

 

After generated G-Code for milling operation place the copper clad PCB in the CNC machine you can place it the way you like. You can stick the copper plate using a double-side tap in the small thickness wood or you can print the base using 3d printer.

  • After placed the copper plate open the software (grbl controller) and goto service and select the “COM” port.
  • After connecting the USB port you can able control the spindle and axis of the machine.
  • Now attach the tool bit you want the mill here we are using V bit 0.1 mm 30 degree
  • Then place the spindle where you start the g-code and select the icon set home position now that point will become X0, Y0, Z0. Shown in below fig
  • now click on open first choose either top or bottom this is one side PCB so i am using bottom and select bottom g-code then click start
  • After bottom completed change drill bit 1mm then run the drill g-code  after cut and take out the PCB

Finished product I have shown below