Week 5

Individual Assignment

This week Individual assignment is to make ans in-circuit programmer by milling and stuffing the PCB and testing it.

Milling Machine

The milling machine in our lab is ROLAND MDX 20, It can also be used as a desktop 3D scanning machine. It has got a maximum working area of 203.2mm x 152.4mm x 60.5mm.


In order to save the bed from wear & tear and for leveling the bed, a sacrificial layer of FR1 PCB is provided.


We also use a vacuum pump to suck the debris to keep the machine and the lab clean.

Milling Tool

There are two types of tools:
1) 1/64 tip - It is used for milling traces on the PCB, The tip size is 0.00156in or 1/64 of an inch
2) 1/32 tip - It is used for milling profiles and to cut holes, The tip size is 0.003125in or 1/32 of an inch
Both these tools have carbide tips.

Setting the Tool on Modella

First stick the copper board to be milled on to the bed using double-sided tape.


L-key is used for tightening the bit with the chuck.



To set the Z-value correctly , we can use multiple ways but the most efficient and easiest way i found is:

• Raise the Z axis to the top
• Release the chuck using the L-key
• Insert the 1/64 inch milling bit a little more in to the chuck
• tight the screw
• Down the z axis close as possible to the bed
• Unscrew the chuck and release the bit
• Slightly press the bit close to the bed and tight the chuck screw
• Done

Making the PCB

I used the brian board design, I followed the instructions from the link http://fab.cba.mit.edu/classes/863.16/doc/projects/ftsmin/index.html

First I downloaded the Traces drawing and Outline cutout drawing from the above link.




Then I exported the drawings to the MODS and gave it for milling. Always mill out the Traces first using the 1/64 bit and change the tool to 1/32 bit and position the tool to the same origin used for tracing.







For My first attempt, I uploaded the traces drawing into MODS, selected the tool and noted down the origin, And then I gave it for milling.




This time I encoutered a problem. The tracing wasn't even all around the PCB. This can be because of the uneveness on the table. So I changed the cut depth and max depth from 0.004in to 0.005in and gave it for milling.



After the second attempt, the milling wasn't proper at the bottom-left corner, so I changed the cut depth and max depth to 0.0065in and gave it for milling.


This time I got a perfectly milled PCB, I then changed the tool to 1/32 tip and selected the tool in MODS and set the origin same and gave it for milling

Soldering the Circuit

I reffered the Board file and schematic file for solderding the FAB ISP




The components used are as follows


The PCB after soldering all the components

Programming the Micro-Controller

For Programming I reffered the link http://fab.cba.mit.edu/classes/863.16/doc/tutorials/fabisp_programming/

First we need to install all necessary software for programming, which include "Avrdude" and "GCC"



Now we need to download and unzip the firmware



My programmer cannot communicate with the computer directly, so I connected it to an already porgrammed programmer which can communicate with the computer and translates the messages to my programmer





So I downloaded and unziped another firmawre from http://github.com/Academany/FabAcademany-Resources/blob/master/files/firmware_45.zip

Now the programmer is ready



The computer recognized my FABISP

Vinyl cutting of PCB

Copper vinyl sheet is using modella. Reffer Computer-controlled cutting week to know more about cutting using modella.

Laser cutting of PCB

I used the Fiber Laser for cutting the PCB. Reffer Computer-controlled cutting week to know more about laser cutting