Sebastiaan FabAcademy

Week 4 Electronics Production

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This weeks assignment is to make a circuitboard. At the Waag in Amsterdam a Roland Modula milling machine is used to mill the FR1 PCB material. Emma has startet the lecture on thursday by explaining how to operate the Roland machine.
The rest of the week I was not able to do anything else because I had the flu with alot of fever. So I had to rest inside my bed

Don't try to remove the PCB in this way, because you can cut yourself very bad

Apply at the backside of the PCB double sided tape

Pressurise the PCB strongly to the table of the Roland

Assemble the table back into the machine

Fabmodules has been used to control the Roland Modula. In Fabmodules the Roland Modula milling machine must be selected first.

Click after selecting the Roland Modula, make_png_rml

In this screen click on load.PNG.

The circuit board of Zaerc is loaded into the fab Modules. In this case first the inside milling .png file should be loaded (the file below the orange hatched file).

First the inside milling operations has to be done. After milling the the circuit, the PCB can milled free from the rest of the PCB

First select the correct mill to mill the traces. In this case choose the mill 1/64 inch Mill traces Mill.

The cutting parameters hat to be checked to look if the right is mill used (Mill traces 1/64 inch). Is the overlap and the mill diameter correct? Intensity, offset error pixels and the Z depthness must also be filled in the software.

The cutting parameters: See picture below

The milling path has to be checked for any problems.

Apply make path and then make file

Mount the small 1/64 inch mill (left) in to the machine. Be carefull the mill is very fragile

After assembling the mill, the zero point of the mill must be devined. The X and Y axis is controlled by coordinates in the software. The Z-axis is adjusted in the machine. Lower the Z-axis untill it coms close to the PCB. The unlock the mill and lower it onto the PCB. Lock it and now the Z-axis is also zerood.
By clicking on Send File the data is transfert to the Roland and the machine starts to mill. After milling the machine must me vacuumed and cleaned.

Check if the mill had cut throught the copper layer. This example looks fine

Now it is time to cut the outside line of the pcb and cut it free. Load the correct outline file and change the mill in the software and in the machine to the Cut Outboard Mill 1/32 inch version. Important is to adjust the correct settings. The diameter is 0.79 mm, the offset 1 ( only the outside shape must milled away, not the complete PCB). The number of cuts in the depth must be applied in to the software as well. The first milling depth is 0,6 mm. Then press make path. Check the path and make .rml. Now start milling.
Remove the PCB and clean the machine and clean the milled PCB with soap and water .

The next steps shows how I soldert the components on to the PCB. I glued a piece of double side tape on the back of the pcb so it did not slided away on the table. I startet soldering without a lens since I have still good and sharp visibility. In the next pictures the soldering proces is captured

I tried to limit the amout of Tin and solder as nice as possible.

After the components where soldered, I used a Multimeter to check the quality of the soldering. At the switch and at the green led the connection was not ok and I had to rework the soldering.
Then I applied extra tin on the USB connections to increas the thickness of the PCB.

With a file the height of the tin soldering was leveled to equal heights, to prevent bad contact.

Time to clean the PCB

A additional small foil is glued under the PCB to increas the thickness of the PCB a little bit more

Hot glue is applied to the connector for reinforcement of the soldering.

In week 8 I try to to program the ISP and put a firmware onto it so it will actually become a working in-circuit programmer.

In week 8 I destroyed the USBTiny. Since then I used an USBTiny from Emma. But I still want to make a new one. But I also like to mill it on the milling machine at Saxion, to practise more with the LPKF milling machine. But this LPKF milling machine works with Gerber files. To get the gerber files I have to draw the USBTiny design in Eagle myself. I used the PGN board layout of Zaerc to reverse engineer the board layout to an schematic. Then make from this schematic an board layout to be able to make and gerber file.

The design is almost finished. My time was up for this moment, but I only have to redesign the 4 USB connections and check the distances between the 4 connections lines and cut the GND layer away. This is the task for the next following days.

Files of week 4