Hacks for Rebaking

[astharora]

Drying conductive ink after soldering

1. You cannot rebake the circuit after assembling components on PCB made through Voltera.
   Problem faced: While removing shorts between 2 traces with the help of a needle or tweezer after placing components it is possible that you make the trace discontinuous.
   Hack found: Heat the circuit manually by using the “Heat” option upto 100 degrees Celsius for 5 minutes. No need to flip the board. Just place it on the hot surface and heat. It worked for me twice and didn’t cause any problem so far.
   Question 1: Do you recommend using this hack?

Question 2: What can be done to prevent shorts between pads of an IC beforehand?
Here’s what I tried:
1)We can control the width between traces by making it more than 15 mil but we cannot control the width between pads of an IC.
2) Calibrated it properly but the amount to be dispensed can be reduced upto a certain level only otherwise it gives bubbly/ discontinuous traces.

[sneaks]

First, make sure you are using a 150 or 100 micron tip. The only thing I use 225 micron tips for is solder. Outside of tip size, there are two different ways I deal with this.

1: MAKE TWO PARTS: As a broad solution, I make two parts in my design software. One with the pad width that is spec’d by the IC manufacturer (for final PCB Production), and one with slightly smaller pads for the Voltera. It is more work up front, however it saves cleaning up the area between all IC pads under a microscope.

2: PASS SPACING: I have a PMIC that has a .65mm pitch; the above solution did not work for this. Fortunately, Mike at Voltera was kind enough to help me figure out the best setup for my .65mm pitch IC. He figured out a 150 Micron tip and .22 Pass spacing made it come out perfect.

I generally use a combination of these two things to fine tune the pad sizing with the Voltera.

**I also wanted to add, calibrating the ink correctly is extremely important. I turn the ink pressure down until the lines start breaking up or disappear. Then I slowly increase 10-30 until I have a nice solid line without ‘Q-Tips.’ My goal is the thinnest line I can get without breaking. If when I start printing, the tracks are not homogenous, I may bump it up another 10-20.