EAGLE: How to make thicker tracks with solder? (Not wider!)

[kahlenberg]

Hi,

I am designing a PCB with Eagle. PCB will have high AC and DC voltages. I want to add extra soldering lines on DC tracks to make DC tracks a bit more thicker (not wider) later during assembling.
How can I do that?

You can see in the image what I mean:

 

[andre_luis]

You could draw another track right above these ones ( perhaps a bit wider ) with the layer bStop.

 

[SLK001]

What you want to do is to leave the solder mask off the traces you want thicker and have openings in your stencil so that more solder is added there. To get the opening in the mask, you have to manually draw a trace on the mask layer, like andre suggested. I've seen oven control boards with these "thicker" traces. Just remember that solder isn't as good of a conductor as copper.

This won't help you carry higher voltages, just higher currents.

 

[c_mitra]

The cut in the board, near the middle of the picture, helps to get higher voltages. In the pic above, there is a high voltage cap across the gap. There is another high voltage component near the top left.

Although the solder is not as good a conductor as copper, it does compensate by sheer volume. The solder line can be about 1mm thick. If the copper foil gets hot, it simply delaminates (it is stuck wtih eopxy glue). This is a good trick for many boards based on paper phenol (bakelite) boards.

 

[SLK001]

The cut in the board, near the middle of the picture, helps to get higher voltages.

It doesn't help get higher voltages, but it is there to meet compliance standards (UL, etc).

 

[FvM]

It doesn't help get higher voltages, but it is there to meet compliance standards (UL, etc).

Do you say the risk of insulation tracking isn't real?

 

[SLK001]

Do you say the risk of insulation tracking isn't real?

No, it's real, but not very likely to occur. Since it does rarely occur, the cuts are to break the path. So it doesn't help get higher voltages (there's nothing magic about the cuts), but instead makes tracking impossible across the gap at line voltages. For compliance, rare occurances must be mitigated to the impossible.

 

[c_mitra]

So it doesn't help get higher voltages (there's nothing magic about the cuts), but instead makes tracking impossible across the gap at line voltages..

The question was perhaps badly asked. We have,say, two identical board (in layouts) but one has a slit across (means in between) the legs of a capacitor. Which board can be used with a higher voltage capacitor?

 

[FvM]

Cutouts do help to get higher long-term withstand voltage on PCBs. Tracking has to be considered when designing creepage distances. It's not just a theoretical quantity in regulations, it causes device failure in real life.

High quality switch mode power supplies are e.g. made with cutouts to increase creepage paths, if have seen failure of low quality Chinese power supplies due to tracking.

 

[marce]

It doesn't help get higher voltages, but it is there to meet compliance standards (UL, etc).

Yes it does its for creepage clearance, a greater than 1mm slot allows for a reduction in creepage distances.