Hello, is it okay to place SMD part pads on traces like this?
I don't see a problem with this but I'm not an expert on PCB design.
The only problem I could foresee, with my limited knowledge, is if your power trace got too big, that it may conduct heat away too quick when soldering, resulting in a poor solder joint.
It would work but Automated Placement might be a problem, as there is no distinct solder ‘pad’ to wick and pull smaller parts into alignment.
Wouldn't the solder mask perform that function?
In a reflow oven the complete PCB is heated. If it was an issue, then think of power planes.
From my limited exposure to board design, pads on power planes I have seen, all had thermal relief spokes (think that's what they are called!). I can see it not being an issue with a hot plate or oven - as you say, everything gets heated to the same temperature.
Does the answer to @amazed question then depend on the way the parts are soldered to the board - thinking oven, hot plate, hot air or soldering iron? Just curious as it will aid my future board designs too.
1 Like
If it is a very wide trace and you want to use a hotair soldering gun to add or replace components it depends on how you make or use the board.
I had to crank up the temperature of my hotair gun to unhealthy levels to melt the solder as too much heat was flowing away into the trace or into the copper pour.
So if I have room on the PCB I prefer heat-spokes or in your case I would lower the position of R2 and R1 and add a small trace. That will give you thermal isolation.
1 Like
Maybe if the pads are somehow asymmetric or there is some other imbalance, there could be a risk of "Tombstoning". Understanding PCB Tombstone: Causes and Solutions
Thanks for all the answers.
KiCad does place a pad there.
I will order it from JLCPCB, but I'm not sure about the soldering method. I think they use reflow soldering.
So as @ledsyn mentioned, the entire PCB is heated during the process and heat conduction away from these type of pads shouldn't be an issue? It makes sense to me.
Thanks in advance.
Absolutely not!
From the continuance i think you have some insight.
If you hand solder, yeah it makes sense to have it in mind when designing the board, but not so much when it comes to power traces as to copper planes. You need to solder to a power trace anyway. If that's giving you grief you need a better iron. 
1 Like
Can you at least say why you want to do this?
I've also seen this advice, which the OP appears to be falling foul of, but I am not sure how up to date it is and how it can be reconciled with other advice to avoid right angle traces. But anyway, here it is:
From: How Many Common PCB Design Mistakes You Should Know - RayMing PCB
Okay, so on an imaginary scoreboard, "Don't do this" is in the lead. 
No particular reason. I'm still learning how to create a decent PCB. As I was reviewing my current design, it occurred to me to question whether it's okay or not to route traces like this. That's all.
Thanks, I also keep this in mind during modification.
I've had JLC review-fail a pcb with that 'feature'(the acute V). Right angle takeoff wasn't an issue, just the V. Fortunately, easily corrected.
What guidance document did you find that in, if I may ask?
I found it on the net somewhere. I'll have to dig it back up when I get home.
1 Like
Traced back to here:
PCB Design Considerations