Best posts made by JuKu

@T3P3Tony said in Solder on the bottom of the Duet 3:

Its not an issue at all, the wave soldering that is used to solder the through hole components on the bottom of the board also sometime leaves some solder on the vias used to transfer the heat. We may mask them in the future but it does not effect the performance.

A few points on solder in thermal vias:

• It’s bad if the vias to suck in solder from the top side. This can cause bad joint to the thermal pad in the bottom, voiding the whole point of the thermal connection. This is the matter of designing the via pattern and solder paste pattern to minimize the possibility. Via size matters.

• If the board goes to a wave, it is good if the vias suck in solder from bottom. This much improves the thermal flow.

• You don’t want to cover the vias from bottom and leave top side uncovered. This creates pockets of air under the chip, possibly covered with solder paste or melted solder from the top. All kinds of funny effects (up to exploding chips) can result.

• You can tent the vias on both sides, but tented vias for thermal pads are tricky.

And folks at Duet3D know all this already. I’m just commenting out from my manufacturing experience why it is made the way it is, and why I think it is according good engineering practice, even though it might not always look pretty.

This would also make it simple to implement jogging. Button down, send movement command towards machine limit. Button up, send stop.

@dc42 “you could either detect USB disconnection/reconnection in your C# program…” Yes, I was asking how to do that. It is possible but not trivial to get notification for this on a particular device. Further, it needs deeper knowledge of the actual driver providing the serial interface to the application, which I don’t have. So I asked if anyone might have this.
But my approach was wrong. I don’t have that info, but I don’t need it either: The right way to do it is to hook to the general device event and know that some device dis-/reconnected. That is enough, I can then look at the uptime or a variable to find out if it was the Duet.

Macro parameters have been discussed a few times before, but are not implemented yet. In my application, these would be huge. And almost everything I can think of now could be done by simple text substitution:

M98 P"examplemacro.g 100 200 300"

In the macro file, substitute all <P1> 's with 100, all <P2> 's with 200 and all <P3> 's with 300. You get the idea.

For me the most useful, by far, would be something that I can set myself: Set object value to something, use the value later. I write the software that sends G code to my machine myself, so I’d be happy with something simple, like
“var1 = xx.xx” and later use “G0 X%var1%”.

Perhaps more generally useful would be a way to set a value from a get command or a previously set value. Examples:
varX = M114 X // set varX to current X position
BedT = M140 S? // set BedT value to whatever was previously set by M140 command

@Sethipus already shoved the cause, effect and solution. I build pick and place machines, and one of my prototypes had GT2 belt going around a smooth idler with teeth towards inside. My machine has a microscope looking at the work surface and software to measure position relative to a mark, so I could measure this. FYI, the effect is about 0.01 - 0.015mm max. I would predict that it is visible on a shiny surface, as beautifully demonstrated above.

@jay_s_uk Seems you are right. No problem, I can do that.