if you see on this image the some pads are we milled while other the copper layer has removed what can i do
not a strictly KiCad question, so probably a more generalistic electronic forum could be a better place for the question.
However you should check the planarity of your build surface. the flatter the better results.
It also depends on which technology is your milling head. Do you use a standard milling machine (router)? and the type of v-bit mill you are using.
For pcb manufacturing some specialized heads exists…
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Check once more the basis for the decision to mill the PCB yourself instead of ordering it from the PCB manufacturer.
Do you really are in such harry that you need to have PCB being done immediately after it was designed?
Our local PCB manufacturer has the ‘prototype offer’ - you get it done in 5 working days. But once a month he has the promotion and these prototypes are cheaper than normal (realizing prototype orders is easier for them when they had lots of them at the same time).
Even I can have each PCB be done in 5 days I always prefer to wait month to get it cheaper. As month for me is not a problem I have a problem to imagine what are the reason some people are in such hurry that decide to manufacture themselves PCB having no vias, no solder mask, pads not gold plated.
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…btw, vias under the qfn/qfp will be almost impossible to do without some type of conductive ink technology…
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I’m allergic to yelling so I removed the all capital thing from your post title.
Also fixed some spelling errors in the title.
For the rest, I don’t want to encourage that sort of behavior, so I did not even read beyond the title, (or responses from others).
This is definitely off topic for this site. Nevertheless, as others have said, it’s at least partly because your PCB is not as flat as you likely think. Lots of solutions - suggest you look elsewhere for details - particularly how to best secure your board on the mill. You can also probe the board area using the milling bit and run an autoleveling routine to adjust your Gcode. Have a look here for some useful tips autoleveller.
TBH, I’ve largely abandoned milling pcbs - it’s ok for non critical THT stuff - like making speaker crossovers, adapter boards etc. For SMD work with finer traces, it’s not worth the effort. Sure, it can be done but you have to have a very well controlled process. Boards are trickier to solder with no solder mask and prone to random shorts from whiskers of copper. Milling PCBs was one of the reasons I bought a small CNC machine a few years ago but nowadays I hardly use it for this any more.
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I’ve posted Tip’s on PCB milling so won’t repeat much of it here.
Will just mention:
• Avoid V-Bits unless your Platen and mounted PCB is dead-level.
If it’s Not, the Depth of Cut will ‘vary’ (because of the angled edges) resulting in varying Width of Pads, Traces…etc.
Best to use 0.7mm End-Mill Bit’s. (0.6mm is okay but they can easily break)
• Using an End-Mill Bit will eliminate your problem if you set the Depth Of Cut such as to ensure it’s deep enough to not ‘Skim’ the surface of a Non-Level PCB.
Example Of Bit’s Info from my Testing
Result Example (Before and After Tinning) with my Homemade Tinning Solution
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thank you
this should work ,because you are engraving big traces and pad. what if you are engraving small pad like 0.2m with bit of 0.6mm i think the result will be different .
It’s about the ‘Pitch’ (the distance between the Pads).
Making a 0.2mm Pad isn’t the problem unless the Gap between the Pads and other items isn’t wide enough for the Bit. Try a smaller Bit and go slower and not as deep in depth-of-cut setting for each pass.
Practice on scrap boards. Or, try a V-Bit and play with depth-of-cut until satisfied…
I’ve made 0.5mm Pads with V-bits, no problem. But, 0.2mm could be challenging… I’ve broken too many Bits smaller than 0.6mm (they’re delicate). V-Bits are strong so, play around…
yeah it take time to play with bits to get the desired result. But changing the distance between pad will not be possible as the footprint will be changed and the components will not match on it .because we need to do pad that that will match with the hardware