Hi Team
can any one let me know, what is design constraint for class3 interns of
| Minimum Trace Width |
| Clearance Between Traces |
| Pad-to-Pad Clearance |
| Annular Ring |
| Copper to Edge Clearance |
| Minimum Drill Hole Size |
| Max Aspect Ratio (Thickness/Drill) |
| Via-to-Via Clearance |
| Via-to-Trace Clearance |
| Solder Mask Clearance |
| Solder Mask Dam Width |
| Silkscreen-to-Pad Clearance |
| Minimum Silkscreen Line Width |
| Minimum Board Thickness |
| Copper Thickness (Inner/Outer) |
| Hole-to-Hole Clearance |
| Component Spacing |
| Fiducial Size |
| Fiducial Clearance |
I’d recommend you read our Class 3 Design Guide.
I red the document, there is no specification for design rules. I could see Class3 Manufacuring standard like annular ring, copper thickness and others. can share any documents regarding this
That is because like most standards, there are design and assembly levels to be considered. Classes can mean different things depending on what you are designing. The actual physical differences between designing for Class 2 and Class 3 is minimal in many aspects however Class 3 tends to require much more verifications to make sure that the result meets Class 3. From a PCB design standpoint, the main things that I can think of that are physically different between Class 2 and Class 3 are minimum copper in the hole for wall thickness, % allowable hole breakout, and minimum annular ring. For a complete understanding, you really need to read multiple IPC design and assembly standards. Standards tend to be copyrighted so sharing is frowned upon.
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When is comes to hard numbers to design to, I recommend starting out by reviewing what the fab shops publish that they can produce. Many fabs list their capabilites and I recommend that you compare a few websites for comparison. Sierra’s capabilites are here:
https://www.protoexpress.com/products/rigid-pcb/
I tend to avoid designing towards the minimums as a chart like this suggests. Just because a fab says they can do something, it does not mean they will not charge more as some processes are more difficult and may have a lower producability level (read as scrap %). Ideally you want to design towards industry common capabilities which is the sweet spot for keeping costs down and producability levels high.
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I can’t believe you found the IPC Standards Handbook. We just published it a few days ago and I haven’t even promoted it yet. 
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