Pocket Guide to Excellent
V-Scoring
FAQ (3)
General Web Thickness Guidelines
For Panel Scoring .062" Thick FR-4
| Individual PCB |
< .5" | .5" to 1.0" | 1.0" to 3.0" | 3.0" to 6.0" | > 6.0" |
| Finished Array Size |
|||||
|---|---|---|---|---|---|
| < 5" | .005" | .007" | .009" | .010" | N/A |
| 5" to 10" | .006" | .008" | .010" | .012" | .012" |
| 10" to 15" | .007" | .009" | .010" | .012" | .013" |
| 15" to 20" | .005" (break only) |
.009" | .011" | .013" | .015" |
| > 20" | .005" (break only) |
.005" (break only) |
.012" | .014" | .015" |
Note: These are GENERAL guidelines. The final decision on web thickness should be made only after careful consideration of future process and handling requirements... THIS GUIDE IS FOR REFERENCE ONLY! +/-0.002" is standard tolerance. For more information on depaneling without damaging the board or components, see references to Jump-Scoring in the FAQ's that follow for more advanced details on web thickness vs. producability.
Notice how the web gets thinner as the individual board size gets smaller. The smaller the part, the less leverage that you can apply to the score line.
One of the great features of most modern CNC scoring equipment, is the ability to easily program the web thickness from line to line and axis to axis. One popular application for this feature of varying web thickness is called "Deep Cut" or Framing. This is where the outside border of the array is cut to a relatively thin web of down to .006". This allows for an easy break off of the scrap frame. This is also commonly used to easily separate multiple arrays from a production panel, without the worry of breaking the wrong line. More clever ideas lie ahead...
Need Clarification? Just e-mail your question(s) to info@accusystemscorp.com
Index Introduction How Deep?
Web Thickness Guidelines
How Wide? What Tolerances Can Be Held? Some Finer Points
Jump Scoring
"Break-Through"
Conclusion
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