Pocket Guide to Excellent V-Scoring
FAQ (5)

What Tolerances Can Be Held?

Good Question! Most modern CNC V-Scoring Machines are designed to hold at least +/-.002" on all dimensions (X, Y and Z). Machine maintenance, condition, age and operator attention/proficiency can effect tolerances as well as drilling, imaging and laminate stability. But, what makes this question so good is that, when the individual board is de-paneled after assembly, what was once the v-groove, becomes a special kind of edge. That edge is illustrated here...

Break-Away Characteristics

(Cross-section of .062" FR-4 Panel / 30 Degree Score)

"X" = Programmed in Board Size (‘Y’ & ‘Z’ Dimensions +/- .004")

As column "Z" illustrates, the end result is that the individual boards will measure slightly oversized. The amount is dependent on the material type and the web thickness. This phenomenon is a result of a slight unevenness in the edge at the center of the cross-section, where the boards were separated. This oversized condition usually does not present a problem because, unlike a routed edge, a scored edge is relatively "soft", and will yield to pressure when fitted into a frame or case. If an oversize condition will cause a problem, a simple scaling using the chart above, should yield satisfactory results.

"Score to Fab", is a smart time saver too. Parts that do not otherwise require routing for slots, cutouts or chamfers can be v-scored instead of routed. A light pass with sand paper or equivalent on the edges, makes a smooth and serviceable finish that will rival that of a routed edge, while maintaining the programmed specifications, thereby easing the load on your busy fab area.

FAQ's Index

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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