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V-score cracking components

Views: 2262

Joe Wesley

#37312

V-score cracking components | 25 October, 2005

Looking for idea''s on how to reduce cracking of components along viscore. We are placing within 0.020 and0.030 from edge in some cases but are seeing cracks on components placed all the way out at 0.150 off edge.

Has anyone heard heating the boards and doing the v-score separation while boards are hot. Does this improve yields?

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KEN

#37319

V-score cracking components | 25 October, 2005

I have never heard of heating boards prior to v-score.

Have you established any trends on component orientation and cracking?

What is your v-score thickness range? Do you have your blades regularly sharpened? Have you measured your blade alignment? Are you absoutley sure its the depanel equipment? (I only ask because it is quite common to blame the singulator for breaking parts when there are 50 other entry points for component damage.)

0.020 is unusually close. I bet the parts breaking at 0.150 are mounted parallel to the shear axis.

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#37334

V-score cracking components | 26 October, 2005

Don't V score, unless you absolutely have concurrence with your QUALIFIED fab and assembly operations.

Routing is best for all chip devices close to board edge. It's better and cleaner for everything when seeking quality and reliability.

Visit http://moonmanondarkside.com for free downloads about this and other subjects vital to effective process management and product quality.

MoonMan moonshine@provide.net

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#37339

V-score cracking components | 26 October, 2005

I have never heard of heating the board for separation. You may want to try some of the following.

-Using a roller cutting type depaneler helps reduce the stress. -Using a combination of routing in areas with components near the edge and v-score the rest helps. -Make sure the v-score is the correct depth and angle to obtain easy separation but maintain the required strength for assembly. Jerry

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Erik

#37724

V-score cracking components | 8 November, 2005

I haven't heard of heating boards pre-depanel either.

We have done extensive studies on cracking of ceramic caps close to V-scored edges and have decided to have our board vendors pre-rout any areas with caps close (<.150") to the edge.

If we had the resources, we would definately switch to all-routed edges for all our assemblies, since cracking components is a very real issue.

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URL

#37756

V-score cracking components | 9 November, 2005

Cracked components will occur when the component is stressed. The only way to stop this is to not stress the part when removing the score. This can be done by fixturing the board top and bottom so it doesn�t bow when breaking off the breakaway.

Visit WWW.Meaningless.com for free downloads about this and other subjects.

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Samir Nagheenanajar

#37757

V-score cracking components | 9 November, 2005

I visited the site. The guy with the green smock at the screen-printer looks familiar.

I didn't find any info. on V-Score design.

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bobpan

#37758

V-score cracking components | 9 November, 2005

hahhaahha....wow....now thats funny

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#37759

V-score cracking components | 9 November, 2005

You may remember the guy in the green smock from H-P Spokane about 6 years ago.

The V score routing is in the free downloads.

MoonMan

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#37760

V-score cracking components | 9 November, 2005

You may remember the guy in the green smock from H-P Spokane about 6 years ago.

The V score routing is in the free downloads.

MoonMan

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Samir Nagheenanajar

#37767

V-score cracking components | 9 November, 2005

I thought the green smocked fellow is the MoonMan himself! That's not you?

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#37773

V-score cracking components | 10 November, 2005

Break off the break-away? If you are going to fixture the board why not just buy a cutter?

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URL

#37782

V-score cracking components | 10 November, 2005

I have a tool room that I can have fixtures made. The product or board has no budget to buy a cutter.

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Joe Wesley

#37869

V-score cracking components | 15 November, 2005

Since I asked the question - here is what we have identified. We are doing what we call a jump score. Routing critical areas with v-score in non-critical areas. We have optimized the v-score depth as much as we can without having separation through handling. We use stadard roll blade separation equipment and change blades often. But as some of you have found out parts that are parrallel to shear axis seem to crack much easier. Where we can we are avoiding htis in design and have added to DFM evaluations. Our final evaluation was to test routed boards and sure enough it dropped considerably and cracking that remains seems to be from handling. While we are waiting for the router equipment we have tested the heating methods and found some relief but not enough to justify the time and energy in handling. Biggest problems with cracking on v-score: support, operator training, and design.

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Samir Nagheenanajar

#37877

V-score cracking components | 15 November, 2005

We used to affectionately nickname our "roll blade" equipment.... A very technical term....

THE PIZZA CUTTER!

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3D SPI

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