Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

SMTnet
»
Electronics Forum
»
Breaking scored boards, breaking components.

Breaking scored boards, breaking components.

Subscribe to Thread

We are leaving 12-18 thousands material when scoring. Seve... - Nov 08, 1999 by Brian Larson

Oh boy, does that bring back memories!!!!! You are most li... - Nov 08, 1999 by

We have recently purchased equipment that would probably so... - Nov 09, 1999 by

Brian, We recently investigated a depaneling press that mi... - Nov 09, 1999 by John Sims

This may help you regarding the V-Groove or scored board de... - Nov 09, 1999 by

Ok, help me out here guys and gals...... I have never unde... - Nov 16, 1999 by Scott Cook

Brian Larson

#8623

Breaking scored boards, breaking components. | 8 November, 1999

We are leaving 12-18 thousands material when scoring. Several components are cracking during depanelization. The pizza cutter machines out there are either too expensive or too slow to solve our problem. I am looking for a magical solution. In case Merlin does not respond, we will go to routed panels. I am also unhappy with our current "tab/webbing" configurations. You know, the little doohickeys you break off that go between the circuits and the panel edges on routed panels. Does anyone know of any links to board layout sites that would suggest other tab configurations?

reply »

Brian W.

#8624

Re: Breaking scored boards, breaking components. | 8 November, 1999

Oh boy, does that bring back memories!!!!!

You are most likely breaking components when the board is flexed during separation. Any components perpendicular to the score are candidates for mechanical stress. We overcame the problem by making our own "pizza cutter" and by making fixtures. The fixture was a jointed frame that supported the board and prevented any warping during the separation. Separation was accomplished by simply bending the frame at the joint (we put little handles at the top). This also works for the breakaway tabs you mentioned .

Hope this helps. Brian

reply »

Steve Owen Snr prod eng.

#8625

Re: Breaking scored boards, breaking components. | 9 November, 1999

We have recently purchased equipment that would probably solve your problem. We are using 1.6mm pcb material 1/3 of which is left unscored. When the pcb is de-panelized there is no damage to any components and we have cut our break time in half.

reply »

John Sims

#8626

Re: Breaking scored boards, breaking components. | 9 November, 1999

Brian,

We recently investigated a depaneling press that might suit your application. The labor savings over pizza cutting will probably make it justifiable for you. The company seems to be lesser known in the US, but is partnered with a Japanese company looking to break into the market. You can check it out at www.pioneerdie.com. In some applications, it is capable of depaneling boards that have not been scored at all.

Hope it helps,

John S.

reply »

John Sims

#8627

Re: Breaking scored boards, breaking components. | 9 November, 1999

Brian,

Hope it helps,

John S.

reply »

Robert Culpepper

#8628

Re: Breaking scored boards, breaking components. | 9 November, 1999

This may help you regarding the V-Groove or scored board designs. With respect to material left, I did some experiments and found that for our process .009 of material seemed to be ideal. There was minimal stress required to break the boards apart yet the panel maintained enough strength to undergo our SMT and TH processes. This of course is relative to the component mix and weight you have on the board. Hope this will help if your still considering the manual labor approach. The key I've found to preventing component cracking is DFM and training for the person doing the manual depanelization so that the PWA is help firmly on a flat surface e.g. a work bench edge and then breaking the panel away and the boards out individully.

(Stress on keeping the panel flat on the work bench)

Also we found while investigating board shears, the majority of board shops seem to be headed away from V-Groove / Scoring. However the company we do a lot of volume with based on service and pricing that can provide the service as well as a panelization optimization tool is Graphic Electronic Inc. "GEI". There # is 800-889-1138. If you would like some suggestions on route and perf let me know. Good Luck,

Robert C.

reply »

Scott Cook

#8629

Re: Breaking scored boards, breaking components. | 16 November, 1999

Ok, help me out here guys and gals......

I have never understood the concept of scoring on mixed technology or SMT boards. It is quite obvious to me that the potential for SMT solder joint damage through the mechanical stresses of breakout are high. The last time I looked at scoring capabilities in a board house was admittedly over 5 years ago. But at that time, the BEST kerf alignment guarantees for top and bottom scoring blades on their processes was about .007". So that also ensures a mandatory smoothing or sanding operation after breakout on many Class II products.......(or used to).

Add the necessary fixturing costs to prevent these stresses to the solder joints, and I just don't get it. Now add that scoring is a SECONDARY operation in board houses. Yet routing is an integral part of the process, and can be implemented easily with good breakaway web / tab designs which do NOT require smoothing or sanding afterwards.

So, I am thinking the key to panelization is good planning and routing. Tell me how I'm flawed in my thought process......

Scott Cook scook@unicam.com

reply »