Reply to: RE>>ASSY: PCMCIA Board Depanelizing
Lucy:
I cast a second vote for either in-line or off-line routing and a vote AGAINST
scoring or shearing for PCMCIA boards for the following reasons:
1) PCMCIA cards are typically built with 0.020"-0.025" thick fabs. Scoring
will NOT leave enough support for the reflow oven after pick/place. While it
is true that scoring "works well for boards with straight edges" as Steve
O'Hara stated, reducing a 0.020" thick board to 0.010" with scoring weakens
the panel strength during reflow, unless a pallet or carrier is used for
assembly.
2) Breakoff tabs MAY be necessary for the array of boards, especially if the
board is densely populated with components close to the edge. Remember that
the pick/place machines need >4mm of edge clearance for the conveyors that
transport the panel through the assembly process. The breakoff tab can be
ROUTED off as well, providing no residual material outside of the board
profile.
3) Shearing machines CAN do the job also, as Emad Khan stated. However, if
the panel contains multiple boards (e.g. 6-9 board images side-by-side) and
uses breakoff tabs along the long axis for the conveyors, depaneling with a
shear will require TWO mechanical setups to complete singulation of the lot,
one for the tabs and another for singulation of the boards themselves.
Routing does NOT have to be in-line, even though it would be more efficient.
Off-line routers could be used to do the job without the expense of conveyor
feed complexity, etc. Using a baseplate containing mechanical tooling pins
for each board image (2 pins per board to prevent movement during routing),
the ENTIRE panel can be routed in one continuous operation, resulting in a
clean board profile without solder joint damage or board damage due to
flexing.
Sorry for the long-winded response, but this issue was near and dear to my
heart while supporting the manufacture of 1.8" disk drive boards for a "small"
disk drive company named Seagate!
Bill Fabry
Process/Quality Assurance Mgr.
Truevision, Inc.
[log in to unmask]
(408) 566-4166
--------------------------------------
Date: 10/9/96 4:00 PM
To: Bill Fabry
From: STEVE_O\'HARA@HP-Vancouver-om2
Item Subject: ASSY: PCMCIA Board Depanelizing
Try scoring. This works well with boards with straight edges.
______________________________ Reply Separator
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Subject: ASSY: PCMCIA Board Depanelizing
Author: Non-HP-lucyr ([log in to unmask]) at HP-Vancouver,shargw2
Date: 10/9/96 4:58 AM
From: Lucy N. Rojao
Process Engineering and Development--Power Business Unit
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~
Subject: ASSY: PCMCIA Board Depanelizing
Thank you,
Lucy N. Rojao
Phone: (416) 448-5866 Internet:[log in to unmask]
Celestica Inc.
*** Forwarding note from EMADKHAN--TORVMFG1 10/02/96 12:31 ***
To: LROJAO --TORVMFG1
*** Reply to note of 09/30/96 17:28
From: EMAD KHAN
Subject: ASSY: PCMCIA Board Depanelizing
Here you go Lucy...this might help:
The most efficient depaneling techinque for PCMCIA cards is having an
inline routing operation. The method can be extremely costly but yields
great results with speed. Problems, however, can be incountered in
panelizing PCMCIA cards. One may be restriced to three to six cards per
panel due warpage issues. Normal inline routers can depanel 9 PCMCIA
cards at a time. If the full capabilities of routing are not to be
utilized then this might not warrant the costs involved.
Break-off tabs are farely reasonable. You would have to experiment with
how many you would need to ensure stability in your panelization.
Break-off tabs also leave a rough finish in your product. Another concern
of break-off tabs is the possibility of introducing solder defects when
ripping a tab off (especially on thin cards). One must also not position
them close to any egde component (ceramic components in particular).
I would recommend a shearing machine for low to medium volume
productions. Shearing can achieve quite tight tolerances with an
excellent finish. Fixturing and the problem of edge components is a
concern when implementing this type of process.
Regards
Emad O. Khan
Power Products Paneling Engineer
Depaneling Engineer (Site Support)
Advanced Products Mechanical Assembly Engineer
Process Engineering
Department 110
(416) 448-4738
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