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protection against vibration

V

veeresh

Jan 1, 1970
0
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?

Thanks and Regards,
Veeresh
 
D

David L. Jones

Jan 1, 1970
0
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?

Thanks and Regards,
Veeresh

If the board is close to a panel of some sort them you could use that
thermally conductive matting stuff between the PCB and the panel that
also acts as a vibration absorber.

Got a link to the actual package?

Vibration tests are done for a reason, if it's failing then you have
trouble. Do you just want to a) pass the test (as you seem be to
implying), or b) do you want to pass the test and make your product
more reliable?

Dave.
 
S

Spehro Pefhany

Jan 1, 1970
0
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?

Thanks and Regards,
Veeresh

Can you link to a package drawing?


Best regards,
Spehro Pefhany
 
M

MooseFET

Jan 1, 1970
0
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?

The breaking is often caused by the PCB flexing. During the vibration
test, the vibration may hit a resonant frequency for the PCB. Adding
another attachment point ot the PCB can help.

Placing a rubber foot such that the PCB bumps into it if it deflects,
will often help to damp a resonance.

Changing details of the mounting will often help. Basically, you want
to push the resonant frequency up and increase losses. It matters
less how you do this than that it is done.
 
T

Tim Wescott

Jan 1, 1970
0
MooseFET said:
The breaking is often caused by the PCB flexing. During the vibration
test, the vibration may hit a resonant frequency for the PCB. Adding
another attachment point ot the PCB can help.

Placing a rubber foot such that the PCB bumps into it if it deflects,
will often help to damp a resonance.

Changing details of the mounting will often help. Basically, you want
to push the resonant frequency up and increase losses. It matters
less how you do this than that it is done.
Or going to a thicker PC, or attaching stiffeners to the PC -- One of
these will be the least expensive for you, but it depends on your situation.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
T

Tim Wescott

Jan 1, 1970
0
veeresh said:
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?
I think I would want to make my product better, and pass vibration tests
as a consequence, rather than being focused on passing the tests and
damn what happens to my product in the field.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
M

Marra

Jan 1, 1970
0
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?

Thanks and Regards,
Veeresh

Rubber mounts on the pcb should reduce it.
 
J

John Larkin

Jan 1, 1970
0
Hi,
On one of my PCBs i'm using a heavy IC. It is a 70pin gull wing
package. And, the problem is that the pins are breaking near the IC
package. I don't want to use RTV, as it's difficult to remove. What
best I can do to protect this against vibration tests?

Thanks and Regards,
Veeresh

As others have mentioned, it's flex resonances of the board itself
that are probably the problem. Boards will blur at resonance, and
literally throw parts off. The board should be stiffened, damped, or
vibration isolated.

John
 
V

veeresh

Jan 1, 1970
0
Can you link to a package drawing?

Best regards,
Spehro Pefhany
Hello Sir,
Thanks for the kind response from all of you.

It has passed the tests some times. But when tested for many times,
the pins break. I want to make it rugged... exactly option (b) :)
The PCB is housed in an enclosure with screws at every 5cm w.r.t each
other. Please check the link below for package diagram.

http://www.ddc-web.com/FileLibrary/Default.aspx?type=Datasheets&div=MIL-STD-1553


please consider the data sheet of BU-61580(second one ). I'm using the
gull wing package - page 44 of 46. I took this perticularly to save
the space.
Now, I've kept a sil pad below the device, super glue on four corners,
and RTV on pins. Is this fine, or something better can be done?

Regards,
Veeresh
 
V

veeresh

Jan 1, 1970
0
If the board is close to a panel of some sort them you could use that
thermally conductive matting stuff between the PCB and the panel that
also acts as a vibration absorber.
I think I can fill upto 1 inch to reach the top plate, using sil pad.
~Veeresh
 
V

veeresh

Jan 1, 1970
0
As others have mentioned, it's flex resonances of the board itself
that are probably the problem. Boards will blur at resonance, and
literally throw parts off. The board should be stiffened, damped, or
vibration isolated.
Hello Sir,
What can we use for this vibration isolation? Is it some kind of
washers, and studs that we use to fix the board in the box?
~veeresh
 
V

veeresh

Jan 1, 1970
0
Hello Sir,
Thanks for the kind response from all of you.

It has passed the tests some times. But when tested for many times,
the pins break. I want to make it rugged... exactly option (b) :)
The PCB is housed in an enclosure with screws at every 5cm w.r.t each
other. Please check the link below for package diagram.

http://www.ddc-web.com/FileLibrary/Default.aspx?type=Datasheets&div=M...

please consider the data sheet of BU-61580(second one ). I'm using the
gull wing package - page 44 of 46. I took this perticularly to save
the space.
Now, I've kept a sil pad below the device, super glue on four corners,
and RTV on pins. Is this fine, or something better can be done?

Regards,
Veeresh

please consider the link below
http://www.ddc-web.com/
FileLibrary/Default.aspx?type=Datasheets&div=MIL-STD-1553
 
V

veeresh

Jan 1, 1970
0
Hello Sir,
Thanks for the kind response from all of you.

It has passed the tests some times. But when tested for many times,
the pins break. I want to make it rugged... exactly option (b) :)
The PCB is housed in an enclosure with screws at every 5cm w.r.t each
other. Please check the link below for package diagram.

http://www.ddc-web.com/FileLibrary/Default.aspx?type=Datasheets&div=M...

please consider the data sheet of BU-61580(second one ). I'm using the
gull wing package - page 44 of 46. I took this perticularly to save
the space.
Now, I've kept a sil pad below the device, super glue on four corners,
and RTV on pins. Is this fine, or something better can be done?

Regards,
Veeresh

please consider the link below
http://www.ddc-web.com/
FileLibrary/Default.aspx?type=Datasheets&div=MIL-STD-1553
 
V

veeresh

Jan 1, 1970
0
Hello Sir,
Thanks for the kind response from all of you.

It has passed the tests some times. But when tested for many times,
the pins break. I want to make it rugged... exactly option (b) :)
The PCB is housed in an enclosure with screws at every 5cm w.r.t each
other. Please check the link below for package diagram.

http://www.ddc-web.com/FileLibrary/Default.aspx?type=Datasheets&div=M...

please consider the data sheet of BU-61580(second one ). I'm using the
gull wing package - page 44 of 46. I took this perticularly to save
the space.
Now, I've kept a sil pad below the device, super glue on four corners,
and RTV on pins. Is this fine, or something better can be done?

Regards,
Veeresh


please consider the link below. Sorry for inconvinience.
http://www.ddc-web.com
/FileLibrary/Default.aspx?type=Datasheets&div=MIL-STD-1553
 
V

veeresh

Jan 1, 1970
0
Hello Sir,
Thanks for the kind response from all of you.

It has passed the tests some times. But when tested for many times,
the pins break. I want to make it rugged... exactly option (b) :)
The PCB is housed in an enclosure with screws at every 5cm w.r.t each
other. Please check the link below for package diagram.

http://www.ddc-web.com/FileLibrary/Default.aspx?type=Datasheets&div=M...

please consider the data sheet of BU-61580(second one ). I'm using the
gull wing package - page 44 of 46. I took this perticularly to save
the space.
Now, I've kept a sil pad below the device, super glue on four corners,
and RTV on pins. Is this fine, or something better can be done?

Regards,
Veeresh


please consider the link below. Sorry for inconvinience.
http://www.ddc-web.com
/FileLibrary/Default.aspx?type=Datasheets&div=MIL-STD-1553
 
V

veeresh

Jan 1, 1970
0
Have you considered asking the manufacturer? Why don't you tell us
how much it costs so Joerg can have a heart attack? Last part I used
from that company was in the high four digits (USD).

US$ 1000 :)
 
V

veeresh

Jan 1, 1970
0
Have you considered asking the manufacturer?
actually they suggested putting glue on the pins, and all. But once
glue is put, the maintainance will be diffiult

Why don't you tell us
 
J

John Larkin

Jan 1, 1970
0
Hello Sir,
What can we use for this vibration isolation? Is it some kind of
washers, and studs that we use to fix the board in the box?
~veeresh


Google "vibration isolator". The classic vendor for this stuff is at
lord.com.

John
 
S

Spehro Pefhany

Jan 1, 1970
0
Hello Sir,
Thanks for the kind response from all of you.

It has passed the tests some times. But when tested for many times,
the pins break. I want to make it rugged... exactly option (b) :)
The PCB is housed in an enclosure with screws at every 5cm w.r.t each
other. Please check the link below for package diagram.

http://www.ddc-web.com/FileLibrary/Default.aspx?type=Datasheets&div=MIL-STD-1553


please consider the data sheet of BU-61580(second one ). I'm using the
gull wing package - page 44 of 46. I took this perticularly to save
the space.
Now, I've kept a sil pad below the device, super glue on four corners,
and RTV on pins. Is this fine, or something better can be done?

Regards,
Veeresh

Have you considered asking the manufacturer? Why don't you tell us
how much it costs so Joerg can have a heart attack? Last part I used
from that company was in the high four digits (USD).


Best regards,
Spehro Pefhany
 
D

David L. Jones

Jan 1, 1970
0
I think I can fill upto 1 inch to reach the top plate, using sil pad.
~Veeresh

That's a lot of Sil-Pad dude, and it ain't cheap.
There are much easier ways to solve your problem.

Dave.
 
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