Actions
Forum Thread Details
  • Replies 9 replies
  • Subscribers 180 subscribers
  • Views 947 views
  • Users 0 members are here
Related

Copper Pours - Manufacturability of PCB

autodeskguest

Hi -

 

I've got a PCB with a fair number of sensitive analog parts on it so I've

flooded a large area of the top layer of the board with a copper ground

plane using the Polygon feature of Eagle.  Another large section of the

board has been left without the top layer copper plane.  All is OK with this

and the PCB is about ready to manufacture.

 

It occurred to me that this could be problematic in the PCB manufacturing

process.  Having half the board covered with copper where the traces are

isolated by a narrow gap and then the other half with narrow traces and all

the surrounding copper removed could present problems for the etching

process.

 

On the other hand, removing less copper by leaving large copper pours should

be more environmentally friendly.

 

Do PCB manufacturers have a preference one way or the other?  (I've checked

a number of PCB vendors websites and haven't really found any information.)

 

Sincerely,

 

John

 

 

 

 

Parents

  • John M. Jarvis schrieb:

     

    I've got a PCB with a fair number of sensitive analog parts on it so I've

    flooded a large area of the top layer of the board with a copper ground

    plane using the Polygon feature of Eagle.  Another large section of the

    board has been left without the top layer copper plane.  All is OK with this

    and the PCB is about ready to manufacture.

     

    It occurred to me that this could be problematic in the PCB manufacturing

    process.  Having half the board covered with copper where the traces are

    isolated by a narrow gap and then the other half with narrow traces and all

    the surrounding copper removed could present problems for the etching

    process.

     

    It's not a problem of the etching process, but more of the galvanics.

    Areas with low copper density will get a too high current density, so

    metal is disposed too quickly (one says they "burn") - looks like small

    flowers preferrably at the edges of the copper structures.

     

    For good manufacturabilty, you should avoid having too great differences

    in copper density on your boards. Simply add some amount of copper by

    hatched polygons where only a few traces are. Then you won't have any

    problems.

     

    Tilmann

     

Reply

  • John M. Jarvis schrieb:

     

    I've got a PCB with a fair number of sensitive analog parts on it so I've

    flooded a large area of the top layer of the board with a copper ground

    plane using the Polygon feature of Eagle.  Another large section of the

    board has been left without the top layer copper plane.  All is OK with this

    and the PCB is about ready to manufacture.

     

    It occurred to me that this could be problematic in the PCB manufacturing

    process.  Having half the board covered with copper where the traces are

    isolated by a narrow gap and then the other half with narrow traces and all

    the surrounding copper removed could present problems for the etching

    process.

     

    It's not a problem of the etching process, but more of the galvanics.

    Areas with low copper density will get a too high current density, so

    metal is disposed too quickly (one says they "burn") - looks like small

    flowers preferrably at the edges of the copper structures.

     

    For good manufacturabilty, you should avoid having too great differences

    in copper density on your boards. Simply add some amount of copper by

    hatched polygons where only a few traces are. Then you won't have any

    problems.

     

    Tilmann

     

Children
No Data