Hello everybody. How to make a similar plug on the board circled in red in Eagle cad? And how to make such a board size circled in blue. Thank you.
Hello everybody. How to make a similar plug on the board circled in red in Eagle cad? And how to make such a board size circled in blue. Thank you.
Hi Morten,
There are some issues you also need to take care of, and Eagle is not
helping much. They need to be specified to the manufacturer next to the
gerbers.
You are right, special care needs to be taken to ensure that the board manufacturer sees and acts upon the additional information. Is there a standard way other tools do this that you know of? I've only ever seen notes added to drawings which are printed and supplied as part of the gerber set... But I have seen those completely ignored previously so you have to work especially hard to ensure that your board house really has paid attention to any additional information supplied.
1-Make sure the PCB thickness is matching your socket (Yea, I've managed
to mess up this once!). If it's 1.6mm, you have a great chance of
accidentially getting it right.
That's a very good point, I guess lots of people learn that lesson the hard way.... In fact I will be designing a board with a card edge soon so I will make a note of that now so I don't forget and have a stupid fail on the first prototype! 
2-The card edge needs beveling (v'shape) to be gentle to the receptor.
See datasheet of the receptor for recommendations.
3-The contacts need special coating to prevent oxidation. Normally this
is done in production by shorting all the pins before final cutout,
applying a voltage to them all while the edge of the pcb is dipped into
some chemical for coating deposit, then the shorts are cut out and
beveling applied. You can often see the thin tracks that used to short
circuit all the pins as leftover on the wider pads.
These are the two things I mentioned in my post, but I probably wasn't clear enough about the gold plating. So, the process you refer to is actually to produce a harder gold plating for the connector fingers rather than the softer plating you get when you have a typical gold finished board. It's not about a surface to protect from oxidation, its so it's mechanically strong enough surface that it can withstand insertion into the edge connector socket without damaging the surface. I didn't actually know how it was done and that extra shorting traces were required which were then removed as part of the bevelling. Very useful info, thanks 
Also see http://www.eurocircuits.com/blog/gold-plating-for-edge-connectors/
Ahhh, Eurocircuits, my go to board house for prototype boards. I've bookmarked that link for my upcoming project. Thanks
Best Regards,
Rachael
Dmitriy,
Card edge connectors have been discussed several times in this forum.
Rachael, Gerald, and Morten all provide very good advice. Board
thickness, plating, and corner bevels are all important.
Morten mentioned using a special coating for the contacts. This coating
is usually gold (Au), for two reasons. The first and foremost reason
was mentioned by Morten - it prevents oxidation. The second reason is
to prevent galvanic corrosion. Galvanic corrosion occurs when two
dissimilar metals are in contact in the presence of an electrolyte. In
our case, the electrolyte is water vapor and oxygen in the air. The
contact and subsequent corrosion will cause unwanted voltage offsets and
intermittent connection.
In school, did you ever insert a copper strip and a zinc strip into a
potato or a lemon and measure the voltage it produced, or used it to
power an LCD clock? When the experiment was complete the electrodes had
corroded. This experiment exploits galvanic corrosion to harvest
energy. Obviously the goal, in your case, is not to exploit these
effects, but to to avoid them.
The connector used to attach to the card edge will most likely have gold
contacts. Therefore, it is imperative that the contacts on the card
edge also have gold plating. Since gold is a relatively soft metal
(considerably softer than copper), the connector and card edge both have
a limited number of insertions before the gold is worn away in critical
spots.
Nickel or tin plating may also be available. The cost is about the same
as gold plating (it's the process that drives the cost - not the
material). But whatever you choose, make sure the same material is
plated onto the circuit board.
Look for my post on 21-Jan-2014 titled "Re: Help for footprint (edge
mounted connector)". I posted card-edge.lbr.zip which contains a 50-pin
edge connector setup in three different packages - one for the left end
of the edge, one for the right end of the edge, and one for somewhere in
between. I believe a link to the thread is
http://www.element14.com/community/message/101512.
From that post:
Carsten,
The attached isn't exactly what you want, but it should serve as a guide
on how to design an edge connector. It's a 50-pin card edge connector
with three different configurations - left end of board edge, right end
of board edge, and middle of board edge. As Richard mentioned, you will
have to work with your board house to specify the gold plating.
Note that zero-width wires are placed in the Dimension layer to specify
the cutout. What's NOT in the design is a polygon or rectangle that
specifies the top and bottom finish. Eagle has tFinish and bFinish
layers to specify exactly this. You can add sections to your CAM job to
produce gerber files for these two layers, then name the output files
AuTop.gbr and AuBot.gbr. That and a note in the README file should make
it pretty obvious to the board house which pads should be gold plated.
I have attached to this post a zipped copy of the library.
HTH,
- Chuck
On 06/06/2017 08:01 AM, rachaelp wrote:
Hi Morten,
There are some issues you also need to take care of, and Eagle is not
helping much. They need to be specified to the manufacturer next to the
gerbers.
You are right, special care needs to be taken to ensure that the board manufacturer sees and acts upon the additional information. Is there a standard way other tools do this that you know of? I've only ever seen notes added to drawings which are printed and supplied as part of the gerber set... But I have seen those completely ignored previously so you have to work especially hard to ensure that your board house really has paid attention to any additional information supplied.
1-Make sure the PCB thickness is matching your socket (Yea, I've managed
to mess up this once!). If it's 1.6mm, you have a great chance of
accidentially getting it right.
That's a very good point, I guess lots of people learn that lesson the hard way.... In fact I will be designing a board with a card edge soon so I will make a note of that now so I don't forget and have a stupid fail on the first prototype!
2-The card edge needs beveling (v'shape) to be gentle to the receptor.
See datasheet of the receptor for recommendations.
3-The contacts need special coating to prevent oxidation. Normally this
is done in production by shorting all the pins before final cutout,
applying a voltage to them all while the edge of the pcb is dipped into
some chemical for coating deposit, then the shorts are cut out and
beveling applied. You can often see the thin tracks that used to short
circuit all the pins as leftover on the wider pads.
These are the two things I mentioned in my post, but I probably wasn't clear enough about the gold plating. So, the process you refer to is actually to produce a harder gold plating for the connector fingers rather than the softer plating you get when you have a typical gold finished board. It's not about a surface to protect from oxidation, its so it's mechanically strong enough surface that it can withstand insertion into the edge connector socket without damaging the surface. I didn't actually know how it was done and that extra shorting traces were required which were then removed as part of the bevelling. Very useful info, thanks
Also see http://www.eurocircuits.com/blog/gold-plating-for-edge-connectors/ (https://www.element14.com/community/external-link.jspa?url=http%3A%2F%2Fwww.eurocircuits.com%2Fblog%2Fgold-plating-for-edge-connectors%2F)
Ahhh, Eurocircuits, my go to board house for prototype boards. I've bookmarked that link for my upcoming project. Thanks
Best Regards,
Rachael
--
To view any images and attachments in this post, visit:
On Tue, 6 Jun 2017 09:12:35 -0400, Chuck Huber
<chuck.huber@dukepro.com> wrote:
Dmitriy,
Card edge connectors have been discussed several times in this forum.
Rachael, Gerald, and Morten all provide very good advice. Board
thickness, plating, and corner bevels are all important.
Morten mentioned using a special coating for the contacts. This coating
is usually gold (Au), for two reasons. The first and foremost reason
was mentioned by Morten - it prevents oxidation. The second reason is
to prevent galvanic corrosion. Galvanic corrosion occurs when two
dissimilar metals are in contact in the presence of an electrolyte. In
our case, the electrolyte is water vapor and oxygen in the air. The
contact and subsequent corrosion will cause unwanted voltage offsets and
intermittent connection.
In school, did you ever insert a copper strip and a zinc strip into a
potato or a lemon and measure the voltage it produced, or used it to
power an LCD clock? When the experiment was complete the electrodes had
corroded. This experiment exploits galvanic corrosion to harvest
energy. Obviously the goal, in your case, is not to exploit these
effects, but to to avoid them.
The connector used to attach to the card edge will most likely have gold
contacts. Therefore, it is imperative that the contacts on the card
edge also have gold plating. Since gold is a relatively soft metal
(considerably softer than copper), the connector and card edge both have
a limited number of insertions before the gold is worn away in critical
spots.
Nickel or tin plating may also be available. The cost is about the same
as gold plating (it's the process that drives the cost - not the
material). But whatever you choose, make sure the same material is
plated onto the circuit board.
Look for my post on 21-Jan-2014 titled "Re: Help for footprint (edge
mounted connector)". I posted card-edge.lbr.zip which contains a 50-pin
edge connector setup in three different packages - one for the left end
of the edge, one for the right end of the edge, and one for somewhere in
between. I believe a link to the thread is
http://www.element14.com/community/message/101512.
From that post:
Carsten,
The attached isn't exactly what you want, but it should serve as a guide
on how to design an edge connector. It's a 50-pin card edge connector
with three different configurations - left end of board edge, right end
of board edge, and middle of board edge. As Richard mentioned, you will
have to work with your board house to specify the gold plating.
Note that zero-width wires are placed in the Dimension layer to specify
the cutout. What's NOT in the design is a polygon or rectangle that
specifies the top and bottom finish. Eagle has tFinish and bFinish
layers to specify exactly this. You can add sections to your CAM job to
produce gerber files for these two layers, then name the output files
AuTop.gbr and AuBot.gbr. That and a note in the README file should make
it pretty obvious to the board house which pads should be gold plated.
I have attached to this post a zipped copy of the library.
HTH,
- Chuck
On 06/06/2017 08:01 AM, rachaelp wrote:
Hi Morten,
There are some issues you also need to take care of, and Eagle is not
helping much. They need to be specified to the manufacturer next to the
gerbers.
You are right, special care needs to be taken to ensure that the board manufacturer sees and acts upon the additional information. Is there a standard way other tools do this that you know of? I've only ever seen notes added to drawings which are printed and supplied as part of the gerber set... But I have seen those completely ignored previously so you have to work especially hard to ensure that your board house really has paid attention to any additional information supplied.
1-Make sure the PCB thickness is matching your socket (Yea, I've managed
to mess up this once!). If it's 1.6mm, you have a great chance of
accidentially getting it right.
That's a very good point, I guess lots of people learn that lesson the hard way.... In fact I will be designing a board with a card edge soon so I will make a note of that now so I don't forget and have a stupid fail on the first prototype!
2-The card edge needs beveling (v'shape) to be gentle to the receptor.
See datasheet of the receptor for recommendations.
3-The contacts need special coating to prevent oxidation. Normally this
is done in production by shorting all the pins before final cutout,
applying a voltage to them all while the edge of the pcb is dipped into
some chemical for coating deposit, then the shorts are cut out and
beveling applied. You can often see the thin tracks that used to short
circuit all the pins as leftover on the wider pads.
These are the two things I mentioned in my post, but I probably wasn't clear enough about the gold plating. So, the process you refer to is actually to produce a harder gold plating for the connector fingers rather than the softer plating you get when you have a typical gold finished board. It's not about a surface to protect from oxidation, its so it's mechanically strong enough surface that it can withstand insertion into the edge connector socket without damaging the surface. I didn't actually know how it was done and that extra shorting traces were required which were then removed as part of the bevelling. Very useful info, thanks
Also see http://www.eurocircuits.com/blog/gold-plating-for-edge-connectors/ (https://www.element14.com/community/external-link.jspa?url=http%3A%2F%2Fwww.eurocircuits.com%2Fblog%2Fgold-plating-for-edge-connectors%2F)
Ahhh, Eurocircuits, my go to board house for prototype boards. I've bookmarked that link for my upcoming project. Thanks
Best Regards,
Rachael
--
To view any images and attachments in this post, visit:
If you look at the PCI specification, or even the Connector
specification. Details of the mating card are outlined and can just be
copied into your eagle design as FAB notes. The FAB hosue will know
what to do, as others have mentioned the choice of a hard gold finish
on the contacts is important.
My first PCI board came out just fine using notes from the PCI spec.
The board house can add the connecting wires for the plating so it's
not necessary to show them.
Cheers
