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'[EE] Creating rectangular holes in component footp'
2009\05\08@230041 by Vitaliy

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Hi List,

Our CM wants us to use the part they suggest, which is a power connector
that looks sort of like this:

http://media.digikey.com/photos/CUI%20Photos/PJ-002A&B.jpg

Note that the leads are flat, so rectangular holes are needed.

An example part in EAGLE (con-shiua-chyuan.lbr) has the holes drawn usin
zero width wire, in the mill layer. The question is, do you export the mill
layer into a separate Gerber file?

If anyone has experience with this, your feedback would be much appreciated.

Best regards,

Vitaliy

2009\05\09@083326 by olin piclist

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Vitaliy wrote:
> Our CM wants us to use the part they suggest, which is a power
> connector that looks sort of like this:
>
> http://media.digikey.com/photos/CUI%20Photos/PJ-002A&B.jpg

That looks like a common part.  Design your PCB for the CUI part.  Those are
cheaply available and there are various knockoffs from east Asia.

> Note that the leads are flat, so rectangular holes are needed.

No they're not.  Square pegs do fit into round holes as long as the holes
are big enough.  Use the smallest common hole size that the tab is
guaranteed to fit into.

If they still don't like it, tell them to use a flat drill.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2009\05\09@131141 by Bob Blick

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Vitaliy wrote:

> Note that the leads are flat, so rectangular holes are needed.
>
> An example part in EAGLE (con-shiua-chyuan.lbr) has the holes drawn usin
> zero width wire, in the mill layer. The question is, do you export the mill
> layer into a separate Gerber file?
>
> If anyone has experience with this, your feedback would be much appreciated.

I don't use Eagle. But the choice to make for these flat holes in this
case is plated or non-plated. It's cheaper to do non-plated since it
won't require a machining stage before plating. In that case put the
flat holes in the same Gerber file as the board outline since it will be
programmed in at the same stage in the production process.

Cheerful regards,

Bob

2009\05\10@021138 by Vitaliy

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Olin Lathrop wrote:
>> Our CM wants us to use the part they suggest, which is a power
>> connector that looks sort of like this:
>>
>> http://media.digikey.com/photos/CUI%20Photos/PJ-002A&B.jpg
>
> That looks like a common part.  Design your PCB for the CUI part.  Those
> are
> cheaply available and there are various knockoffs from east Asia.

Yeah, the datasheet we got for the suggested alternative, point to CUI as
the manufacturer.


>> Note that the leads are flat, so rectangular holes are needed.
>
> No they're not.  Square pegs do fit into round holes as long as the holes
> are big enough.  Use the smallest common hole size that the tab is
> guaranteed to fit into.
>
> If they still don't like it, tell them to use a flat drill.

They don't like it, and in order not to delay the project in question when
this issue came up several weeks ago, we told them to use the part as
specified (our prototype used a power connector with round leads). The part
with the flat leads is considerably cheaper, however.

Vitaliy

2009\05\10@022443 by Vitaliy

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Bob Blick wrote:
>> Note that the leads are flat, so rectangular holes are needed.
>>
>> An example part in EAGLE (con-shiua-chyuan.lbr) has the holes drawn usin
>> zero width wire, in the mill layer. The question is, do you export the
>> mill
>> layer into a separate Gerber file?
>>
>> If anyone has experience with this, your feedback would be much
>> appreciated.
>
> I don't use Eagle. But the choice to make for these flat holes in this
> case is plated or non-plated. It's cheaper to do non-plated since it
> won't require a machining stage before plating. In that case put the
> flat holes in the same Gerber file as the board outline since it will be
> programmed in at the same stage in the production process.

Thanks, Bob. A colleague also suggested putting the mill layer in the "fab
print" gerber (where the dimension layer is exported, along with holes and
drills).

As far as planted or non-plated... good question! The traces that run to
this connector, are on both sides of the PCB. Do you think solder will have
a hard time working its way up, to connect the lead to the top layer traces?

There are SMT parts on the top layer, but there are plenty of through-hole
parts as well, so I'm not sure what method the CM is using (reflow only, or
wave & reflow).

I emailed their engineer late Friday night, and hope to get an answer
straight from the horse's mouth, as it were, on Monday.

Vitaliy

2009\05\10@025152 by Bob Blick

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> As far as planted or non-plated... good question! The traces that run to
> this connector, are on both sides of the PCB. Do you think solder will have
> a hard time working its way up, to connect the lead to the top layer traces?

You should arrange the traces so the connector only has copper on the
bottom side, because without plating you will not get any solder through
to the top side. And it will cost you plenty to have the slots plated.
Because although you will pay extra for non-plated slots compared to
drilled holes, it is significantly more expensive to have plated slots
since they have to do a milling pass before plating.

Cheers,

Bob

2009\05\10@083754 by olin piclist

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Vitaliy wrote:
> They don't like it, and in order not to delay the project in question
> when this issue came up several weeks ago, we told them to use the
> part as specified (our prototype used a power connector with round
> leads). The part with the flat leads is considerably cheaper, however.

Why don't they like using a round hole?  What is are the dimensions of the
flat tab you want to connect to.

I used a similar 1.3mm power connector on the ReadyBoard-02
(http://www.embedinc.com/products/ready02).  It is P9 at the top edge of the
board near the left side.  From the drawing you can see all 3 holes are
round.  The hole on the left is actually for a flat tab.  It was just a
matter of sizing the hole to accept the tab.  It soldered up fine.  Unless
your tab is significantly bigger, using a round hole shouldn't be a problem.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2009\05\10@092709 by Gerhard Fiedler

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Olin Lathrop wrote:

> Vitaliy wrote:
>> They don't like it, and in order not to delay the project in question
>> when this issue came up several weeks ago, we told them to use the
>> part as specified (our prototype used a power connector with round
>> leads). The part with the flat leads is considerably cheaper,
>> however.
>
> Why don't they like using a round hole?  What is are the dimensions
> of the flat tab you want to connect to.
>
> I used a similar 1.3mm power connector on the ReadyBoard-02
> (http://www.embedinc.com/products/ready02).  It is P9 at the top edge
> of the board near the left side.  From the drawing you can see all 3
> holes are round.  The hole on the left is actually for a flat tab.
> It was just a matter of sizing the hole to accept the tab.  It
> soldered up fine.  Unless your tab is significantly bigger, using a
> round hole shouldn't be a problem.

I've done this as well, with an Allegro current sensor (they have
rectangular connections for the current path). Worked well with round
holes big enough for the leads.

Gerhard

2009\05\11@092555 by alan smith

picon face

I believe you can do it on the milling layer.  If you have a "pad" with a milled section, and ask them to plate it, you should get what you want.

Now with that said, most of the "cheap" houses have a cost adder for any milling besides the board outline.


--- On Sun, 5/10/09, Gerhard Fiedler <spam_OUTlistsTakeThisOuTspamconnectionbrazil.com> wrote:

{Quote hidden}

> --

2009\05\11@094638 by olin piclist

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alan smith wrote:
> I believe you can do it on the milling layer.  If you have a "pad"
> with a milled section, and ask them to plate it, you should get what
> you want.
>
> Now with that said, most of the "cheap" houses have a cost adder for
> any milling besides the board outline.

It's not just more than the simple 4 points milling.  He wants a whole
separate milling step since it needs to be done before plating.  I expect
that will be more than a trivial surcharge.

Again, what's wrong with a normal circular hole?


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2009\05\11@135523 by Isaac Marino Bavaresco

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Olin Lathrop escreveu:
> alan smith wrote:
>  
>> I believe you can do it on the milling layer.  If you have a "pad"
>> with a milled section, and ask them to plate it, you should get what
>> you want.
>>
>> Now with that said, most of the "cheap" houses have a cost adder for
>> any milling besides the board outline.
>>    
>
> It's not just more than the simple 4 points milling.  He wants a whole
> separate milling step since it needs to be done before plating.  I expect
> that will be more than a trivial surcharge.
>
> Again, what's wrong with a normal circular hole?
>  

I use some connectors that need elongated holes, because the pins are
rectangular ( approx. 0.8mm x 4mm ). A round hole of about 4mm diameter
would touch its neighbor.
I contacted the manufacturer and they told me to put a series of holes
separated by half diameter and add a note in a file saying that the
holes must be merged in a slit.

It appears that their drilling machines have some limited milling
capabilities and they don't charge extra for this.

Regards,

Isaac

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2009\05\11@144218 by Tamas Rudnai

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On Mon, May 11, 2009 at 6:55 PM, Isaac Marino Bavaresco <
.....isaacbavarescoKILLspamspam.....yahoo.com.br> wrote:

> I use some connectors that need elongated holes, because the pins are
> rectangular ( approx. 0.8mm x 4mm ). A round hole of about 4mm diameter
> would touch its neighbor.
> I contacted the manufacturer and they told me to put a series of holes
> separated by half diameter and add a note in a file saying that the
> holes must be merged in a slit.
>

And what diameter should you use in this case?

Thanks
Tamas
--
http://www.mcuhobby.com

2009\05\11@150508 by William \Chops\ Westfield

face picon face

On May 11, 2009, at 10:55 AM, Isaac Marino Bavaresco wrote:

>> Again, what's wrong with a normal circular hole?

The fit of these connectors is very "sloppy" in round holes, even  
after you modify a "standard" footprint to more closely fit the actual  
sizes.  It wouldn't surprise me if the fit was loose enough to cause  
problems during various sorts of automated assembly.

On the other hand, everybody seems to do it, short of high-volume  
consumer gear where holes (and slots) are presumably punched rather  
than drilled.

> I contacted the manufacturer and they told me to put a series of  
> holes separated by half diameter and add a note in a file saying  
> that the holes must be merged in a slit.

And this is the right answer: "Ask your PCB manufacturer."  I've heard  
that some take significant exception to this sort of drilling.  OTOH,  
the "correct" solution of having a separate milling step before TH  
plating is indeed likely to be expensive.  Or perhaps not, depending  
on the drilling machine being used.  You won't KNOW till you ask.

BillW


2009\05\11@155025 by Isaac Marino Bavaresco

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Tamas Rudnai escreveu:
> On Mon, May 11, 2009 at 6:55 PM, Isaac Marino Bavaresco <
> EraseMEisaacbavarescospam_OUTspamTakeThisOuTyahoo.com.br> wrote:
>
>  
>> I use some connectors that need elongated holes, because the pins are
>> rectangular ( approx. 0.8mm x 4mm ). A round hole of about 4mm diameter
>> would touch its neighbor.
>> I contacted the manufacturer and they told me to put a series of holes
>> separated by half diameter and add a note in a file saying that the
>> holes must be merged in a slit.
>>
>>    
>
> And what diameter should you use in this case?
>
> Thanks
> Tamas
>  

I used seven 1.2mm diameter holes, yielding a slit of 1.2mm x 4.2mm.

Regards,

Isaac

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2009\05\11@175239 by Jinx

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>> I contacted the manufacturer and they told me to put a series of
>> holes separated by half diameter and add a note in a file saying
>> that the holes must be merged in a slit.

I've had one board made with slots to take a DC connector. I didn't do
the gerbers, the board house did from my schematic and instructions. It
looks to me like it was 3 holes very close together that were merged. As
there were only 10 boards per run they may have routed them one board
at a time with the drill bit. There are cutouts in the board that I'm sure
are
in the mill layer and those cuts are a lot wider than these 'drilled' slots

2009\05\15@042841 by Vitaliy

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CM said round holes will cause problems during assembly. They sent an
Excelon file showing how they want the holes. Here are the relevant parts
(units are mm, trailing zeroes, 3 digits left of the decimal point):

   // tool size
   T21C0.7F423B423S6H2000
   // the three "slots" for the flat leads:
   T21
   X153916Y123436G85X153916Y125179
   X159837Y127497G85X157581Y127497
   X157578Y121297G85X159858Y121297

"G85" means the machine switches to milling mode, and goes from the first
set of X,Y coordinates to the second set of coordinates.

There is no way this sort of thing can be specified in EAGLE, correct? So
I'm guessing we'll just export the mill layer, and ask the CM to manually
modify the drill file, every time (yuk!).

Vitaliy

PS In case anyone finds this useful, here's a detailed description of the
Excellon file format:

http://www.excellon.com/manuals/program.htm

2009\05\15@080552 by olin piclist

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Vitaliy wrote:
> CM said round holes will cause problems during assembly.

Did they say why?  I've done that a bunch of times without issue.  Unless
the tabs are wide (more than around .052 or .061 hole I'd say), I don't see
why they object.

> There is no way this sort of thing can be specified in EAGLE, correct?
> So I'm guessing we'll just export the mill layer, and ask the CM to
> manually modify the drill file, every time (yuk!).
>
> PS In case anyone finds this useful, here's a detailed description of
> the Excellon file format:

Since you know the Excellon file format and the commands the CM wants, it
doesn't sound hard to write a program to detect overlapping drill holes and
convert them to the drill and slide commands the CM specified.  Overlapping
drills should not otherwise occur.

Have you asked Cadsoft about this?  Maybe there is some way to get Eagle to
specify it directly, or maybe someone has already written a utility to help
with it somehow.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2009\05\15@181117 by Vitaliy

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Olin Lathrop wrote:
>> CM said round holes will cause problems during assembly.
>
> Did they say why?  I've done that a bunch of times without issue.  Unless
> the tabs are wide (more than around .052 or .061 hole I'd say), I don't
> see
> why they object.

The language barrier, and the fact that we are working though an American
intermediary make it difficult to understand exactly what their concern is.
So we just have to take their word for it. :)


{Quote hidden}

Overlapped holes sound tacky. It would be better to have a separate mill
layer (like in the image from the original post), and have the script grab
it from there.


> Have you asked Cadsoft about this?  Maybe there is some way to get Eagle
> to
> specify it directly, or maybe someone has already written a utility to
> help
> with it somehow.

I have not asked Cadsoft about this. For some reason I assumed this is a
common problem and people on this list would have a solution. :)

I'll try to get in touch w/ Cadsoft, and report what they say.

Vitaliy

2009\05\16@163728 by olin piclist

face picon face
Vitaliy wrote:
> The language barrier, and the fact that we are working though an
> American intermediary make it difficult to understand exactly what
> their concern is. So we just have to take their word for it. :)

Or better yet, use a manufacturer with whom you can communicate effectively.
This won't be the last such problem, and the next one is likely to have more
serious consequences.


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Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2009\05\17@015114 by Vitaliy

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Olin Lathrop wrote:
>> The language barrier, and the fact that we are working though an
>> American intermediary make it difficult to understand exactly what
>> their concern is. So we just have to take their word for it. :)
>
> Or better yet, use a manufacturer with whom you can communicate
> effectively.
> This won't be the last such problem, and the next one is likely to have
> more
> serious consequences.

I must admit that I expected this comment. :)

We've been working with this CM since 2003. There are very strong economic
incentives to stay with them. Periodically, we request quotes from other
companies, and they always come back higher. In addition, there's always
risk involved in starting a new relationship, and most companies want you to
pay for the first few orders upfront (we have Net terms with our current
CM).

Vitaliy

2009\05\17@101438 by olin piclist

face picon face
Vitaliy wrote:
> We've been working with this CM since 2003. There are very strong
> economic incentives to stay with them. Periodically, we request quotes
> from other companies, and they always come back higher.

But you have to consider the cost on your end to deal with these guys too.
Think about how much time (=$$) you have already spent with this slotted
hole silliness.  You'd have to be getting one heck of a deal or have very
high volumes for that to still come out ahead compared to a manufacturer
with slightly higher price but much lower hassle level.

When I switched from a Chinese manufacturer to Djula, my overall cost went
down even though Djula's price per unit was a bit higher.  Think about your
total cost in time to manage the production process, wasted time due to
ambiguous communication, cost of dead units you either have to eat or
repair, etc, and the production price by itself is no longer a good
indicator.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2009\05\17@135144 by William \Chops\ Westfield

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On May 15, 2009, at 1:28 AM, Vitaliy wrote:

>    // tool size
>    T21C0.7F423B423S6H2000
>    // the three "slots" for the flat leads:
>    T21
>    X153916Y123436G85X153916Y125179
>    X159837Y127497G85X157581Y127497
>    X157578Y121297G85X159858Y121297
>
> "G85" means the machine switches to milling mode, and goes from the  
> first
> set of X,Y coordinates to the second set of coordinates.
>
> There is no way this sort of thing can be specified in EAGLE, correct?

Sure there is.  Easiest solution: put your slots in the milling layer  
as "correct", and write a ULP that processes the routing layer and  
outputs the excellon format as above in a separate file that can be  
appended to the main drill file.  (or, perhaps it can append to the  
drill file automatically.  I don't recall whether EAGLE ULPs can  
append to existing files...)

(alas, last time I looked, you couldn't invoke the CAM processor from  
ULPs, or I'd suggest using a ULP to do ALL the cad file generation.)

BillW

2009\05\18@013803 by Vitaliy

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face
Olin Lathrop wrote:
>> We've been working with this CM since 2003. There are very strong
>> economic incentives to stay with them. Periodically, we request quotes
>> from other companies, and they always come back higher.
>
> But you have to consider the cost on your end to deal with these guys too.
> Think about how much time (=$$) you have already spent with this slotted
> hole silliness.

Surprisingly, not that much, actually. :)


> You'd have to be getting one heck of a deal

We are.


> or have very
> high volumes for that to still come out ahead compared to a manufacturer
> with slightly higher price but much lower hassle level.

There's also the "cost of entry" factor that I mentioned in the previous
post, that needs to be considered.


> When I switched from a Chinese manufacturer to Djula, my overall cost went
> down even though Djula's price per unit was a bit higher.

How do you know this? Is this a gut feeling you get, or have you actually
crunched the numbers?

This is a real question. The hardest thing about doing these sorts of
estimates, is that a lot of times, the data is simply not available. How do
you convert "ease of communication" to US dollars?


> Think about your
> total cost in time to manage the production process, wasted time due to
> ambiguous communication, cost of dead units you either have to eat or
> repair, etc, and the production price by itself is no longer a good
> indicator.

We got quotes from Djula a couple of times. Of course, my opinion is
subjective, but at this time the difference was enough for us to justify
staying with out current CM.

Vitaliy


2009\05\18@040654 by Alan B. Pearce

face picon face
>How do you convert "ease of communication" to US dollars?

Surely this comes down to how much 'hand holding' (i.e. time spent talking
them through what is needed, when you really should be doing something else)
of the supplier you need to do to get the job done.

2009\05\18@084738 by olin piclist

face picon face
Vitaliy wrote:
>> When I switched from a Chinese manufacturer to Djula, my overall
>> cost went down even though Djula's price per unit was a bit higher.
>
> How do you know this? Is this a gut feeling you get, or have you
> actually crunched the numbers?
>
> This is a real question. The hardest thing about doing these sorts of
> estimates, is that a lot of times, the data is simply not available.
> How do you convert "ease of communication" to US dollars?

Some of it I can measure directly, such as number of working units received,
number of units that were repaired, time to repair them, and number of units
that were ultimately scrapped.

The frustration of carefully wording a question and them having them answer
what they felt like, usually raising more questions that wouldn't get
answered next go around, is harder to measure.  Considerable time was spent
and reception of finished product delayed.  Selling physical stuff like PIC
programmers and development boards is just a sideline.  Embed's main
business is engineering services.  I've got plenty of work and always have
stuff I can do for billable time.  Having to screw around with a contract
manufacturer takes away from billable time and therefore has a direct cost
equal to my bill rate, which is currently $125/hour.  I also feel my
aggrevation is worth something.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

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