Homebrew_PCBs

I have a project idea that would require hundreds (possibly thousands)
of very small PCBs, each one being a circle approx. 1/2 inch in
diameter. Does anyone know if it would be possible to punch them out
of thin FR4 with a punch press? That is, use the material that is
normally discarded when punching out a hole.

Aside from that, what (if any) are the issues with using thin (0.010"
- 0.030") PCB material in general?

-p.

On 5/10/2014 8:31 PM, Peter Johansson rockets4kids@...
[Homebrew_PCBs] wrote:

>
> I have a project idea that would require hundreds (possibly thousands)
> of very small PCBs, each one being a circle approx. 1/2 inch in
> diameter. Does anyone know if it would be possible to punch them out
> of thin FR4 with a punch press? That is, use the material that is
> normally discarded when punching out a hole.
>
> Aside from that, what (if any) are the issues with using thin (0.010"
> - 0.030") PCB material in general?
>
>

Hello--

If your board has a ground plane (i.e., is two-sided) and is made of thin
stock, the punching operation can stretch copper around the board's edges
and thus cause possible creepage problems.

This can be a problem if traces on the board's top side go all the way to
the edges.

73--

Brad AA1IP

---
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Peter,

You’re going to wear your punch very fast as FR4 is loaded with glass which is very abrasive.
Unless you can have a very high resistance punch which would cost hundreds of dollars.

I used a punch press to cut boards in a previous job. The wear of the punches and dies were very costly.
so we replaced the whole process by a router. But that was for 0.062” FR4. You have also to make sure that
there is no copper in the cut area.

Jean-Paul
AC9GH

On May 10, 2014, at 8:31 PM, Peter Johansson rockets4kids@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:

> I have a project idea that would require hundreds (possibly thousands)
> of very small PCBs, each one being a circle approx. 1/2 inch in
> diameter. Does anyone know if it would be possible to punch them out
> of thin FR4 with a punch press? That is, use the material that is
> normally discarded when punching out a hole.
>
> Aside from that, what (if any) are the issues with using thin (0.010"
> - 0.030") PCB material in general?
>
> -p.
>
>

You might try a 5/8"OD diamond thin wall core drill; it may be close
enough to 12"ID and I think the FR4 would clear any copper buildup, and
likely wear well.
Just a thought...
Roger
On 5/10/2014 7:10 PM, Jean-Paul Louis louijp@... [Homebrew_PCBs]
wrote:

> Peter,
>
> You’re going to wear your punch very fast as FR4 is loaded with glass which is very abrasive.
> Unless you can have a very high resistance punch which would cost hundreds of dollars.
>
> I used a punch press to cut boards in a previous job. The wear of the punches and dies were very costly.
> so we replaced the whole process by a router. But that was for 0.062” FR4. You have also to make sure that
> there is no copper in the cut area.
>
> Jean-Paul
> AC9GH
>
>
> On May 10, 2014, at 8:31 PM, Peter Johansson rockets4kids@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>
>> I have a project idea that would require hundreds (possibly thousands)
>> of very small PCBs, each one being a circle approx. 1/2 inch in
>> diameter. Does anyone know if it would be possible to punch them out
>> of thin FR4 with a punch press? That is, use the material that is
>> normally discarded when punching out a hole.
>>
>> Aside from that, what (if any) are the issues with using thin (0.010"
>> - 0.030") PCB material in general?
>>
>> -p.
>>
>>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo Groups Links
>
>
>
>

On Sat, May 10, 2014 at 10:10 PM, Jean-Paul Louis louijp@...
[Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:

> You’re going to wear your punch very fast as FR4 is loaded with glass which is very abrasive.
> Unless you can have a very high resistance punch which would cost hundreds of dollars.
> I used a punch press to cut boards in a previous job. The wear of the punches and dies were very costly.

This is my concern as well. This is part of the reason I want to go
with as thin a board as I can get away with. Do you recall how many
cuts you were getting per punch/die set?

> so we replaced the whole process by a router. But that was for 0.062” FR4.

That is my other option. I am looking at something on the order of
several hundred boards for my prototype run, and if I go into
production beyond that I will probably have the boards professionally
made. There are still a few unknowns, and I would prefer to work them
out making the PCBs myself before setting up a job.

Speaking of which, does anyone know a board house that is friendly
towards lots of (cutting) routing?

> You have also to make sure that there is no copper in the cut area.

Yes, I had figured that the punch could damage any traces along the
cut. That shouldn't be a problem.

-p.

Regardless of the cutting method used there should never be any copper
near the cut line.

Mind that round hand operated punches typically have a pip in the
center to locate a center punch mark.
You may have to grind that off or maybe you can have a small hole
there and use it.

Some punches heavily deform the disc ( to make it smaller and fit
through the die easier), those may not be suitable.

I have seen small circular PCBs manufactured, and they were routed.
There are good reasons, routing is a standard manufacturing step the
commercial PCB supplier can do.
Also leaving the discs connected via breakout tabs means the whole
panel can be processed for machine assembly and testing.

ST




On Sun, May 11, 2014 at 8:32 AM, Peter Johansson
rockets4kids@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com>
wrote:

> On Sat, May 10, 2014 at 10:10 PM, Jean-Paul Louis louijp@...
> [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>
>> You’re going to wear your punch very fast as FR4 is loaded with glass which is very abrasive.
>> Unless you can have a very high resistance punch which would cost hundreds of dollars.
>> I used a punch press to cut boards in a previous job. The wear of the punches and dies were very costly.
>
> This is my concern as well. This is part of the reason I want to go
> with as thin a board as I can get away with. Do you recall how many
> cuts you were getting per punch/die set?
>
>> so we replaced the whole process by a router. But that was for 0.062” FR4.
>
> That is my other option. I am looking at something on the order of
> several hundred boards for my prototype run, and if I go into
> production beyond that I will probably have the boards professionally
> made. There are still a few unknowns, and I would prefer to work them
> out making the PCBs myself before setting up a job.
>
> Speaking of which, does anyone know a board house that is friendly
> towards lots of (cutting) routing?
>
>> You have also to make sure that there is no copper in the cut area.
>
> Yes, I had figured that the punch could damage any traces along the
> cut. That shouldn't be a problem.
>
> -p.
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo Groups Links
>
>
>

A comment on the question of "... what (if any) are the issues with
using thin (0.010" - 0.030") PCB material in general?" I did a run of
an SMT bds about 2.5": x 2.5" in 0.010" thick material and regretted
it. It was just too flimsy and if you intend to do the core drill idea
I'd be suspicious about possible tearing. I'm now using 0.023" thick
material and think it is quite satisfactory and I suspect that it would
be fine in a 1/2" disk. The 0.023" is about as stiff as K&S 0.015 SS
shim. This shim is 430 SS in a dead soft condition. I mention the K&S
shim as it is often available in US craft and hardware stores if you're
trying to get a feel for the stiffness.
Regards,
Charles R. Patton


On 5/10/2014 10:50 PM, Roger Blair Roger.Blair@...
[Homebrew_PCBs] wrote:

> You might try a 5/8"OD diamond thin wall core drill; it may be close
> enough to 12"ID and I think the FR4 would clear any copper buildup, and
> likely wear well.
> Just a thought...
> Roger
> On 5/10/2014 7:10 PM, Jean-Paul Louis louijp@... [Homebrew_PCBs]
> wrote:
>> Peter,
>>
>> You’re going to wear your punch very fast as FR4 is loaded with glass which is very abrasive.
>> Unless you can have a very high resistance punch which would cost hundreds of dollars.
>>
>> I used a punch press to cut boards in a previous job. The wear of the punches and dies were very costly.
>> so we replaced the whole process by a router. But that was for 0.062” FR4. You have also to make sure that
>> there is no copper in the cut area.
>>
>> Jean-Paul
>> AC9GH
>>
>>
>> On May 10, 2014, at 8:31 PM, Peter Johansson rockets4kids@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>>
>>> I have a project idea that would require hundreds (possibly thousands)
>>> of very small PCBs, each one being a circle approx. 1/2 inch in
>>> diameter. Does anyone know if it would be possible to punch them out
>>> of thin FR4 with a punch press? That is, use the material that is
>>> normally discarded when punching out a hole.
>>>
>>> Aside from that, what (if any) are the issues with using thin (0.010"
>>> - 0.030") PCB material in general?
>>>
>>> -p.
>>>
>>>
>>
>> ------------------------------------
>>
>> Be sure to visit the group home and check for new Links, Files, and Photos:
>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo Groups Links
>>
>>
>>
>>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo Groups Links
>
>
>

On Sun, May 11, 2014 at 2:23 PM, Charles R Patton
charles.r.patton@... [Homebrew_PCBs]
<Homebrew_PCBs@yahoogroups.com> wrote:

> A comment on the question of "... what (if any) are the issues with
> using thin (0.010" - 0.030") PCB material in general?" I did a run of
> an SMT bds about 2.5": x 2.5" in 0.010" thick material and regretted
> it. It was just too flimsy and if you intend to do the core drill idea
> I'd be suspicious about possible tearing. I'm now using 0.023" thick
> material and think it is quite satisfactory and I suspect that it would
> be fine in a 1/2" disk.

Thanks for the heads up. I found some cheap single sheets of 0.010"
and 0.026" at electronics goldmine and I am currently awaiting
delivery on those for testing.

I did price out diamond core drills and gacked at the $50 - $150 price
tag. Between the price, the dust issues, and the potential for the
cut-outs to get caught up in the bit I am going to keep this as a last
resort.

-p.

Do you really need a fiberglass backed board? There are other
materials available that would allow punching with far less problems
with punch wear.

I would talk to a PC board manufacturer. I am sure they can make some
good suggestions.

On Tue, May 13, 2014 at 7:22 PM, Paul Alciatore palciatore@... wrote:

> Do you really need a fiberglass backed board? There are other
> materials available that would allow punching with far less problems
> with punch wear.

I don't need fiberglass, but I have not found a source for thin,
non-fiberglass board

> I would talk to a PC board manufacturer. I am sure they can make some
> good suggestions.

At the suggestion of others I have investigated this. It turns out
that routing out all these discs is not going to be nearly as
expensive as I had thought, and that is now the route I am going to
take.

-p.

Most boards are made with fiberglass but an internet search for "thin PCB material" instantly yielded over two million results. I am sure that somewhere in there you would find a supplier of a suitable material.

But I see you are going another way so good luck with it. I have my own boards to make now. Bye!