PCB Cutting

Mark Jones wrote:

Is scoring the copper clad really going to achieve a clean break? Seems to me
you'd have to at least score through the copper into the fiberglass.
Click to expand...
Agreed. If you score through something like 1/8th to 1/4 of the way
through the board from each side, than the break isn't too fuzzy and
doesn't cause delamination to extend too far into the board from glass
fibers being pulled out of the matrix. After sliding the board along
a piece of silicon carbide sandpaper on the bench, the edged can look
pretty good.
But, yes, the scoring needs to be more than a surface blemish.

A negative I haven't seen mentioned in this thread about sawing
methods is the very hazardous properties of the fiberglass dust
generated. It is one of the reasons I dislike any method that
involved high speed cutters that disperse the dust into the air. I
have had months of respiratory problems following such procedures.
--
John Popelish
 
John Popelish wrote:
Mark Jones wrote:


Is scoring the copper clad really going to achieve a clean break? Seems to me
you'd have to at least score through the copper into the fiberglass.


Agreed. If you score through something like 1/8th to 1/4 of the way
through the board from each side, than the break isn't too fuzzy and
doesn't cause delamination to extend too far into the board from glass
fibers being pulled out of the matrix. After sliding the board along
a piece of silicon carbide sandpaper on the bench, the edged can look
pretty good.
But, yes, the scoring needs to be more than a surface blemish.

A negative I haven't seen mentioned in this thread about sawing
methods is the very hazardous properties of the fiberglass dust
generated. It is one of the reasons I dislike any method that
involved high speed cutters that disperse the dust into the air. I
have had months of respiratory problems following such procedures.
Click to expand...
I seldom use fiberglass for small projects or prototypes, so scoring and
breaking works just fine for phenolics.

--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm
 
Jim Thompson wrote:
On Sun, 13 Mar 2005 15:43:46 -0600, "James T. White"
SPAMjtwhiteGUARD@SPAMhal-pcGUARD.org> wrote:

"Jim Douglas" <james.douglas@genesis-software.com> wrote in message
news:UMednZIpwM2FxanfRVn-hw@comcast.com...
How do you guy's do this, I have bare PCB that is 6x6" and I am building a
board of 2x3", what do you use to cut the boards. Before this I used the
paper cutter at the office but got caught and don't want to get yelled at by
the admin again! I am thinking a trip to Home Depot or ??


Jim,

I've used a table top jigsaw with reasonable results. Good points are that the
saw kerf is really small so you don't waste a lot of board material. Bad points
are that FR4 is a bit tough on the blades (at least they are cheap) and the
small blade tends to want to follow the lay of the fiberglass which can make
"straight cuts" difficult at times.

While I've never tried it, I always thought the ideal way to cut PCB material
would be a band saw with a fine tooth, carbide tipped blade. Using a panel
cutting jig so you could clamp the PCB material down and cranking the blade
guide down would make cutting even small PCB's pretty safe.

As I have access to them, I also thought about using a table saw or power miter
with a fine tooth carbide blade but never did due to the amount of waste in the
saw kerf. FR4 is relatively hard and brittle so the chipping might be excessive
even with a fine tooth carbide blade designed for cutting wood. Using a
non-ferrous metal carbide blade with a negative rake angle might solve this but
still removes about 1/8" of material. Table saw safety would dictate using a
panel cutting jig with clamps for the PCB. With the power miter you could just
clamp the PCB down to the saw table.

I'd be interested if you figure out any better ways to cut PCB material. Good
luck and be safe.

Reminds me that friend DOES use a small-bladed, carbide-tipped, table
saw to cut FR4.

I've also, on rare occasions, used a small hand-held rotary tile saw
(Makita) with a diamond blade. Cuts the FR4 cleanly, but tends to
"mooosh" the metal edge when you cut across a ground plane.

...Jim Thompson
Click to expand...
It doesn't get any better than this:


http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=80463


In case that link is broken, start here and click on the little table saw:

http://www.micromark.com


This thing, with the carbide blade, makes an edge that is perfectly
smooth and straight.


Love it!




Good day!





--
_______________________________________________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarleRemoveThis@BOGUSsandia.gov
NOTE, delete texts: "RemoveThis" and "BOGUS" from email address to reply.
 
On Tue, 15 Mar 2005 08:25:33 -0800, Chris Carlen
<crcarleRemoveThis@BOGUSsandia.gov> wrote:

Jim Thompson wrote:
[snip]

Reminds me that friend DOES use a small-bladed, carbide-tipped, table
saw to cut FR4.

I've also, on rare occasions, used a small hand-held rotary tile saw
(Makita) with a diamond blade. Cuts the FR4 cleanly, but tends to
"mooosh" the metal edge when you cut across a ground plane.

...Jim Thompson

It doesn't get any better than this:


http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=80463


In case that link is broken, start here and click on the little table saw:

http://www.micromark.com


This thing, with the carbide blade, makes an edge that is perfectly
smooth and straight.


Love it!




Good day!
Click to expand...
Nice!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"Jim Douglas" <james.douglas@genesis-software.com> wrote in message
news:UMednZIpwM2FxanfRVn-hw@comcast.com...
How do you guy's do this, I have bare PCB that is 6x6" and I am building a
board of 2x3", what do you use to cut the boards. Before this I used the
paper cutter at the office but got caught and don't want to get yelled at by
the admin again! I am thinking a trip to Home Depot or ??
Click to expand...
Jim,

I've used a table top jigsaw with reasonable results. Good points are that the
saw kerf is really small so you don't waste a lot of board material. Bad points
are that FR4 is a bit tough on the blades (at least they are cheap) and the
small blade tends to want to follow the lay of the fiberglass which can make
"straight cuts" difficult at times.

While I've never tried it, I always thought the ideal way to cut PCB material
would be a band saw with a fine tooth, carbide tipped blade. Using a panel
cutting jig so you could clamp the PCB material down and cranking the blade
guide down would make cutting even small PCB's pretty safe.

As I have access to them, I also thought about using a table saw or power miter
with a fine tooth carbide blade but never did due to the amount of waste in the
saw kerf. FR4 is relatively hard and brittle so the chipping might be excessive
even with a fine tooth carbide blade designed for cutting wood. Using a
non-ferrous metal carbide blade with a negative rake angle might solve this but
still removes about 1/8" of material. Table saw safety would dictate using a
panel cutting jig with clamps for the PCB. With the power miter you could just
clamp the PCB down to the saw table.

I'd be interested if you figure out any better ways to cut PCB material. Good
luck and be safe.

--
James T. White
 
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