Author Topic: Cutting a trace  (Read 24122 times)

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Offline requim

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Cutting a trace
« on: October 31, 2011, 09:22:51 am »
What's the best way to cut a trace (ie disconnect it) on an existing PCB?  The service notes on a power supply i own required that I do it.  Needless to say the circuit board, while still working, looks awful having taken a screwdriver to it since nothing else seemed to work.
 

Uncle Vernon

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Re: Cutting a trace
« Reply #1 on: October 31, 2011, 10:38:24 am »
What's the best way to cut a trace (ie disconnect it) on an existing PCB?
A utility knife, a scalpel even hand twisting a small diameter drill bit seem to work effectively.
 

Offline requim

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Re: Cutting a trace
« Reply #2 on: October 31, 2011, 01:59:02 pm »
Looks like it is high time I drive down to Office Depot to pick up that X-acto knife I've been meaning to get.  Wish I could undo the damage I did to that poor PCB.  C'est la vie.
 

Offline Cj1corbystarlet

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Re: Cutting a trace
« Reply #3 on: October 31, 2011, 02:15:24 pm »
I find a Dremel tool with a 1mm or 1.5 mm ball tools does the job for me.

Just don't consume any coffee before hand, Wait until the the job is one then pour a pot.

Regards
Ben
 

Offline hacklordsniper

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Re: Cutting a trace
« Reply #4 on: October 31, 2011, 03:56:20 pm »
If i do not have to connect this trace later i just drill it in the middle with a drill bit little more wider than trace. If i really need it to look professional i "delete" it with CNC for PCB manufacturing  :)
Oh, the joy of sending various electronics to silicon heaven
 

Offline Time

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Re: Cutting a trace
« Reply #5 on: October 31, 2011, 04:17:19 pm »
I've used a metal engraver before.  Worked nicely.
-Time
 

Offline Rufus

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Re: Cutting a trace
« Reply #6 on: October 31, 2011, 05:55:50 pm »
What's the best way to cut a trace (ie disconnect it) on an existing PCB?

A sharp craft knife with pointed blade. I prefer the snap off blade ones like http://www.stanleytools.com/default.asp?CATEGORY=SNAP%2DOFF+BLADE&TYPE=PRODUCT&PARTNUMBER=10-475&SDesc=Stanley%AE+FatMax%AE+9mm+Snap+Off+Knife.

Make a two cuts slightly apart with the the blade at 45 degrees as though you were cutting a V groove. The copper between the cuts will lift. Don't press too hard the copper is soft and thin, no need to hack into the fibreglass.
 

Offline requim

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Re: Cutting a trace
« Reply #7 on: October 31, 2011, 06:54:25 pm »
I went ahead and ordered the Stanley 9mm snap-off.  I'll pickup a dremel another day. Thinking I'll still probably pickup a scalpel and a x-acto knife since I imagine they all perform differently.

Thanks for the suggestions.
 

Offline DBaron

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Re: Cutting a trace
« Reply #8 on: October 31, 2011, 10:12:30 pm »
I've personally found a brand new, or at least very sharp, single edge razor blade to be very effective.  You can buy a 100 pack of them for around $7 (US) at your local home store.   Just slice the trace at both ends of the section you want to remove, then you can lift the removed copper right off with the corner of the blade.

I find they're better than an x-acto or utility knife as you get 200 fresh sharp edges that really slice through the copper cleanly with little force, so it minimizes the chance of slipping and cutting more than you bargained for.

Of course you do have to be careful with the blade, as they don't come with quite as nice of a handle...
 

Online IanB

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Re: Cutting a trace
« Reply #9 on: October 31, 2011, 11:02:39 pm »
Thinking I'll still probably pickup a scalpel and a x-acto knife since I imagine they all perform differently.
Don't fall into the trap I fell into of thinking that the genuine X-Acto brand knife must be best. I only realized after buying one that it didn't come with a protective blade cover. Since then I've noticed that every other brand of craft knife is not only less expensive but also it often comes with a protective cap for the blade. So look carefully at what you get before you just grab one off the shelf.
« Last Edit: November 01, 2011, 04:35:11 am by IanB »
 

Offline requim

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Re: Cutting a trace
« Reply #10 on: November 01, 2011, 04:23:34 am »
Well I went ahead and purchased an X-acto knife at Office Depot this evening as well.  It came with a blade cover and was $4.69 including tax.  Seemed reasonable to me.  If I don't like it I won't buy any more X-acto stuff, and if I do, I will.  May try the razor blade thing too.  Razor blades are always handy to have around.  In fact I know I bought a small pack of them within the last few months.  Now where did I put them??
 

Offline sonicj

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Re: Cutting a trace
« Reply #11 on: November 02, 2011, 05:39:23 am »
my two favorite blade type tools i own are the Olfa AK-4 and Olfa SVR-1. both are guaranteed for life.

*tip* you can easily sharpen your #11 (and similar) blades using 400 to 600 or so sandpaper. it takes some practice but its not difficult by any means. i do this until i nick the blade badly or snap the tip, then i bin 'em.
-sj
 

Offline BravoV

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Re: Cutting a trace
« Reply #12 on: November 02, 2011, 06:32:52 am »
X-acto cutter are nothing compared to a good quality Japanese made Olfa brand cutter, simply no contest here, its like night and day.

Olfa products will survive many decades to come if you buy one new now, still have my grand-dad's cutter made in early 60s, took quite some beating and harshly used, still works flawlessly and their blade is known for very durable and won't blunt easily.

Offline requim

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Re: Cutting a trace
« Reply #13 on: November 02, 2011, 07:24:36 am »
Wish I'd known that yesterday..  I figure I'll use the X-acto knife either till it gives up or until I don't feel like it's living up to its end of the bargain.
 


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