My experiance cutting printed circuit boards

[Michael Simpson Virgina]

I have designed several printed circuit boards many of them have several small boards that must be cut out. This is done for a couple reasons.

1. When I had them made it was cheaper to included duplicates of several small circuits on a larger board.

2. Some of the circuits are modular and can work together or as a single circuit.

One of the boards has 24 duplicate circuits. I normally have used a bandsaw with a bi-metal blade to cut them into individual boards. This has been a long and tedious process in the past.

Well I spent some time today and now have a system where I can do them on my laser. What I do is do two deep scores on the front of the board and two on the back. The laser is a 100% power and 80% speed and does two passes. I then flip the board and run it again.

When its done I simply wipe the board down with a little rubbing alcohol and can snap them apart by hand. It takes very little effort as the boards are almost cut through. At 70% speed the cut is complete.

This process seems to leave the least residue on the board. The edges are still black but results are better than using the band saw. Its faster and I get more consistent results.

I just finish separating about 2000 boards today.

[Howard Garner]

Want material for the PC boards?

[Kim Vellore]

You can use a shear to cut and if not too thick just score and snap them. What is your PCB material.

Kim

[AL Ursich]

Excellent website too!!!!

AL:rolleyes:

[Michael Simpson Virgina]

I don't know the actual makeup of the material but its that standard fiberglass like stuff. Its pretty dence stuff. And it sparks and spits like there is no tomorrow when you cut it. I can cut all the way through but the method I described below gives me a very nice cut that requires little cleaning.

On the left is the scored board and on the right are some boards that have been snapped off.

[AL Ursich]

Very Nice.... I hand drew my first circuit board and used this green film to make a photo mask to make a photo sensitized board. Pored the board developer Xylene or something nasty like that in the plastic tray to developer the board.:eek: I was doing this on a Navy Tin Can off the coast of Japan in 1978. The developer melted the plastic tray.... Should have used the aluminum tray.... The Plastic for the Ferric Chloride to etch the board. Well the bottom of the board fell out of the plastic tray.

It was a long month waiting for a new kit... In a day before the Internet and email.... Snail Mail both ways....:(

I have made a few hobby board over the years.

Excellent use of the Laser to score the boards.

AL

[Scott Challoner]

Most circuit boards today are made of FR4. Are you making them yourself or do you have a board house make them? Since you have silk screening on them I am assuming you are having them made. The board house should be able to score them for you. That or route them and leave breakaway tabs. Might save you from some of those nasty fiberglass splinters.

[Scott M Smith]

I like the idea of scoring it with the laser. Do you have a belt sander that you can run the edge on after you break them apart?

[Michael Simpson Virgina]

I have them made. There are only a couple PC board manufactures in the US. Most companies you see in magazines and on the web use these. The US PC manufactures are by far the best in the industry. I have had boards made from many other countries and they just don't hold up like the US boards.

Every thing you have done costs when making a large qty of boards. Routing, scoring, Engineering tests. Most boards I design are only dual layer (top and bottom). They start getting real expensive.

The board shown here is one of my more complicated boards. It contains my main microcontroller as well as a motor and servo controller and computer interface. Its my robot board.

Most of the boards I am cutting now are boards I made 5 or 6 years ago when I didn't have any sense.

My scores are so deep that you don't need to sand them. As a matter of fact I run the laser speed at 80% if I do the same run at 70% they cut through. but there is more residue on the top of the boards. I also find it easier to wipe the boards when they are all still attached. I also sell some boards wholesale and these will now ship out attached and scored so the reseller can break them apart.

[Scott Challoner]

I had no idea the laser would be able to cut the FR4 deep enough to score it. I worked in the electronics manufacturing industry before buying my laser. I was in charge of designing the arrays and approving the artwork from the board houses. Once in awhile, we would get in boards that weren't scored so we would have to send them out. Now I think I know of another service to offer. I've got a few boards lying around. Time for some experimenting.

You're right. Not too many US board manufacturers anymore. There used to be a bunch in the Minneapolis area. Now there are two I think. Same with Chicago. Even the ones that are still here have overseas parters that they farm stuff out to. Probably 90% of the stuff I was working with came from China.

[Keith Outten]

Waytech Electronics
1104 McConville Road
Lynchburg, Va 24502
043-423-7639

They make circuit boards.
.

[Tony Lenkic]

Micahel,

We have number of PCB manufacturers around Toronto area.
Long before I got involved with engraving I was in automation systems mfg. sect. I have good friend and former co-worker that designs en builts custom PCB's. If you check his site you will see some interesting product mostly for plastic industry.His site is: dot-microinterfacedesign-dot-com

[Dan Hintz]

It is simply no longer worth my time to cut and/or etch PCBs. I can have 50 5"x5" dual-layer PCBs etched, routed with complex outlines, silk screened, and gold-plated for <$300 shipped to my door in a week and a half. I have a powerful laser and some serious design software at my disposal, but it's still MUCH cheaper to send it out.

[Martin Reynolds]

That's neat.

I've been cutting PCBs up using a diamond saw: laser scoring will be easier.

[Michael Simpson Virgina]

@Dan
This is true. When I do boards its normally in the 1000's. Like I said these are older boards and I got a good deal having them done this way. The cost per individual ckt is on the order of 15 cents. Considering they sell unpopulated for $4.95. That is a major profit margin even though they had to be cut. Now its done all the individual ckts have been cut out. I have so many that I doubt I will ever have to have them made again.

Back when I started making my own boards there was PCB PRo and PCB express and a couple others. Now they are all owned by Sunstone.

[Dan Hintz]

Yeah, my proto runs are typically in the 25 count range with actual runs in the 500-1k count area. With actual runs, I pay about $0.01/pad to have all components installed, so small board may cost me $0.50 to completely manufacture (not including component cost) up to $5 for larger boards. At those prices, I can't even pay myself to put full boards into the laser. If I need a next-day proto, I might consider it.