Laser cutter for DIY PCB

[KamalS]

I am interested in knowing how many of you have experimented with a laser cutter for DIY PCB?

Would love to hear what kind of experiences you have had.

This method does away with worrying about a laminiator and laser printer but in this case too, just like toner and paper's critcal for toner transfer, the choice of spray is extremely imporant!

For those who have good experiences using a laser cutter, could you share the details of the spray used?

From what I have read, bad choice of a spray can generate the following issues in the least:

- melts with the laser and cools over the traces which were just engraved, ruins everything

- is very difficult to remove using acetone or thinner (even after etching) in order to solder on the traces; requires to be scrubbed off (potentially damaging very thin traces)

- evaporates but leaves behind a film/residue on the board that is resistant to etching (some can be removed with alcohol/acetone)
This last issue has been well documented on this picture set:

http://groups.yahoo.com/group/Homebrew_PCBs/photos/album/540603270/pic/551305033/view?picmode

What vers5d did first was spray the copper clad with some Rustoleum paint: something like **broken link removed** .

The picture "Before etching" is what he got *after* using the laser cutter to "cut away" that spray on resist from places that needs to be etched later.
(This is the reverse process of toner transfer/plot. Pretty timeconsuming I believe. Perhaps making a pattern like that used in isolation milling would require less time?)

Then he wiped the right hand portion of the PCB with some acetone, thus clearing away the spray residue.

After this he proceeded to etch the board to get "After etching"

"After cleaned" is what he got after scrubbing the board after it was etched

I agree with his observation "With the right resist and some adjustment for the laser's dot size. It should work nicely."

I am interested in taking this further and would entertain exchange from others who are interested likewise.

 

[Sceadwian]

The Yahoo Groups link you provided is dead to anyone that refuses to go through the entire registration process. I see no practical information which shown this has ever actually worked more than once, it's far more complicated than a toner transfer mask resist, and has benefits only to an elite crow of highly technical people which can implement it's advantages over a simple toner resist.

 

[SABorn]

It really sounds like a lot of work and doing things the hard way.

Using Photo resist is 100 times easier and gives perfect results, no laser needed just UV light, that can be just a bunch of UV leds or fluro tubes, etc.

Commercial grade precoated board is not very dear and gives consistant results.

 

[KamalS]

The Yahoo Groups link you provided is dead to anyone that refuses to go through the entire registration process. I see no practical information which shown this has ever actually worked more than once, it's far more complicated than a toner transfer mask resist, and has benefits only to an elite crow of highly technical people which can implement it's advantages over a simple toner resist.

The pictures were just to demonstrate the issues with some brand of sprays that could have otherwise been a good etch resist.

This post I made is not detailed enough to help people get started with this, but more a request for people who have got it working to share.

It really sounds like a lot of work and doing things the hard way.

Using Photo resist is 100 times easier and gives perfect results, no laser needed just UV light, that can be just a bunch of UV leds or fluro tubes, etc.

Commercial grade precoated board is not very dear and gives consistant results.

Commercial grade precoated board would be a good thing to have: what are good sources?

I see a few at Fry's : $25 for a 4"x4"!

 

[SABorn]

I see a few at Fry's : $25 for a 4"x4"!

Gee that is dear, i pay $25.00 for a 300mm x 400mm sheet.

Not sure on a supplier in your neck of the woods, but a google search might find a few suppliers.

I like Kinsten brand board and it works well, it really is a very simple process once you are set up to expose the boards.

You dont need a laser printer as bubble jet works fine (if not better than laser)

Pete.

 

[Sceadwian]

Kamal, I think you missed the point, that Yahoo group requires you to be a member of it in order to view any of it's content, the link your provided is broken to anyone that isn't registered, you can't expect every member from this board to become a member in order to view the images.

www.mpja.com is one site that sells pre-sensitized boards.

SABorn, what process are you talking about that uses a bubblejet, do you mean a bubble jet printed resist on transparency? I'd recommend a good laser printer over bubblejet any day, laser toner is almost totally opaque compared to bubblejet ink, there has to be some degree of UV bleed through on bubblejet inks.

I haven't had the need to make boards myself yet, but the basic laser printed transparency on coated boards is definitely very simple.

 

[KamalS]

I might have some good news.

Someone messaged me that they have had very good results with a different Rustoleum paint.

Will keep you posted.

I am sorry about that link: didn't realize it was members only. I will see if I can upload them somewhere else after I get permission from the owner.

 

[SABorn]

SABorn, what process are you talking about that uses a bubblejet, do you mean a bubble jet printed resist on transparency? I'd recommend a good laser printer over bubblejet any day, laser toner is almost totally opaque compared to bubblejet ink, there has to be some degree of UV bleed through on bubblejet inks.

I haven't had the need to make boards myself yet, but the basic laser printed transparency on coated boards is definitely very simple.

Sceadwian,

I feel that i have banged this drum many times in the past.
Transparencies is not a good material to print onto for photo resist, transparencies are designed to allow light through the ink for overhead projection, and printers wont print enough ink on the plastic film without smudging.

What i have used for over 1000 boards with excellent results, with either bubblejet or laser is just a good quality plain white paper, UV light will go through plain white paper, and a good amount of ink can be applied without smudging, it fractionally increases exposure time but for the home hobbyist that is neither here or there, its cheap and we all have plain paper on hand.

The trick i use is to wipe vegetable oil (cooking oil) over the paper after printing (it wont effect the ink) this makes the paper almost see through and decreases the exposure time.

A bit of paper towel (or toilet paper) with a dob of oil and wipe it over the paper, wipe off any excess and you are ready to expose your board.
I guarantee you will get better results than with transparencies, and at a fraction of the price, with the ability to use any printer you have.

Try it yourself with a page of printed text and wipe a dash of oil over the paper, you will soon see how clear the text will show through the paper.

Pete.

 

[Wp100]

Hi,

"I feel that i have banged this drum many times in the past."

Glad you have done - its the first time I have seen your comments.

UV light will go through plain white paper,

Learnt something there, have been using tracing paper in the past, seems to allow laser toner to adhere quiet well.

The trick i use is to wipe vegetable oil (cooking oil) over the paper after printing

Will certainly give it a try on my next board, but should the oil be on the toner side or the back side - if it makes any difference ?

 

[SABorn]

should the oil be on the toner side or the back side - if it makes any difference ?

I apply the oil on the back side but it will soak through so wipe the excess off of bothe sides.

After exposing the board, give the board a gentle wipe over with a soft tissue to remove any oil smudges before developing, the oil wont hurt anything but can make developing uneven if the film is left on the board.

You soon get the proceedure in hand without problems but would rather point out the minor issues, so you know what to look out for to start with.

Dont reuse the artwork after 24-48 hours as the grain in the paper changes with the oil and effects the image, i find it much easier to keep the artwork in file on the PC and just print a fresh copy when needed anyway, rather than to store previous prints.

Pete.

 

[Sceadwian]

It seems far easier to use a laser on transparency, no muss or fuss with the oil, and I still question the absolute UV blocking ability of bubblejet inks. Toner is as nearly opaque as it is possible to get.