Dustin Andrews
08-16-2012, 5:16 PM
(tldr: 1. Cermark makes great marks on copper boards meant for circuit boards. 2. Cermark is dissolved by the same chemicals that dissolve copper, so it doesn't make a great etching mask.)
Hi! I've been lurking around the board for a while. I have learned so much from this forum. Thanks to everyone who has posted such useful information.
I've been having a lot of fun using my laser to make geared toys for my family and enclosures for electronics. I prototype a lot of circuit boards and I get good results with the toner transfer method, but the laser seems to have a lot of potential. After looking around the internet and this forum I decided I would do some experimentation and see if I could come up with a workable process. If I can get the laser working it will cut my prototyping time in half or less.
In order to be useful I need to be able to etch traces that are 8 mil wide with 10 mill clearances between (6 would be ideal). I can (just) do 10/6 with a laser printer and toner transfer.
The ideal process would use the laser to etch the mask in one step. I've been experimenting with Kapton tape. The results are promising, but I haven't found a setting that will vaporize all the tape without destroying the fine details. I suspect I might be able to dial it in with some more work. It might take two or three passes at different power to get it to work.
This week I got a bottle of Cermark and experimented with it on 1/2oz copper clad fiberglass (aka PCB). Here is what I have learned so far.
239268
On the left is the Cermark after coming out of the laser. I superimposed my speed and power notes in the image.
I started the test at 100% power and slow speeds. The Cermark got hot enough to burn the copper right off the board at really low speeds. My 40 watt laser can't mark the copper at this speed alone. The blobs at the bottom are where the burning was worst. Then I used a sponge with some Ferric Chlorid and rubbed the board gently until all the copper between the tests was gone.
The results were mixed. On the plus side the Cermark made a good clean mark on the board that I couldn't scratch off easily. It also worked somewhat decently as a mask. The Ferric Chloride actually removed the Cermark as well as the copper. I was hoping that it wouldn't remove it at all. Still, the copper pattern was preserved decently.
This first pass showed me that I was going to hot. So I did another pass (on the back side of the same board) with lower settings.
239269
In this image you can see the Cermark made a really good mark on the copper at 1000 DPI, Speed 100% Power 50-70%. The top is before rinsing off the Cermark. The middle shows after rinsing and light scrubbing with a soft sponge. The bottom is after etching. This time I switch to etching with Muratic Acid + Hydrogen Peroxide. It's a bit gentler etching solution and I soaked instead of rubbed.
Results: I realized I should have been using a negative image so this board is the inverse of the one above. The detail in the etching is not quite good enough, but the marks are once again excellently bonded. The wires are just touching in places where they should be separate. Once again the Cermark dissolved in the etchant, but not before protecting the copper long enough to get a halfway decent etch.
70% worked the best, so I ran one more test bracketing that setting. I also changed to the lowest DPI setting to see if that would have any affect.
239273
Results: 250 DPI was no better or worse than 1000 and a three times faster. All of the marks at these speeds and powers were great. The Etchant once again ate into the Cermark a little too fast. The etches all look different, but the differences (IMHO) are mostly due to the way the etchant works as you gently agitate it. None of the traces came out usable.
Cermark may yet be usable. I have some "trf" film that can be used to seal toner in the toner transfer process. Most likely it will stick like a champ to Cermark. However, it's "blobby" and can't do the resolution I need for my smaller designs. I may give it a try and post some results just to see if it will stick to the Cermark for use in decorative etching.
Hi! I've been lurking around the board for a while. I have learned so much from this forum. Thanks to everyone who has posted such useful information.
I've been having a lot of fun using my laser to make geared toys for my family and enclosures for electronics. I prototype a lot of circuit boards and I get good results with the toner transfer method, but the laser seems to have a lot of potential. After looking around the internet and this forum I decided I would do some experimentation and see if I could come up with a workable process. If I can get the laser working it will cut my prototyping time in half or less.
In order to be useful I need to be able to etch traces that are 8 mil wide with 10 mill clearances between (6 would be ideal). I can (just) do 10/6 with a laser printer and toner transfer.
The ideal process would use the laser to etch the mask in one step. I've been experimenting with Kapton tape. The results are promising, but I haven't found a setting that will vaporize all the tape without destroying the fine details. I suspect I might be able to dial it in with some more work. It might take two or three passes at different power to get it to work.
This week I got a bottle of Cermark and experimented with it on 1/2oz copper clad fiberglass (aka PCB). Here is what I have learned so far.
239268
On the left is the Cermark after coming out of the laser. I superimposed my speed and power notes in the image.
I started the test at 100% power and slow speeds. The Cermark got hot enough to burn the copper right off the board at really low speeds. My 40 watt laser can't mark the copper at this speed alone. The blobs at the bottom are where the burning was worst. Then I used a sponge with some Ferric Chlorid and rubbed the board gently until all the copper between the tests was gone.
The results were mixed. On the plus side the Cermark made a good clean mark on the board that I couldn't scratch off easily. It also worked somewhat decently as a mask. The Ferric Chloride actually removed the Cermark as well as the copper. I was hoping that it wouldn't remove it at all. Still, the copper pattern was preserved decently.
This first pass showed me that I was going to hot. So I did another pass (on the back side of the same board) with lower settings.
239269
In this image you can see the Cermark made a really good mark on the copper at 1000 DPI, Speed 100% Power 50-70%. The top is before rinsing off the Cermark. The middle shows after rinsing and light scrubbing with a soft sponge. The bottom is after etching. This time I switch to etching with Muratic Acid + Hydrogen Peroxide. It's a bit gentler etching solution and I soaked instead of rubbed.
Results: I realized I should have been using a negative image so this board is the inverse of the one above. The detail in the etching is not quite good enough, but the marks are once again excellently bonded. The wires are just touching in places where they should be separate. Once again the Cermark dissolved in the etchant, but not before protecting the copper long enough to get a halfway decent etch.
70% worked the best, so I ran one more test bracketing that setting. I also changed to the lowest DPI setting to see if that would have any affect.
239273
Results: 250 DPI was no better or worse than 1000 and a three times faster. All of the marks at these speeds and powers were great. The Etchant once again ate into the Cermark a little too fast. The etches all look different, but the differences (IMHO) are mostly due to the way the etchant works as you gently agitate it. None of the traces came out usable.
Cermark may yet be usable. I have some "trf" film that can be used to seal toner in the toner transfer process. Most likely it will stick like a champ to Cermark. However, it's "blobby" and can't do the resolution I need for my smaller designs. I may give it a try and post some results just to see if it will stick to the Cermark for use in decorative etching.