Discussion in 'General Engine Discussion' started by stevehuckss396, Dec 26, 2012.
Steve, what do you call a "gerber file"
Gerber files are the files that circuit board layout programs create.
I think I can generate one, but never tried. I am using the free version of Eagle.
I have three failed attempts at toner transfer here, the main problem being that I was too low on toner to get good thick coverage. Comparing the two methods, I have gotten much better resolution with the photoresist. My test strip was two PIC programming boards for SS and SSOP, and under magnification the pads and 10mil traces were unbelievably sharp. The time and effort put into soaking the paper off made photoresist much faster too. Its well worth the $1 or so extra for resist coated boards
thanks for the info, it's kind of strange I have 3 different programs
to make PCB board and none of them call it GERBER file
Luc, I've tried that myself with mixed results. The iron never seemed to have enough pressure to get the transfer to occur. I suspect flatness was an issue. Any ideas?
Also, the specific printer used made a lot of difference. The LaserJet 2035 at my desk didn't work well at all. Then I tried it using a color LaserJet printing in black. That worked MUCH better.
The whole concept really worked well if I passed the board and transfer paper through a laminator! But, the thickness really taxes the laminator.
That said, Laser toner seems to work very well as a resist if you can successfully get it to transfer over to the copper. What I do know for sure is cleanliness of the copper is of prime importance for decent results.
A Gerber file (also known as RS-274X files) is usually generated by the layout program as a separate operation. Since Gerber files don't know anything about the netlist or footprint information, PCB software saves the board project in its own native file. There is one Gerber file for each layer in your board.
The downside is that a lot of freebie packages use a proprietary format that only allows you to deal with the manufacturer associated with the software. That being the case, there is no GERBER file generator. ExpressPCB comes to mind as an example.
So, in order to generate GERBER files, you usually have to configure the output, then command the software to generate the files as a separate operation. I've seen it in several different programs and all manage it diffrent:
File | Export | Gerbers,
File | Generate Fabrication Drawings
Tools | Create Gerber Files
There doesn't seem to be any standard file extension for Gerber files. Most PCB layout software generates a report file or a readme document that specifies what Gerber file corresponds to what feature on the board. For example, top layer, solder side layer, intermediate layers, solder mask, silkscreen, etc.
All that said, it's up to you to specify to the board manufacturer the layer stack-up order, thicknesses of copper and prepreg, finished thickness, whether you want to cap vias, etc. See some examples below from boards I did... A scanned hand sketch is fine too. Having this information zipped up with your gerbers, will save a day getting the boards fabricated since they won't have to figure it out themselves, or call you for support.
Yes ,maybe I should have mention that to:hDe: for the iron I did purchace a small soldering iron from the hobby shop. The one use to shrink the plastic on air planes wing and other stuff. It's 1/4 the size of a regular one with a nice small tip on it. Usualy I will iron for about 5 min minimum
The main reason why I prefer kodac paper is that you can use the sheet to
it's fullest , Transfer paper once it's used it's over kodac paper trans fer your circuit put it back in the printer select the area you whant to print and there you go. my 2cents of experience and love it. When I'm only trying something
I use an etch resist marker draw my circuit manualy on the copper and it,s done there's many way to kill a cat :fan:
6 years later and I'm rebuilding your circuit for a full scale motorcycle. The polarity of C1 has got me puzzled: isn't C1 reverse biased when the points or hall effect are open? It gets discharged through R4, R1 and U1, but it also supplies current to the base resistor of U2 through R1, sending a current through C1 that will build up a reverse voltage.
Or maybe it didn't cause a problrm in your application, feeding the circuit with 6V instead of the 14.4V that I will be feeding it.
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