ATTN: PCBers SUBJECT: New website and exposure box design for your creative needs

[Leon]

Did you download that file I attached to my last post? It's a Pulsonix PCB file and you should be able to open it by double-clicking it. Alternatively, open it from within Pulsonix.

My paper printout would have been at 600 dpi (default printer setting). I only use 1200 dpi (with the HP Premium Inkjet Transparency setting) when actually creating the artwork on the JetStar film, I have a special setting for the printer in the CAM/Plot output settings. The film will always be superior to ordinary paper, because the latter absorbs the ink. If I used the paper used for printing photographs at 1200 dpi, the printout would probably be about the same as the Jetstar.

[idbruce]

Leon

Yes, I did download the the file and opened it with Pulsonix, but when I tried to print it, it came out HUGE It would probably take me several hours to figure out how to scale it down to the proper size.

Bruce

[Leon]

Did you use the Output > CAM/Plot dialogue to print it? That should output it 1:1, by default.

[idbruce]

Leon

Did you use the Output > CAM/Plot dialogue to print it?

No I did not. Like I said, it would have taken me several hours to figure that out. Thanks for the tip, because it worked like a charm. There is definitely a problem with Eagle and the 4/4 pattern, because with Pulsonix, there is a definite seperation between the lines.


As I mentioned in a previous post, the quality of your print out was much better on a sheet of transparency. I highly doubt it, but I wonder if a laser printer would also have better line definition on a transparent print out. I guess there is only one way to find out.

Bruce

[idbruce]

Leon

Now I wonder about the rest of the patterns in Eagle, even though they look fine to the naked eye, they may also be off ever so slightly.

Bruce

[Leon]

The CAM/Plot dialogue can look complex, but it's actually quite straightforward - you just need to select Windows for output. Mirroring isn't used with Gerber output, but the top layer needs to be mirrored for printed artwork. I think that file of mine was set up for PDF output.

Laser printer output should be better on film, as I suggested for inkjet output. The paper fibres will introduce "noise", even with toner.

You should be able to set Eagle up for accurate output. Perhaps you should ask on the Homebrew PCB group, lots of people there use Eagle. I think that only one person there uses Pulsonix, and he bought it on my recommendation for use where he works.

[idbruce]

I just got finished from disassembling, cleaning (including the laser optics), and reassembling the LaserJet 6L. Once again, it prints immaculate looking sheets at 600 DPI.

So I decided to print out Leons test pattern with once again using Pulsonix in combination with the LaserJet 6L. And once again, there was a definite separation of the lines in the 4/4 pattern.

FOR THOSE OF YOU USING EAGLE (INCLUDING MYSELF), PLEASE BEWARE THAT THE SPACING IS INACCURATE WHEN PRINTING POSITIVES, ESPECIALLY CONCERNING 4/4 PATTERNS

As opposed to learning a new layout editor, I will probably continue to use Eagle until I find more substantial problems.

Bruce

[Wa_Mo]

Interesting thread.

I am also thinking about making my own boards. So, I scoured the net and found these two items:

http://quinndunki.com/blondihacks/?p=835
http://www.youtube.com/watch?v=tWnfnt2rNO0

which I found to be of interest.

[idbruce]

Hello Everyone

Today is the day for some more experimentation I have several masks printed, and I am almost ready to try and create some more boards. However, today I am going to try a different method.

Pertaining to some previous comments that I made, I have given up on trying to acquire the 4/4 pattern, and additionally my main goal has changed. My new goal is to be able to create high quality boards with photo masks being created with the minimum of a 600 DPI laser printer. The two main reasons for changing my main goal is as follows:

1. Most people probably would not want to invest the money to obtain a high quality laser photo plot for a simple hobby circuit.
2. Most people probably have access to a 600 DPI laser printer.

In an effort to help me obtain my new main goal, I am now going to test with a minimum trace width of 10 mil, however, I have one sample mask that necks down one of the traces to approximately 6 mil.

One of the main problems that I have had in the past is that my masks were not truly opaque. Since I will not be testing with a laser photo plot, I have decided to double up the transparencies to help create a more opaque mask. Basically two transparencies will be printed for each layer to be exposed, they will then be cut to size, and the two identical transparencies will then be aligned in respect to each other and bonded together by smearing glue along their perimeters. As an additional step to make the masks more opaque, the transparency of each mask that will be placed against the board face will be top-coated with Acrylic Krylon Crystal Clear Satin to blend and darken the toner from the printer. I am sure that this method will vary my exposure time slightly, but I think it will produce much better boards in the long run.

I still have a little work to finish before I start testing, so testing may extend into tommorow. I will begin my testing by trying to achieve a high quality sample of the small image attached below. If and when I achieve this high quality sample, I will then proceed to make a much larger board. For more information pertaining to the larger board, please refer to this thread:

http://forums.parallax.com/showthrea...-And-Education

Hopefully, I will soon have a new sample board and a new stepper motor driver board.

Bruce

[idbruce]

Leon

A while ago, I read somewhere that developer gets old within a 24 hour period, and that you should always mix new batches when developing boards. In your experience, is there any validity to this?

Bruce

[Leon]

I use sodium hydroxide. It lasts indefinitely and I've been using the same stuff for months.

[idbruce]

Leon

That's what I thought. He must be using something different. However, when I started mixing sodium hydroxide, it did appear to get old overnight, so I have been mixing fresh batches all the time. I mixed up a new batch yesterday and there is still a lot left, so instead of discarding the leftover, I figured I would ask you.

Thanks Leon

Bruce

[Leon]

What do you mean by "getting old"? How are you storing it? I keep mine in a plastic milk bottle.

[idbruce]

Leon

I mean it just did not seem to develop as well 24 hours later as compared to when it was initially mixed. Instead of making 16 oz. batches, I have been making 12 oz. batches, and storing it in a glass jar with a plastic lid.

Bruce

[Leon]

Mine works just as well months after I make it up. There just isn't any way it can deteriorate, apart from by absorbing CO2, and that will be minimal. It should be at normal room temperature, about 20C, of course. It takes about 20 seconds to remove the resist, with continuous agitation.

[idbruce]

Leon

I mean it just did not seem to develop as well 24 hours later as compared to when it was initially mixed.

This could have been due to an improper exposure time, but I thought I timed it correctly, and after what I read, I assumed it was fact. Anyhow, it is good to know that that instance was probably just a case of improper exposure and that my mixed chemicals will remain useable.

Thanks Leon

Bruce

[idbruce]

For Those Of You Following Along

For the last several days, I have been spending a lot of time working on another thread which discusses photo masks:

http://forums.parallax.com/showthrea...ing-these-days

As I have determined through experimentation, my biggest problem has been that my photo masks are not truly opaque, and as reflected in the other thread, I have been creating a tool and experimenting with fusing two transparency layers together in an effort to obtain more opaque photo masks. For my first experiments with double layer masks, I created two masks, a top and bottom layer for a 15/16" X 15/16" board. The PDF file attached below, represents the two masks that I created. After a little experimentation, it was determined that the double layer mask definitely needs a longer exposure time, which of course makes perfect sense.

After a few tries, the results are beginning to look quite promising. My last experiment had an exposure time of two minutes as compared to 1 1/2 minutes for a single layer mask. However, it now appears that the double layer masks may still need additional exposure time.

Depending upon my ambition, hopefully I will have a nice sample board later today which will reflect the file below.

Bruce

[idbruce]

To Those That May Be Interested

As mentioned in the previous post, my biggest problem with making PCBs has been the opacity of the photo masks, however, another problem still remains and it is quite significant. Philmore DATAK Premier Series positive acting boards require a developer temperature between 100 and 110 degrees fahrenheit. If the temperature of the developer is below this temperature range, the board will not develop, and if the temperature of the developer is above this temperature range, it will quickly dissolve the photoresist from the board surface. I have ruined many samples and many experiments have gone bad, simply because the developer was not within the specified range, and todays experiments and sample tests are no exception to these minor disasters. At a cost of $0.39 per square inch (including shipping), repeatedly destroying board material can become a little expensive. Considering that my samples are approximately 1" X 1", I have thrown many $0.39 experiments into the trash bin due to improper developer temperature.

Considering that I believe I now have a solution for my photo masks, I now want to tackle the developer temperature problem, because I am tired of ruining board material. In addition to developer temperature, etchant temperature is also a concern. The etchant temperature for these boards should be with the same range as the developer. So by solving the problem for one situation, I also solve it for the other. So my very next goal is to a permanent solution to these problems. The samples will have to wait just a bit longer.

Bruce

[idbruce]

To Those That May Be Interested

Since the creation of the Exposure Box/Cylinder a certain someone (not mentioning any names) has continually claimed to have a better and easier process. However, this unnamed person has never accepted the challenge of producing a quarter size double-sided board that is well aligned on both sides. Now this same person continually battles all my ideas. I personally think he is jealous and incapable of producing such a small board that looks as good as the one provided below.

Now that my PCB Prototyping Table is complete and now that I have much better control over the temperature of my chemicals, I can now start experimenting with the exposures of my double-layered photo masks.

Let's see if he can keep up, shall we?

Over the next several days, we will see which one of us has the better technology and setup, and who can put out the highest quality board.

Let the competition begin!

Bruce

[Leon]

Let's see a real board, with 8/8 mil tracks, and drilled holes.