37 lines
1.9 KiB
Markdown
37 lines
1.9 KiB
Markdown
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title = 'Testing the Upgrade of the UV Exposure Unit'
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date = 2026-09-09T20:12:00+02:00
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draft = false
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cover = 'cover.jpg'
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So, what about the exposure time? As part of a project that had been on the to-do list for quite some time and has now been tackled (see the following article), the exposure unit was put to use. However, since no exposure series had been performed with it after the [upgrade to 96 LEDs (a doubling of the number)]({{< ref "posts/2026/04/exposure-unit-upgrade.md" >}}), it was now time to do so.
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The basis for this is a test board, which is divided into 5 sections and primarily contains conductive traces of various thicknesses.
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The design was printed (unfortunately not mirrored ;) on two sheets of foil (using an inkjet printer) and glued with the printed side facing the photo-coated raw PCB, after which I proceeded to expose it. First, I exposed everything for 19 minutes, and then gradually covered the respective columns with aluminum foil. The following table shows the respective exposure times:
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| Column | Time [min] | Condition |
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| ------ | ---------- | ------- |
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| T0 | 19 | very good |
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| T1 | 20 | very good |
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| T2 | 21 | good |
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| T3 | 22 | good |
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| T4 | 23 | good |
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There are some visible breaks in certain places, such as next to the label `2.0mm`. However, this is due to the printout. The same reason explains why the conductor paths merge at the thinnest point.
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The circuit board was then etched in 300 g of sodium hydroxide solution (etchant: NaOH) at a ratio of 1:100. The etching time was a little over 10 minutes.
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## Conclusion
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So: the exposure time is 19-20 minutes, which is as expected - the time has been cut in half, from 42 minutes to a nice round 20 minutes!
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In any case, for the next project (which will be the subject of an upcoming article), the imagesetter produced results with this setting that were truly satisfying—at least for me. |