clean up

Readme.md

@@ -25,11 +25,13 @@ sudo apt update
 sudo apt install kicad
 ```
 
-### 2. KiCad: Set your design grid
+### 2. KiCad: Set your design grid (Optional)
-In KiCad's PCB editor, go to `Preferences → Preferences → PCB Editor → Grids` and add a custom grid of 0.017 mm. This ensures trace edges land on pixel boundaries and avoids the sub-pixel rounding that causes the ±1px size error people see with arbitrary grids.
+In KiCad's PCB editor, go to `Preferences → Preferences → PCB Editor → Grids` and add a custom grid of 0.017 mm (your MSLA printer's pixel size). This ensures trace edges land on pixel boundaries and avoids the sub-pixel rounding that causes the ±1px size error people see with arbitrary grids.
 
 ### 3. Export gerbers from KiCad
 
+*If you want to automate the conversion of gerber to printing files, you can jump to the section [Appendix: Automated script](#appendix-automated-script).*
+
 - Open your PCB project in the KiCad PCB Editor.
 - Go to **File -> Plot** and select `Plot format` as `SVG` and set the `Output directory`.
 - In the `Include Layers` section select layers `F.Cu`, `B.Cu`, `B.Mask` and `F.Silkscreen`. Each layer will be ploted as a separate SVG file.
@@ -49,8 +51,6 @@ This file is reused for every job — it carries the correct LCD resolution meta
 
 ## MSLA PCB Exposure
 
-*If you want to automate the conversion of gerber to printing files, you can jump to the section [Appendix: Automated script](#appendix-automated-script).*
-
 `UVtools` has a dedicated `PCB Exposure` tool that converts a Gerber file to a pixel-perfect image given your printer's LCD resolution, specifically for exposing copper traces.
 
 ### 1. Install `UVtools`
@@ -120,7 +120,11 @@ Use the project [kicad2gcode](https://gitea.virtonline.eu/2HoursProject/kicad2gc
 
 Automate the conversion from KiCAD to print files using a script.
 
-### 1. Install dependencies
+### 1. The `Dummy.pm4n` file
+
+Make sure you have the `Dummy.pm4n` file specific to your printer. See the section [5. Create the `Dummy.pm4n` file](#5-create-the-dummypm4n-file) above.
+
+### 2. Install dependencies
 
 ```bash
 python3 -m venv .venv
@@ -130,7 +134,7 @@ pip install pygerber Pillow numpy
 
 Or activate the `venv` once and put `source .venv/bin/activate` in your shell profile.
 
-### 2. Export multiple layers (e.g. copper + soldermask + silkscreen)
+### 3. Export multiple layers (e.g. copper + soldermask + silkscreen)
 
 ```bash
 ./export.sh \
@@ -161,18 +165,18 @@ output/pm4n/Flow_Controller_Panel-F_Silkscreen.preview.png
 output/pm4n/Flow_Controller_Panel-B_Silkscreen.pm4n
 output/pm4n/Flow_Controller_Panel-B_Silkscreen.preview.png
 ```
-#### 2.1. Check the layer preview
+#### 3.1. Check the layer preview
 Check the `output/pm4n/Flow_Controller_Panel-*.preview.png` images — traces should appear black on white background.
 - background = UV exposed = resist removed = etched away
 - traces = dark = resist kept = copper stays
 
-#### 2.2. Check the printer exposure
+#### 3.2. Check the printer exposure
 Open the `.pm4n` in `Chitubox Basic` slicer to visually verify before printing.
 
-#### 2.3. Adjust exposure
+#### 3.3. Adjust exposure
 Start with `--exposure 60` and bracket from there — Bungard presensitized at 405nm typically lands between 30–120s depending on board vintage and storage.
 
-### 3. Export single layer (e.g. copper)
+### 4. Export single layer (e.g. copper)
 
 Export the front layer as gerber
 ```bash
@@ -194,6 +198,8 @@ output/pm4n/Flow_Controller_Panel-Front.pm4n
 output/pm4n/Flow_Controller_Panel-Front.preview.png
 ```
 
+### 5. Verify
+
 Open the preview image
 ```bash
 xdg-open output/pm4n/Flow_Controller_Panel-Front.preview.png