From the manufacturing files of your schematic program, the app mills a single-sided board in three steps: Isolate (a fine engraving bit separates the traces from each other), Drill and Cut out.
Reading the files
Choose File → New → Circuit board or the Circuit board (Gerber) card in the “Import” window. Then drag the ZIP with the manufacturing files or single files into the window. Gerber and drill files dropped straight onto the canvas open the window as well.
The app reads Gerber (RS-274X with X2 attributes) and Excellon drill files from KiCad, EasyEDA, Eagle, Altium and Fritzing. It recognises each layer by content and file name. Under Files and layers you can change any assignment or leave a file out with “Don't use”.
If the outline is missing, the app estimates the edge from copper and holes with a 2 mm margin. The preview then shows it dashed.
Choosing the side
If the board has copper on both sides, choose Top or Bottom below the preview. Each side is its own project. The bottom appears mirrored, the way it lies on the machine after flipping.
Isolating
A V-shaped engraving bit mills around every copper area. The width of the cut depends on tip, angle and depth. The window shows the cut width for the chosen depth. Passes side by side (1 to 5) widens the gap between traces, which makes soldering easier.
The most robust bit whose cut width still fits between the closest traces is preselected. Narrow spots marked in red are smaller than the cut width; traces stay connected there. Choose a finer bit or less depth. A depth of 0.05 to 0.1 mm is common, as the copper is usually only 0.035 mm thick.
Drilling
For each diameter the app suggests a matching drill from the library. Similar diameters share one drill. Holes without a matching drill (such as mounting holes) and slots are milled. Choose a thin cutter for them under “Cut out”.
Cutting out and blank board
A corn cob cutter cuts the board out along its edge. Holding tabs keep it in place until the end. Cutouts inside the board are milled along their inside. For the blank board, enter the thickness (usually 1.6 mm) and the margin around the board.
The finished project
Create board adds the layers “Isolate copper”, “Drill Ø …” for each drill, “Mill holes”, “Cut outline” and the hidden “Silkscreen” for orientation. The material is a circuit board with matching cutting data. In the Cutting tab each cutter is its own program, in the right order.
Stick the blank board fully onto a flat spoil board with double-sided tape. Even a tenth of a millimetre of warp makes the isolation cuts uneven. Probe Z again after every tool change, see Probing Z.
Height probing
Hardly any blank board lies perfectly flat. A tenth of a millimetre of warp is enough for the bit to leave copper connected in one place and cut too deep in another. That is why the machine probes the board in a grid before isolating.
- Set the origin as usual and probe Z on the board.
- Attach the clip to the engraving bit. The counter contact must touch the copper: a second clip on the board edge, or the touch plate laid flat on the copper outside the cutting area. The bit itself is now the probe.
- Choose Machine → Height probing … or Height probing in the machine panel.
- Test the contact: touch the bit and the copper at the same time with a screwdriver. The indicator switches to “contact”. Some controllers only report the probe while probing; then press Test contact: Z moves up slowly by 3 mm, and while it moves you bridge bit and copper. The controller stops at once and the app reports “contact detected”. If you checked the contact another way, tick Probe without contact test.
If the indicator does not switch, the controller will not notice the touch while probing either, and the bit drives into the board down to the search depth. Common causes: the clip is loose, the counter contact is not on the copper, or the copper is oxidised or lacquered. Rub the contact point briefly with a fine abrasive pad. The search depth starts at 0.5 mm below Z 0.
The machine visits the points in a snake pattern, covering the toolpaths plus a small margin. The map shows low spots in blue and high spots in red; below it you see the lowest and highest point and the range between them. With Use height correction when cutting switched on, every toolpath follows the measured surface. Long moves are split into 1 mm pieces for this, and values between grid points are interpolated.
The map belongs to the clamped board and stays in the browser until you probe again or discard it. If the range is more than 0.5 mm, the board probably does not lie flat; stick it down again. After a tool change, probe Z at the same spot as before, and the map still fits.
For engravings and uneven material
Height probing is available for every project, not only PCBs: otherwise engravings, V-carving and shallow pockets get uneven depth on a warped, tilted or unevenly thick board. The bit is the probe; wood and plastic do not conduct, so lay thin aluminium foil flat on top (its thickness is negligible) or clamp a touch probe. The milling assistant reminds you for engravings. The correction also applies to loaded G-code files, see below.
Loaded G-code files (autolevel)
A program from another CAM (Fusion, FlatCAM, VCarve, Estlcam …) can follow the measured surface too, like with the AutoLeveler of bCNC or UGS:
- Load the file in the machine window (Program → Open file …) and set Z zero on the surface.
- Open Height probing. The window names the file and suggests the area from its toolpaths, even if they extend beyond the material of the drawing. The toolpaths are drawn into the map.
- Check the safe height of the file. The suggestion is the lowest height at which the file travels sideways in rapid. Below it the file is corrected; rapids at this height and above stay as they are.
- Probe. The window then shows how many moves were corrected and by how much (from/to); the machine window shows Height correction: on.
When correcting, long straight moves are split into short pieces (a quarter of the grid spacing, 0.5 to 2 mm) and arcs (G2/G3 in all three planes, with I/J/K or R) are broken into lines. The app handles mm and inches (G20/G21), absolute and relative (G90/G91). Between the highest cutting height and the safe height the correction fades out, so plunging causes no step. The original file stays unchanged; turn the correction off at any time with Use height correction when cutting.
For safety the app warns when toolpaths lie outside the map (the height at the edge is used there), when the map jumps between neighbouring points (usually a false contact), or when uncorrected rapids travel only just above the highest measured point. If the map deviates by more than 3 mm, the file shifts the zero point (G10, G52, G92), changes the coordinate system, uses G93 or moves a rotary axis at depth, nothing is corrected and the milling assistant says why. Drilling cycles (G81 to G89) stay unchanged.
Large files (from about 200,000 characters) are corrected in the background. The machine window and the Height probing window show the progress in percent; you can keep working meanwhile. Milling only starts once the correction has finished. Cancel loads the file without correction and switches the correction off.
Height maps in your account
With an account you can save a measured map under a name, e.g. per board, spoilboard or fixture. The maps belong to the machine profile: in the Height probing window, Saved height maps lists all maps of the selected machine with grid, size and time of measurement.
- Save to account: enter a name and save. If the name already exists, that map is replaced.
- Load: the map applies immediately, the correction is switched on.
- Rename (pencil) and Delete (bin, with confirmation).
A map only fits as long as the board is clamped the same way and the zero is where it was when measuring. The window therefore points out when the map is older than one day or when the XY zero of the connected controller differs from the one when measuring (with the offset in X and Y). Then set the zero as when measuring or probe again.