Visual alignment¶

Visual alignment is an official extension package (org.openglow.alignment). It shows the head camera's live video with a crosshair on the spot where the laser will hit. You put the crosshair on the spot where your job starts, by jogging the head or by sliding the material, and press Done. The laser is then on that spot, and you start the job from the current position in your Grbl sender.

It is a package like any other (Extensions): a page on the panel's Extensions tab, and a service on the machine that does the work.

Installing it¶

Get it from the catalog on the Extension packages card. You can also upload org.openglow.alignment-<version>.ffx from the releases of its repository, openglow-org/forgefirm-extension-alignment. Either way it reads as Official. It asks to:

The last two are yours to grant: tick both when you install it, or the install is refused.

Using it¶

1. Open the Extensions tab and press Use the alignment tool. The machine must be idle and homed.
2. The head moves about 25 mm, slowly, so the camera is over the spot where the laser will hit. The video starts.
3. Put the red crosshair on the spot where the job starts. Jog with the pad or the arrow keys, or open the lid and slide the material. Up is toward the back of the machine, as in the video. The step is 0.1, 1, 5, or 10 mm, or with the panel in inches 0.01, 0.05, 0.25, or 0.5 in.
4. Press Done: put the laser on the crosshair. The head moves back by the same distance, and the laser is on the spot. If the head cannot get back (the spot is past the edge of the work area), Done still lets your sender back in, and the page says the laser is not on the spot.
5. In your Grbl sender, connect again and start the job from the current position. In LightBurn, that is Start From: Current Position.

Light sets the head's own light for the video, from 0 to 1023. On the bench reference, about 60 shows the grain of light wood and 1023 turns it white. The level you set is kept.

The head camera works with the lid open, so you can watch while you place the material. It looks straight down at the bed, and it is the only camera that does; the lid camera still stays off with the lid open (Cameras).

Your Grbl sender is disconnected while you use it¶

While the tool is in use, the head stands about 25 mm from where the laser will hit. A job started then would land in the wrong place. So the machine disconnects your Grbl sender when you press Use the alignment tool, and it refuses to let a sender connect until you press Done. Your sender shows the message The machine is in use: senders are kept out for now. Connect again after Done.

The tool starts only when the machine is idle and homed, and the sender is not sending. If a job is running, or the sender just sent something, wait and try again. Home the machine first (Homing): until it is homed, nothing keeps the head's moves inside the work area.

The panel shows a banner while the tool keeps the sender out. Let the sender back in ends it at once. The tool then moves the head back, as Done does; wait for that before you start a job.

If the page closes¶

The tool runs on the machine, not in your browser. If the page closes, the browser crashes, or you switch the panel to another tab, the tool waits about 10 seconds and then finishes by itself: the head moves back so the laser is on the spot the crosshair marked, and the sender is let back in. A browser tab left in the background for several minutes counts too, because the browser then slows the page down. Keep your hands out of the machine while the tool is in use, since the head can move when you are not pressing anything.

If the tool itself stops while it is in use (for example, you turn the package off), the head does not move. The panel then shows a notice that names the package. Check where the laser is before you start a job. If the tool starts again within two minutes, it finishes the use: the head moves back and the notice goes away.

The jogs and the tool's own moves never fire the laser. The tool's own moves run at 10 mm/s.

The crosshair¶

The video is what the camera sees. Nothing in it is corrected, stretched, or moved: only the crosshair is drawn over it. The crosshair has a tick at each millimeter to 5 mm and a ring at 10 mm, or with the panel in inches a tick every 0.05 in to 0.25 in and a ring at 0.5 in. The page shows every length in the panel's units. The ticks and the ring follow the material height that you type, because the camera sees a surface closer to it as larger. The height changes nothing else: the crosshair's center is correct at any height.

Calibration¶

The camera is beside the laser, not over it. On the bench reference the laser hits about 24.6 mm to the right of the camera's center, at every material height. The tool starts with that value, and a calibration measures it on your machine. Calibrate once, and again after the head is removed or replaced.

The calibration burns a small mark, so it is a laser job and every gate of a job applies.

1. Home the machine, put scrap material under the head, and close the lid.
2. Open Calibration and press Burn the mark. The head first traces the mark without the laser; a mark closer than 1.5 mm to an edge of the work area is refused. Press the button on the machine when it lights. The mark is a plus sign 3 mm wide, burned where the laser is.
3. The head moves by the offset, about 25 mm, so the camera sees the mark.
4. Drag the blue crosshair onto the center of the burned plus, then nudge it by one or ten pixels.
5. Press Jog to the blue crosshair. Repeat 4 and 5 until the burned plus sits under the red crosshair.
6. Press It lines up: save. The tool is then in use as usual, and Done puts the laser back on the mark.

What is kept is the difference between two positions of the head: where it stood when the mark was burned, and where it stands when the mark is under the crosshair. Nothing is kept in pixels. A wrong material height costs one more pass, never accuracy, because the calibration ends on what the camera shows at its center.

If the arms of the burned plus are not parallel to the crosshair's, the camera is turned a little in the head. The alignment is still correct at the crosshair's center, and the tool does not try to correct the picture.

Its settings¶

The tool keeps these as its own settings, and they stay across an update of the package.

How a package keeps the sender out, and how it ends when the package stops, is in A package keeps the Grbl sender out.