Laserkalibrering

Calibrating the X700 lasercutter

The Bitraf laser cutter is from the Chinese company Redsail. To use the laser, training is required in the form of the laser-workshop. To learn how to maintain the laser, you should attend the Maintenance-workshop.

Maintenance

The most important thing to keep clean is the metal mesh that ventilates the cutting area. Clean with a wet cloth/paper and dry it after. If this is blocked, smoke will build up and that will reduce the effect of the laser. It will also stick to the mirrors, so make sure the cutting area is always well ventilated. Preferably - start each session by cleaning the mesh.

The second most important thing is to check that the mirrors are clean. We have special cleaning swabs available in the Laser supplies box. only use these, but DO NOT clean the mirrors excessively! Only clean them when they are visibly dirty since (just like glasses) they will become a little more matte with each cleaning. As long as the cutting area is well ventilated, you will rarely need to clean them.

Calibration

Over time, the optical system looses focus and the mirrors must be aligned. Once every two months will be enough, but be aware that this is a task not done by someone without extensive laser experience. If the laser is not cutting optimally, DO NOT try to focus it yourself. Instead contact Thomas or others in the Bitraf board and they will find someone to do the calibration (but you are very welcome to join in on the calibration session to learn!).

Each mirror has 3 adjustment screws and two fastening screws. The fastening screws have a spring resting on a disc. The screw should not be fully tightened. It needs to apply pressure, but be flexible so that you can tweak the adjustment screws. Each screw also has a locking ring. When calibrating, it's useful to loosen this completely. As soon as a mirror is perfectly aligned/centered, make sure to fasten the rings as the movement of the laser will eventually vibrate the screws loose.

The process is simple, but time consuming. You'll need some white(ish) masking tape (or similar), a screwdriver, a hex key and cleaning swabs. Set the laser to pulse 0.2 seconds at 20% effect (if not already set). On the mirror you want to align, place a piece of masking tape in front of the mirror. Each pressing of the pulse button will then leave a nice, little brown mark on the masking tape and you use this to align the laser beam.

There are 4 steps to calibrating:

Step 1: first mirror (fixed)

Right at the exit of the laser tube, there is a mirror that is fixed to the machine itself with 4 screws. These can come loose to make the beam hit the second mirror perfectly in the center. When this is roughly ok, the remaining sub-millimeters can be fine tuned using the three screws.

Put a piece of masking tape in front of the mirror. Pulse the laser and notice where the laser leaves a mark. Keep in mind that the tape is offset by a couple millimeters, so you'll need to compensate for this and make sure the laser hits 100% in the middle of this first mirror or you will never be able to finish the calibration.

If you pulse and there is no marking, try to pulse again. If it still isn't a visible mark, you're not hitting where you think you are. Use a large piece of paper to see where the beam is pointing and adjust the mirror again.

Step 2: Second mirror (x axis)

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Step 3: third mirror (y axis)

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Step 4: optics and height

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