Laser 02

I was starting to prep a file to cut, and realized that I should take a step back and photograph more carefully--I will see if I can do it on the Christmas Holiday.  Work has a way of shrinking my free time--and, because work is creative (designing buildings in 1:1), it often leaks into what might otherwise be hobby hours--that has been happening over the past few days.

A few people have asked for a closer look at the laser. . . .

The guts of the thing are very simple:

Lifting the control panel reveals the back of the switches and the power supply.  The enameled metal box in the front covers the USB card installed by Full Spectrum.  You can see the USB cable emerging on the lower right--only complaint here is that the USB is vulnerable to being bumped, and, this can put stress on the cable or board--I will probably make a guard for it at some point soon.  The duct tape that snuck into the frame on the right is necessary item for cutting painted or laminated paper, as sometimes the paper has a subtle warp: taping it down can really help.

The main lid has a simple magnetic safety interlock.  This interlock shuts down the laser, but not the other movements.  A little test confirmed this--lifting the lid interrupts the cutting, but all other movements continue--so, there is no tie between the interlock and the software, it is a simple shut off switch for the laser.

The field of play is about 9-1/2" x 14-1/2".  I have this platen drawn in all of my cad files.  Since I draw at full scale, I simply multiply my frame by the scale factor that is appropriate: 48, 87, etc. 

This is the business end of the laser.  The angled cylinder holds the mirror (you can see the diagonal mirror in the background), and the conical portion of the the head contains the lens.  The laser tube is in the back of the unit, and reaches the cutting area by way of the two mirrors shown here, and, another shown in the back.

The small tubing entering the cone is the air supply from the compressor--which is the "air assist" that blows down inline with the beam to facilitate vaporization and combustion, and reduce burning in the work piece itself.

You will also notice a little red dot laser pointer: it gives an approximation of the location of the cut, but it is not precise.  If one uses a beam cominer, the laser pointer can be moved to another location, and will show through the lens, and therefore be more precise--but as I said before, I have yet to need this.  When I need to align cuts I use templates and jigs--since that is more precise than lining a dot.  Registration can vary from session to session, so I find if more useful to create registration marks in the cut file, and fire them from the laser, then align the work piece.  It gives me exact registration each time with incredible precision- again, more on that later.

Here you can see the diagonal mirror with its adjustment screws, and the drive belt.  You can also see the carriage bars and their bushings.  In my travels on the net I have seen one person have a problem with this after "crashing" the laser into the end stops--not sure how they did it--but they had one of the parallel belts that drive the y axis (as conventionally understood) skip a tooth, which resulted in slightly skewed cuts.  After reading this I take care with the belts and the carriage.  The carriage moves freely providing that the laser is on--when it is powered off, it is locked stiff, and I never attempt to move it.  I also keep an eye out for any soot on the moving parts.  When it comes to any piece of equipment, cleanliness seems to count.

The plastic exhaust fan is very quiet--I did create a cardboard gasket between the fan housing and the machine, and used foil tape to hold it in place.  This gasket improves suction from the unit.  With the exception of the blue flex you see here, the entire path out of the building is through hard pipe that is sealed.  The duct is shared with a kiln that is nearby, so, I have a second fan available should the fumes be perceptible in the room.

Extraction in this case is about more than your health--you do not want smoke or soot to collect on the optics, so it is best to get them out of the theatre efficiently.  You do not necesarrilly want to super power the fan, as a draft could create havoc with a cut too--you just want a continuous negative pressure in the cabinet.  Fresh air is drawn into the unit through various cracks.

Removing the fan, and opening the back compartment reveals the laser tube, briefly discussed in the last post.

The surgical tubing is for the previously described cooling system--a bucket of distilled water and an aquarium pump.

The focussing is similarly simple--four screws that raise and lower the platen, connected by a toothed belt.  I checked level at set up.  This is controlled by a "knob" at the bottom, and distance set to a particular part of the equipment using a template.  Attaching the knob is about all the assembly you have to do when you get the unit, save for making any needed adjustments to the mirrors.

I will cover more specifics, and a couple tips when I get to running a cut file.  Questions are always welcome.