2.x Laser Cutter

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HackRVA is building a laser cutter based on the 2.x laser build.

Useful Links:

Project Notes (mostly our Team LAZER email chain which probably should be cleaned up and condensed):

6/24/14 Buildlog has a short blurb about the air pump. The fittings look like the same fittings that are sold at local hardware stores. http://www.buildlog.net/wiki/doku.php?id=2x:sources_for_laser_parts

6/23/14 As you may recall, the laser can be controlled at least three ways:

1) Using a dedicated DSP. Typically Windows-only, but fairly small learning curve and supports a large number of file types. No upgrades, so built-in obsolescence They are available from a number of places - let me know if you want to go this route as I may be able to get a deal on the price.

2) Using LinuxCNC. A bit more trial and error as LinuxCNC wasn’t designed to control a laser, but folks with a machining background will find this comfortable to use. It’s done quite a bit I’m told and some guidance can be found on the buildlog.net site (including a patch/module for travel-speed-dependent laser pulsing).

3) Using the Arduino UNO running LasaurGRBL and a Windows/Mac/Linux app called LasaurApp ( https://github.com/stefanix/LasaurApp ). I’ve attached a zip file of the firmware mods I made to the LasaurGRBL firmware to make it compatible with the laser cutter laser control board. Build with preprocessor macro BUILDLOG2X defined to get the right settings. The LasaurApp can be downloaded from github. It needs a little work to be able to control the elevation of the bed (or put a manual crank on the threaded-rod). I didn’t make any progress on that, as it is written in something called JSON and jquery, or some other evil magical stuff.


6/22/14 For the mechanical/machining folks: - The mirror mount in the left, rear has two holes for mounting a mirror-holder. Unfortunately, it seems that the holes in the mirror mount don’t match the mirror holder. I suspect they may need to be re-drilled. The mirror mount is HDPE supplied by the designer of the laser. I suspect the mirror holder (supplied by lightobject.com, http://www.lightobject.com/Laser-Reflection-Mirror-Mount-P205.aspx#) may have been redesigned a little bit. I believe there may have been a discussion about this on buildlog.net.

- Water cooling system - Joe Shepherd had been thinking this over late last year. Commercial options are available if we can’t get a working design.

- The top, front, right corner has a cutout for a user-configurable control plate to be attached. A lot of things can be done with it, but one option is to put a toggle switch (manual, cnc), a push button for test firing, and a 20mA analog meter in the panel. Those parts are in the bin below the laser cutter if you wish to use them. Someone will need to sketch up a matching plate with mounting holes and then cut it to fit (wood, acrylic, aluminum, etc.).

For the “optically inclined” folks: - Mount and align the mirrors and final stage lens. Tools to help this along include a couple of white plastic disks (in a ziplock bag, I think) and a standard red laser pointer (I believe I put one in the bin). The white plastic disks (printed curtesy of Catherine Clements) should fit into the laser tube brackets and be held by the set screws. The one with the larger center hole is designed to hold the laser pointer and should be installed in the right-most laser tube bracket. Turn on the laser pointer and align the mirrors sequentially (as described on a number of the laser cutter build sites). Using the white disks and the red laser pointer lets you easily get a reasonably good alignment before the final alignment using the -invisible- CO2 laser. I’ve been told that thermal cash register paper can be used to see where the CO2 laser is hitting. (The other one or two white printed plastic items in the ziplock bag are designed to mount a red laser to the lid so that it swings down into the optics path when the lid is opened - might help with setting up the material to be cut.

For the electrical folks: - Wiring the motors and limit switches. Flexible cable runs can be used for wiring originating on the gantry. Other wires can optionally be hidden in the groves of the aluminum tslot. There are a few pieces of plastic strip in the bin that can be cut up and used to hold the wiring in the tslot grooves.

- Mounting the laser controller board. There is a fan in the bin that should be mounted over the stepper drivers. Standoffs are in the bin along with (I think) bolts to match. Here’s the manual for the stepper driver board: http://www.buildlog.net/wiki/doku.php?id=elec:laserinfcpcb . The user manual describes installing the fan as well as what to attach to the DB9 and DB25 connectors. I’ve rigged up a test system that’s laying by the laser cutter with (brief) pin descriptions for the connectors. A better description is found in the PDF attached to this email.

- The electronics are intended to be mounted on the wooden sled, which is supposed to be attached to the rear aluminum connections plate. The designer’s idea is that the electronics can be mounted and tested on the sled, then the whole thing slid into the laser cutter and the final wiring hooked up. Joe and I worked on the wooden sled and attaching the aluminum plate, but I wasn’t really satisfied with the results. Your mileage may vary.

- Some users of this laser design had noise issues if the high voltage power supply isn’t far enough away from the laser control board and the low voltage power supply. In some cases they put the high voltage power supply on an “upper level” in the electronics bay. This was accomplished by putting a plate across the middle tslot bars. Some say that a plain carbon steel plate has advantages in blocking EMF if grounded to the frame. Either way, if you decide to add a “second floor” to the electronics bay, there are 4 or 6 little 90 degree angle brackets in a bag in the bin. These brackets were designed to bolt to the vertical faces of the horizontal tslot bars. In that manner the other leg of the brackets stick horizontally into the bay with attachment points for a tray/plate of whatever material you choose. This should provide enough vertical clearance for the high voltage power supply.