Technarium:

• LazerinisPjovimas

Last updated at 2020-11-11 10:45:53

Tekstas apačioj iš dalies pritaikytas iš noisebridge wiki. Papildymai ir pataisymai labai laukiami.

Community-generated RDWorks manual:RDWorksLab_com Manual V1- 5 Mar 19.pdf

Usage

Only people who have been trained and approved can use the laser cutter. If you're interested in learning to use it, join #cnc-laser on Slack and ask there.

The laser cutter was bought by a group of Technarium members, so we must return the money to them in time. In addition to that, the laser cutter has costly parts that wear out over time -- especially the laser tube. The cost for using the laser cutter is 17E per hour, calculated using your RFID card and send to you as a separate invoice once the sum you are to pay reaches 50E.

TL;DR flight checklist is at the bottom of this page

TODO

Basic Safety

The laser cutter is generally a very safe machine to use. However, as with all industrial machines, you need to treat it with respect. The main safety concerns are creating fires, hurting your eyes or skin, getting crushed by the machine, and creating toxic fumes. The laser affects your material by heating it. Your job can change in seconds with the accumulation of heat in your material. Never leave the room while the laser is in operation. If you leave the laser unattended, your access to the laser cutter will be permanently revoked. Know where the fire extinguisher is in case of a fire (on the left side of the laser).

The basics:

• NEVER LEAVE THE LASER CUTTER UNATTENDED!
• DO NOT STARE DIRECTLY BECAUSE BURN-GENERATED VISIBLE LIGHT IS VERY BRIGHT!
• USE YOUR PERIPHERAL VISION!
• OPEN THE LID if you see a fire
• BLOW IT OUT if the fire keeps burning
• DON'T CUT UNAPPROVED MATERIALS!
• DON'T FORGET TO TURN ON THE VENTILLATION!
• And turn it off afterwards!
• NEVER USE THE AUTOFOCUS! IT IS NOT RELIABLE AND CAN DESTROY THE LASER HEAD.

Chlorine material test

Before you cut any new material you *must* check that it is safe to cut; specifically that it will not produce chlorine gas when it is burned by the cutting laser. Chlorine is extremely dangerous in its gaseous form and so must be avoided at all costs.

To test a new material, you'll need a sample of the material, a small copper rod (about the thickness of a coat hanger), a pliars, and a handheld propane torch. We'll test for the presence of chlorine by burning a sample of the material in a high temperature propane flame and observe the visible emission spectra. Chrlorine produces a bright green light when burned, and so will be very obvious when you're testing your material.

First, turn on the ventilation on the Sparkle Forge. The switch for this is under the sign that says "For Non-Laser Fires Only", and above the non-laser fire extinguisher. Then, light the propane torch and set it to rest upright on a stable surface. Taking the pliar, hold the piece of copper in the blue part of the flame to heat it. As the copper begins to heat sufficiently it'll cause the flame to turn an orange color. A consistent orange color means that the copper has no residue material on its surface and so is clean enough to use as a test. If you observe non-orange flames when you burn the copper you may need to clean in further, either by waiting for the excess material to burn off, or by scrubbing the surface of the copper when it has cooled.

Once the copper is burning, take the hot copper and melt a sample of the new material onto it. For example if you were testing a new form of plastic you can roll the hot copper rod on the material, melting some of it onto the copper rod's surface.

With this done, place the copper rod back into the blue part of the flame. Observe the colors of the emission spectra from the new material burning. If you observe a bright green color, then the material contains chlorine and thus *must not* be burned further. Ventilate your surrounding area to avoid breathing it in. If you observe no green color as you burn your material sample, then the material is likely safe to use with the laser cutter.

Here is a video example by Zach in NYCResistor with a known good and known bad material: https://www.youtube.com/watch?v=D0_4NLmeSTI

BANNED MATERIALS (NEVER USE THESE)

These materials must not be used in the laser cutter. Never cut something if you are not sure what it is.

Damage to eyes and skin

The laser beam can instantly and permanently blind you. It can also burn your skin.

• The lid's window will block the infrared laser beam, but it doesn't block the visible light produced by the burn. THE VISIBLE LIGHT CAN BE BRIGHT ENOUGH TO DAMAGE YOUR RETINA! DO NOT STARE DIRECTLY AT THE CUT! Use your peripheral vision.
• You don't ever want any part of your body in contact with the beam.
• As long as the door is closed, you're safe to look at the laser. There are interlocks on the door that help ensure the laser never operates with the doors open. Don't disable them.

Crushing danger

The laser cutter is a dumb machine. It doesn't care whether your hand is in the way when it's moving. The head can move when the door is open. Always make sure everyone's hands are out of the machine before moving the head.

Also be very careful not to crash the head into other parts of the machine. Be very careful when moving the z-axis to not crash the head into the bed.

If you need something to weigh down your material, use the weights that are kept near the laser; nothing else. Do not let the laser head crash into these; if it does immediately stop the job.

Be *very* careful to not put the weights (or any other material) in such a situation where they may be dragged by the head. The head should never bump into anything, and *especially* never drag anything.

Fumes

The laser cutter burns the things it's cutting, which can create toxic fumes.

• ONLY CUT APPROVED MATERIALS. Cutting non-approved materials can release really toxic gases, including chlorine and cyanide. These are really bad for humans, as well as being very damaging to the laser cutter.
• The blower switch should always be running if the laser cutter is on, even if it's not cutting. It's currently wired such that you can't turn on the laser cutter without the fan turning on, but please make sure it's running.

Workflows

Overall Workflow

This is the overall structure of the workflow. Each part is elaborated below. See LazerinisPjovimas/RotaryAxis for instructions on how to use the rotary engraving rig.

1. Laser start up
2. Material setup
3. Convert file to DXF
4. Load file onto the machine
5. Dry run
6. Cut/Engrave
7. Laser shut down
8. Cleanup

Laser start up

The laser chiller is the box on the left of the laser. If the chiller is not turned on, the laser will not cut.

1. Open the exaust ports for top and bottom of the laser bead.
2. Turn on the exaust system. Currently, turn it on sequentially up to mark "5".
3. Turn on the chiller and ensure that the fan and chiller are running. If you do not hear beeps when the laser starts up, the chiller is not running and you must turn it on.
4. Ensure the laser table is free of material, weights and scraps. Laser head will move to the upper left corner in the shortes path when homing.
5. Insert you ID card into slot. The laser will turn on and will perform homing sequence.
6. Move the head as far forward and right as possible, close to the controls

Material setup

1. Clean the bed of any scraps that may be on it
2. Move the cut head as far forward and right as possible (near the controls)
3. Raise the laser head as far up as possible
4. Raise the bed to the desired height, watching the laser head to avoid crashes
5. Move the laser head as far back and right as possible
6. Place material on the bed
7. Focus the laser (do at least for each distinct thickness, optimally do for each piece of material)

Focusing the laser

The bottom of the blue tape on the laser head needs to be locked to 185mm above the surface of the material you're cutting.

1. Place the material on the cut bed
2. Move the cut head to the center of the area to cut, watching the laser head to avoid crashes w/ material
3. Hit Z/U on the laser controls and navigate the menu until Z axis (or something similar) is selected. Then use the left and right arrows to move the bed up and down. Target is 184 mm from the top of material to the mark on the laser head.
4. Press Esc to exit the menu.

Convert an image in Inkscape to a DXF file

1. Load the image into Inkscape
2. Set the different cut paths to different colors (for controlling settings, etc.)
3. Perform any debugging steps (by default you should perform all of them b/c of errors in the laser software)
4. Save as a DXF. Be sure to make the units be millimeters so that importing later will correctly scale the image.

Loading into the laser cutter software

1. Import the file with File > Import

2. Resize as needed, tho if the file was exported w/ millimeter units, the software should also import the image with the correct size.
3. Set the cut order:

   • EITHER Set the cut order to inside-out (Handle > Cut optimize > Inside to outside)

   • OR Manually specify cut order with the Set cut property tool (Edit > Set cutting property). See below for more details.

4. Set the speed and power for the layers as necessary, and the process mode for each layer to either cut (for continuous line cutting) or dot (for dashed line cutting) or scan (for engraving)
5. Optionally, simulate the cutting/engraving process.
6. Download to the machine (Laser Work panel on the bottom right).

Manually specifying cut order

In the Set cutting property window (Edit > Set cutting property), you can manually re-order the cut paths. In the window, you'll see an image of the workpiece, and to its right, two lists of paths. When you first open the window, all of the cut paths are in the left. If you select a path (either in the image or in the list) and click the button labeled ">>", this path will be transferred to the end of the right list of paths. If you click ">>>", all of the paths in the left list will be moved to the end of the right list (preserving order). Similarly, clicking "<<<" will move the right list to the end of the left list. If you select a cut path in the right list, the up and down arrow buttons will reorder that path in the chosen direction.

Loading speed and power settings from library

1. In the top right panel, double click the layer of interest
2. Click "Load parameters from library"
3. Select the library item
4. Click "Load"

Saving power and speed settings to library

1. In the top right panel, double click the layer of interest
2. Make sure the layer is set to the desired parameters
3. Click "Load parameters from library"
4. Click "Save as"
5. Enter a name and optionally some notes
6. Click "Ok"

Simulation

1. Open the simulation window with either Edit > Preview or the toolbar button labelled with a monitor.

2. Click the Simulation button in the right panel

Cutting

1. Select the file to use using the File button
2. Move the head to the initial guess origin with the arrow buttons
3. Set the origin by pressing Origin
4. Test the frame with the Frame button. Adjust origin as necessary
5. Test the cut by turning the laser power off and pressing the Start/Pause button
6. Turn the laser power on
7. Cut by pressing the Start/Pause button
8. It is generally a good idea to put the laser head into one of the top corners and resetting origin before opening the laser if you plan on adding new material to avoid collisions with a moving head.

Engraving

In the laser software, open the layers you wish to engrave in the layer parameters panel, and send the processing mode to "Scan". This will do a raster scan of the region bounded by the paths in that layer. An even-odd rule is used to assign regions to the "inside" vs "outside" of the engraving.

Cancel a cut/dry run

1. Pause with the Start/Pause button
2. Cancel and move back to the origin with the Esc button

Laser shut down

1. Move the head as far forward and right as possible (near the controls)
2. Raise the laser head as far up as possible
3. Set origin with the origin button (this helps avoid the laser swinging across the bed later)
4. Remove the ID card. The laser wil ltuon of in a minute.

5. Let the fan run for a little bit (~30 seconds)

6. Turn the power off

7. Shut down the exaust system, swiching backwards from "5" to "OFF".
8. Close the exaust ports for top and bottom of the laser bead.
9. Make sure the chiller is below 23°C and turn it off.

Cleanup

[[Image:Laser_tray.jpg|thumb|right|upright=3|alt=Laser bottom tray| This is the bottom tray of the laser, which should be cleaned out after use.]]

* Remove pieces of material scrap left on the bed * Open the tray door on the front bottom and empty the scraps left there

Materials

TODO: sources of materials

Troubleshooting

Help! All the menu options turned to gibberish!

The RDWorks software can be buggy. Go to the top menu, the right-most or or 2nd-right-most tab will have a Language option. Select English. When that happens, the bed size settings might also have changed. Double check Config -> Document Settings (?). The proper settings are 1300mm × 900mm. (TODO: need to double check the exact menu labels, doing this from memory at the moment)

SOLIDWORKS

Apparently DXFs exported from Solidworks (at least v 2017) break when directly imported into RDWorks. The workaround is to import the DXF into Inkscape and re-export it from there.

Debugging DXF Problems

Sometimes exporting to DXF introduces bizarre extra lines. There are two things to try to debug. The first is to convert objects to paths:

# Select all the problematic shapes # Path > Object to Path

If this fails to resolve the issue, you can try a more radical solution which will eliminate all bezier paths entirely:

# Select all the problematic shapes # Convert bezier paths to lines (Extensions > Modify Path > Flatten Bezier).

Flatness 0.5 is good to start with. Smaller = better approximation of the curves. A lower flatness number takes more time to compute, but also produces a better approximation to the curve. Be sure to ungroup (sometimes multiple times) before trying this, as grouped objects cannot be flattened as a group. This is especially important for text which is by default a group (each character being a separate object in Inkscape once you've turned it into a path).

Sometimes need to select the path's directly with the path tool (but not the points!).

Also see http://www.pstoedit.net/ for conversion from svg to dxf files.

https://webclient.nestingcenter.com/ is an online parts nesting tool.

Feeds and speeds

Discovered feeds and speeds.