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Using The Laser Cutter (redirected from Using The Laser)

Page history last edited by Iain 6 years, 8 months ago

Note that use of the laser cutter requires training, if you need to use the laser in the meantime see one of the 'trainers'.

 

CAUTION: DO NOT press the "Datum" button when the LCD shows "Z-AXIS OPERATE", this causes the bed to be moved upwards until it hits the conical fitting on the head (I assume this is for auto focusing with a limit switch on the lens, which is not fitted to our laser).

Also be aware that when powered on the laser will home the X and Y axis automatically.

 

Please check the Laser Cutter Settings page before starting any machining to check your material is safe to use with the laser.

 

If for any reason the laser develops a fault or is generally not working as expected, stop using the machine and let one of the maintainers know.

 

LaserCut5.3 is awful drawing software, hence I will assume you have a DXF from your CAD package of choice ready to import:

  • LibreCAD
    • DXF 2000 works
    • DXF R13 causes LibreCAD to die using 100% CPU on Ubuntu 12.04 (not tested on other platforms) 
  • DraftSight
    • R2000-2002 ASCII DXF works
    • Binary formats may have issues? 
  • Illustrator cs6
    • This works when saving as DXF R13 and preserve appearance in the options

 

  • Inkscape
    • Save as DXF R14  - recommend UNTICKING the robo-master and lwpolyline options. (See https://wiki.nottinghack.org.uk/wiki/Laser_cutter/Inkscape for further details) 
    • If using features like text, you need to select them, then Path->Object to Path before saving as DXF, or they aren't saved in the DXF. 
    • Occasionally you might need to edit the DXF (try opening it in Inkscape) to remove any rogue paths (sometimes you get odd lines from Object to Path on text that mean it won't engrave properly) 
    • I believe Greg put together a good guide about how to prepare text and I managed to get good results converting images to be engraved. 
    • You can trace around an image using Trace Bitmap, then its' outline can be cut or engraved.
    •    

For anyone unsure of what CAD package to use, if you want to make a "part" (e.g. a quadcopter frame) use either LibreCAD or DraftSight (LibreCAD is a little easier, DraftSight is more like AutoCAD), if you want to make something decorative or that is majority engraving (e.g. some of the things JAS had on their MakerFaire stand) use InkScape or possibly DraftSight.

 

Note that the power key, focus tool and USB flash drive for transferring drawings are kept in a blue tray on the machine bed, the white box is now just spare parts and general maintenance stuffs.

 

Maker Space Requirements

 

To use the laser at Maker Space you must:

  • Be a member of Maker Space
  • Pay for your time on the machine.  The current rate is £6 per hour and applies to time your job is running as opposed to the setup time etc.  The machine tells you how long each job has taken.
  • Record your laser time.  As well as for working how much your time has cost, this is also to record the total laser usage so we know when we should expect to have to replace some of the parts.

 

To pay for your time, you should make a payment directly to the Maker Space bank account making sure you include the word LASER followed by your name.  Also, please try to keep the value of your payment easy to process e.g. multiples of £6 or £10.

 

Materials

 

You are expected to provide your own materials for using on the laser cutter.  However, there are lots of scraps and offcuts available so you might be able to use them for a smaller job.

Some materials can not be cut using the laser as they could be hazardous to people or the laser.  You should make sure you check your material is on the list on the Laser Cutter Materials page.

 

 

Maintenance

 

The laser requires regular maintenance in order to keep it running nicely.  Before starting to use the laser, check the maintenance register on the wall behind the machine.   If maintenance is overdue you may not get a very good cut and you should ask a Maintainer to have a look at it for you.

The list of Maintainers can be found on the Laser Cutter Users page.

 

 

Preparing a job

 

  1. Ensure the laptop you are using is connected via USB to the laser cutter (the dongle is now hidden inside the cutter permanently) and does not need to be connected specifically.
  2. Open LaserCut5.3, select File->Import and select your DXF
  3. Depending on the CAD package DXF layers may or may not be preserved, if not group select (Ctrl+Click) items and assign them a layer by clicking one of the colours at the bottom of the window
  4. Each layer has it's own machine settings shown in the top right of the LaserCut window (need to scroll RIGHT to see other settings)
  5. Select the appropriate (very inaccurately labelled) type for each layer:
    • Cut for anything vector (even engraving)
    • Engraving for raster engraving (no filled area needed on design, will compute fill area from outline) 
    • GraveEngrave for rubber stamps (this may or may not actually do anything useful) 
    • Hole for dot patterns
  6. Edit the settings for each layer by double clicking the power or speed settings
    • Settings we have used are here: Laser Cutter Settings  
    • Vector
      Set the speed (mm.s-1) and power (%MAX) for the cut, corner power should be lower then power as this is used when the head is moved slower round corners - around 80% of the power setting is probably a good starting point.
    • Raster
      Set the power (%MAX) and scan gap (mm), smaller scan gap gives better fill but takes longer, larger scan gap is faster but has noticeable lines (0.05mm is a good starting point)
  7. Note that if you are doing any raster engraving a space to the left and right of the engraved area is needed to allow the X axis head to overshoot while it is accelerating, if the engraved area is at the edge of the table this can cause issues with the engraving not being aligned properly, to ensure this does not happen try to give at least 50mm of clearance between engraved areas and the extremes of the X axis bed.
  8. Ensure "Immediate" is ticked and notice the blue dot in LaserCut, this is where your job will start relative to the head position.   If this is not seen, you can confirm it's location by selecting Laser->Origin from the toolbar at the top of the software.  (We usually use Right-Top as laser origin)
  9.  It's USUALLY worth highlighting your job and selecting the Tools->Unite Lines option (0.1mm is probably about right for tolerance) before uploading. 
  10. If doing complicated things, try the simulate option before cutting to see what the results will be before starting.
  11. The job is configured and should be good to go, click the stopwatch in the top menu bar to get an estimate of the job duration (this also does error checking and will shout at any errors) 

 

 

Running a job 

  1. Turn on the laser and water cooling pump at the power socket.  Insert the key into the keyswitch on the cutter and turn clockwise to turn it on.  The control panel should light up, and you will hear the X and Y axes home to their datum point (top right) of the bed.
  2. Click "DownLoad" in LaserCut5.3, if any jobs are listed click "Del All" then click "Download current"
  3. If the laser head isn't homed (at top right of the bed) press 'Datum' on the control panel.
  4. Ensure Honeycomb Bed is all the way to the right and the top (furthest away from you) of the Z recess. There should be no gap along the right and top edges of the Honeycomb Bed. You might need to lift the front edge of the Honeycomb Bed up a little so the edge clears the underlying Knife Bed on which it sits. The red aligning dot should now fire through the Honeycomb at the top right edge when X and Y axes are homed.
  5. Press "Esc" on the laser cutter and move the head to the approximate start position for the job, moving the Z axis down if needed to make sure the laser head does not hit the workpiece.  Note the start position should be the top right of your job, assuming you have not altered the laser origin setting in LaserCut.
  6. Focus Time!
    1. Acquire a Magic Laser Focus Tool or the impossible to find Acrylic focus tool
    2. Place your material on the work bed. 
    3. Press the "Z" button on the machine and use the up and down buttons to move the bed height
    4. Hook the tab of the focus tool over the large rim at the top of the conical lens
    5. Move the bed until the bottom of the focus tool sits flush with the workpiece
    6. Press "Z" again to exit Z-axis mode 
  7. Focusing makes the red laser be in the correct place so you may need to move the X and Y axis again to get back to the intended start position
  8. Press the "Test" button to see the outline of where your job will be cut - make sure this is within the margins of your material.
  9. Laser Time!
    1. Start the air pump and fume extractor.  Check again that the water cooling is switched on.  Check the CO2 fire extinguisher (red, with a black label saying CO2) is to hand.
    2. Close the guard and press start
    3. Do not leave the laser unattended whilst the job is running. 
    4. Wait for completion (jobs can be stopped using the membrane "Stop" button if it has gone wrong) 
    5. In case of emergency, press the large RED stop button at once.
  10. Note the time displayed at the bottom of the LCD, this should be recorded on the LaserCutter Logbook page
  11. After the job is finished the air pump can be turned off immediately, the extractor is best left running for about a minute after to flush any remaining fumes from the machine and pipes
  12. Press "Esc" then "Datum" to return the X and Y axis to their home position
  13. Turn off the laser cutter
  14. Turn off the water pump 5-15 minutes (depending on laser run time) after the laser cutter to ensure the tube has had a chance to cool.

 

 

Recording your time

 

Don't forget to record your laser time on the form here

If the internet isn't working, you should still be able to access the form on your phone.

 

If that doesn't work, you should record your time on a piece of paper or the whiteboard and make sure you enter it later.

 

You can also review how much time you've recorded on the Summary Page.

 

 

But wait! It didn't work

  • Did the compiler fail with a message about unclosed polygons?
    You probably have a layer which is set to engrave, this needs to be a closed area so a raster scan path can be computed
    Lasercut5.3 has some fantastic features for fixing this:
    • Tools->Data Check
      This will highlight any polylines which are not closed, if your design has no issues you should see that count read 0
    • Tools->Unite Lines
      This will attempt to fix any issues detected, it is not guaranteed to work, when it does fail it fails comically
  • Did it say "SOFT STOP"?
    If so delete the job off the machine, power cycle and try again
    This error is caused by the controller thinking that the job will cause the head or bed to run off an axis
  • Did it still say "SOFT STOP"?
    It may be a genuine message, check your drawing dimensions.  This means that the job is either too big for the bed, or your start point means the laser would hit the edges of its' cutting area.
  • Does it smell bad?
    Some materials (mainly plastics) usually do
  • Really bad?
    Pause the job and check the extractor is not leaking
  • I want to use a new material
    Ensure the material is not listed on the "Materials that should not be used" list on the Laser Cutter Materials page

          Look at the current table of materials and see what it is closest to, then have a play with the settings
          If you get it working well then add the material to the list

  • Did it not cut all the way through the workpiece?
    Play with the settings a little, prefer slower feed rates over increase in power
  • Did it not engrave?
    I've noticed an issue with power settings lower then ~10%
    Try increasing power and feed rate
  • Did it catch fire?
    You're doing it wrong.
    Check the air pump is powered and the hose is not blocked, some (usually wood based) materials can start to flame if not cooled
    Please tell us what settings you used so we can warn others!
  • Did the workpiece turn into green jelly?
    This is the choice of Steins Gate

Comments (1)

Jon Davies said

at 9:19 am on May 2, 2014

I wanted to try cutting a banana, but it did indeed turn into green jelly :/

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