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Lasercutter

Page history last edited by Jaz 8 years, 2 months ago

You can also check out this page here for the Lasercutter - Setting and Examples.

 

The lasercutter was partly funded by robots and dinosaurs, but the majority came from member's donations. Special thanks to Gavin, Jeremy, Vorn, Brendan, Max, Rebecca, talsit(david), Mitchell, Macca, Jason B, Kean, David B (shig), Tristan, Adriaan & Chris B for their support. 

 

The Machine & Specs:

The machine is an SG-3040A, which has a 40W laser, and a 300x420mm working area. The following specs are from the manufacturer, take them with a grain of salt. 

  • Stepper motor drive
  • 0.01mm precision
  • 0-500mm/S speed (engrave)
  • 0-40mm/S speed (cut)



Note: There are some obstructions into the working area due to the bed lift mechanism, so it's not a pure 300x450mm rectangle. There will be a template near the machine we can use to mark out stock before cutting. Alternatively you can put purely rectangular stock of a size up to about 260x420mm straight in the machine.

The machine is water cooled and also has an air assist pump and nozzle added as an extra, which blows air past the cut and helps prevent fire. If you’re considering buying a machine, it’s well worth the extra $50.

The machine came with ‘NewlyDraw’ software to control it. It’s quite primitive, but reasonably stable. Unfortunately it’s also dongle based, so you couldn't work on the files away from the cutter. 

Update: After a persistent problem with the laser diving off to the bottom right corner we purchased a DSP laser controller from Lightobject.com and two Geckodrive 251 stepper drivers to replace the original controller/stepper driver PCB. PHCAD software is used to prepare files and 'download' them to the DSP. Once a file is in the DSP memory it can be run or rerun by hitting the start/pause button on the keypad.

 

 

Prerequisites:

  • a DXF file of the object to be cut
  • a JPG or similar of any bitmaps you want to engrave (Note: You can combine these two inside the newlydraw software and have the cutter engrave everything first, then automatically cut shapes)
  • Material to cut it from (see the 'List of Doom' for forbidden materials that can case fire or toxic fumes)



See the ‘Software’ section below for free software that can output DXF files.

 

Instructions for use:

Before using, you must be trained. This info is here as a refresher only.

See also the PHcad manualPHCADmanua_v4x.pdf (you can ignore all the installation and setup instructions) 

 

Step 1: Import the files to PHCAD

Import the files you want to cut into PHcad using File-->Import (not file-->open).

Note on free software: Inkscape is nice to use, however the latest version produces DXF files that do not open in PHCAD. Open then save them in QCAD first. Using layers in Inkscape and QCAD works. Using colours in QCAD works.

 

Step 2: Select cut or engrave as necessary then set power & speed

PHcad treats each colour as a separate line item in its job list on the right. Select part of your design and change its colour if you want to use different setting than the rest of the design. For example: settting one element to engrave and the rest to cut or multiple engraving elements at differing power levels. 

 By default all engraving operations will be done before cuts.  This is because the material may fall away after a cut operation, and if you engrave or cut it afterwards, then it will be slightly out of focus and may have moved.


There are two ways to control the laser power, set by a toggle switch inside the case on  the right.
Manual power: The power level is set by the dial on the front of the machine. Note:  this is a 10 turn potentiometer, so make sure you’re in the right ballpark.
Automatic power: The power level for each line item is controlled by the settings saved in the file sent to the DSP. 

 

Step 3: Download your job to the DSP

Click the Download button on the mid right of the PHcad window once your happy with your settings. In top right of the dialogue box give your job a name (defaults to the last used name) and in the Work times field enter how many times the laser should repeat the job. Repeat delay is how many seconds it will pause between repeating the job.

Then click 'download document' and wait for the DSP to beep signalling the download is complete.

 

Step 4: Position the material on the bed and focus the laser

Put the material on the honeycomb bed, and adjust the focus. The top face of the laser head should be 62mm above the top surface of the work.

Use the z-crank in the bottom right nut to raise or lower the table. Remember to remove the crank before use, otherwise the laser can collide with it.

The honeycomb bed is used to support the material but allow the heat and ‘laser goop’ that’s produced when cutting to drain away. You can remove it and cut on solid material, but it’ll stain a bit.

 


 

Step 5: Position the head and start the cut

  • Use the arrow keys on the DSP keypad to position the head where you like. Then push the Origin key to save that location. The top left corner of your design will be placed at this position.  

  • You can get a rough idea of where it will go by pressing ‘Box’ on the keypad or 'run box' in PHcad. The head will trace out the rectangle enclosing the entire cut. Pressing ‘clip box’ in PHcad does the same, but uses the laser to put engrave a feint line on the workpiece.

  • Arm the laser with your RFID card.

  • Double check for obstructions like rulers, focus tool etc.

  • close the lid and press the Start/pause button. 

 

Step 6: Watch for fire!

It’s important to keep an eye on the laser while it’s cutting. Even easy-to-cut materials like acrylic can suddenly burst into flame.

  • To pause the operation push 'Start/pause'
  • Push stop to stop and cancel the rest of the operation.
  • To Kill all Power push down the Emergency Stop switch.

 

           Note: When the power is resumed the DSP will ask if you want to continue your cut.

 

 

List of Doom: (Forbidden materials)

Cutting certain materials with the lasercutter can make toxic fumes which are hazardous to people's health, and can also damage the optics in the laser.

 

Materials that are out include:

  • MacBooks with plastic casing (Contains polycarbonate. Not the Aluminum 'Pros or Airs, they're OK)

  • Moleskine notebooks (The cover contains chlorine)

  • Wiring (Insulation may contain PVC, which contains chlorine)
  • Polycarbonate plastics (a.k.a. Lexan)
  • PVC and vinyl plastics (contains chlorine)
  • Any unknown plastics. Information on how to test is here, and involves a blowtorch and being outdooors

Materials that are OK include: 

  • Acrylic
  • ABS
  • Delrin
  • HDPE (supposedly melts badly, though) 
  • Paper & wood (watch carefully for fire), including MDF
  • Cloth (provided it doesn't contain vinyl or chlorine, do test above) 
  • Kapton tape 
  • Teflon 
  • Styrene 

 

Tips:

  • Sometimes Inkscape brings in SVGs at the wrong scale (80% of normal). If this happens, select everything and object-->transform to a scale of 125%  (Caused by 90 DPI vs 72 DPI standards)
  • If you’re making a box or other enclosure, use the web based box creator or the ‘Box-o-Tron’ script by Zignig to create a makerbot style enclosure as a starting point. This saves heaps of time!
  • Inkscape can make mangled DXF files at the drop of a hat. To get around this as a final step before you save as a DXF, select all the objects and do Object-->'Convert all objects to paths
  • PhCad can reject DXF files that have visible 'blocks' in the file.  

 

Resources:

 

Software:

 

      

  

 

 

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