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  • Author Author: ralphjy
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Laser Cutting at Community College

ralphjy

I've wanted to try using a laser cutter but haven't had the opportunity until today.  There is a campus of Portland Community College (PCC) just up the hill from me.  Spring term was the first time that they've offered Maker community education courses (3D printing and laser cutting).  I was fortunate to get into the first laser cutting class.  They have 3 laser cutters from Universal Laser Systems in their MakerLab.   They have a 60 Watt model with a work area of 32"x18"x9", a 30 Watt model with a work area of 24"x12"x9" and a 30 Watt model with a work area of 16"x12"x4".  They mainly work with wood and plastics and active ventilation is required to remove the smoke that is generated.  They don't have the capability to process metal.  The class that I took was a single 3 hour introduction to laser cutting but even with the queuing time we were each able to make a pre-designed LED "lantern" box and also a project that we designed ourselves.  The software that they use to design the projects is Adobe Illustrator.

 

Laser cutters

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LED lantern box

You can see the good detail in the cutouts.  I was impressed by the ring around the planet.

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Here is the bottom with the MakerLab logo engraved into the wood.  Engraving is done at a lower power level and it takes longer than cutting does.

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There is a great website to design boxes and save them in the SVG format that can be imported into Illustrator.

https://www.makercase.com/

 

For my individual project I designed a "treat" box for my granddog.

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I had a great time at the class.  I'm glad that PCC is creating new opportunities for the community to be able to access their maker equipment.  I'd really like to make some case designs for my electronics.  Maybe try engraving and cutting some acrylic panels.

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  • Hi Ralph,

     

    Those test pieces look so neat and tidy - I bet you cannot wait to get your designs on there now. Any plans for what you want to mke next? I see the laser removes to a set depth or can cut the plywood completely - do you think it PWMs the beam or reduces current to achieve that level of control ?

    Rod

  • in reply to 14rhb

    Hi Rod,

     

    I actually do have a project that I'd like to cut a case for.  I'm working on a Snips interface to control an ipcamera (I currently use Alexa).  I've been having issues with my 3D printer but that's fodder for another blog post.

     

    The laser has settings for pulse frequency (pulses per inch, PPI) and power (percentage).  The drawing program assigns settings by color so in this instance black was set to cut through and red to do the engraving.  Reasonably intuitive to set up but as with a 3D printer you can do a lot of tweaking.  If you get the settings wrong there's a lot of smoke and sometimes fire.  I think that's why they restrict materials that are used until they can thoroughly vet them.  With these cutters the height calibration was mechanical (against a standard "post") not optical.

     

    Ralph

  • in reply to ralphjy

    Good luck with the future project - I'll keep a watch out for any blog you make on it. The use of colours in the CAD to translate to cut depths makes sense, and I guess you canalso  keep the head up off the work unlike a 3D printer as the beam probably doesn't diverge much...the benefit being you can keep it clear from splattering (wood resins, molten plastic particles etc). I'm now thinking you could perhaps make a PCB on there?

     

    Rod

  • in reply to 14rhb

    The focal length of the lens is 2", so it is a fair distance from the material being cut.  The cutting does generate a quite a bit of smoke (at least with wood).  I should have tried to get a video with my phone.  The instructor said that they have to clean the smoke residue off the lens assembly at least daily because the laser can heat the deposited residue and damage the lens.  Seems like they would have made this process easier but at least it's only a few non-captive screws (they do it over a sheet of paper so dropped screws don't get lost).

     

    I've seen some articles about trying to make PCBs using a laser cutter.  It seems that copper is a difficult material to use with a laser cutter because of its thermal conductivity and reflectivity.  I do see FR4 listed as a material that can be cut.  We used to make quick prototype PCBs on a small CNC mill.  You've probably done that also.  That's probably still the tool of choice although it makes quite a mess.

     

    Ralph

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  • in reply to 14rhb

    The focal length of the lens is 2", so it is a fair distance from the material being cut.  The cutting does generate a quite a bit of smoke (at least with wood).  I should have tried to get a video with my phone.  The instructor said that they have to clean the smoke residue off the lens assembly at least daily because the laser can heat the deposited residue and damage the lens.  Seems like they would have made this process easier but at least it's only a few non-captive screws (they do it over a sheet of paper so dropped screws don't get lost).

     

    I've seen some articles about trying to make PCBs using a laser cutter.  It seems that copper is a difficult material to use with a laser cutter because of its thermal conductivity and reflectivity.  I do see FR4 listed as a material that can be cut.  We used to make quick prototype PCBs on a small CNC mill.  You've probably done that also.  That's probably still the tool of choice although it makes quite a mess.

     

    Ralph

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