How to use HSBNE's laser cutters

To use this machine you either need to be supervised by a Laser Supervisor, be inducted, or be a Laser Supervisor yourself. For casual use or newcomers the first option is the one you want as induction takes multiple sessions over multiple days; the easiest way to organise a time with one of the Laser Supervisors is during Tuesday Open Nights as normally there's more than one present anyway. If that's not an option for you the next best choice is to ask in the #cause-digifab channel or the general channel on Discord chat, or the forums in the Digifab section.

With that in mind you will also need to be aware of what materials are safe to use in the laser cutter, and what is not.

Material choices

There's many things you can use in the laser cutter but many things you cannot. Here's some examples of things that are and aren't suitable, but note that neither of these lists are complete. There are other lists you can find on the internet that may list more materials (but more worryingly many contain inaccuracies). As an example there's a large list by ATX Hackerspace, and another list with more specific individual material details by Pololu.

  • Acrylic/Plexiglass/Perspex/Lucite/Acrylite
  • Most woods
  • MDF
  • Plywood (as long as it says the glue is laser cutter safe & doesn't contain metallic particles)
  • Paper/cardboard (watch it like a hawk for fires though)
  • Cork
  • Cloth/cotton/felt, aka natural fibre fabrics
  • Natural leather/suede/nubuck (NOT artificial leather, nor chrome-tanned natural leather). Can be cut if thin, or engraved at any thickness
  • Ceramic tile (engraving only)
  • Glass (engraving only; must be covered in painter's tape first)
  • Any metals of any thickness. Yes, even Aluminium foil. It won't cut any of them, this laser operates at the wrong wavelength, they reflect the beam back through the optics
  • Any material containing Chlorine. This creates gaseous Hydrochloric Acid which dissolves the machine's insides, along with phosgene which is highly toxic (as in, it was used as chemical warfare during WW1)
  • PVC
  • Vinyl
  • Artificial leather, pleather, moleskine etc, as well as chrome-tanned natural leather
  • Polycarbonate/Lexan/Makrolon (melts & burns, smokes like crazy & gives an uneven, lumpy & discoloured edge)
  • Polystyrene, including common Polystyrene foam
  • Nylon (it melts & burns)
  • ABS (produces cyanide gas)
  • HDPE/milk bottle plastic
  • Epoxies such as those found in resins or glues, including epoxy-coated items
  • Fibreglass, including Carbon Fibre, unless you have an MSDS that states that specific fibre & resin combination are specifically suitable for laser cutting
  • Cutting printed circuit boards (FR4 and other material types)
  • PTFE/Teflon (produces gaseous Hydrofluoric Acid)
  • Food of any description
  • Body parts (I mean really)

This section is NOT a substitute for either having a Laser Supervisor around or being inducted, but a quick reminder on the individual steps involved for those who have already been inducted. Each one of these items could easily be expanded into a few paragraphs of specific do's and don'ts that are being glossed over. So don't read this and think that you now know how to use the laser cutter.

  • If the whiteboard indicates it's been more than 3 weeks since Digifab was last cleaned, clean the room. This means vacuuming the floor and wiping down most of the horizontal surfaces. Don't forget to write down the date & your name so the next person doesn't have to clean it again too!
  • Make or load your design in Inkscape. We strongly recommend you make it entirely within Inkscape if possible, or otherwise download Inkscape, convert it yourself and check everything's imported correctly on your own computer before even organising a time with a Laser Supervisor
  • Send the design to Visicut
  • Position/scale/rotate the design on the bed in Visicut
  • Tell Visicut the material & thickness you are using
  • Tell Visicut which parts of the design to cut/mark/engrave
  • Place material on bed & prep laser cutter for use
  • Bleed air assist line of water
  • Turn on the laser cutter & associated equipment
  • Tell Visicut to export the job to the laser cutter
  • Put money in the donation tin
  • Test run to check coolant temperature, air assist operation, etc
  • Start the job on the laser cutter control panel
  • Do not leave the machine unattended, even for just a few seconds, until it has finished. Get someone else to watch it or pause your job if you need to go to the bathroom etc
  • Once your job's finished, properly clean the machine (skip this step & you'll be temporarily banned from using the laser cutter)
  • Take photos of the thing you just made & post them on the forums! We'd love to see what people create & we need more examples of the kind of stuff that's possible with this machine

Inkscape is a free, open-source, vector-based drawing application that we use with the laser cutter. It's available for Windows, Mac OS and most distributions of Linux. You can draw your design directly in Inkscape or load it from an existing SVG/AI/DXF/PDF/etc vector file that you've downloaded or created in other software. We strongly recommend you either create your design directly within Inkscape, or you download Inkscape, import it & check it's imported correctly yourself first as some software packages don't like to export their files into the standard formats that Inkscape supports. This also reduces the amount of time you'll spend fixing things in Inkscape on the laser cutter's computer. It's possible to trace a raster bitmap eg JPG/PNG/GIF/BMP/etc within Inkscape, but this often needs some manual fixing to get it right.

You can either draw the whole assembled design on a single sheet sized for material or the bed, or you can draw individual elements that you arrange later on. The second way is easier for simple jobs, because it means that you don't need to worry about the page size or the location of the design on the page at this point, but the first way gives you more control if you need to fine-tune your layout. If you have lots of fine detail cuts or engraves planned over the whole bed we recommend breaking your design up into 2 or 3 segments, just in case something goes wrong during your job.

If the design combines different types of laser operation (cutting, outline vector marking, raster engraving) then make sure you assign a different colour to each different operation. Note that Inkscape measures the size of shapes including the stroke width while Visicut measures the size of shape excluding the stroke width. This means for very fine works needing sub-millimetre precision, we recommend having no stroke and using fill colours to differentiate between operation types instead.

Once your design is ready, you can send it to Visicut using the Extensions→Lasercut Path menu item. You have two options - Send to Visicut or Add to Visicut. Selecting Send to Visicut will bed and load just that design on a new, empty bed. Selecting Add to Visicut will add the design to the elements already in Visicut; you can use this multiple times to build up a plate of multiple designs or design elements - say, a whole bunch of gears.

You can send only some objects or elements to Visicut by selecting just those objects when you press the menu item. This is handy if you want to cut just part of a design, or if you haven't already split up the cutting/engraving/rastering objects by colour. You can't separate objects in Visicut, so this is your last chance to differentiate between laser operation modes!

Visicut is a free, open-source laser cutter controller. Each time Add To Visicut is run from within Inkscape, it will create a new item on the build area on the left side of the Visicut window. You can move, scale, rotate or delete each item in this area, which corresponds to the cutting area of the laser cutter.

Note that Visicut is only used once your design is finished. It's not possible to edit an object or split them apart from here; to do that go back to Inkscape, make your edits and resend them back to Visicut.

On the right side of the Visicut window you need to select the material to cut and its thickness, which will load presets for laser power and speed. In the bottom right there's a tabbed window that lets you select which operation to perform on the selected item. This lets you select each vector path in your design for different operations, such as cutting or etching. Which operation is used is automatically decided based on the vector path colour, which is called “mapping”. Sometimes it's easier to colour the elements in Inkscape, send the entire design as one item, then set up a mapping to automatically decide the cutting/engraving/rastering for you, while sometimes it's easier to send the cut elements separately to the outline mark/raster engrave elements and configure them individually.

On another tab you can configure the laser speed and power for the cut/outline mark/raster engrave operations. These are specific to the selected material and thickness, and if you edit them you will update the material profile. Adding new materials or thicknesses is also easy. You shouldn't need to do this if it's a common material, but at this point we're still filling up the list of materials/thicknesses matched to powers/speeds.

Once the design is arranged on the bed properly, put your material on the laser cutter bed. The top-left corner of the design window is the same as the top-left corner of the laser cutter bed, which is also the laser's home position.

You can now close the lid and turn on the laser cutter. After a few seconds you can click the “Execute” button in the lower-right of the Visicut window, which will start the laser cutter and send the job.

Hardware Tips/Quirks

  • Be careful and slow when opening & closing the main lid. Don't let it bang either open or shut, as the vibrations can mess up the alignment of the optics.
  • Don't lean on the lid while observing your job. This over-compresses the sealing foam on the lid and means we have to replace it more often.
  • Don't ever manually jog the head past the e-stop microswitches. They are electronic stops only, they won't physically stop the head from colliding with the edges of the bed area and causing a head crash.
  • Go slowly and carefully when using the dial interface on the laser cutter's control panel. It's easy to accidentally select the wrong thing, and if you do that, you could cause all manner of issues and very easily permanently damage the machine.
  • If too much water comes out of the air assist line when bleeding it, the auto bleeder may be clogged or playing up. Manually check and trigger the auto bleeder to confirm it's working as it should. It's hard to give a written description here of how much is “too much”; this is something that can unfortunately only be learned over time using the machine and depends on recent weather etc.
  • The window on the opposite side of the green room catches a lot of wind. This is fantastic on a warm day and it's perfect for helping vent any fumes out of the room, but it means rain enters very easily too. And the wooden frame to this window has both water & termite damage. Close this window the moment it starts spitting with rain. The machine needs air to operate, and outside air is generally less dusty than the green room's air, so it's best to open the window even just a tiny crack if possible.
  • The exhaust system extracts the fumes out of the room, but depending on the wind's direction the fumes can blow back inside the nearest green room window. This doesn't happen often now that we have a stack venting it above our roof line, but if the wind's blowing the wrong way it can still happen. It's common courtesy to close that green room window if the wind is blowing the wrong way before you start cutting & stink out the entire green room.
  • If the temperature on the coolant circulator reads above 29°C then you can't use the laser cutter until it cools down. Note that because it only cools the water down to the ambient air temperature, yes this means that some days in summer when it's 33'C you just can't use the machine. This room has an air-conditioner to try and compensate for this, but because the extraction fan extracts out so much of the room's air this is only barely a solution and it can take nearly an hour to adequately pre-chill the room & coolant loop. The room is chilled by turning on the air conditioner, manually configuring the laser cutter so the coolant loop is running but the air assist or extraction fan aren't, and using some pieces of wood to redirect the air conditioner's output to the chiller's input (pay attention to the proper airflow inputs/outputs of both units). Don't let the coolant loop get too cold compared to the room's temperature or condensation will form both on the lines and inside the machine. Buying a proper chiller unit is on our wish list, if someone wants to donate or build us one that would be fab. Building proper removable flexible ducting to attach the air conditioner to the cooler would also be awesome too.
  • howto/lasercutter
  • Last modified: 5 weeks ago
  • by hsbnewiki