Laser Cutter Manual

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Laser cutter one-page manual.

The laser cutter is now at a level where it can be used by inducted members, but can be improved.

Required Software

The computer at the laser cutter work station has the required software (VisiCut) installed and set up to work directly with the laser cutter. This software is only for importing your files and setting them up for lasering, you can not draw things directly in VisiCut like you can with some other laser software.

You can however download VisiCut to your own computer, and set complex work up at your leisure, then save the file as a "VisiCut Portable Laser File / .plf" to load directly into VisiCut at the HackSpace.

Preparing Your Files For Cutting

Prepare your work-piece on your own computer at your leisure, using Illustrator, Inkscape, FreeCAD or any similar program that can export SVG, EPS or DXF files, Note: If you are using Illustrator CC 2015? Use these settings when exporting your SVG files, or colours won't be saved properly.

Lines to be cut by the laser need to be vectors, engraving can be bitmaps / raster images.

Save your files onto a USB stick.

At the laser cutter workstation, wake the computer up by moving the mouse or hitting any key on the keyboard (very rarely it may be turned off, the power button is on the top of the tower PC) and enter the password you were given at your induction. On the left hand side of the screen are a few icons, the bottom one 'VisiCut' is the one you want to import your work and output it to the laser cutter, so click on that icon once (the computer runs Linux, so no windows double clicking :)

In VisiCut, Click 'File' from the top menus, and select 'Open' or 'Import' and open your file.

You will see your work-piece appear on the 'preview' part of the screen, you can grab it and move it about if you wish, if you zoom in, please remember to zoom back out when you finish so as not to confuse other users into thinking the workspace is smaller than it really is.

There is an occasional issue where items imported from Inkscape may be scaled approximately 30% larger than you wanted when in VisiCut, so if your cuts are larger than expected, back in inkscape you can select your entire work piece, then in 'Fill And Stroke : Stroke Style' reduce it by 30% or so.


At this point you need to decide what kind of lasering you will be doing:

The top of the right hand panel of VisiCut has a drop down selection for the material you are using, this will load previously used settings for you, but always check the board to the right of the laser to see how it's cutting lately, and adjust the settings accordingly if needed, selecting the material thickness should change the cutting settings accordingly, but again double check.


Below the material selection you have 3 tabs, 'Mapping' 'Position' and 'Laser Settings'

In Mapping you can select a few different procedures. the basics are:

  • Under One Profile For Everything:
  • Cut everything This simply cuts through your material where ever there is a line.
  • Engrave Dithered Everything This pulses the laser on and off as the head moves along your 'raster design' line by line and produces an almost 3D style engraving a little like a lithograph.
  • Please note that we are still calibrating the machine for raster etching and this function is not yet available reliably.
  • Engrave Solid Everything This engraves a raster image but it results in a single height of the engraving.


Scrolling further down the list of cut options you'll find :

  • Advanced Mapping...
  • This allows you to set different things for different colours of shapes (stroke colour / fill colour / layer etc) You can select the different colours of items in your work and set them to cut, mark or engrave in one job.

You select the colour / layer of the lines / image you want to work with by clicking the 'enabled' tick box, and then select what you want to happen with it, cut, mark, engrave etc, you can also move the different parts of the job up and down, you want to do all engraving operations before cutting, as parts will move slightly as they are cut out.

Once you have set the laser operation you want to happen (cut, mark, engrave or the combo of them all) click the right hand tab labelled :

  • Laser Settings You can change the power and speed here, Please don't go above 87% power, as you get no more power but it kills the laser tube fast by over driving it, a list of setting is displayed on the board to the right of the laser cutter for you to use, but experiment, and if you find a setting that works well write it on the board for others to use.

The faster you can cut lines, the less melty / charred the cuts will be, if you want to cut slower consider dropping the power down too, or you may end up with charcoal edges on wood cuts, and on plastic it may melt back together before you can remove the cut pieces.


Here is a test file to use during inductions and when calibrating materials: https://wiki.leedshackspace.org.uk/wiki/File:LASER_TEST_FILE_-_NO_RASTER.svg And here is a cute owl: https://wiki.leedshackspace.org.uk/wiki/File:Hsowl.svg


Now you have VisiCut set up and ready to send the file to the laser, it's time to set your material up in the laser cutter.


Setting Your Material Up In The Laser Cutter

Turn on the Laser cutter using the switch on the control panel. This starts the booting sequence.. the display will cycle through a few screens showing the status, and it's done booting when 'Main' is shown.

Place your material on the honeycomb bed in the laser cutter, you now need to focus the laser by setting the distance from the cutting head's lens to the work piece, which is 50.8mm. A quick measurement is the width of a member card placed between the workpiece and the bottom of the cutter head's mounting plate on the right hand side, or use the handy focusing tool hanging on the board to the right of the laser, instructions on how to use it are on the board.

To focus you move the bed up or down, using the switch on the front panel, most people tend to cut 3mm material, so if you are doing the same the bed may be positioned correctly, but check, as an out of focus laser beam makes a shallow wide mark rather than cutting.

Note that if you have adjusted the bed height, there is a good chance the controller may lock up (it stops responding to commands), at which point you have to switch the cutter off and back on again.


Now it's time to transfer your design to the laser, back in VisiCut, press the 'EXECUTE' button on the bottom right of the screen, if it is a large file with engraving, you may see the laser cutters display saying 'receiving file' and once the file is finished loading onto the laser cutter, the display will change to 'Start Job'

The blue button below the display is a 4 way joystick with an enter key if you push it centrally, if you are certian your material is placed correctly for the cut paths, you can press down on the blue joystick, and the laser will start straight away (Remember the laser won't fire untill the lid is closed and your member card is in the reader, procedrue described shortly)

Instead of starting the job imediately, you can press the blue joystick right once and the display should read 'Boundaries' press down on the blue button and the laser head will move to where the cuts / engraving will start, and then the head will move around the outline of all your work, use this to position your workpiece so it will be cut how you wish. After the head has ran around the boundries, the display will show the co-ordinates, press the joystick down and it will go back to boundries, and you can press it again to get the head to do another boundry sweep.. handy if you are positioning your material exactly.

With the material positioned to your liking and the bed height set so the laser beam is focuses right, you are now ready to start the job, close the lid, then insert your member card in the reader and wait for the 'Enable' LED to illuminate, this allows the laser to actually cut (without your card in the reader, the machine will go through the motions of cutting, only the laser beam will not fire, likewise if the lid is open the laser will not fire, but the machine can be commanded to 'cut' it will just move the head in the job's paths)

Now you can either move the joystick to get 'Start Job' on the display, OR YOU CAN press the red button on the controller, this takes you back to the beginning on the menu's, move the joystick right until you see 'Start Job...' click the joystick, and 'Run....' will display, click the joystick once more, and the machine will start lasering away.

You should be keeping a track of your usage at this point (Clock on the wall behind the laser is for this) time spent with your card in the slot is what is chargeable. It costs £1 per 10 minutes with a £1 minimum charge.

Payment for laser usage is to go in the blue money box mounted on the board with cutting settings written on it, your payment goes towards the cost of replacing the tube, mirrors and lens which all have a limited life span, also other parts wear out from use and need occasional replacement (recently the laser needed a new high voltage power supply)


Cleaning Up After Yourself

When you have finished cutting, remove your member card from the reader to avoid the system clocking up time you are not really using it, and if you have no more jobs to do on the laser, it's time to tidy it up for the next person.

There is a hoover near the laser cutter, first hoover the honeycomb bed area to get out any little bits or material that gets trapped in it, then remove the lower panel and hoover up any material that has fallen through the honeycomb.

Close VisiCut and any other programs you may have had open, and don't forget to remove your USB stick if you used one.


Advanced Laser cutting

Cutting order: Because some materials (mainly ply) can be warped it is useful to set up your job in the following order: Engrave, Mark, Cut. Cutting out your piece should always be last, because if the material is warped or raised it will move up or down when cut out and this will affect the focus of the laser. You can change the order by selecting a process in the list and then clicking the up or down arrows on the right.

If you need to hold down the board you’re cutting there are some flat metal bars on the table beside the laser cutter. If you use them you must do a boundary check before cutting to make sure that the bars are outside your work area.

Using Mark

  • Mark Shallow and Mark Deep are essentially exactly the same except for one very important difference - Mark Deep will not mark any line inside another, so if you have a circle inside a square it will only mark the square; if you Mark Deep a spiral it will only mark the outermost ring. There must be a reason for this but we haven’t been able to work it out yet.
  • Using Mark on plywood, the settings become a bit less obvious. The reason for this is that the glue between the sheets that make up the ply is much harder to laser than the wood. So cutting through just the top layer is easy having a wide range of values between just cutting the wood and not quite cutting through the glue. Cutting through the top two layers is extremely difficult as the power required to cut through the first layer of glue is more than enough to cut through the wood layer below and most of the glue layer below that.

Cutting through only the top layer of plywood then allows you to do 'fake marquetry' by staining areas with different dyes, a technique that doesn't appear to have spread beyond Leeds Hackspace (see display cabinet at the front of the Hackspace for examples).

Artwork: Preparing the artwork for successful cutting is the most time-consuming part of the whole job. There are various problems that may arise:

  • VisiCut can not deal with text as text. All text must be converted - to outlines for cutting and marking or to a bitmap format (png, jpg, etc.) for engraving.
  • VisiCut can’t handle some forms of groups so it’s best to Ungroup everything before sending the image to the laser cutter.
  • Importing an SVG file made in Adobe Illustrator on a Mac will bring up a message in VisiCut that the resolution has been changed from 90ppi to 72ppi. SVG is a vector format so is not resolution dependent and so this message can be ignored.
  • Illustrator can also create empty points that don’t connect to anything and so have no stroke or fill. VisiCut does not like these at all, so it is a good idea to select everything and Clean Up (Object > Path > Clean Up).

Complex Images Using a vector image that was designed for print may not work in the laser cutter. Lots of lines close together (for shading or whatever) will darken a print image. On the laser cutter each cut heats up the ply/perspex/mdf around the cut, so if the next cut is close by it will cut deeper. Before long you will end up with charcoal. The laser cutter works best when doing simplified images - outlines and the essential basics. There are other ways to do shading that won’t destroy your piece: staining, painting, pyrography etc. This can be particularly annoying if you’re trying to Mark smallish text. One possible solution is to select every other letter (once they have been turned into outlines) and give them a different colour stroke. This way the material has time to cool down a bit before doing the adjacent letter and is less likely to cut too deeply.

If you do want to make a complex image it’s best to divide it up into several smaller parts. The easiest way to do this is to give a different stroke colour to different parts. When it comes to lasering, select By Stroke Colour and VisiCut will list all the colours separately. You can then set them to be lasered as you want (remembering to leave Cut until last) and it will deal with them in that order.

This is very useful as damage limitation because the more complex an image, the higher the probability the laser will freeze on you. Once you have restarted the laser you can resend the image, leaving out the parts that it has already done. (hacky technique - if it freezes in the middle of a colour you can restart it and set it running with your card out of the machine. By doing this the laser won’t fire but it will go through the motions in exactly the same order, so when it gets near to the point that it previously froze put your card back in and the laser will come back on for the rest of the process.... or hold in the "Laser Inhibit" button on the front of the laser instead of doing the card thing)

Debugging

The most common fix is the old 'Turn it off and back on again'

There are various safety interlocks on the laser cutter, as well as the member card reader node, all of these need to be operating to get the laser tube to fire.

Water flow, there must be water flowing through the tube to protect it when firing, this machine has a combined water pump and chiller unit which starts up automatically when you turn the machine on (the beeps you hear when you first turn the machine on are the no water flow sensor / interlock) If there is a problem with the water flow, the alarm will sound and stop the tube from firing.. another possible problem is the laser machine has recently been moved and the power plug for the water chiller has been dislodged, so have a quick look at the water chiller (on the floor below the computer) and see that the digital temperature display is on)

Lid interlock The main lid of the cutter has a safety switch on the lower right hand corner, if that switch does not activate the tube will not fire, sometimes debris from cutting can get accidentally lodged between the lid frame at the front, this will keep the lid from fully closing and activating the interlock switch, or the switch could be pushed out of alignment from rough handling.

Lower access panel interlock a small micro switch is activated when the below bed clean out access panel is closed, it is possible to put this panel on wrong, with one of the bottom prongs not located in it's hole, this will hold the panel away from the micro switch and stop it from activating.

RFID card reader,

4 lights on the reader tell you what's going on... Power means the reader is receiving power, Status means it's connected to the HackSpace central server so it can verify cards, Denied means your card is not registered for laser cutter access, and Enabled means your card is accepted, and the card reader interlock is activated so the laser can fire.

Very occasionally the card reader may not respond to cards, if this happens, turn the entire laser machine off at the wall and back on, the reader will reboot and hopefully work now.


If everything appears correct but the laser is still not cutting, you can contact someone who is authorised to perform maintenance on the laser, ideally by posting your issues on slack or the mailing list.


Do not take the side panels off and go messing about with wires or modules, the high voltage PSU in the electronics enclosure puts out up to 25 thousand volts, and there are some very big capacitors in it that hold a charge for a long time.

The tube cover if removed exposes you to not only that high voltage, with the possibility of capacitive coupeling (i.e. getting a shock from being too close to the tube and not even touching a wire) but the full power of the laser beam... you do not want to get a shock by touching the wrong thing or getting the laser beam in your eyes, it will seriousely ruin your day, besides, the tube is delicate and expensive...

If you want to look at one, a brand new tube is mounted above the workshop door... the power connection post broke during install rendering it scrap before it was ever fired.

The laser cutter when operated properly is safe, the plastic viewing panel in the lid absorbs any stray laser beams before they can do dammage to a user, and the entire machine is in an earthed metal enclosure, as long as you are on the outside of that you are safe.


If you have any or repeated problems, please post with detail (software, hardware used, the file you were cutting, etc.) on the mailing list.