Warning: Use of undefined constant description - assumed 'description' (this will throw an Error in a future version of PHP) in /homepages/32/d763672482/htdocs/clickandbuilds/CNCMakerZone/wp-content/plugins/thingiverse-embed/thingiverse-stream-widget.php on line 12 LASER cutting – CNC Maker Zone
Aluminium extrusions are common on low-end mini CNC machines, particularly the 20mm square 2020 variety. In some cases, such as my cheap Chinese 1610 CNC machine, they’re used to create the whole framework for mounting stepper-motors, spindle motors, LASERs, controller boards, and all manner of other things. Yet, they’re often left open, basically as cut, at the ends. So, I decided I’d design some simple end caps in OpenSCAD to 3D print: you can see the result in the photo below.
Recently I realised that my CNC setup was getting a bit complicated. For one thing, I was using three separate power adaptors: one each for the CNC itself, my 5W LASER module and the extractor fan I previously wrote about. The CNC machine has a 24V supply, whereas the other two use 12V. Also, I had separate switch locations for the CNC and fan, while the LASER had no control switch: basically power supply on and off was simply plugging or unplugging the mains plug. While still perfectly usable, I decided it was time to change that setup for something better: the 3D printed control box shown in the photo below.
As you can see, I decided to make it not just functional, but also visually in-line with a more professional look than you might expect for a cheap CNC machine. So I decided to paint it, add some inkjet-printed water-slide transfers, then clear coat it. The bumpers I gave a few coats of brass-look paint and clear coat. To finish them off I LASER-cut inserts from 1.5mm Mahogany sheet which I finished with Danish oil and some clear coat, lightly sanded to give an old-style effect. It’s not perfect, but I’m quite pleased with how it turned out.
Electrically the box contains a 24V input from my CNC power supply, which goes through an automotive voltage/current meter straight to the CNC control board. Then I connected an automotive 24V to 12V regulator to the 24V output and ran the 12V through the white switches to the LASER module and fan, together with a 12V supply for adding lights later. The spindle motor simply connects through the switch, so it can be used to isolate the motor power, as a replacement for my previous spindle switch project. And to give an idea of how I connected the box to those parts I’ve put a photo of the rear of the box below.
So, finally, if you’d like to make your own version why not click here to go to the Thingivers.com page, where you can download the 3D printing files, the OpenSCAD code for adapting if necessary, the water-slide transfer images and a file for LASER-cutting the end inserts too.
Size isn’t always the most important thing when selecting a CNC machine. For example, I have a small and inexpensive Chinese 1610 machine, which has a bed 160mm wide and 100mm deep. For the kind of Maker things I do the small size isn’t a problem: in fact it works quite well in my equally small work zone. However, for LASER-cutting I wanted a little more distance along the Y-axis so I looked into how to simply modify the machine.
Obviously I could just replace some side frame parts, along with a couple of guide rods and a lead-screw, making the plan area whatever I’d like. However, that seemed like overkill for my needs so I thought a little more and came up with a very inexpensive way to up my cutting size to 160mm by 140mm. An extra 40mm doesn’t sound much, but for a lot of projects it makes a big difference. And, all it took was a bit of 3D printing filament and ten new hold-down bolts. You can see the results in the photo below.
The risers just raise the bed up a few millimeters but, together with moving the guide rod slider blocks in by one slot, they allow the bed to ride over the guide rod mounts. That riding over is what gives the extra 40mm. I decided that 20mm of overhang front and back during cutting wouldn’t be a problem, which saves the cost of buying a new 160x100mm 2020-section aluminium bed. The original bolts used to mount the bed were 10mm long, so I replaced them with 16mm ones which fitted perfectly. I also took the opportunity to replace the drop-in T-nuts with slide in ones, which gives me more confidence that the bed is properly fixed down. You can see how I fitted the risers, and moved the blocks, in the photo below.
It’s Easter season in CNC-land, so I thought I’d have a go at designing an egg themed project. Of course, the most famous egg is probably Humpty Dumpty, and he’s also a nursery rhyme character so a fun project even if you don’t do Easter celebrations. So I came up with a simple design that can be LASER-cut from thin wood sheet on a CNC machine even with a low-power diode-LASER. I also decided to make the design symmetrical, and add a small registration mark in the lower-left corner, so it can be cut and engraved one side, flipped over without removing the sheet, and just engraved on the back. The finished project is shown in the photo below.
As you can see in the photo, I cut two versions from 6mm thick Basswood around 80mm high (using my GCoderCNC 2.5D web app – click here to launch this project there). That turned out to be a good size as I’d cut them at 90% power and 100 mm/min feed rate with 4 passes, so small areas of burning next to lines didn’t spoil anything and were easily sanded away. If you look closely you’ll notice that the engraved lines in the right-hand version are slightly mis-aligned. That’s because I made them two-sided: so I was quite happy that they turned out looking OK on the rear.
The smaller version was cut from 1.5mm Cherry wood, at the same LASER settings but just two passes. It’s smaller but turned out quite well, with just some charring around the eyebrows that was hard to remove. The Cherry was a little thin as the legs and arms were narrower than the larger Basswood versions, so I cut two and stuck them together with wood glue for added strength. Overall though, for a quick design I was quite pleased with the results, and I hope you enjoy making one too 🙂
If, like me, you like to spend time surfing the internet looking at photos of CNC accessories, you’ve probably thought how nice it would be to have a pendant (i.e. a controller on a cable) for cheap Chinese CNC machines using GRBL controller boards. In fact, I wanted one so much I decided to build one to allow me to jog and zero axes, as well as to let me turn the LASER on for focusing and accurate jogging. I decided to do it using an ESP32 microcontroller as it allows the pendant to act as a Bluetooth link for G-Code sending/receiving as well. I thought my finished design might be useful for others to base their pendant designs on too, so I made it open source, and you can see what it looks like in the photo below.
It’s important to note that this could probably be described as an advanced maker project, as it requires skills with 3D printing, circuit making, soldering and Arduino coding. But if you’re up for the challenge you can get all of the files and details needed on Github and Thingiverse. The links are below and good luck making one as they can be an invaluable CNC accessory 🙂
LASER cutting on a cheap and cheerful CNC machine is lots of fun, but I can’t say the same about the smoke and fumes. That’s why I posted before about a simple extraction system. But since then I decided to try to do better using a larger fan mounted on the CNC’s 2020-extrusion frame. So I used OpenSCAD to make a design based around an Arctic Air 80x80x25mm PC fan, as it’s designed for higher airflow than cheaper fans. You can see the result in the photo below.
The extractor fan housing mounted on the CNC’s 2020-extrusion frame
The design did quite a good job and the air flow-rate was quite impressive in my opinion. However, it has the disadvantage of covering a large area so the suction around the LASER-cutting area turned out less than for my previous design. So I decided to adapt the design to allow the fan housing to be mounted to a simple enclosure I’m prototyping for my machine. That led to me adding side supports that stick to the housing and have flanges with holes for bolts.
Using the fan with the enclosure works really well, with hardly any smell of smoke or fumes coming out while LASER-ing, as it’s all blown through a flexible 60mm hose out through a nearby window. You can see the side supports in the 3D assembly picture below. And, if you’d like to have a go at making your own extractor fan from this design, click here to go the Thingiverse page which includes all the STL files and the OpenSCAD design file too.
If you’ve read the introduction to our GCoderCNC 2.5D web app you may be wondering how you can get started using it for some LASER cutting. If so, here’s a quick tutorial that should have you engraving a happy face onto some wood with only a few simple steps and a little time at your CNC machine.
Firstly, opening GCoderCNC 2.5D really is as easy as going to its’ secure website at Github.io. It should launch with the happy face design already loaded as shown in the screenshot below. To make life easy for you, just click here, or on the screenshot, to open the web-app in a new web-browser tab.
The app will have started up in router mode, whereas we’re doing some LASER cutting. That’s easily sorted, just go to the ‘CNC mode’ menu at the top of the app window and select ‘LASER mode’. There’s a screen-grab below showing the menu options. In case you’re wondering, the difference between the router and LASER modes is simply that router mode allows cutting tools to go up and down, and LASER mode keeps the LASER at the same height all the time. For advanced use you can actually use router mode for LASER cutting, using the depth to vary the laser height when cutting thick material. But for now, using LASER mode keeps things nice and simple.
Next we need to tell the web-app what settings are relevant for our own LASER. That really comes down to your CNC machine and LASER module. For example, a 50W CO2 LASER will need much lower power to etch the surface of wood than a 2W diode-LASER. So, if you’re unsure, it’s best to read your manual or ask the manufacturer. I use a cheap Chinese 1610 CNC machine with a 5W diode-LASER, so I find a feed rate of 200 mm/min and 20% LASER-power works well for etching plywood. When you’ve decided, simply move the two sliders at the top of the ‘Default settings’ box, at the left side of the app, to the right values, as in the screen-grab below, keeping the other options unchanged.
Now that the design is all set up we just need a g-code file for our CNC machine to follow. That’s really easy to get: just go to the ‘Export’ menu and select ‘Export G-Code…’ and the dialog box shown below will appear. You’ll notice that the width and height of the finished piece are already set to a default size. If you want the happy face to be bigger or smaller, just change one of those values (the other will change to keep the design proportional automatically).
Now you need to set the ‘GRBL version’ dropdown in the dialog. Older versions of GRBL (say v0.9-ish) used values of 0 to 1000 to represent 0% to 100% spindle motor speed, but more recent versions (say v1-ish) use values of 0 to 255. Don’t worry if that confuses you, as you should be able to find out from your CNC manual or manufacturer. If not, you can try selecting ‘Speed 0 to 255’ and, if your LASER seems to be etching too lightly (spindle speed values are used for LASER power too), you’ll know to use ‘Speed 0 to 1000’ instead. Having done all that you can click the ‘Download the G-Code’ button. Your browser should tell you that it’s downloading ‘happyface.nc’ which should end up in your downloads folder.
If you’ve done all the above then it’s now down to you to make your own happy face. Obviously the first thing you need to do is put some wood on your CNC machine: I used some 2mm thick plywood blanks I bought in Hobbycraft, but most woods should work. Once that’s done and you’ve focused your LASER (and still using LASER-safe glasses and ventilation) you need to move the LASER-dot to the lower left corner of the area you want to burn the happy face into: that’s the default origin and you can see what I mean in the image below.
Now, once you’ve turned off the LASER in your CNC control software, you need to zero your CNC axes in that software. That makes all of the g-code commands relative to that position, or the origin as we call it. If you’re not sure how to do that you need to read your CNC manual as it’s a really important thing to know how to do. And then it’s the exciting bit, where we tell the CNC software to burn/etch our design onto the wood. If all went well, you should end up with something like the one shown below 🙂
Creating g-code files for CNC machines is an essential task for our computer-controlled routing and LASER cutting projects. However, most CNC software packages are either overly complicated or limited to a single platform and operating system. So, to help avoid those issues CNC Maker Zone UK has published its’ own free-to-use and open-source web-app designed for ease-of-use on all PCs and tablets (but not smartphones) including on Windows, Linux, Mac, Chromebook and Android in a HTML5 web-browser.
Below is a screen-grab showing what the web-app, which is called GCoderCNC 2.5D, looks like running in the Chrome web-browser on Windows, with our Darth Vader Head project open (click the image to go straight to the web-app in a new tab). It’s designed as a web-capable app so if you add it to your home screen, in the web-browser menu, you should be able to run it in its’ own window, which is especially exciting when using it on a tablet. And, it’s been designed to create g-code for routing and LASER-ing, and even has some advanced features like variable routing depth for v-carving.
GCoderCNC 2.5D allows you to import an SVG file and export it as a g-code file, all without cookies or uploading your files to the internet: it’s all done on your computer in your web-browser. It’s intended to be usable and useful for anyone interested in CNC making, so hopefully you’ll find it works well for you once you’ve played with it and learnt the basics of its’ use. So, finally, here’s a couple of links to help get you started using GCoderCNC 2.5D:
Sometimes it seems like there’s no end to the range of projects we can make with a CNC machine. And it’s quite amazing that even cheap versions are accurate enough to make miniature projects for model scenery and even dolls houses. So I thought it might be fun to try making some miniature fruit crates, as the photo above shows, and post the design here for anyone to have a go at making some too. At full size they would be around 450mm long, 300mm wide and about 200mm high but at 1/12th scale, commonly used for dolls houses, they’re much smaller: I’ve included a photo below with a one pound coin for comparison.
I’ve put an SVG file below for you to download, or you can click here to launch it in the GCoderCNC web-app. If you need to edit it, or make a DXF file for your CNC software, you can do that with Inkscape quite easily. The red box is there in case you need to get scale in your software, but doesn’t need to be cut: it should be 70mm wide by 65mm high for 1.5mm thick wood (or other materials such as plastic, or even cardboard, if you prefer). If you use thicker material you can scale it proportionately, such as 2x scale for 3mm thickness. The design works for LASER cutting but can be adjusted easily for routing by offsetting the lines through half the cutting width.I LASER-cut a prototype in Oak (the one on top in the photo above) and the rest in Basswood, both from 1.5mm sheets. Once cut they are quite simple to put together. I started by putting the sides onto the bottom of the crate, then slipped the ends on one at a time. I also used glue at all the push-in joints: the base could be left floating but the glue helps prevent the thin pieces of wood at the joints breaking away when sanding. To finish the crates off I used 400 and 1000 grit sandpaper, including using a finger sander, followed by a couple of coats of Danish Oil to give the wood a nice look without too much of a shine. Personally I’m quite happy with the results and hopefully you’ll enjoy making some on your CNC machine too 🙂
