There’s no getting away from it: routing with a CNC machine can cause lots of vibrations to travel into the work surface below, causing quite a bit of annoying noise too. To combat that I separate the machine from the work surface using 25mm thick firm sponge sheet: the blue non-flammable foam sold for furniture. It does an excellent job of isolating machine vibrations, but is really overkill for a small machine. So I decided to play around designing some flexible feet to fit onto the 2020-section aluminium frame that would do a similar job of preventing machine vibrations being transmitted to the hard work surface.
Obviously the best way of doing that would be to use a soft material that will wobble around: not enough though to flop down, and not so little that the rigidity transmits vibrations through it. As I’d recently bought some flexible TPU filament for my 3D printer, which is quite elastic, it seemed a good choice for making a squidgy wobbly thing (other flexible filaments may work well too). Designing a dampening system is obviously a rather complicated thing to do, probably best done by professionals using finite-element modelling and things like that. But that’s no reason not to have a go anyway!
For a DIY approach building a damper that flexes with the frequency of the vibrations, and preferably does that inefficiently, can be a good starting point. That way some of the job is also done simply because some vibrations will be cancelled out by others that are out of phase with them. So I went through a few iterations of small dampers so that I could squash them and get an idea of how rigid or squishy each design would be. It turns out that making squishy models at small scale using TPU isn’t as easy as you might expect: even with 10% infill density shells, creases and corners all increase rigidity too much. In the end I came up with the design below in OpenSCAD.
The design includes a flexible adapter at the top to squeeze into the slot in a standard 2020-section aluminium extrusion, as used on many cheap CNC machines. It’s the best design I’ve managed so far for a TPU damper just 20mm wide, and was designed to be printed without support material. It’s not floppy even though it has only 10% infill density, but has enough ‘squidginess’ to flex slightly under the weight of the CNC machine using a damper at each of the back corners and one under the middle front of the frame. If you want to have a go at printing your own, you can get all the files, including the STL file for 3D printing, by visiting the Thingiverse page.
The good thing is that this prototype allows vibrations to set up flexing in a variety of directions that can help prevent them being transmitted straight through to the surface below. Of course, I realise this is a work in progress, but the design does seem a useful starting point for some more experiments: perhaps tweaking the infill density and dimensions to start with so as to fine-tune flexibility while retaining the ability to support the CNC machine without bouncing around. And as a final note the design was easy to fit to a 2020-extrusion even though the slot ends were closed off: I’ve put a photo below to show what a finished and fitted damper looks like 🙂
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.
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 🙂
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:
Recently I bought some 1.5mm thick Walnut sheet as I wanted to try it out with my CNC router and see how good the results would be. Walnut is quite a dark wood with a nice dense grain, so it seemed like an excellent opportunity to take my CNC intergallactic by making a small inlayed Darth Vader from Star Wars. Hopefully George Lucas will approve if he happens by, so below is my completed Darth Vader head (at around 10% water content, in case you’d like to know).
I was quite pleased with the results, the details being routed to 0.75 mm deep in two passes, and the edge being cut in three passes, using the 1.2mm diameter end-cutting bit shown above (which gave finished grooves almost 2 mm wide). As the image at the top of this page shows, the Walnut sheet cut quite well and cleanly with the spindle at 1000 rpm and a feed rate of 50 mm/min to minimise potential breakage of the bit. The above photo is then after I’d given it some sanding with a fine grit paper, which took little work. Even sanding out the recesses with folded over sandpaper was quite easy, with a little patience. So overall I’m looking forward to some more small projects using this lovely wood.
CNC routers are wonderful machines for cutting and shaping wood and other materials but sometimes there’s no choice but to use a router without computer control. For example, when trimming the edges of wood to size, or for using the router as a finisher with sanding drums. When that kind of work is needed I don’t want another machine: rather I want to use my CNC router for occasional manual feeding. To do that a fence is very useful, as it allows pieces of feedstock to be pushed past the tool/sander in a straight line. Not only can that help ensure edges are kept parallel, but it also allows creation of small mouldings with edge-shaping bits.
This 3D printing project is my attempt at creating a very simple fence system for my cheap Chinese CNC. The fence part simply slides into the groove along the top of the CNC bed, after light sanding to get a good fit that doesn’t wobble. However, for manual feeding we don’t want the fence to be able to move along the bed groove, so a part is included for a simple stop that can be used to prevent that happening. The stop connects to the side of the bed using a winged hold-down nut as shown in the photo below. You can download the 3D printing files by clicking here, including the OpenSCAD file for any adjustments you’d like to make.
Hopefully you won’t mind if I finish with a word of caution. But, using a CNC router for manual feeding of materials brings risks you may not be experienced with. Probably two of the main ones are the dangers of having hands near your tool/cutter (which can be avoided using a proper push/feed stick) and extra dangers of pieces of tools and feedstock breaking and flying away (which can be largely avoided by feeding slowly and wearing sensible clothes and eye protection).
Another rookie error is to feed material with the rotation of the tool, which means it could unexpectedly get pulled through and shoot out like a javelin (I did that on a router table years ago and it’s amazing how fast the expelled material can be). Not only is that dangerous: it can even ruin your work. You may also want to wear ear protection as the sound level will be higher working close to the motor and tool. Basically, please be very careful and don’t take chances using the 3D models provided here 🙂
Sometimes it’s nice to make a video, even a timelapse one, of a project coming to fruition on a CNC machine. Maybe just as a keepsake, or to share, or even to make some educational Maker instructions. So being able to add a GoPro camera, or other camera that uses GoPro mounts, is something you may want. I did anyway, so the project shown above is a simple 3D printed mount that clips onto a 20mm-extrusion on the front frame of my CNC, which can be positioned right in-line with the work-bed centre.
It’s a very simple 3D printing project that doesn’t even need any support material, so shouldn’t be a challenge if you have access to a 3D printer. The files you can download from Thingiverse by clicking here, which include the OpenSCAD file in case you need to customise or adjust it. Once made you use it to fix on a sticky mount base like in the photo, for your camera arm to fit onto. And below is a photo of my GoPro session mounted on my CNC so you can get a better idea of how it works.