Would you like to build your own CNC hot wire foam cutter using 3d printer electronics for around $200/£160/€170? The pictures below are just a few of the RC models I’ve built with my CNC foam cutter.
So why do I use a Hot Wire CNC foam cutter to make RC planes?
Surely it’s cheaper to buy foam models than building with a Hot Wire CNC foam cutter.
- Yes, it can be to start with but some of the big EDF foam jets can be quite expensive. I’ve seen a few crashes beyond repair at my flying club. The first flying wing I built with the machine flew fantastic until I crashed it. Well, I crashed it a few times but the last one was it’s final. So power up the machine cut some new wing cores and I was back in the air in a few days.
- Another reason is to build models that you can’t buy or if you could they would be very expensive. I really enjoy researching and designing my own and there’s some great software you can use now.
- Learning CNC has been great fun and the bug soon bit me. I now have a CNC router and 3d printer as well. These are great for those other parts that you can’t easily find.
How much will it cost to build
Probably not as much as you think. Building the USB version in 2020 is going to cost approximately $200/£160/€170. If you would prefer to build the Parallel port version then that’s going to be around 30% more.
There is free software you can use as well to generate the G-code which works well and maybe all you need. More details later in this article.
Plans and eBook
The new eBook and plans contain full details with a step by step instructions, there is a small charge for the plans but the eBook is free. The full-size plans can be printed on any printer except for two parts. These are then used as templates to get exact hole locations.
The plans also include G-code for a Clark-Y airfoil to test the machine once built and also the G-code to make a 38″/960mm flying wing. Full setup of the fly wing is included in the ebook.
I’ve had some great feedback and one question that pops up quite often is Can I use the USB interface on my computer for the CNC Hot Wire Foam Cutter? Yes, you can but I decided it was time to make a new version of my original CNC foam cutter.
So why a new design?
My old design, see below, used an old computer with a parallel port to run the CNC controller. This has been fantastically reliable and never failed me. But these older computers may become more difficult to find. Since 3d printers are so popular and the hardware is relatively cheap I’ve decided to use these in my new version. This also helps to reduce the cost by about 30%.
The eBook also includes details on how to build the old parallel port interface if you still want to use that option with bigger NEMA23 stepper motors.
My original plan was just to convert the old design that I built with 18mm HDF(high-density fibreboard) which I over-engineered. But when I started to investigate the options using 3d printer stepper motors it soon became apparent the smaller steppers would struggle. It was a heavy machine and using smaller steppers could cause steps pulses to be lost. So a lighter machine would be required to use 3d printer NEMA 17 stepper motors.
The main goals of the new CNC Hot Wire Foam Cutter
- To run from modern computers with USB connectivity
- Lighter Design using 12mm MDF
- Utilise 3d printer stepper motors and controllers
- Comprehensive Plans, full size for key parts and detailed instruction,
- Easy to build.
- Still, be able to use the old parallel port interface with Mach3 and LinuxCNC if that’s your preferred option.
- 4 part video series showing how to build the new version.
We will start with the electronics first because we can get this tested and working before we install it in our machine. It’s good to know it all working if you just purchased the parts. If we did the mechanical first it could be a while before we notice a problem with the electronics
I’ve spent a considerable amount of time researching and testing the electronic components and have used the same stepper motors as my Anet A8 3d printer. This helps to keep the cost down.
This new build uses the same type of controller found in many 3d printers. We will be using the Arduino Mega 2560 with a RAMPS 1.4 board attached.
I highly recommend buying a geniune Arduino Mega if you can. Because I have seen it myself that the USB can sometimes be problematic on connecting. The Chinese boards use cheaper compoents and the build quality is not always the best. One off my boards the sockets where the RAMPS board plugs in was not straight. I did manage to staighten them and luckily it worked OK.
The stepper motors will be NEMA 17 size and a 12 Volt Power Supply. Here’s the link to the Full parts list with a PDF download.
This is can be the most challenging part of the build but once you’ve had some practice it gets a lot easier. I have several videos on YouTube that will help you.
There are two parts to this, first, we have to get some g-code for our new wing or fuselage design and then we need software to translate the g-code into machine movements.
To generate g-code check my article here which you can use both free and paid options For the second part, the software is free and needs to be uploaded into our Arduino Mega.
You may have heard of Mach3 or LinuxCNC which are very popular in the CNC world but these can’t be used with the Arduino controller. The ebook has full details and this website has tutorials with links to videos if you want to use either of these.
I originally used the firmware and software modified by a user on RC groups called Rasciodc. It’s based on the GRBL 0.8c2firmware. The article he’s made is excellent and provides some great software and firmware.
I modified the parameters to suit this machine and you can use the Windows software to control the hot wire temperature via a slider
Updated firmware and software
This new firmware and software based on the original but using later GRBL Mega 5X firmware with a few configuration changes to suit foam cutting with a 4 axis machine. Please read the post linked below for full details. You can now also upload precompiled firmware which is much easier if you are new to this.
The updated software has bee reworked to better suit foam cutting and the later firmware,
Alternative Firmware and Software – DevCNC Foam
DevCNC Foam is purpose-built for 4 axis foam cutting and will run on several hardware configurations. It can even be used to make an old parallel port controller compatible with USB using an Arduino. DevCNC Foam cost €60 in 2020.
One benefit as well is very easy to install and doesn’t require the Arduino IDE to load the firmware. It checks the controller board and will upload the correct version. You can try it for free for up to 400mm of total movement. Just enough to confirm your hardware works OK before you purchase a license. DevCNC Foam is very good and the wire path display is in 3d. It will also run in simulation mode so you can check how the foam would be cut. Very good for spotting errors. It’s saved wasting foam a few times for me.
What tools do I need?
To ensure the holes are drilled straight a pillar drill is very useful. I used M6 cross dowels with socket/Allen key heads to join the major parts, which are available at most DIY stores. These are great because you can take the machine apart very easily if you need too, without having to wonder which size screw did I use on this part.
For the mechanical part of the build, you need anything fancy just screwdrivers, pliers, measuring tools and a few clamps.
Building the mechanical side
Full instructions are included in the eBook together with a cutting list along with the plans. The plans are full-size plans with hole centre marks, except for 2 larger parts. The design uses metric dimensions which are a little easier to work within my opinion.
I’ve used 6mm cross dowels and barrel nuts to join the main parts together with a few screws
To save yourself time and some expense take the cutting list to your local DIY store and get them to cut all the parts. My local store does this and you only pay for what you need and you’ll get them cut to the correct size with nice square cuts.
Some of the links on this website are affiliate links so if you use them to purchase from thank you very much. You don’t pay any more but I earn a little commission which helps the cost of running the website.
The parts list can be found here which includes the USB and Parallel Port versions.
Software to generate g-code
Once you’ve built your CNC foam cutter you’ll need some software to generate g-code to cut the foam wings or fuselage sections.
The software can be the most challenging part of CNC foam cutting. I would suggest starting out with the free versions first and upgrade as your skills and knowledge grow. I’ve used all the options listed below which will produce G-code for your designs. The paid options are excellent and worth the money in my opinion.
Here is a free g-code generator that will generate the code for a wing. http://swarfer.co.za/rc/wire/index.php I’ve used it on my machine and it’s easy to use and may be all you need Start with this first. The G-code generated uses the axis letters XYUV but this build uses XYUZ but this isn’t a problem. All we need to do is use a text editor like NotePad++ and use the search and replace function replacing the V with Z.
David has released an update here on GitHub which will generate the correct axes letters. You will need to have Python on your machine to run the code.
Another free option is JediCut https://www.jedicut.com/en/ my video here is a tutorial on how to use Jedicut. Not the most intuitive thing to use but very good for free software. If you install Jedicut it won’t work with the Hot Wire Controller. Here’s my post on how to modify its settings so it works.
WingWire is another option as yet I haven’t used it. Very impressive. Here’s the link on Thingiverse https://www.thingiverse.com/thing:3676825/files
The following software options need to be purchased which are a lot more comprehensive. You can use the demo versions which are full versions but the only restriction is you can’t save the g-code.
The software comes from the DevCAD team who are based in Italy. DevWing Foam2 one costs €125 and DevFus Foam 2 €95 in (2020). I think this is quite reasonable when you consider how many models you can make. Most foam models will cost more than that and once you’ve built a few the investment pays for itself.
Profili2 Pro was the software I started with and it was very good for generating the code for wings and has a massive database of airfoils. I used it for several years and it’s now been replaced by DevWing Foam 2 http://www.devcad.com/eng/devwingfoam.asp which I’ve just recently upgraded to. I have a new video tutorial series on DevWing Foam 2
DevFus Foam will generate the g-code to produce the fuselage sections. My Hawker Hurricane and T45 Goshawk fuselages were built using this software. Once I could make wings the next logical step was fuselages. I have a full video series on my channel showing how to use DevFus Foam
The response to this project has been amazing and I do get quite a few questions from builders. So I’ve made a video covering the most common issues and questions. It’s a long video so I’ve included time codes below
01:29 Axis Not working
09:36 All axes not working
20:22 Axis direction needs reversing
30:21 Buttons Missing from GRBL HotWire Controller
34:59 Jedicut display looks weird
40:03 Arduino Line Numbers
41:35 What size wing can I make with the foam cutter?
47:46 How to power the Hot Wire
52:10 Tensioning the Wire
53:24 What type of wire do I use?
54:07 Wing size incorrect – Calibration and Foam Placement
54:29 Saving GRBL Settings
1:00:43 Can I use these Stepper Motors?
1:08:10 What types of Foam do I use?
1:10:35 Can I use the Arduino Uno?
1:12:19 Can I use leadscrews instead of threaded rods?
1:13:38 Can I use Limit/End Stops switches?
1:21:17 Looking at using some updated firmware – just a heads up.
I’ve been making foam aeroplanes for several years with my machine and it’s a real buzz to fly something you’ve made yourself. You’ll soon have people saying can you make me one.
If you have any questions first check the FAQ page https://www.rckeith.co.uk/hot-wire-cnc-faq/ and if that doesn’t answer them then please drop me a line from the contact page. Good luck with your build, it’s a real sense of achievement when you see it it all working.
Check the builder’s gallery showing some of the guys that have built the machine. Some have put there own interpretation on the design. Please send me pictures of your build and any models you’ve made and I’ll add them to the page.
If I can do it then so can you.