How to Build a USB Hot Wire CNC Foam Cutter – Free eBook

posted in: CNC, Hot Wire | 0

Would you like to build your own CNC hot wire foam cutter using 3d printer electronics? 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 2019 is going to cost approximately $200/£160/€180. 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.


hot wire cnc fly wing
Another Wing

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.


USB CNC Foam Cutter
New Design
4 axis cnc hotwire foam cutter with airfoil
Old Design

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. Part 4 out very soon.
usb cnc foam cutter

Electronics

We will start with this first because we can get the electronics 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. The stepper motors will be NEMA 17 size and a 12 Volt Power Supply. Here’s the link to the Full parts list

Software

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’ve decided to use the firmware and software modified by a user on RC groups called Rasciodc. It’s based on the GRBL firmware. The article he’s made is excellent and provides some great software and firmware.
I’ve modified the parameters to suit this machine which can be download from here

We will need to compile and upload the firmware to our Arduino Mega board. This is a simple process with full details in the eBook and Part 2 of the video series.

Please note I have not written any of this software and a big debt of gratitude goes to the developers.

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.

Affiliate Disclaimer

The links below are affiliate links so if you use them to purchase from them thank you very much.  You don’t pay any more but I earn a little commission. 

Parts List

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 grows. 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.

Free options

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.

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.

Paid options

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 and each one cost €95 (2019). 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 is 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 a new version called DevWing Foam http://www.devcad.com/eng/devwingfoam.asp which I’ve just recently upgraded to. Keep checking on my YouTube channel as I will have a tutorial up toward that latter half of 2019.

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 progression was fuselages. I have a full video series on my channel showing how to use DevFus Foam

Finally

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 http://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. If I can do it then you can.

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