How to build a Hot Wire CNC Foam Cutter – Parallel Port Version

posted in: CNC, Hot Wire | 2

This post details my original CNC Foam Cutter build which I’ve now updated with a new version. Here’s the link if you prefer to build the USB version https://www.rckeith.co.uk/how-to-build-a-usb-cnc-hot-wire-foam-cutter/

I would encourage you to build the USB version because the configuration of Mach3 and LinuxCNC on the parallel port computers is quite lengthy. Calibration is also more involved. So if you are new to CNC foam cutting then build the USB version which is much easier,

The parallel port has long since been discontinued but in 2020 it’s still a viable option. If you check on Amazon or eBay there are still many CNC controllers being sold that still use it. If you have and old PC kicking around it’s an ideal candidate, or you can buy a parallel port add-on card for a more modern PC.

Why build a Hot Wire CNC Foam Cutter?

For me, it was a way to build wings and fuselages for RC aeroplanes that weren’t readily available. Doing it yourself (DIY) is not as hard as you may think.

Traditional building methods for RC aeroplanes involves lots of Balsa wood cutting and glueing.  I can cut a foam wing core in about 15 minutes and usually I cut several at a time.  Building your own models is very rewarding and when they fly well its a real buzz.

I built my first machine in 2012 and here a few of the projects I’ve made with it

Main sections

How does it work?

If you’re not sure what a Hot Wire CNC foam cutter is, then let me explain. Most types of foam can be cut with a hot wire and if you can control the wire accurately then you can make wings and fuselages for RC aeroplanes and many other things e.g. signs. It’s possible to do without a CNC (Computer Numerical Control) machine just by guiding a hot wire over templates. This method is less expensive and is a good place to start on the hot wire CNC foam cutter journey. You’ll get a good experience of working with a hot wire. My Super VC10 wings were made this way before I had my machine.

Is it difficult to build?

No. If you are reasonably practical then you have all the skills you need. Don’t be put off by the electronics. It can look a little daunting but if you follow my articles on the website or sign up for the eBook you have all the information you need. If you do need help reach out to me via the contact page and I’ll get back to you with some answers. I get quite a lot of questions from all over the world asking for advice and recommendations on parts to buy. I’ve provided links to all the parts I’ve used and recommendations.

After a lot of research and some really good advice from CNC forums, I designed this version. Full details on this page http://www.rckeith.co.uk/cnc-detailed-build-and-plans/

How much does it cost to build a Hot Wire CNC Foam Cutter

Probably not as much as you think. My 4 axis CNC kit came from China which included the stepper motors, controller board and a few cables. These vary in price so check the parts list for the latest  I check them regularly to make sure they are still the best in my opinion. 

The power supply I made from two old computer PSU and the rest came from local DIY stores. See the build page for a full list with links. I’ve spent more money on software than the rest of the build, but there are now some very good free alternatives, check the build page

The majority of the cost, if you use the free software options will be the CNC controller, stepper motors and power supply. If you have an old desktop PC with a parallel port then this will keep the cost down. Working on average prices in 2020  if you had to purchase everything except the PC, then I would budget for around $280 (US) £220 (UK), but you may be able to do it for less if you have some suitable materials already.   The USB version is a little cheaper around $200 because it’s based on 3d printer components. Which are so popular now it keeps the costs down. But do check the parts list for the latest prices.

It’s a bit of an investment but it won’t take you long to recover the cost. I’ve built several wings and a couple of fuselages and it’s a real buzz when that wing core reveals itself from the foam block.  Foam models can be quite expensive now, guys at my flying club often pay £200 to £400 for a jet with a big EDF. I’ve seen a couple of these destroyed beyond repair.

Parts required to build a Hot Wire CNC Foam Cutter

  • Stepper Motors – these drive the towers where the hot wire is attached
  • Control Board 4 axis – sends signals to the stepper motors to move a certain amount and in which direction. Receives inputs from limit switches and pendants
  • Computer – drives the control board. It receives g-code and turns that into signals for the control board.
  • Lead Screw – connected to the stepper motors and then the towers to move them in the desired direction,
  • Software – I did use LinuxCNC but started with Mach3 which turns the g-code into a signal that the controls board and stepper motors can use. I then use Profili2 Pro and DevFus Foam to generate the g-code from the design. You can use LinuxCNC and free software to generate g-code for wings and fuselages. Check my article Free CNC Software
  • Drawer Slides – used to provide vertical and horizontal movements for the two towers
  • Power Supply 24V – this powers the control board and the stepper motors
  • Hot Wire – usually nichrome wire.

Foam Cutter Accuracy

I’ve decided to use threaded rods for the lead screws because the accuracy required for hot wire foam cutting is not as critical as a CNC router.  But I still get very good results when I compare the cut parts with the scale drawings.

Lead screws are a lot cheaper now compared to when I first built the machine but still more expensive than the threaded rods. If you prefer I would use T8 lead screws link here

Power Supply -24 Volt

I used 2 PC ATX Power supply in series to give 24 Volts. This can be a little dangerous if you’re not careful to isolate the second PSU, so I’d recommend purchasing one specially designed to give 24 Volts. These are now quite cheap and take up less space. Details in the parts list

Original Build of the Foam Cutter

Below are some pictures of my original build. It used materials form an office clear out. This was high denisty MDF and was very stable but heavy. I was on a limited budget and this wood was free so I built the machine with it.

Back in 2012 3d printing wasn’t as popular as it is now so I puchased a 4 axis CNC kit that included all 4 NEMA23 stepper motors and the TB6560 all in one controller board. It proved to be 100% reliable and now its used on my CNC Router since moving over the the USB version of the foam cutter.

4 axis cnc hotwire foam cutter with airfoil
Finished

The build was finished see pictures above and video below. Tested and it works. I used RJ45 cables and sockets to connect motors to the controller.

CNC Foam Cutter Controller Software

To control the CNC machine you need some software and after much research, I originally decided to go with Mach3 from ArtSoft http://www.machsupport.com/ it’s very well supported and there are several videos on YouTube that describe how to install and configure. The unlicensed version allows 500 lines of g-code but you’ll be surprised how many lines it can take to make a wing. The licensed version costs $175.

What Computer can I use?

The computer needs a parallel port the one that printers use to connect to. These are obsolete now but you can still find them quite easily. Mach3 or LinuxCNC will run perfectly well on very modest hardware.

I’ve used an old Dell GX620 computer running XP and no other unnecessary software installed for Mach3. For LinuxCNC I use the same machine and just swap the disk over. There are other options now for USB and Ethernet(LAN) connections check my post here http://www.rckeith.co.uk/mach3-parallel-port/

Software to generate G-code

G-codes are the instructions sent to the machine that tells it how far and what direction to move the stepper motors. You don’t need to learn g-code as software converts drawings into the code. I’ve originally used Profili 2 Pro and have now upgraded to DevWing Foam 2 which does a lot more than generate g-code for wing profiles. Here’s video tutorial series for DevWing Foam which on my YouTube channel link here

DevWing Foam 2 is the next generation of software replacing Profili  2 Pro. If you’re just starting out I wouldn’t recommend this just yet as it can look a bit daunting. My advice would start with the free options below and then as your skills and needs progress then get DevWing Foam 2. It’s the best software for generating the g-code and is well supported.

Here is a free wing g-code generator that will generate the code for you http://swarfer.co.za/rc/wire/index.php I’ve used it on my machine and it works well and is fairly easy to use.  Check my post here http://www.rckeith.co.uk/foam-wing-free-cnc-software/.

Another free one is JediCut which I’ve made a video on How to cut a tapered using Jedicut and this CNC foam cutter  https://youtu.be/_UFOHJPlza8  You can download Jedicut from here  https://www.jedicut.com/en/

The Hot Wire

The wire between the 2 towers was tensioned by a spring so the towers can move independently for tapered wings. I’ve now converted it to a pulley with a weight attached.  The springs are OK for wings but I’ve found when making fuselages the wire can get some very steep angles which puts to much tension on the towers. Using a pulley with a weight keeps constant tension on the wire whatever angle it’s at.  I’ve used a 20-pound fishing line with a wheel on an axle to route the fishing line with a 1.5 lb or about .7kg lead weight. The pictures below should help explain it.  Ran a few tests and it seems to work well.

The wire is usually ni-chrome but several others can be used including guitar strings. I’ve powered my wire with the iCharger 206 which has a foam cut program but I have used a car battery charger connected to a house dimmer switch for manual cutting. This allows control of the heat and works very well.  An RC battery charger set to NiCad of NiMH also works.

I get best results from very thin wire about 0.4mm in diameter.  Doesn’t require as much current to heat. The kerf value, the amount of foam melted away is very small.  This helps in the design process.  I mostly use the default settings in the software I and sometimes adjust the kerf value for swept wings.

It works

It’s quite exciting when you get it all powered up and move the cursors keys and see stepper motors spinning. The video show a small test aerofoil which was about the 5th attempt. The hot wire cuts my radiance so it’s basically melting the foam in front of it. My first pieces were not very good as the feed was too slow but as you can see it didn’t come out too bad when I got the cut the feed right

Below is the flying wing which was the first model plane I made with the machine. This was just a quick test as a proof of concept and its proved to be the model I fly most now. It flies really well and is fast. Profili2 Pro was very good for generating the code and has a massive database of aerofoils. It’s been replaced by

Hope you found this of interest and if you need any advice or help then you can contact me through this website.

I’ve included the configuration for Mach3 with the TB6560 controller board on this page Mach3 TB6560 configuration For LinuxCNC check my article here on how to configure it http://www.rckeith.co.uk/foam-wing-free-cnc-software/

The first aeroplane made with the Hot Wire CNC foam cutter

This is the first flying wing I made with the CNC machine and it was a little gem. I did fly it most weekends. It super fast with a 2200KV motor and a 6×4 prop. It’s a blast. If you want to build it then check http://www.rckeith.co.uk/hot-wire-cnc-ymf-38-flying-wing/ I’ve included the g-code for each wing as well. 

Crashed her in 2017, pilot error, doh!.  So I made another here’s the full playlist 

Hot Wire CNC flying wing
First flying wing made with the foam cutter

I’ve now made a Hawker Hurricane with the CNC machine both wing and fuselage, you can see it here http://www.rckeith.co.uk/cnc-hot-wire-hawker-hurricane/

I’ve also made a much bigger wing for FPV(First Person View) with it as well details here http://www.rckeith.co.uk/fpvfw/

The CNC machine is now starting to pay for itself as I don’t buy ARTF models anymore, nothing against them but I just enjoy researching and making my own RC aeroplanes.

Updates I’ve made to the Hot Wire CNC foam cutter

I’ve now retired this original machine and use the new USB version. During its use, I decided to make an effort to get LinuxCNC working in 2018  and it’s was my prefered software for the parallel port version of the foam cutter  My video below shows how to make wings using Free software with LinuxCNC

After making several models and getting through a lot of foam I’ve only changed the couplers to the stepper motors. The rubber hoses occasionally came off which ruined some foam so I purchased some proper couplers and these have been very reliable. Details on the build page.

The TB6560 kit was very reliable and never missed a step and I use it on my CNC router

Parallel Port Build Details

Plans, Parts and Instructions

The new USB foam cutter can also be built to use the Parallel Port full details are in the eBook.


8600mm Drawer Slides x 2 pairs – 4 in total
450mm Drawer Slides x 2 pairs – 4 in total
Purchase from a local DIY store
4CouplersFlexible couplers x 4
M10 x5mm for NEMA17
M10 x 6.35 for NEMA23
Get the couplers here NEMA17 are 5 mm x 10
4tee-nuts for cnc foam cutter10 x 1.5mm T-Nuts x 4USA Price Check
UK Price Check
40cross dowel and barrel nutM6 Cross Dowels Bolts 50mm and Barrel Nuts x40
Get the Cross Dowels here
4threaded rod for CNC foam cutter10 x 1.5mm x 1000mm (cut to size) Threaded Rod x 4
If you prefer to use T8 Lead Screws
M5 x 8mm couplers will be needed as well.
450mm for vertical
750mm for horizontal
The step/mm will need to be re-calculated as well.
Purchase from a local DIY store.

Alternative T8 lead screws UK

Alternative T8 lead screws USA
1MDF Sheets12 mm MDF Moisture resistant or paint after the build.Purchase from a local DIY store.

The parallel port build is almost identical to the USB version except for the electronics. The plans have an alternative part B for NEMA23 stepper motors. These are bigger than NEMA17’s which you can still use if you prefer.

The controller board and the stepper I’d recommend you buy as a kit including the power supply. Loads on Amazon, AliExpress and Gearbest check the parts list below to see what I’ve used and recommendations. 

TB6560/TB6600 controller with the parallel port

This controller is used with Mach3 or LinuxCNC which interprets the g-codes and via the controller board moves the stepper motor.  There are a few alternatives but I’ll just list the ones I’ve purchased and used.

The all in one board may be a little easier to build with. With the separate drivers there is a lot more wiring. My all in one board has been 100% reliable and never missed a step. You may find comments on CNC forums saying they are no good but I’ve had no issues with mine. It’s now used on my CNC router since retiring my old foam cutter and using the USB version now.

QtyImageDescriptionLinks
1Nema23 Breakout Board and TB6560 drivers4 Axis TB6560 Controller Board Amazon US
Amazon UK
1CNC-DIY-Parts-4-Axis-Tb6560-Stepper-Driver-4x-Nema23-Motor-Software-LPT-Cable 4 Axis TB6560 Controller Board
All in one with power supply.
Drivers all on one board usually cheaper
Amazon US
Amazon UK
4NEMA 23 Stepper Motors 57BYGH56-401A or similar.Amazon US
Amazon UK

TB6560 DIP switch setting on my Blue Board

I’ve had a few comments on the website from people struggling to get their machine working correctly. Here’s how I have mine set up.

tb6560 dip switches 4 axis

This is configured for 75% current, fast decay mode and 1/2 micro-stepping. My stepper motors are rated at 2.8 amps and the drive will supply 3 amps at 100% so I reduced this to 75% to give me 2.2 amps and the motors work fine and have run like this for several years.

LinuxCNC and Mach3

LinuxCNC used to called EMC2 and has been around for some time and I did prefer to use this instead of Mach3 for both my machines. I’m now using the USB version. I have a full post on installing configuring and LinuxCNC here

Mach3 has been around for a while and is extremely well documented with some good tutorial videos on their website. Although not specifically for a hot wire machine they are worth watching. I’ve watched them several times http://www.machsupport.com/help-learning/videos-tutorials/

Mach3 and LinuxCNC are designed to use the old parallel printer port which is now legacy, which modern PC’s don’t have any more. There are a few options:

  • Get hold of an older PC with a printer port. Mach3/LinuxCNC doesn’t need a high-performance PC so most older PC’s will work just fine. This is what I have done and I have a few spare ones as well. Plenty on eBay from around £50/$80
  • Install a printer port add-on card. This one on Amazon has good reviews http://amzn.to/2fTsJIY
  • Use a USB or Ethernet motion controller board. This with the driver software will configure Mach3 to use either your USB or Ethernet port. The TB6560 then plugs into the motion controller.  Check my article for options https://www.rckeith.co.uk/mach3-parallel-port/

Using Mach3 

I used an old Dell GX 620 ussf running Windows XP with 2GB of RAM. Mach3 will only work on a 32-bit version of Windows. I use LinuxCNC on this machine as well.  I have a disk for each and just swap out when I need the other.

My PC was a fresh install of Windows for Mach3 and nothing else on it. It’s not connected to the internet so I have no need for anti-virus and updates. I’ve even switched lots of unnecessary services off. I get the g-code on by USB memory sticks.

The configuration of Mach3 with the TB6560 and all my setting go to this page http://www.rckeith.co.uk/4-axis-cnc-hot-wire-configuration-for-tb6560-and-mach3/ includes setting home and limit switches. 

Using LinuxCNC

This is a good option and works well I have full details here http://www.rckeith.co.uk/foam-wing-free-cnc-software/ 

The display is much better in my opinion for 4 axis foam cutters, Mach3 can look a little weird on 4 axes.

I now have it working on my OX router as well.   There’s a video on my YouTube channel and an article on this website LinuxCNC .

Finally

The parallel port version of the CNC Foam Cutter is still a viable option in 2020 and if you are building a very large machine may be just what you need. For an RC Hobbyist building wings and fuselages, I would recommend the USB version, it’s much easier to configure the electronics and software. But don’t be put off if you really want to build the parallel port version. Just drop me a line if you are having any issues and a few pictures to add to the builder gallery

Happy CNC foam cutting

This kit is good value on Amazon and has everything you need for a parallel port build.

4-Axis-1-2N-Stepper-Motor-3-5A-Driver-TB6560-Nema23-USB-Interface-Board-CNC-Kit
TB6560 separate drivers

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