How to Build a USB Hot Wire CNC Foam Cutter - Part 2 Electronics

[@rcpowres]

That is so great to get such a compact instruction!!! Thumbs up

[@rckeith]

Thanks for your kind words, makes it all worthwhile

[@antonl1894]

Got the electronics today and followed your guide and everything is working! thanks

[@rckeith]

Glad it's all working good luck with your build.😀

[@antonl1894]

@@rckeith Yeah the tutorials are great!! how thick is your resistant wire?

[@rckeith]

@@antonl1894 0.4mm

[@antonl1894]

@@rckeith found some .2 mm at the local hardware store, think im going with that and springs:)

[@rckeith]

@@antonl1894 Should be OK I prefer to use very thin wire. I have tried many types even guitar strings but thin always gives me the best results

[@markgreco1962]

Gathering parts can’t wait THANK YOU👍

[@shakeyjakefpv7855]

Am I missing something with the RAMPS board power input? In the video you have jumper wires running from the power supply inputs at the RAMPS board to the other + and - terminals. Are these necessary? What are they powering? Do they need to be 16 AWG?

[@rckeith]

The RAMPS board has two outputs 11 Amp and 5 Amp . So it's to feed these circuits. The hotwire can use the 11A which I think is D8. Hope that explains it.

[@shakeyjakefpv7855]

Keith Howlette oh, I see. I was having difficulty cramming two 16 AWG wires in the terminals with the fan as well but I got them in. Thank you. I also wired the fan into some open terminals direct to the power supply.

[@rckeith]

@@shakeyjakefpv7855 I don't use the RAMPS board to control the hotwire anymore. It does work but I found it difficult to get good temperature control. It was either too hot or not hot enough. I don't think it's the RAMPS board fault but the software. I use my iCharger 206 which has a foam cut option which works by supplying a constant current. You can also use most Lipo chargers with a NiCad option and set that to around 2 Amps as a starting point.

[@ΑΛΕΧΑΝΔΡΟΣΤΡΙΑΝΤΑΦΥΛΛΟΠΟΥΛΟΣ]

Great video, thank you very much. I want to cut letters 60cm in height. Can I do this if I decide to buy your plans? Do I have to change anything?

[@rckeith]

Probably not the machine was designed mainly for rc models. It would need to be much bigger and then the electronics would need to be upgraded to handle a heavier machine. So the cost would be more. Sorry it won't work for you.

[@markgreco1962]

One more thing in the pdf on page 12 you have drv2855 drivers should they be drv8825?????

[@rckeith]

Hi Mark, yes sorry for the confusion. I'll get it changed and send an update out to all those that have downloaded. Thanks is for letting me know, I must have read it 50 times and not spotted it. Old age 😊

[@tvideo1189]

You just jumped over to "let's test the motors" and spun the stepper motors, but didn't say what software you are using to test????? Please advise.

[@rckeith]

Hi, sorry a bit of an oversight. I've released an updated version of the software since the video which you can download from here www.rckeith.co.uk/download/grbl-hotwire-mega-5x-application-v3-2/ there is also a video and a post on the website to explain its installation and configuration including the later firmware as well/ www.rckeith.co.uk/grbl-hotwire-mega-5x-for-cnc-foam-cutters/ Check the playlist which has all the videos for the later software and firmware. Testing the motors hasn't changed with this later software. Keith

[@tvideo1189]

@@rckeith Thanks! Will do.

[@drugacijeigre8919]

Hi, I'm into building 4 axis foam cutter, your design is simple and easy to build. Can I use Arduino UNO and 4 axis shield instead of Arduino Mega and Ramps? I ask because I have Arduino One sitting in my drawer and I'd like to use it. Thanks.

[@rckeith]

You can but the firmware on the website won't work with it. You can use the firmware for DevCNC Foam www.devcad.com/eng/devcncfoam_f1.asp but it's not free €60. It works very well and I now use it on the Mega with the RAMPS board. Hope that helps

[@ivandzeletovic6485]

Hi. I just finished most of this CNC foam cutter. When I connect the HotWire Controller to the ArduinoMega I tried stepper motors through the HotWire Controller and they work. But when I do connect, an error occurs at the end of the frame Status: error grbl: Bad number format. Can you explain what the problem is?

[@rckeith]

Hi Ivan, I didn't write the firmware so I don't know where the error comes from. But it doesn't have any effect on the machine, I've run mine many times and it works fine so just ignore it. Keith

[@ivandzeletovic6485]

Thanks for your reply. These days I will test the CNC. Is it the same procedure with cutting 2D plans? I woul try to cut the ribs for the wing on this CNC? Is that possible?

[@rckeith]

@@ivandzeletovic6485 Hi Ivan. It's a little different you need a program like DevWing foam or Jedicut(free option) to generate 4 axis gcode. Have a look at Part 4 of the video series where I show how to generate the gcode for a simple wing. 😁

[@BowDwn2]

Has 1/8 stepping worked ok? How do you make it 1/32 stepping?

[@rckeith]

Hi Chris, yes absolutely fine. Remember this is foam we are cutting and doesn't need the accuracy of a 3d printer or milling machine. If you use 1/32 micro-stepping you loose some torque on the motors. Every model I've made with my foam cutters has always used 1/8 micro steeping. If you did want to use 1/32 then you will need the DRV8825 drivers as the A4988 only support 1/16. The jumpers under each driver on the RAMPS board will need setting to 1/32 and the steps/mm in firmware will need to be recalibrated. I don't think you would gain anything on the foam cutter using 1/32 in my opinion. Hope that answered your question. Keith

[@leonhuynh3074]

I did the same but only 1 motor works. The other 3 motors didnt. Pls help

[@rckeith]

Have you set the vref to match the current of your motors. Which model of motors are you using.. Try moving the motors to the axis that works to make sure you motors are OK. Sometimes the wiring of the motors needs to be changed. Some guys have found that an issue.

[@now_watch_this]

sorry to ask you but im new to this, i have an arduino Uno R3 Atmega328p and it does not match your firmware, can you help me find the correct firmware for this particular model? thank you for all the help you can give me.

[@rckeith]

This is the firmware that will work with the Uno www.devcad.com/eng/devcncfoam_f1.asp When you run the application it installs the correct firmware to the Uno. But it's not free and costs 60 Euros. You can try it for free to confirm your hardware works OK but it will stop after 400mm of movement until you purchase a license. It works on several hardware configurations including the Arduino Mega as well. I use now and it's very good.

[@onscenefx6520]

I was unable to get the ebook. When it prompts my first and last name my keyboard disappears and I can’t continue to the payment process. Please advise.

[@rckeith]

I've just tried to download the ebook and it works fine. Maybe try a different computer.

[@markgreco1962]

Would the A4988 driver work??

[@rckeith]

Yes, they can work but don't handle quite as much current only about 1 Amp continuous. You would need to make sure your stepper motors don't need any more than that. Also, use a cooling fan as well. So as long as the steppers don't need high current they should be fine. Here's a link comparing various drivers www.pololu.com/category/120/stepper-motor-drivers

[@markgreco1962]

Keith Howlette I going with your drivers.

[@ismailcalik7786]

Hi sir. Grbl arduino files is not found on your site. Can you share with me. Thank you for your interesting 🙏

[@rckeith]

All the files are on the website check here rckeith.co.uk/file-downloads/

[@ismailcalik7786]

​@@rckeithsorry sir i couldn't find this file img.onl/KjpBIS