I get quite a few questions from users all over the world most asking very similar questions so I thought I’d post the most common questions and my answers here
Connect/Disconnect and ReScan buttons missing
Some users have reported the “Connect/Disconnect and the ReScan” buttons are missing when they run the software. It seems to be caused by a screen resolution of 1366×768. If you can change your screen resolution to 1920×1080. If not, run the program in “Windows 8 Compatibility Mode”. To do this open the properties of “Grbl HotWire Controller.exe” and on the “Compatibility Tab” select Windows 8. You may also need to set the Taskbar to auto-hide. On my old Compaq Presario, I could just see the edge of the button until I did that. Afterwards, the two buttons were visible.
Please upgrade to the latest software which fixes this issue GRBL HotWire Mega 5X for CNC Foam Cutters
Can I use NEMA 17 steppers motors for the machine?
Yes Check my new build using 3d printer electronics here
Can I use 8mm lead screws
Instead of threaded rod. Yes, you can but the steps/mm will need recalibrating. There is a great resource here https://blog.prusaprinters.org/calculator/ . Where it has a calculator that you can enter your lead screw and motor specifications and it will give you the steps per mm. You still need to do a calibration to confirm the motor moves the correct distance. Check my video at this time code to see how it’s done https://youtu.be/CHbdUzbDYh8?t=692
Can I use the demo version of Mach3?
Yes, you can but it’s limited to 500 lines of g-code. So for a very simple design, you may get all the coordinates in 500 lines. What happens then is after 500 lines, it just stops.
Can I use LinuxCNC (EMC2)
Yes, you can. Here’s how to install it and configure it.
For foam cutting, this is the link https://www.rckeith.co.uk/foam-wing-free-cnc-software.
For routing, this is link https://www.rckeith.co.uk/free-linuxcnc-openbuilds-ox-router/
The TB6560 controller board is it OK?
The TB6560 gets some bad press on some of the CNC forums but I’ve had no issues with mine. I purchased it as a kit with the NEMA 23 stepper motors. As you probably are aware these come from China and quality control can be an issue when things are built to a price. I don’t use my CNC machine all the time, in fact, it’s built to be easily dismantled due to space restrictions. I have used it on several occasions for most of the day and its performed perfectly. One thing I would ensure is that your machine axis moves very easily. The way I test this is without any power to try and turn each threaded rod by hand and it should not bind or feel tight. I spent some time making sure the alignment of the steppers and threaded rods were very straight and true which makes sure the steppers are not stressed.
How much will it cost
My latest USB CNC Foam Cutter should cost around $200/£160/€180 check the details here https://www.rckeith.co.uk/how-to-build-a-usb-cnc-hot-wire-foam-cutter/
The biggest costs for me has been the software Mach3, DevWing Foam and Dev-Fus Foam. I’ve spent more on this than the build. There are free options that work well for simple designs but I highly recommend the software from DevCad. I would advise starting with the free options and as your needs and knowledge grows to invest in DevWing Foam and DevFus Foam
Here’s my post on the free options https://www.rckeith.co.uk/foam-wing-free-cnc-software/
My post on DevWing Foam is here with links to videos I’ve made as well
Here is a free g-code generator that will generate the g-code for you http://swarfer.co.za/rc/wire/index.php Here’s my video showing how.
What type of foam do I use
I use mainly white polystyrene which is very easy to come by at most DIY stores. I have also used XPS foam which is a pink colour and similar to blue foam. But when sanding this foam the dust now causes me some problems. So all my future builds will be with white polystyrene foam.
What type of hot wire do I use
I’ve tried several different types including MIG welding wire and guitar string but the best results I get are with very thin Ni-Chrome wire about 0.4mm. It needs less power and the amount melted is very small which helps in calculating the kerf value. This is used in the software to allow for the amount of foam melted away. With the wire being very thin and you haven’t got the kerf value right it doesn’t make too much of an impact on your design
What speed and current do I use on the hotwire/ powering the wire
I set the speed at 2mm/s or 120mm/min and adjust the current for a 750mm length on white foam I set the current to around 2.2-2.3 Amps.
Can I use a laptop with Mach3
You can but it’s not supported by Mach3 and you probably not have a parallel port on yours, unless it’s an old one. I believe its to do with power saving and it can interfere with step pluses. My advice is to get an old desktop, I use Dell’s compact GX620 which has a small footprint and a parallel port. You can buy an add-on card to go in a more modern desktop and that works.
Check my link here because if you use a special USB adapter or board then a laptop can be used https://www.rckeith.co.uk/mach3-parallel-port/
What other controller boards can I use
Check this page and it covers several options including USB https://www.rckeith.co.uk/mach3-parallel-port/
What software can I use to generate g-code from my design
Check this page for the latest software https://www.rckeith.co.uk/foam-wing-free-cnc-software/