Hale Design Tech - Torch Height Controller
Added Video Build Guide and Q&A. See Below. 3/3/21
Arduino based THC that reads plasma cutter voltage and send Up and Down signals to Plasma Torch Actuator to adjust voltage to target value. Plus a bonus Breakaway Torch Holder Design
How to Build Video:
Aim is to create a 3D printed low cost and easy to use Torch Height Controller with off the shelf parts, simple easy to read code and as little electronics tinkering as possible. This is a standalone type of THC so it requires an NEMA23 actuator to move the torch independent of the CNC machines controller. If you interface this THC with your CNC Machine please post how you did it!
The unknown we are trying to solve for here is the Torch Height from the Workpiece measurement. It's important for a plasma arc to be stable and be a set height from the workpiece to be cut. The main reason for this is the plasma arc will cut a bevel on the side walls if the height is not set right or crash into the workpiece... This is because the plasma arc is not like a laser with straight edges but more like an egg. Making the problem worse is the fact the metal can warp and contort when a hot plasma arc cuts into it. Using the Arc Voltage is a good way to estimate the distance to the workpiece from the torch head.
The proportional correlation is the longer the arc the higher the voltage. So, we can measure the plasma voltage and feed that into a PID Algorithm to calculate the torch height to change the voltage to a setpoint. It is unwise to measure the Arc Voltage Directly off the plasma torch because the levels there can be deadly. Most CNC ready Plasma Cutters on the market have 50:1 - 16:1 arc voltage dividers built right into the machine. If yours doesn't have this then you will need to do surgery and add a voltage divider circuit to your plasma cutter... Check the Technical Specs of your plasma cutter: Don't Die.
This is completely my own design in not based on any other torch height controller.
3rd Party software used
- About Hale Design Tech: http://hdt.xyz
- Auduino IDE
- FastPID Library
- Nextion Editor
- Video Build Guide:
- Wiring Schematic
- Model STL Files and Software. See Attachments Section Below
- THC Fusion 360 Design File: Fusion
- Breakaway Holder Fusion 360 Design File: Fusion
- Software: HaleDesign/TorchHeightController
- Needs Dust filtering
- Connections rushed and could be better
- Needs raw arc voltage to 50:1 converter and isolation for safety
- Return home after cut finish ( if not could exceed actuator limit ) #! This has been fixed, sketch upload to gethub
- Movement screen some buttons display reversed ( dang it copy and paste ) #! This has been fixed, sketch upload to gethub
Standalone Torch Height Controller for CNC Plasma Cutting
A Torch Height Controller helps improve plasma cut quality and can save a CNC Machine from crashing. This design doesn't require you to know electronics or need any custom circuits... Its plug and play! This is a COMPLETELY standalone controller with a built-in Driver powerful enough to run just about any stepper motor. (maybe a little to powerful for a NEMA17)
- Build License:
- GNU (GPL3+) General Public Licence
Reason for this BuildI needed one, and the options available are too expensive or closed source. So I made my own and now you can too.
Qty Part Name Part Link Comments 1 C-Beam® Linear Actuator Bundle https://openbuildspartstore.com/c-beam-linear-actuator-bu... Link Torch Height Actuator - 250mm Sliver - Include Motor 1 Rubber Feet Set (4 Pack) https://openbuildspartstore.com/rubber-feet-set-4-pack/ Link 1 Arduino: Uno R3 https://www.amazon.com/gp/product/B008GRTSV6 Link Mainboard: Note options for Mega are now ready 1 MKS TMC2160-OC Stepper Motor Driver https://www.amazon.com/gp/product/B0831KFCFM Link Driverboard 1 Variable DC Power supply https://www.amazon.com/gp/product/B07K1LV2CM Link AC 100-240V to DC 3-12V 5A 60W 1 Nextion 3.5" Display NX4832T035 https://www.amazon.com/gp/product/B07916QBDZ Link very important must be ver: NX4832T035 2 Fan 40 x 40 x 10mm 12V DC https://www.amazon.com/gp/product/B07GVD3NWT Link Sold in 5 pack but only need 2... So I'll have a few extra 1 Fasteners Kit https://www.amazon.com/gp/product/B07951KS72 Link various sizes of M3 and M5s are used 1 Breadboard Jumper Wire Kit https://www.amazon.com/AUSTOR-Preformed-Breadboard-Assort... Link These work well for Arduino Connections 1 Electrolytic Capacitor Assortment Kit https://www.amazon.com/REXQualis-Electrolytic-Capacitor-A... Link Only need one 1 - 3uf cap for this project but its good to have a few extra 1 Cat6 RJ45 Keystone Jack https://www.amazon.com/gp/product/B07F5YVLJ7 Link 1 USB A - USB B Cable https://www.amazon.com/AmazonBasics-USB-2-0-Cable-Male/dp... Link For uploading sketch to Arduino... bet you already have one though 1 8GB Micro SD Card https://www.amazon.com/Gigastone-2-Pack-Surveillance-Secu... Link For uploading Tft file Nextion Display... bet you already have one though 1 Quick Release Plates Camera Mount https://www.amazon.com/gp/product/B07R9Q748Y Link Optional for Breakaway Torch Holder 16 3/8 X 1/4in neodymium cylinder magnets https://www.kjmagnetics.com/proddetail.asp?prod=D64-N52 Link Optional for Breakaway Torch Holder 1 Arduino Mega 2560 REV3 [A000067] https://www.amazon.com/ARDUINO-MEGA-2560-REV3-A000067/dp/... Link Mega is optional upgrade over the Uno but recommended ( don't buy a clone! )