We use our 6-axes DSP Motion controller with our CNC to control rotating bevel head with HARRIS(tm) oxy-fuel torch. We made one- and two-pass bevel cutting of plates with 16, 20 and 50 mm thickness.
The best equipment in the world for plasma bevel cutting provides beveling of 38 mm plate thickness with 30 degree bevel angle as a maximum. With oxy fuel CNC bevel cutting we can do more.
Here are samples of oxy-fuel bevel cutting with bevel cutting rotator.
In articles in this area you can find other pictures and movies with CNC bevel cutting.
CNC controller hardware package.
Structure of CNC controller.
1. PC-compatible computer.
Minimal system requirements: P-III 600MHz/ 128M RAM/ 512M Hard/Solid disk drive
For central CNC computer could be used any PC-compatible computer main-board with 1 free PCI slot. For example it can be mini-ITX desktop mainboard D945GCLF2 with integrated Intel Atom processor.
2. In free PCI slot Master-controller should be installed. Master-controller is PCI card which provide interface between centarl CNC computer and other components of CNC controller (Motion controller, Operator console controller, Autogas controller, Automation controller and so on). Master controller is controller of serial bus (wired or fiber-optic). Up to 16 unit could be connected with serial bus.
Master-controller provide wired or fiber-optic connection with other peripheral system components. It is hightly recommended to use fiber optic connection for heavy industrial application, especially for plasma cutting application. With Fiber optic connection we have central CNC computer completely electrically isolated from other electronic circuits which is extremely important for heavy condition of electro-magnetic noise while oscillator and plasma arc ignition/working. With fiber-optic connection central computer can be installed sepapately from the machine on the distance up to 100 meters.
3. For connection peripheral units with central computer is used HUB-board. The HUB is "fiber-optic to wire" converter with 6 channel buffer/amplifier.
4. Other peripheral devices (like autogas controller, automation controller and motion controller) are connected through hub-board.
On the picture below is shown automation controller connected with the CNC Control system through hub-board.
Automation controller is a multi-functional board which includes:
Monitoring all input sensors like:
end switchers;
gas pressure sensors for air, oxygen and other gases for plasma or oxyfuel gas cutting;
coolant flow sensor for plasma cutting;
plasma arc sensor;
Initial height system input sensors;
Plasma arc voltage and Power source voltage measure for Arc Voltage Height control system
Driving DC actuator (24V or 48V, 8A) which is used for Z-axis;
Control of pneumatic unit which is used for Automatic or Manual gas system for plasma cutting;
Control components for Initial Height control system;
Control of turning on/off of Plasma power source and plasma ignition unit (oscillator);
Arc voltage height control system with integrated PID controller and wide range of settings which can be programmed from central computer or through Operator console;
Extra 14 outputs for relays and 16 opto-isolated inputs with integrated PLC (programmed logical controller) for control wide range of technological processes (any types of plasmacutting equipments, oxyfuel cutting, water jet cutting, laser cutting, other type of instruments);
As you can see Automation controller controls all aspect of plasma cutting technological process (sensors, relays, plasma power source, oscillator, gas system, torch height control, initial height control etc). So if you like to have more plasma cutting heads on your CNC cutting machine, you just need to connect to hub-board another Automation controller with 4-wire ethernet-like cable.
The Serial bus connection reduces wiring through the machines considerably.
CNC software supports up to 4(four) automation controllers and can control them in any combination separately or simultaneously.
5. Motion controller unit is also connected to central PC through hub-board.
5. Operator console. Because all the features of the CNC software are available from standard PC keyboard, CNC controller can be used without any Operator console for hobby-style application. For industrial application we have operator controle controller board with support of sprcial style, reliable and easy-to-use film keyboard, analogues joysticks for X,Y and Z movements of cutting head, switchers for checking gases (purge gas), testing lpasma ignition process, manual cutting.
On the pictures below operator console controller board, top and bottom side of operator console panel with controller board, joysticks,filmkeyboards,akarm key etc.
6. How connection and wiring of listed components of CNC controls look on a real CNC cutting machine for straight plasma and oxyfuel cutting you can see on the gallery below.
7. Oxy-fuel (gas) cutting controller.
Oxy-fuel cutting controller has similair functions as Automation controller, but it controls gas cutting technological process.
Features of gas cutting controller is listed below:
Monitoring input gas pressure sensors for fuel gas, oxygen, air cooling(optional);
Monitoring output analogue gas pressure/flow sensors for fuel gas, pre-heat and cutting oxygen for electronic control of all gases during gas cutting process;
Driving DC actuator (24V or 48V, 8A) which is used for Z-axis;
Control of pneumatic unit which is used for Automatic or Manual gas system for oxyfuel (gas) cutting;
Monitoring capacitory distance sensor for Height control system;
Control of turning on/off of gas cutting ignition unit (oscillator);
Capacitory sensor height control system with integrated PID controller and wide range of settings which can be programmed from central computer or through Operator console;
Gas cutting control board is connected to computer through HUB-board with 4-wires ethernet cable (the same way as Automation and operator console controllers).
CNC software support up to 6 gas controllers on a machine. Each board controls gas cutting head with oxy-fuel torch, DC actuator, capacitory sensor and pneumatic unit.
Automation controller for plasma cutting head. The board includes: opto isolated inputs, outputs for relay, plasma arc current and voltage monitoring, autogas control system for plasma cutting with gas pressures monitoring, drive control for Z-axis DC-actuator, height control based on arc voltage, initial height control;
Autogas control for oxyfuel cutting head. The board includes: opto isolated inputs, relay outputs, autogas control system for oxyfuel cutting with gases pressure monitoring, drive control for Z-axis DC-actuator, height control based on capacitory sensor;
Motion controller. The unit includes: 6- or 3-axes line, arc, spiral and spline interpolator; drive amplifier (invertor) for synchronous or asyncronous servomotors (up to 2kW for each axis); closed loop PID-controller with feedback based on resolvers or encoders.
