MASSO Version 5 and DTHC

This document outlines the requirements for a post processor used with MASSO Version 5 software and the MASSO DTHC Plasma unit.

It is intended for users who wish to design their own post processors.

This post processor:

• Works with both THC and DTHC users

• Does not work with Version 4 plasma software or earlier

A sample Gcode file is provided at the end of this document for reference.

Overview

MASSO has designed an integrated THC unit for use with the MASSO CNC controller.

Because many plasma functions are now built directly into MASSO, a new post processor is required. This simplifies the Gcode.

To support this, a new command has been introduced:

G200

G200 defines the plasma cutting parameters.

Requirements

• G200 must appear before the first M3 command in the Gcode file.

• It only needs to be used once, unless cutting parameters need to change.

• It does not have to be the first line of the file.

• While in Plasma mode, the tool number must remain Tool 112.

• If a new G200 is issued later in the program, it will overwrite the previous settings.

G200 Syntax & Parameters

G200 uses the values to populate the Plasma Parameters tab.

• G200 uses the values to populate the Plasma parameters tab
• F Value – Touch off feed rate
• P Value – Piercing Height
• D Value – Piercing delay This value is defined in Milliseconds
• C Value –Cutting height
• V Value - Cutting voltage , if set to “0” then the system goes into the “Auto Voltage” option where the system samples the voltage at cutting height and then maintains this voltage for the entire cut. To make use of this parameter the MASSO DTHC module is required.
• A Value - Feed rate Anti Dive , (Please note that this parameter has not yet been implemented but will be added at a future date) This value is a percentage of the X & Y axis feed rate below which the Z-axis will lock when under THC control to prevent the torch from moving into the material. The axis will unlock and the THC resume operation once the feed rate increases above this value.
• O Value - Ohmic ON/OFF. 0 is Ohmic OFF, 1 is Ohmic ON.
• S Value - Stop after piercing and wait for Cycle start. 0 is do not stop, 1 is Stop and wait for Cycle Start.

Example Program

N10 G200 F150 P5.5 D500 C3.1 V116 A90 O1 S0

M667 – Plasma – Turn THC Function On

This command is used to switch on the THC automatic Z axis control function in the plasma version.

Syntax & Parameters

• M667

• F value – Sets the Z-axis feed rate used to move the torch up/down while in THC mode.

  • If no feed rate is specified, MASSO will use the maximum Z-axis feed rate.

  • Once a THC feed rate has been set, it is remembered until overwritten by a new F value. This allows later M667 commands to be used without an F value.

Example

N10 M667 F500

The above program switches on THC and sets the Z-axis feed rate during THC control to 500.

M666 – Plasma – Turn THC Function Off

This command is used to switch off the THC automatic Z axis control function in the plasma version.

Syntax & Parameters

• M666

Example

N10 M666

Tool Change Command

• T112 M06 must appear in the Gcode file before cutting starts to put MASSO into Plasma mode (ideally in the file header).

• Changing to a different tool number will cancel Plasma mode.

Example 

 N10 T112 M06

The above program changes MASSO into Plasma mode.

G200 Operation (Active vs Legacy Mode)

G200 defines how your plasma will operate.

Turning G200 OFF (Legacy Mode)

A G200 command with no parameters will turn off G200 operation and the plasma will work in legacy mode, where all operations must be done manually using Gcode.

 G200

Notes

• The default setting when MASSO is powered on is G200 ON.

• If running older files, a G200 command should be added at the start of the file to switch MASSO to legacy mode.

• This can also be done by issuing G200 in MDI, but adding it to the file is recommended.

• Once G200 is turned off, it will remain off until turned on again or MASSO is repowered.

Using G200 with THC / DTHC

G200 can be used with an external THC unit (such as a Proma 150) and is mandatory when using the MASSO DTHC unit.

When G200 is active, many standard plasma operations are automated, which greatly simplifies the Gcode required.

Automatic Start Sequence (When M3 is Issued)

When an M3 command is issued with G200 active, the following sequence happens automatically:

1. Probing starts automatically using the F parameter as the probing feed rate.

2. Once touch off is triggered, the torch height is set.

3. The torch moves to piercing height defined by P.

4. The torch starts the arc.

5. On receipt of the Arc OK signal, the piercing delay timer defined by D starts.

6. At the end of the delay, the torch moves to cutting height defined by C.

Parameter Details

F – Touch Off Feed

Touch off feed rate used during automatic probing when G200 is active.

P – Piercing Height

The height the torch moves to for piercing when G200 is active.

D – Piercing Delay

The time the torch waits for the material to be pierced before moving to cutting height.

• Value is in milliseconds

• Example: D2000 = 2 seconds

C – Cutting Height

The height the torch automatically moves to after piercing is complete.

V – Cutting Voltage

Defines the cutting voltage used by MASSO DTHC to control torch height while cutting.

• If a voltage is defined, MASSO will maintain this voltage while cutting.

• Voltage can be adjusted in real time using Torch UP and Torch Down on the F2 screen.

  • Each press changes the voltage by 1 volt.

• A new value can also be typed into the Cutting Voltage box on the Plasma tab on the F2 screen.

• If V is set to 0 in G200, MASSO uses Auto Voltage, sampling the voltage at cutting height each time the plasma starts and maintaining it for the rest of that cut.

A – Anti-dive (Not yet implemented)

Please note: this parameter has not yet been implemented, but will be added at a future date.

This defines the feed rate anti-dive percentage value. It is intended to lock the Z-axis when feed rate slows down, to prevent the torch dropping into the material (commonly when cutting arcs).

O – Ohmic

MASSO has two touch off inputs for plasma:

• Plasma Touch

• Plasma Ohmic

O0 (Plasma Touch)

Usually a switch built into the torch that activates when the torch contacts the material surface. When this input is used, the Torch Touch Offset is used to calculate torch height.

O1 (Plasma Ohmic)

Uses electrical connection between the torch tip and the material to detect torch height. Ohmic touch does not use an offset value.

You can configure both touch types and select the one best suited at the time. Only one can be active at a time.

You can manually switch between them using the Ohmic button. Ohmic is active when it is yellow.

S – Stop After Piercing (Thick Material)

When piercing thicker material, molten metal can build up on the surface until the material is pierced. This can leave build-up that the torch may collide with.

Use the S parameter in G200 for material that presents this problem.

When S1 is Set

When S1 is set and an M3 command is issued:

• Torch touches off the material

• Moves to piercing height

• After the piercing delay finishes, the plasma turns off

• Torch ascends to the Z home position

• The material surface can be cleaned

• Press Cycle Start to continue

• Torch rapids down to cutting height, plasma starts, and the cut begins

This sequence occurs on each M3 command.

When S0 is Set

If S0 is set, there is no stop between piercing and moving to cutting height.

Defaults and memory

• Default is S0 when MASSO is powered on.

• The last S value is remembered until changed or MASSO is repowered.

Build up left after piercing thick material

Automating S0 / S1 in a Post Processor

One method is to compare the material thickness defined in the job parameters with a reference thickness stored in the post processor or CAM software:

• If thickness is equal to or exceeds the reference thickness - set S1

• Otherwise - set S0

Another method is to provide a job setup option (switch) to turn S on or off. This requires the user to remember to select it during setup, but provides more flexibility.

Sample Gcode File

The following is a sample Gcode file which includes the G200, M667, and M666 commands.

Note: there is no requirement for probing routines in this file.

M03 automatically performs:

• Probing of the material surface

• Piercing delay

• Setting the torch to cutting height
  (using information contained in the G200 command)

Because MASSO manages all Z-axis moves while cutting, there only needs to be moves to Safe Z height between cuts.

Comments added in red.

(Plasma Sample File)

N1 G21
N2 G17
N3 G90
N4 G80
N23 G94
N5 (Plasma)
N6 T112 M6  (This is required to put MASSO into Plasma Mode. The Tool number must always be Tool 112)
N7 G200 F200 P10 D500 C3.5 V116 A0 O0 S0 (This Gcode sets the Plasma Parameters)
N8 G00 Z20.000 (Safe Z move)
N9 G00 X70.000 Y75.000
N10 M03 (Turn Plasma on, Probe, Delay, Set cutting height)
N11 M667 F600  (This will Turn the THC on at a Z axis feed rate of 600mm/min)
N12 G03 X60.000 Y85.000 I-10.000 J0.000 F3000
N13 G03 X35.000 Y60.000 I0.000 J-25.000
N14 G03 X60.000 Y35.000 I25.000 J0.000
N15 G03 X85.000 Y60.000 I0.000 J25.000
N16 G03 X60.000 Y85.000 I-25.000 J0.000
N17 G03 X50.000 Y75.000 I0.000 J-10.000
N18 M666 (This Turns the THC off)
N19 M05 (Turns Plasma Off)
N20 G00 Z20.000 (Safe Z move)
N21 G00 X0.000 Y5.000
N22 M03
N23 M667 F600
N24 G03 X10.000 Y15.000 I0.000 J10.000 F3000
N25 G01 X10.000 Y105.000
N26 G02 X15.000 Y110.000 I5.000 J0.000 
N27 G01 X105.000 Y110.000
N28 G02 X110.000 Y105.000 I0.000 J-5.000 
N29 G01 X110.000 Y15.000
N30 G02 X105.000 Y10.000 I-5.000 J0.000 
N31 G01 X15.000 Y10.000
N32 G02 X10.000 Y15.000 I0.000 J5.000 
N33 G03 X0.000 Y25.000 I-10.000 J0.000
N34 M666
N35 M05
N36 G00 Z20.000 (Safe Z move)
N37 M30

CAD/CAM Toolpath of Sample File with Lead In and Lead Out

Completed Cut of Sample File

Gcode File as Seen on MASSO Screen