Arc welding

Arc welding operation

Programming a toolpath for arc welding basically generates a (welding) cycle, i.e. an operation, that consists of three sections:

• approach (off-process)

• welding process (in-process)

• retraction (off-process)

The welding cycle is calculated and controlled by the programming attributes and events.

Welding cycles

Arc welding supports different global welding cycles.

Continuous	Generates a welding seam along the process path from start to end position.
Stitch	Generates an intermittent welding along the process path, composed of a certain number of smaller welding seams.
Spot	Generates a welding spot (point) cycle at the defined position(s).

On top of these global welding cycles, special features or routines can be applied for maximum optimization, efficiency and performance.

Box welding	Expands the global welding cycle, where at the start and end position of the path the welding parameters need to be different from the rest of the cycle. For example in corners, to reach the path without collision.
Process orientation	Works only in situations where an 1- or 2-rotary axis positioner carries the workpiece and the positioner (motion) is connected to the controller. On each toolpath position the positioner axis are manipulated in such a way that the welding tool normal direction (and therefore also the welding seam) is kept in down-hand position. In down-hand position the liquid welding material remains in place.
Seam calibration	Depending on the method of calibration: Generates a cycle representing the seam calibration operation. For example calibration over touch points. Extends the existing welding cycle with the calibration definition. For example calibration over seam tracking with laser.

Tool angles

In general there are three tool angles to define the welding torch orientation starting from its nominal position.

Work	Travel	Tool

Tool alignment

Each tool has a tool frame that is used to place it at the toolpath in its correct position and orientation. It is essential that this frame has been aligned with the orientation of the process geometry in order to get a correct result. This alignment is the mapping between the tool frame and the process geometry.

When creating the process geometry, a normal direction and a tangent, i.e. travel direction have been defined.

With the Alignment attributes, the tool frame axes have to be mapped with these directions to align the tool correctly.

Seam calibration

The welding operation can be extended with a seam calibration operation to determine the welding seam position.

Several calibration methods are implemented:

	Touch sensing with wire Determination of the workpiece by touching (i.e. collision) between the welding gun wire and the workpiece. Calibration of the workpiece position is done before starting the welding process.
	Touch sensing with nozzle Determination of the workpiece by touching (i.e. collision) between the welding gun nozzle and the workpiece. Calibration of the workpiece position is done before starting the welding process.
	Seam search with point laser Determination of the workpiece by measuring the workpiece position with a laser. Calibration of the workpiece position is done before starting the welding process.
	Seam finding with line laser Determination of the workpiece by measuring, i.e. scanning the start and end position of the welding seam with a 2D/3D line laser. Calibration of the welding seam is done before starting the welding process.
	Seam tracking with line laser Determination of the workpiece by continuous measuring the workpiece position during the welding operation with a line laser.

Programming attributes

The display of the programming attributes in the Programming defaults and Active program dashboards is defined in a Settings.xml file. With a standard installation, a default file is located at the path <install>\E2Plugin\Technologies\ArcWeldingTechnology\Standard\ControllerSettings.

Tech tab	Container	Attribute	Description
Program base		Base frame	The reference frame of the program.
Tool data		Tool resource	The name of the tool.
		Technology	The applied technology.
		Automatic tool change
		Tool frame	The tool frame that runs the toolpath.
		Normal direction	The alignment of the tool frame Z axis with the normal direction of the process geometry.
		Tangent direction	The alignment of the tool frame X axis with the tangent direction of the process geometry.
Manufacturing geometry		Translation in X,Y,Z	The global translation in X,Y or Z direction.
		Rotation around X,Y,Z	The global rotation around the X,Y or Z axis.
		Distance start point	The distance of the first in-process point from the process geometry start position.
		Distance end point	The distance of the last in-process point to the process geometry end position.
		Opposite approach side	Reverse the approach side at the manufacturing start position.
		Reverse process direction	Reverse manufacturing process direction.
		Mode	Approximation mode.
		Max. sag	Maximum allowed deviation between geometry and toolpath.
		Max. distance	Maximum distance between two toolpath elements.
		Event relink tolerance	Tolerance to reconnect existing events after recomputation.
		Contour offset	Offset in bi-tangent direction.
		Sheet offset	Offset in surface normal direction.
Technology base		Weld contour	Defines contour welding operation.
		Calibration	Selector of weld seam calibration methods.
		(Additional)	Additional calibration attributes.
		WPS Automatic	Automatic assignment of welding procedure specification.
		WPS	Manual assignment of welding procedure specification.
		Welding speed	Welding velocity.
		Flyby distance	Motion accuracy on welding path.
		Work (tangent rotation)	Work angle.
		Travel (bitangent rotation)	Travel angle.
		Tool (normal rotation)	Tool angle.
		Process orientation	Maintain tool axes in down-hand direction.
		Tangent absolute	Apply tangent absolute direction automatically.
		Ext. axis backprog.	Propagate external axis values backwards.
		CTS backpropagation	Propagate configuration and singularity state backwards.
		Welding program	Welding program number.
		Weave	Activate weave pattern motion.
		Weave frequency	Frequency of weave pattern.
		Weave width	Amplitude of weave pattern.
		Weave time 1	Left dwell of weave pattern.
		Weave time 2	Right dwell of weave pattern.
		Method	Continuous or stitch welding.
		Seam length	Length of stitch seam.
		Number of seams	Number of stitch seams.
		Distribution	Distribution of stitches along toolpath.
		Pitch	Gap between stitches.
		Gap bridge	Bridge motion between seams.
		Gap height	Height of gap bridge.
		Speed on gap	Velocity on bridge track.
		Flyby on gap	Accuracy to reach bridge height.
		Box welding	Activate box welding process.
		Start / End point offset	Offset start/end position.
		Start / End point tilt angle	Tilt angle at start/end position.
		Start / End length	Transition length at start/end.
		Overrun	Overrun length value.
		Keep original point	Keep or move original point.
		Approach	Number of approach steps.
		Motion	Motion type for approach.
		Speed	Velocity of approach.
		Offset tangential / bitangential / normal	Local offset of approach step.
		Retract	Number of retract steps.
		Speed	Retract velocity.
		Flyby	Use flyby accuracy or exact retract position.
		Flyby distance	Motion accuracy on retract path.
		Offset tangential / bitangential / normal	Local offset of retract step.

Program events

The generic arc welding technology has the following programming events:

Motion events
Speed	Sets the velocity for the subsequent motions.
Accuracy	Sets the accuracy for the subsequent motions.
Dwell	Sets a waiting time at the path element for the tool to remain position until moving further.
Acceleration	Sets the acceleration for the subsequent motions.

IO signal events
Wait for signal	Adds a wait for an input signal event of the active controller.
Set signal	Adds a set output signal event of the active controller.
Synchronize robots	Sets an event to synchronize cooperating robots.
Set resource port	Sets a port of a resource.
Wait for resource port	Waits for a port of a resource.
Adapter actor	Sets a signal of a mechanical parent adapter to create or delete a mechanical connection during simulation.

Technology event
Text	Inserts a comment.

Seam search	Activates and defines the motions to identify the seam location.
Arc on	Powers on the welding arc.
Arc off	Powers off the welding arc.
Touch connect	Assigns the weld seam calibration to the welding operation(s).
Seam tracking	Activates the laser seam tracking.

Process model

The operating conditions of the welding process is given a welding ID. In the controller process table these welding IDs can be inserted with their specific process values. When the welding ID is set for the seam (process geometry), the controller will apply the corresponding process values for that welding operation.

In this welding process model also can be specified if a certain welding setup uses multiple layer welding.

Auxiliary commands

The default arc welding technology delivers a few auxiliary commands that can be executed on the program id, as listed in the Program manager dashboard.

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