Laser welding

Programming a toolpath for laser 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

Laser welding supports different global welding cycle types.


Continuous	Generates a single 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.

On top of these global 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 better reach the path limits.
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 way that the welding laser 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.

Tool angles

In general there are three tool angles to define the welding head 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 (purple arrows) and tangent or travel direction (red arrow) have been defined.

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

Programming attributes

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

The following generic attributes have been defined.

Tech tab	Container	Attribute	Description
Program base
Tool data

Manufacturing geometry

Toolpath calculation

Technology base



Welding




Touch sensing
Operation linking (when applicable)
For automatic link path generation


Toolpath quality


	The program reference information.
Base frame	The reference frame of the program.


	Tool information.
Tool resource	The name of the tool.
Technology	The applied technology.
Automatic tool change
Tool frame	The tool frame that runs the toolpath.


	The mapping of the tool frame axes with the corresponding vectors on the process geometry.
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.


	The global transformation of the 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.


	The boundary conditions on the manufacturing geometry to calculate the toolpath.
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	To reverse the approach side at the manufacturing start position.
Reverse process direction	To reverse the manufacturing process direction, i.e. changes start to end position and vice verse.


	The approximation of the manufacturing contour to calculate the toolpath.
Mode	The mode to approximate the contour.
Max. sag	The maximum allowed deviation between the geometry and calculated toolpath.
Max. distance	The maximum distance between two in-process toolpath elements along the contour.

Event relink tolerance	The tolerance to find the nearest TPE after a toolpath re-computation, to assign the existing event to. This attribute is hidden by default.


	The offset of the toolpath element from its original location on the manufacturing geometry.
Contour offset	The offset in bi-tangent direction.
Sheet offset	The offset in (surface) normal direction.


	The welding tool motion.
Welding speed	The welding velocity.
Flyby distance	The motion accuracy on the welding path.


	The welding angles of the tool, as to be computed at the toolpath.
Preset	The type of welding presets the corresponding welding angles.
Work (tangent rotation)	The work angle, i.e. tangent rotation, of the tool.
Travel (bitangent rotation)	The travel angle, i.e. bitangent rotation, of the tool.
Tool (normal rotation)	The tool angle, i.e. normal rotation, of the tool.


	The process conditions.
Welding program	The (predefined) welding program number.


	Additional (optimization) conditions to calculate the toolpath.
Process orientation	A switch to optimize each toolpath element with use of the positioner axis to maintain the tool axes in down-hand direction. The condition is only available when a 1-2 axis positioner, carrying the workpiece, is connected to the controller.

Tangent absolute	A switch to automatically apply a tangent absolute direction on the in-process path of the operation. The tangent direction of the first in-process point will be used as reference.

Ext. axis backprog.	The axis values of an external resource, like a positioner, as been set at the first position of the in-process path, will be propagated backwards up to the approach of that in-process path.
CTS backpropagation	The configuration, turn and singularity state of the manufacturing resource, as been set at the first position of the in-process path, will be propagated backwards up to the approach of that in-process path.


	The welding method and the seam dimensions.
Method	The method of welding, i.e. continuous or stitch welding.

	For stitch welding:
Seam length	The length of the stitch seam.
Number of seams	The number of stitch seams.
Distribution	The distribution of stitches along the toolpath. By end position: The stitches are equally distributed along the toolpath length. A system minimum pitch determines the maximum number of stitch seams that fit in. If this minimum is not reached, the number of seams attribute will be applied. By gap length : The distribution is calculated by the pitch length. In combination with the seam length, It determines how many stitches can be applied on the toolpath. Therefore it may occur that the total seam is shorter than the manufacturing length.
Pitch	The non-welding transition gap between two stitches.

Gap bridge	The gap bridge to move between two seams.
Gap height	The offset, i.e. height, of the the gap bridge.
Speed on gap	The velocity on the bridge track.
Flyby on gap	The accuracy to reach the bridge height position.


	The transition from the off-process into the in-process section of the toolpath.
Box welding	To activate the box welding process.
Start / End point offset	The offset to move the real start or end position away from the manufacturing geometry limits.
Start / End point tilt angle	The tilt angle (travel angle) of the tool at the start or end position..
Start / End length	The transition length at the start or end, where the tool tilt angle changes over to / from the default travel angle.


	The overrun (extrapolation) at the contour end when programming an operation.
Overrun	The value of the overrun length. A negative value is possible.
Keep original point	Switch to define if the original path element (position) is being moved to the overrun position or remains at its original position. In the last case a new path element is created at the overrun position.


	To define an approach motion towards the in-process toolpath.
Approach	The number of approach steps.

Motion	The motion type for the approach.
Offset reference	The reference to determine the offset directions.

Offset tangential / bitangential / normal	The local offset of the approach step from the in-process toolpath start element.


	To define a retraction motion away from the in-process toolpath.
Retract	The number of retraction steps.

Motion	The motion type for the retract.
Offset reference	The reference to determine the offset directions.

Offset tangential / bitangential / normal	To local offset of the retract step from the in-process toolpath end element.


	The motion definition.
Motion	The motion type for the tool head.


	The way how to move to the next operation.
Link type	The motion type to link the operations.
Circular height	The height of the via point to calculate a circular link.


	The way how to move to the next operation for automatic link path generation.
Link type	The motion type has been set to Automatic linking.
Motion	The motion type along the path.
Collision tolerance	Defines the safety distance when generating the link path.

Unlock external axis	Use of the entire range of the external axis values for the link path generation. Off: The external axis value can only be changed within the interval given by start and end point of the link path. On: The external axis values are to be considered within the full range of each axis (i.e. are unlocked).
Max. #iterations	Defines the maximum number of iterations that the path finding algorithm will run.


	The way how to move to the next operation. Only valid for automatic link path generation.
Speed mode	The motion speed.
Speed value	The speed value of the motion.
Flyby mode	The flyby motion, i.e. the accuracy to move along the link path positions.
Flyby value	The value of the flyby accuracy (when applicable).


	The toolpath quality evaluation criteria. The exact content may vary per technology.
Unreachability	Evaluates unreachable situations of the robot or machine.
Collision	Evaluates collision situations.
Singularity	Evaluates singularity situations of the robot or machine.

Process angle deviation	Evaluates the process angle deviation from its reference value.

Axis limit proximity	Evaluates the proximity to the limits of the driven axis. Separated evaluation value range for linear and circular joint axis.
Axis speed	Evaluates the axis speed of all driven axis as a (absolute) difference between the start and the end motion between positions.

Program events

The generic laser 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	Calibrating the seam location.
Laser on	Activates the welding laser.
Laser off	Stops the welding laser.

More information

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