Jst Optical Seam Tracker Brochure

7/21/2019 Jst Optical Seam Tracker Brochure

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ProductInformation

Model JST Optical

Seam TrackerNon-Contact Operation

Laser Sensor

High Precision

All Types of Weld Joints

Complete Range of Slides

Multi-Pass Capability

IntroductionConventional seam tracking systems with tactileprobes have been used for many years and havea proven record of success. There are, however, anumber of applications where the use of a probewhich must "feel" the weld joint can lead to irregularand unreliable results. In these applications, it hasbeen traditional to resort to special probe designs

and to have the operator monitor the weld processin order to take corrective action if the seam trackerprobe is seen to leave the joint.

The introduction of laser tracking permits automatic joint tracking to be used in the more difficult jointconfigurations. As the system functions with nocontact between the sensor and the joint, there isno tendency for the system to run out of the joint.The system is suitable for all types of joint designand all arc welding purposes.

DescriptionThe complete seam tracking system consists of thefollowing elements:

Laser SensorSeam Tracker ControlPendant ControlMotorized Cross-Slide

All the elements of the system have been devel-oped to be compatible. There is no need for you tomix and match components from different manu-facturers with all the problems that entails.

15 Goodyear St, Irvine, California 92618 U.S.A. • Tel: (949) 951-1515 • Fax: (949) 951-9237

System ElementsLaser Sensor

The compact laser sensor is normally mounted onor near the welding torch. It is of a robust designand construction to function satisfactorily, even inhigh current and heat environments. Units havebeen used in applications with welding currentsup to 700 amps.

The sensor houses laser diodes with optics whichproject a fan of visible laser light on to the workpiece. A CCD camera in the sensor, set at a tri-angulation angle to the laser diodes, receives areflection from the surface of the part which is acontour map of the joint geometry. Using triangula-tion permits not only the horizontal features to be

detected, but also the height (sensor to work piecedistance) to be determined.

The sensor is supplied complete with a spatter shieldwith disposable protective window. This protectsthe laser diodes and the camera from the heatand fumes of the welding arc. Dry compressed aircan be fed to the sensor to assist in cooling and tokeep the protective window free of fume buildup.For high heat applications, a water cooled sensormount is included to integrate with an optional orcustomer supplied water chiller.



MODEL JST OPTICAL SEAM TRACKER

The sensor has an aluminum housing and is avail-able in three versions. The version type is basedupon the width of the laser stripe. The choice ofstripe width is important as this sets the "sensitivity" ofthe tracking process. The narrower the stripe width,the finer the detail which can be sensed. For closebutt joints of the type experienced in GTA welding,the narrowest stripe should be used. This limits the

field of view. For weld joints with more pronouncedfeatures, the wider stripe provides greater latitudefor finding and tracking the joint.

Sensors are available with stripe widths of ¾", 1½"and 2½" (16, 35, and 65 mm). The sensor with thesmallest stripe width is capable of sensing featuresas small as 0.005" (0.1 mm).

Seam Tracker Control

The control receives the video image from thesensor. The control processes the information itreceives and translates it into corrective move-ments of the dual axis cross slide. The processingis carried out in four main modules which functionas a harmonized package.

Video Acquisition ModuleThe video image from the camera in the sensoris fed into a data acquisition board. This digitizesand stores the image, and also runs a convolutionfilter along each line of the video signal. The filter"knows" the width and shape of a typical stripe,and looks along each video line for the closestmatching feature.

Segmentation ModuleThis stage analyzes the stripe data from the acquisi-tion board and divides it into lines. This is done us-ing preprogrammed information about the slopes(angles) to be looked for, and also by knowing thesize of the step or break to be expected basedupon the seam type being sensed. The linesegmentation is based upon features which are

sensed, e.g. a step caused by a lap joint, a breakcaused by the gap between sheets in a butt jointor the angle sensed in a groove or fillet.

Comparator ModuleThis software section looks at the lines defined bythe segmentation software and determines whichlines form the seam. This is done by comparingwhat is actually seen with a theoretical shapewhich has been entered into the computer for thistype of weld joint.

Extractor ModuleThis software stage extracts the seam information

and, according to preprogrammed instructions,sets the torch in its correct relative position with the joint, either in the center or a different position.

Using this information, the control moves the slidesto maintain the correct relative position of thewelding torch.

The system is capable of working with different joint configurations. The seam tracker control ispreprogrammed with a number of standard jointgeometries.

SCHEMATIC DIAGRAM

Note:Video monitor and PC areadditional price options.




Pendant ControlThe operator pendant control is supplied as stan-dard with all seam tracking systems and includesthe following displays and controls:

• Two line fluorescent display• Self-centering jog switches, left-right, up-

down

• Start and stop pushbuttons• Laser on/off pushbutton with warning lamp• Seam pushbutton with lamp• Error pushbutton with warning lamp

The pendant operates in conjunction with theseam tracker control and has different functionsaccording to the setting of the control selectorswitch. In the RUN mode, the display changesdepending on whether the system is in standby ortracking mode.

In the standby mode, the operator has control ofthe following options through the pendant:

• Choose the seam type• Jog the slides• Turn the sensor on and measure the seam

position• Adjust the laser brightness intensity• Teach the desired seam position• Start the operation of the seam tracker

In the tracking (active) mode, the operator has thefollowing controls and indicators:

• Pressing either of the jog buttons offsets thetorch position relative to the preset position.

• The display indicates the error in the seam posi-tion under the sensor head.

• Pressing the seam button displays the currentseam type. If the jog button is pressed at thesame time, the seam type can be changedeven as the weld proceeds.

• Pressing the stop button deactivates the slidesand turns off the laser. The system can bestarted and stopped by a remote signal.

• The display shows the number of images whichhave been successfully captured to control thetracking. This shows how accurately the unitis tracking. The number should be higher than80% unless the sensor is passing over a tackweld

or similar feature.

Motorized Cross-SlideBecause Jetline is a manufacturer of weld fixturing,a large number of slide configurations can be usedwith this seam tracking system. Unless otherwiseordered, each optical seam tracking system issupplied with a set of standard slides. These slidespermit cross seam and arc gap tracking to be car-ried out. Slides are available with various weightcapacities and stroke lengths to permit the rightslide for the job to be selected.

Standard slides consist of a custom aluminumextrusion fitted with hardened vee-way tracks. Acarriage rides on the tracks using hardened vee-way wheels and is driven by a motor with tach-generator which responds to signals from the seamtracker control.

For nonstandard applications, the system canbe interfaced with longer slides and with Jetline

side beam tracks. Slides are available in trackinglengths of up to 36" (900 mm). For applicationswhere the travel required is longer than this, a sidebeam track can be used. These are available withalmost unlimited travel lengths. Long travel lengthsof this type are useful where the system is beingused to track the helical flights on extruder screwsand on augers. For other applications, the systemcan be incorporated with Jetline weld head loca-tors. These provide stroke lengths of up to 10 ft x10 ft (3 x 3 m) and can therefore function as a verylarge cross slide. This is an excellent feature for thetracking of large contoured parts.

The system is available with the following standardslides. For all nonstandard applications, please callour customer support department.

Weight Capacity Stroke

250 lbs (110 kg) 10”x10” (250 x 250 mm)

250 lbs (110 kg) 5”x5” (125 x 125 mm)

40 lbs (20 kg) 3”x3” (75 x 75 mm)

Schematic view of sensor head

CAMERA

LENS

FILTERLASER DIODES

LASER OPTICS

FEATURE(LAP)

LASERSTRIPE



JST-04/2006The right to make engineering refinements is reserved. Dimensions and specifications are subject to change without notice.


See Jetline price list for complete ordering information

Distributed by:

15 Goodyear St., Irvine, California 92618 USATel: (949) 951-1515 • Fax: (949) 951-9237 • E-mail: [email protected]

Web Page: www.jetline.com • www.cyclomatic.com

Special Features

The standard unit is suitable for all straightforwardtracking operations and will maintain the relativeposition of the torch to the work piece in both thecross seam and vertical direction.

Where the condition of the joint is variable orwhere, in multi-pass welds, there is a variation of

fill, alternative systems are available which canmeasure the joint and calculate the necessarychange in travel speed to achieve the necessaryfill. These systems use the same type of laser sen-sor and work in conjunction with the full range ofJetline fixturing to ensure that the perfect weld isachieved every time.

Choosing a seamtracker

The correct choice of seam tracker depends onmany variables. Optical seam tracking is the idealchoice in many circumstances but there may beapplications where a different type of unit is ideal.Jetline manufactures tactile as well as optical style

tracking systems and so has the correct type oftracking system for most of your applications.

The following chart shows the comparison of vari-ous seam tracker types for different joint configu-rations.

Joint Laser Through Inductive Tactile Vision -Arc Capacitive Probe

Narrow Butt 5 1 5 2

Seam with tacks 5 3 1 2

Bends 4 5 1 4

Fillet 4 5 1 5

Seam Find 4 2 2 5

Adaptive Weld 5 2 0 0

Multi-Pass Welds

Initial Root 5 2* 1 2*

Fill Passes 5 1* 1 1*

5 Excellent4 Good3 Average2 Poor1 Inadequate performance0 Not possible* Circumstances could improve performance

SpecificationsSensor Unit

Laser diodes: Two IR. lasers, 40mW, Class 3b

Wavelength typ. 670nm.

Laser optics: Two miniature collimators withbeam shaping optics

Laser safety: Hardware and software interlocks

Stripe width: ¾" (16mm) @ 2½" (65mm) standoff

1½" (35mm) @ 3" (75mm) standoff

2½" (65mm) @ 3½" (85mm) standoff

Camera type: CCD

Pixels: 742 horizontal x 582 vertical

Field of view: ½"(15mm) @ 2½" (65mm) standoff

(Horizontal) 1¼" (30mm)@ 3" (75mm) standoff

2¼" (60mm)@ 3½" (85mm) standoff

Depth of field: ¾" (17mm) @ 2½"(65mm) standoff

1½" (35mm)@ 3" (75mm) standoff

3" (75mm) @ 3½" (85mm) standoff

Cooling: Compressed air - clean & cooled

Water @ 50o

F - 85o

F (10o

C - 30o

C)Max temp: 105oF (40oC)

Dimensions: 4”H x 1½”W x 2½”D, 12 oz

Control

Cabinet: Rack mount enclosure

Imput voltage: 115/230VAC single phase

Frequency: 50/60 Hz

Power: 400 Watt

Dimensions: 16”H x 20½”W x 22½”D, 65 lb

400x 520 x 575 mm, 30 kg)

Cross Slide

Stroke in: 10x10 5x5 3x3

mm: 250x250 125x125 75x75

Capacity lb: 250 250 40

kg: 110 110 18

Height in: 23 18 12

mm: 580 450 300

Width in: 22 17 11

mm: 550 430 280

Depth in: 9.5 9.5 5.5

mm: 240 240 140

Weight lb: 80 65 18

kg: 36 30 14

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Jst Optical Seam Tracker Brochure