Application for Optimization of Laser Beam Welding by Ultrasonic Wave Superposition

The poten­ti­al of ultra­so­nic wave super­po­si­ti­on to impro­ve the pro­per­ties of laser beam wel­ding was inves­ti­ga­ted using sta­tio­na­ry and moving Pie­zos­ha­ker-Sys­tem at the Depart­ment of Cut­ting and Joi­ning Manu­fac­tu­ring Pro­ces­ses (tff) at the Uni­ver­si­ty of Kas­sel. An examp­le of this is the test on the high-strength steel alloy 22MnB5, which is pre­sen­ted here. Adap­t­ati­on to other wel­ding pro­ces­ses and mate­ri­als is possible. 

The influ­en­ces of the various exci­ta­ti­on para­me­ters of the Pie­zos­ha­ker on the ultra­so­nic wave super­po­si­ti­on were inves­ti­ga­ted, e.g. the dis­tri­bu­ti­on of the AlSi-coa­ting par­ti­cles wit­hin the joi­ning zone as well as the weld seam pro­per­ties [1].

The isi-sys Pie­zos­ha­ker-Sys­tem was used for the moving wave super­po­si­ti­on, as shown in Fig. 1 The sys­tem con­tains a 2‑channel Piezoam­pli­fier of the HPDA‑0–180-2C series and two Pie­zos­ha­kers of the PS-W-02 seri­es. The Pie­zos­ha­kers are firm­ly con­nec­ted to the laser optics via a mount and are moved rela­ti­ve to the com­po­nent sur­face at a defi­ned distance from the laser beam. The­se are pres­sed onto the com­po­nent sur­face with a defi­ned for­ce using pneu­ma­tic cylin­ders. Uneven­ness and dif­fe­ren­ces in the thic­kness of the joi­ning part­ners can be compensated.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Fig. 1 (left): The dis­tri­bu­ti­on of the AlSi-coa­ting in com­pa­ri­son without (a) and © and with (b) and (e) influ­ence of an ultra­so­nic wave super­po­si­ti­on by isi-sys Piezos­ha­ker during laser beam wel­ding with fal­se-color images of EDS-ana­ly­sis (d) and (f) [1]

Fig. 2 (right): Super­im­po­sed SEM-images and sec­tion­ed inver­se pole figu­re map­pings (IPFM) of a weld seam without (a) and with ultra­so­nic super­po­si­ti­on (b) mea­su­red with elec­tron back­scat­ter dif­frac­tion shown as inver­se pole figu­re in Z‑direction [1]

[1] Publis­hed in: C. Wolf, S. Völ­kers, I. Kryu­kov, M. Graß, N. Som­mer, S. Böhm, M. Wun­der, N. Köh­ler und P. Mäckel, „Enhan­ce­ment of Welda­bi­li­ty at Laser Beam Wel­ding of 22MnB5 by an Entrai­ned Ultra­so­nic Wave Super­po­si­ti­on,“ In: Mate­ri­als 2022, Bd. 15, 4800.

BCTF-50 — Backlit Calibration Target Fixture

The BCTF-50 — Designed for glass calibration targets

 

BCTF-50 Tech­ni­cal Features

  • Bat­te­ry powe­red back­light illumination
  • 6h run time / 1h char­ge via Micro USB
  • Adap­ter for micro­scope targets
  • Rota­tio­nal axis for til­ting in grid centre
  • Shif­ting via x‑y-z stage
  • Ten­si­le tes­ting machi­ne clamp adapter
  • Tar­get exchan­ge via clip fixture
  • For max. tar­get size of 50 x 50 mm
  • avail­ab­le with dif­fe­rent clam­ping adap­ters for flat or round spe­ci­mens (see below)

 

 

            

 

For fur­ther infor­ma­ti­on, a quo­ta­ti­on or in case of any ques­ti­ons, plea­se don’t hesi­ta­te to con­ta­ct us via info@isi-sys.com

Speckle Pattern Application Kit

The Speckle Pattern Application Kit for the easy and fast production of a perfect speckle pattern for your DIC application!

The cor­re­la­ted solu­ti­ons speck­le com­pon­ents pro­vi­de the pro­duc­tion of ide­al speck­le pat­tern which is important for good signa­tures throughout the area of inte­rest so that con­sis­tent sized sub­sets may be tra­cked with certainty

 

 

Characteristics and advantages:

  • High con­trast, quick pre­pa­ra­ti­on
  • Pre­cisi­on: Opti­mi­sed and con­sis­tent dot sizes
  • 50 % coverage: equal amount of black and white
  • Ran­dom: Per­fect mix­tu­re bet­ween irre­gu­lar and regu­lar pattern
  • Result: impro­ved hig­her spa­ti­al reso­lu­ti­on due to opti­mi­sed sub­set size and high­ly redu­ced noise

 

Why a good speck­le pat­ter is required?

In DIC, a mesh of small sub­sets of the image are tra­cked as the spe­ci­men moves and deforms. To per­form this tracking, the sub­sets are shifted until the pat­tern in the defor­med image matches the refe­rence image as clo­se­ly as pos­si­ble; this match is cal­cu­la­ted by the total dif­fe­rence in grey levels at each point. A good pat­tern will allow the cor­re­la­ti­on to be made with high con­fi­dence and pro­du­ce low noi­se. The examp­le below shows the uncer­tain­ty for the out of pla­ne mea­su­re­ment data in Z‑direction with dif­fe­rent speck­le patterns.

 

 

In order to pro­vi­de con­sis­tent speck­le pat­terns for various sam­ple sizes and mate­ri­als, the speck­le kit inclu­des:

 

Stamp Rol­lers (6 sizes):

  • 0,18mm dot size for 53 – 145mm FOV*
  • 0,33mm dot size for 102 – 296mm FOV*
  • 0,66mm dot size for 203 – 539mm FOV*
  • 1,27mm dot size for 389 – 826mm FOV*
  • 2,45mm dot size for 762 – 2032 mm FOV*
  • 5,08mm dot size for 1524 – 4064 mm FOV*

Flat Stamp Rockers 146 x 146mm (6 sizes)

  • 0,18mm dot size for 53 – 145mm FOV*
  • 0,33mm dot size for 102 – 296mm FOV*
  • 0,66mm dot size for 203 – 539mm FOV*
  • 1,27mm dot size for 389 – 826mm FOV*
  • 2,45mm dot size for 762 – 2032 mm FOV*
  • 5,08mm dot size for 1524 – 4064 mm FOV*
  • Rocker for Flat Stamps

Access­ories:

  • extra ink
  • ink pad
  • hard pad­ded car­ry­ing case

 

* recom­men­ded FOV (image width) for stan­dard 5Mpx sen­sor with 2500x2000px. Alter­na­tively check dot size, which should be mini­mum about 3x3px.

 

For fur­ther infor­ma­ti­on, a quo­ta­ti­on or in case of any ques­ti­ons, plea­se don’t hesi­ta­te to con­ta­ct us via info@isi-sys.com

Polarization filter for HEDLER LED

NEW! The new isi-sys polarization filter for HEDLER LED

The major rea­son for app­ly­ing light forming equip­ment in DIC is to avoid direct reflec­tions. The HEDLER Pro­fi­lux LEDs can be equip­ped with dif­fe­rent light forming access­ories such as usual­ly app­lied in con­ven­tio­nal pho­to stu­di­os. Some of them are also sui­ta­ble for DIC. isi-sys can recom­mend sui­ta­ble access­ories for your application.

Howe­ver the first basic recom­men­da­ti­on is to set up the light source inde­pendent­ly from the DIC sys­tem to adjust a sui­ta­ble illu­mi­na­ti­on direc­tion. In a num­ber of app­li­ca­ti­ons this is suf­fi­ci­ent and the­se access­ories can be avoided, which is of advan­ta­ge, becau­se their app­li­ca­ti­on is com­bi­ned with light losses.

A high­ly recom­men­ded item is the new isi-sys pola­riz­a­ti­on fil­ter espe­cial­ly deve­lo­ped for the high power Hed­ler LED 1000, which hel­ps to work on stron­gly cur­ved and shiny – even wet – sur­faces, when com­bi­ned with sui­ta­ble pola­ri­sa­ti­on fil­ters on the DIC ste­reo system

HEDLER LED light sources

isi-sys offers various light sources from Hed­ler, in par­ti­cu­lar the fol­lowing pro­ducts, for which we also offer a pola­riz­a­ti­on fil­ter spe­cial­ly deve­lo­ped by us (read more»):

 

LED 1000

Focus­able white LED light source with 185W, con­ti­nuous wave

 

 

The HEDLER Pro­fi­lux LED1000 is a new deve­lo­ped con­ti­nuous light unit which gene­ra­tes with one high power sin­gle LED day­light qua­li­ty with approx. 5600K and a CRI > 90 – fli­cker-free! It has an extre­me­ly quiet fan coo­ling and a spe­cial, acti­ve LED coo­ling; the LED has an average life­time of approx. 50000 hours.

It comes with:

  • Fres­nel lens
  • 185 Watts high power sin­gle cell LED
  • Inte­gra­ted Elec­tro­nic Ballast
  • U‑bracket with 5/8″ quick-lock light stand attach­ment and fric­tion bra­ke plus the HEDLER Quick­Fit adap­ter for com­for­ta­ble and fast inter­ch­an­ging of reflectors.

 

 

LED 650

70° expan­ded white LED light source with 75W con­ti­nuous wave

 

 

LED 1000x

75°expanded white light source with 185W con­ti­nuous wave

 

Note: The LED 650 and 1000x are only recom­men­ded for lar­ge FOV >1m app­li­ca­ti­ons at short object distan­ces for cost rea­sons. Ope­ra­ti­on with sepa­ra­te light stand or tri­pod recom­men­ded, as without focu­sing such as for LED 1000.

Blue-X-Focus — LED light source

The new LED light source with 80W up to 120Hz and 1μs flash period

The Blue-X-Focus is a powerful LED light source, especially designed by isi-sys for digital image correlation:

  • The short, sin­gle wave length (blue) impro­ves the opti­cal trans­fer func­tion pro­per­ties espe­cial­ly a) at the image boar­ders for con­ven­tio­nal len­ses and b) for high reso­lu­ti­on, small FOV set-ups such as the Micro 3D ste­reo sensor.
  • The pul­se mode redu­ces moti­on blur and maxi­mi­zes light power at lowest pos­si­ble hea­ting of the object surface
  • Lar­ge beam expan­si­on ran­ge from 3,2° to 60° for small to lar­ge field of view. Ope­ra­ti­on through small windows
  • A pola­riz­a­ti­on-fil­ter (optio­nal) is sup­pres­sing direct reflec­tions in com­bi­na­ti­on with a second pair for the sensors
  • The short wav­elength can be used in com­bi­na­ti­on with band­pass fil­ters for mea­su­ring on hot samples

Further details:

  • Power: Stan­dard ope­ra­ti­on with 80W in con­ti­nuous mode or 120W for pul­se mode depen­ding on duty cycle. Examp­le for 0,7 duty cycle: 105W @ 240Hz and 2,9ms flash peri­od. Power adjus­ta­ble manu­al­ly or exter­nal by pul­se length and fre­quen­cy as well as auto­ma­ti­cal­ly limi­ted depen­ding on temperature.
  • The focu­sing adap­ter for stan­dard DIC is from 5° to 60° expan­si­on. The ver­si­on for small FOV is adjus­ta­ble from 3,2° to 4,7° expan­si­on cor­re­spon­ding to e. g. 5mm x 3mm at 53mm WD or 300mm x 140mm at 1800mm WD (working distance)
  • Moun­ting is pos­si­ble hori­zon­tal or ver­ti­cal via M6 or ¼” threads
  • The coo­ling air stream is direc­ted from the front inlet to the backside to avoid hot air waves in the images.Power: Stan­dard ope­ra­ti­on with 80W in con­ti­nuous mode or 120W for pul­se mode depen­ding on duty cycle. Examp­le for 0,7 duty cycle: 105W @ 240Hz and 2,9ms flash period.

Application example for DIC on small FOV (magnification 1:1 approx. 14x10mm @ 12Mpx, Rodagon 135mm)

DAQ Devices

The isi-sys DAQ devices are set up for ope­ra­ti­on with the Vic soft­ware for Digi­tal Image Cor­re­la­ti­on (DIC) by Cor­re­la­ted Solu­ti­ons and func­tion as inte­gral part of isi-sys turn-key DIC sys­tems. They main­ly ser­ve for trig­ge­ring the came­ras (hard­ware trig­ger) and simul­ta­ne­ous­ly record­ing ana­log data as well as for deli­vering ana­lo­gue real-time out­put gene­ra­ted by the Vic-Gau­ge software.

The­re are three DAQ types with dif­fe­rent per­for­mance and fea­tures (and pricing):

 

DAQ-STD-8D

Only the DAQ-STD- 8D Syn­chro­niz­a­ti­on- / Trig­ger Device can be used for syn­chro­niz­a­ti­on of the came­ras via a perio­dic signal (sup­por­ted by the Ful­crum Modu­le of Vic-Snap or the isi-sys syn­chro­ni­sa­ti­on soft­ware modu­le / isi-Studio

 

 

 

 

 

DAQ-T8D-16

 

Isi-sys also offers a 16-bit device — the DAQ-T8D-16. Both devices have +/-10V out­put channels.

 

 

 

 

 

 

DIC-DAQ-Box-klein
The DAQ-T4D-12 is a 12bit device with 5V ana­log output

 

 

 

 

 

 

 

Camera Trigger & Power supply

Hard­ware trig­ge­ring and the power sup­ply for the came­ras are trans­mit­ted via the 12-pin Hiro­se con­nec­tors on the DAQ device. Two of the­se con­nec­tors are avail­ab­le for con­nec­ting up to two came­ras. Isi-sys also offers Y‑cables for ope­ra­ting 4 came­ras (two ste­reo sys­tems) or more. It is also pos­si­ble to ope­ra­te more than two came­ras with one DAQ device. We will be hap­py to advi­se you.

 

Computer Connection 

Con­nec­tion to a com­pu­ter is done by USB cable (type A <-> type B connector).

 

Analog inputs

isi-sys DAQ devices are avail­ab­le with eit­her dif­fe­ren­ti­al or non-dif­fe­ren­ti­al ana­log inputs. The ana­log input con­nec­tors are BNC type, the ran­ge is +/-10V.

 

Further IO connectors

Bes­i­des ana­log inputs, all isi-sys DAQ devices can also be equip­ped with ana­log out­puts (BNC type con­nec­tor), which dif­fer in vol­ta­ge ran­ge depen­ding on DAQ type. Digi­tal IO con­nec­tors (BNC type) are avail­ab­le as well.

Vic-3D Educational System

The new VIC-3D Edu­ca­tio­nal (EDU) Sys­tem from Cor­re­la­ted Solu­ti­ons is a low-cost solu­ti­on deve­lo­ped for aca­de­mic insti­tu­ti­ons to assist in tea­ching the Digi­tal Image Cor­re­la­ti­on tech­ni­que to under­gra­dua­te and gra­dua­te students.

The VIC-3D EDU sys­tem uti­li­zes the same accu­ra­te DIC algo­rith­ms found in the power­ful VIC-3D soft­ware, while allowing users to acqui­re data quick­ly and easi­ly. The sys­tem fea­tures a sim­pli­fied set­up, stream­li­ned image acqui­si­ti­on, and ide­al post-pro­ces­sing fea­tures. The ste­reo came­ras are moun­ted insi­de a pro­tec­ti­ve enclo­sure, which inclu­des an inte­gra­ted LED light source, a coo­ling fan, and an exte­rior USB & power con­nec­tors. The sys­tem also inclu­des a tri­pod, tri­pod head, speck­le rol­ler, ink pad, cali­bra­ti­on tar­get, and a con­ve­ni­ent car­ry­ing case.

This pro­duct is the per­fect addi­ti­on to engi­nee­ring cour­ses such as solid mecha­nics, mea­su­re­ments, struc­tures, auto­mo­ti­ve design, aero­space, safe­ty, FEA vali­da­ti­on, and many others. Fur­ther­mo­re, the VIC-3D EDU soft­ware has the abi­li­ty to pro­cess images acqui­red from any VIC-3D EDU sys­tem, which allows users to share images not only across cam­pus, but also with col­leagues at other uni­ver­si­ties. The sys­tem sim­ply requi­res a com­pu­ter with one avail­ab­le USB3 port and one avail­ab­le power source. Whe­ther you are tea­ching stu­dents new mea­su­re­ment tech­ni­ques or vali­da­ting FEA models, this sys­tem will surely enhan­ce the qua­li­ty of your department’s curriculum.

 

 

VIC-3D Educational System

 

 

VIC-3D Educational System specifications:

 

Came­ra Resolution 1920 x 1200 (2.3 Megapixels)
Frame Rate 20Hz live, .5Hz acqui­si­ti­on, 100 frames per capture
Expo­sure Time 19µs – 1s
Field of View Fixed: 150 x 200mm
Dis­pla­ce­ment Resolution In-pla­ne: +/-2µm; Out-of-pla­ne: +/-4µm
Strain Mea­su­re­ment Resolution 50µε
Strain Mea­su­re­ment Range  0.005% to >2000%
VIC-3D EDU Licenses Unli­mi­ted
Soft­ware Features 3D dis­pla­ce­ments, strains, gra­phing tools, and much more

 

For more infor­ma­ti­on or a quo­ta­ti­on plea­se don’t hesi­ta­te to con­ta­ct us on info@isi-sys.com  or via pho­ne: +49 561 739798–0.

3D-Micro-DIC System

The 3D-Micro-DIC ste­reo sen­sor sys­tem is deve­lo­ped for full field strain and defor­ma­ti­on mea­su­re­ment on small FOV with hig­hest pre­cisi­on and reso­lu­ti­on over the com­ple­te field of view by 3D digi­tal image cor­re­la­ti­on (DIC). It also ope­ra­tes as exten­so­me­ter for real-time stain con­trol. The Examp­le below shows the new sen­sor ver­si­on 2019 for 1:1 magni­fi­ca­ti­on. FOV ran­ge starts from 2:1 with 4.2 x 3.5 mm @ 5Mpx and 75Hz.

Advantages and features of  the 3D-Micro-DIC system:

  • Com­pact and rigid design, quick set-up and easy handling
  • Pre-adjus­ted, fixed field of view and sta­ble calibration
  • Spe­cial­ly desi­gned for small and very small field of view (FOV)
  • Reli­able and fast USB 3.0 inter­face for Desk­top or Lap­top PCs
  • Turn-key solu­ti­on inclu­ding Vic-Snap and Vic-Gau­ge 3
  • DRo­bust and reli­able post-pro­ces­sing with Vic-3D

strainograph-test-sample

strainograph-diagram

Technical highlights of the 3D-Micro-DIC system

  • 3D full field (5Mpx@75Hz frame rate) con­ti­nuous­ly record­ing on SSD
  • Hig­her frame­ra­tes at redu­ced resolution
    (e. g. [Pixel@Hz]: 1600x1200@133; 1920x1080@148; 1280x720@217; 800x600@258; 640x480@315; 320x240@576).
  • sui­ta­ble for Video-Exten­so­me­ter func­tions and real time feed­back control
  • Strain noi­se level of ±0,001% (±10µstrain) and bet­ter by time averaging
  • Defor­ma­ti­on sen­si­ti­vi­ty in nm ran­ge (1/100 pixel) depen­ding on FOV

 

Available small FOV versions [mm]

1:2 Magni­fi­ca­ti­on (~ 16mm x 12mm @ 2.8 mm FOD)

1:1 Magni­fi­ca­ti­on (~ 8mm x 6mm @ 1.2 mm FOD)

2:1 Magni­fi­ca­ti­on (~ 4.2mm x 3.5mm @ 0.25 mm FOD)

Data acquisition units (DAQ) for 3D-Micro-DIC

strainograph-daq2

  • Image syn­chro­nis­ed ana­lo­gue data record­ing (8x dif­fe­ren­ti­al mode,16 bit, ±10V)
  • 2 x ana­lo­gue out­put chan­nels for feed­back con­trol (16 bit, ±10V)
  • Came­ra trig­ge­ring and (optio­nal) pha­se syn­chro­ni­sa­ti­on for perio­dic signals
  • Ful­ly inte­gra­ted and sup­por­ted by all VIC TM soft­ware modules

Principle of Digital Image Correlation

Digi­tal Image Cor­re­la­ti­on (often refer­red to as “DIC”) is an easy to use pro­ven opti­cal method to mea­su­re defor­ma­ti­on on an object sur­face. The method tracks the gray value pat­tern in small neigh­bor­hoods cal­led sub­sets (indi­ca­ted in red in the figu­re below) during defor­ma­ti­on. Digi­tal Image Cor­re­la­ti­on has been pro­ven over and over to be accu­ra­te when com­pa­red to valid FEA models. The com­mer­cial­ly avail­ab­le VIC-2D and VIC-3D sys­tems from Cor­re­la­ted Solu­ti­ons both uti­li­ze this advan­ced opti­cal mea­su­re­ment technology.

 

Digital Image Correlation Overview

Below are the rea­sons why its ver­sa­ti­li­ty, robust­ness, and ease of use make it the only choice when it comes to digi­tal image correlation.

DIC - Principle of Digital Image Correlation

Two-dimensional Example

In the two pic­tures below you can see a speck­le pat­tern on an alu­mi­num sam­ple with two off­set semi-cir­cu­lar cut-outs. The two pic­tures were taken from an ani­ma­ti­on with the left image taken from the begin­ning and the right pic­tu­re taken from the end of the ani­ma­ti­on. Sin­ce the defor­ma­ti­on is pre­do­mi­nant­ly in-pla­ne, a sin­gle came­ra can be used to mea­su­re the deformation.

VIC2D

Small Defor­ma­ti­on

VIC2Da

Lar­ge Deformation

The pic­tures below show the hori­zon­tal strain mea­su­red by two-dimen­sio­nal image cor­re­la­ti­on for the pic­tures shown above.

VIC2D-2 VIC2D-2a
VIC2D-2b


Three-dimensional Example

The­se two speck­le images below were taken simul­ta­ne­ous­ly with the left and right came­ra of a ste­reo-sys­tem. The sam­ple its­elf is a pie­ce of glass with the com­pa­ny logo sti­cker adhe­red to the sur­face.  The speck­le pat­tern was app­lied using stan­dard off-the-shelf flat white and black spray paint.  Can you make out the shape?

VIC3Dleft
Left View
VIC3Dright
Right View

In the plot below the shape of the logo sti­cker mea­su­red with the VIC-3D Sys­tem is shown. The thic­kness of the logo sti­cker is appro­xi­mate­ly 0.003″ or 0.070mm.

VIC3D-2
For more info­ma­ti­on have a look at our DIC pro­ducts or con­ta­ct us via info@isi-sys.com or +49 561 — 739798–0