Remote laser welding systems can usually focus a laser beam to diameters of 0.1 mm. Therefore, high quality clamping and precise teaching is needed in order to achieve appropriate process tolerance ...for a sound weld. This brings reservation in the field of small series and user-customized manufacturing, where product individualization requires flexible and adaptive systems as workpiece geometry is not exact due to manufacturing tolerances and thermal deformations during welding. The preparation for welding is therefore often time-consuming. To solve this, we have developed an innovative system, which enables in-line adaptive 3D seam tracking. The system consists of an industrial robot (Yaskawa MC2000), a scanning head (HighYag RLSK; working area 200 mm × 300 mm × 200 mm) with optical triangulation feedback and a fiber laser (IPG, YRL-400-AC; 400 W). A feed-forward loop was used to achieve positioning accuracy of under 0.05 mm during on-the-fly welding. Experimental results show that between welding speeds of 25 and 150 cm/min, average tracking deviations are 0.043 mm and 0.276 mm in
y
and
z
directions, respectively. Moreover, teaching times for a specified seam can be shortened for more than 10 times due to the fact that only rough seam teaching is required. The proposed system configuration could be adapted to other classical welding processes.
•Laser power is controlled via triangulation camera in a remote laser welding system.•Relationship between interaction zone's area and process parameters is discussed.•Stable partial penetration is ...achieved for investigated welding parameters.
Remote laser-welding systems are being used more frequently because of their larger working areas, shorter downtimes and ability to weld different seam types with high accuracy at greater speeds in comparison to conventional welding. Therefore, precise process-monitoring methods are needed in order to achieve weld traceability and good process and quality control to accompany different welding situations. This paper proposes the use of optical triangulation feedback on a remote laser-welding system that makes it possible to monitor a larger working area. This configuration means we can monitor the interaction zone itself, analyze the 3D position of the laser beam and key process estimators as a result of laser welding. AISI steel plates were welded in a lap configuration to show that stable partial penetration can be achieved. First, a dependency matrix was constructed for the different welding parameters (material thicknesses, welding speeds and laser powers) in order to describe the change of the weld's penetration depth with respect to the key estimators. An approximation was used to characterize the change of the weld's depth according to the change of the estimators. The experimental results demonstrate that the interaction zone's area can be used to successfully control the laser's power output in order to achieve a stable partial penetration with an error of less than 7 % of the desired target weld depth. Longitudinal macrographies show a significantly more constant weld penetration depth and laser-induced plume reduction during welding.
One of the key challenges in robotic remote laser 3D processing (RL3DP) is to achieve high accuracy for the laser’s working trajectory relative to the features of the workpiece. This paper presents a ...novel RL3DP system with an automatic 3D teaching functionality for a precise and rapid determination of the working trajectory which comprises a robot manipulator, 3D scanning head, fibre laser and an off-axis positioned camera. The 3D measurement is based on laser triangulation with laser-stripe illumination using the laser’s pilot beam and scanning head. The experimental results show that the system has a precision better than 70 μm and 120 μm along lateral and vertical direction respectively inside the measuring range of 100 × 100 mm. The teaching time is 30-times shorter compared to a visual teaching procedure. Therefore, such a system can lead to large cost reductions for modern production lines that have constant changes to the products’ geometries and functionalities.
One of the key challenges in robotic remote laser 3D processing (RL3DP) is to achieve high accuracy for the laser's working trajectory relative to the features of the workpiece. This paper presents a ...novel RL3DP system with an automatic 3D teaching functionality for a precise and rapid determination of the working trajectory which comprises a robot manipulator, 3D scanning head, fibre laser and an off-axis positioned camera. The 3D measurement is based on laser triangulation with laser-stripe illumination using the laser's pilot beam and scanning head. The experimental results show that the system has a precision better than 70 microm and 120 microm along lateral and vertical direction respectively inside the measuring range of 100 x 100 mm. The teaching time is 30-times shorter compared to a visual teaching procedure. Therefore, such a system can lead to large cost reductions for modern production lines that have constant changes to the products' geometries and functionalities.
Remote-laser welding shortens processing times but bring reservations in the field of small series and user-customized manufacturing, where product individualization requires flexible and adaptive ...systems with simplified clamping devices. Also, the workpiece geometry is not exact due to thermal deformations during welding. To solve this, we have developed an innovative system, which enables in-line adaptive 3d seam tracking and laser power control. The system consists of an industrial robot, scanning head with optical triangulation feedback and fiber laser. It enables shorter and easier welding trajectory teaching, laser focus positioning precision of under 0,06 mm and stable partial penetration welding process.
One of the key challenges in robotic remote laser 3D processing (RL3DP) is to achieve high accuracy for the laser’s working trajectory relative to the features of the workpiece. This paper presents a ...novel RL3DP system with an automatic 3D teaching functionality for a precise and rapid determination of the working trajectory which comprises a robot manipulator, 3D scanning head, fibre laser and an off-axis positioned camera. The 3D measurement is based on laser triangulation with laser-stripe illumination using the laser’s pilot beam and scanning head. The experimental results show that the system has a precision better than 70 µm and 120 µm along lateral and vertical direction respectively inside the measuring range of 100 × 100 mm. The teaching time is 30-times shorter compared to a visual teaching procedure. Therefore, such a system can lead to large cost reductions for modern production lines that have constant changes to the products’ geometries and functionalities.
A system for adaptive robotic deburring with a correction of the errors in workpiece positioning is presented. The correction is based on 3D measurements of the workpiece's surface and its ...registration to the target surface, measured on a reference workpiece. The surface measurement is performed with a laser-triangulation profilometer. The reference tool path is determined using robot teaching on the reference, already deburred, workpiece. The positioning errors of the currently processed workpiece are compensated by tool path adaptation in accordance with the registration results by means of rotation and translation. The experiments showed that the average precision of localization is 0.06 mm and the average bias between the true and measured values is 0.23 mm. The developed adaptive system is also applicable in other similar applications where it is difficult to ensure repeatable clamping of the workpiece. Keywords: adaptive robotic machining, deburring, laser triangulation, position error correction, localization Nastanek igle pri ulitkih predstavlja velik problem, saj lahko poskoduje delavca in zmanjsuje kakovost samega izdelka. Rocno razigljevanje je dolgotrajen, zahteven in drag proces odstranjevanja materiala igle, zato je potreba po avtomatizaciji procesa ocitna. Vecina sistemov za robotsko razigljevanje temelji na premikanju obdelovanca z robotsko roko pod orodjem za razigljevanje. Pot robotske roke je obicajno dolocena s postopkom robotskega ucenja, kjer operater na referencnem obdelovancu doloci mnozico tock, prek katerih nato robot premika obdelovanec. Pri tem se predpostavlja, da so vsi nadaljnji obdelovanci enake oblike in se nahajajo na isti lokaciji. Medtem ko je prvi prepostavki pri razigljevanju ulitkov lahko zadostiti, je tocen polozaj obdelovanca odvisen predvsem od njegovega vpetja v robotsko roko. Obicajen pristop je zagotovitev ponovljivega vpenjanja obdelovanca v robotsko roko, kar je v primeru ulitkov zelo tezko zagotoviti. Drug pristop, ki je predstavljen v tem prispevku, pa temelji na adaptaciji poti robotske roke glede na izmerjen polozaj trenutno vpetega obdelovanca. Korekcija poti robotske roke temelji na 3D merjenju povrsine obdelovanca in poravnavi te povrsine na povrsino, ki je bila izmerjena na referencnem obdelovancu. Za 3D merjenje se uporablja laserski triangulacijski profilomer, s katerim najprej izmerimo povrsino referencnega obdelovanca. Na tem obdelovancu izvedemo tudi ucenje robota. Kasneje, po pritrditvi vsakega naslednjega obdelovanca, izmerimo tudi njegovo povrsino. To povrsino poravnamo na povrsino referencnega obdelovanca. Rotacije in translacije, ki so bile potrebne za poravnavo, uporabimo za adaptacijo premikov robota. Tako ti ustrezajo polozaju obdelovanca, ki je trenutno vpet v robotsko roko. Za karakterizacijo predstavljene metode smo izvedli dva eksperimenta. Pri prvem smo povrsino istega ulitka v istem vpetju izmerili desetkrat in tako ugotovili natancnost metode. Ta je bila 0,03 mm v X smeri, 0,01 mm v Y smeri in--0,07 mm v Z smeri. Pri drugem eksperimentu smo ulitek v istem vpetju z robotsko roko premikali od 0,0 mm do 4,0 mm s korakom po 0,5 mm iz zacetnega polozaja v vsaki izmed osi, na koncu pa se v vseh treh socasno. Rezultate translacij, izmerjenih s predstavljeno metodo, smo nato primerjali z dejanskimi pomiki robotske roke. Tako smo izmerili tocnost korekcije. Rezultati kazejo, da je bila povprecna razlika med izmerjenim in dejanskim polozajem robotske roke 0,23 mm s standardnim odklonom 0,12 mm. Povprecne razlike v posameznih oseh so bile 0,05 mm (0,10 mm) za X,--0,02 mm (0,03 mm) za Y in--0,03 mm (0,15 mm) za Z os. Ceprav obdelovanci niso bili namenoma rotirani, so bile izmerjene manjse rotacije, ki pa niso presegale 0,020. Izmerjene povrsine so v povprecju vsebovale 77582 (493) tock. Za poravnavo je sistem potreboval povprecno 1,52 s. Ob redcenju na 6 % izvornega stevila tock se je cas poravnave skrajsal na 0,22 s, pri cemer razlike med rezultati 3D poravnave niso bile statisticno znacilne. Rezultati tako kazejo, da je metoda korekcije polozaja dovolj tocna za uporabo v sistemih za adaptivno robotsko razigljevanje. Primerna pa je tudi za uporabo na vseh podobnih sistemih, ker se srecujemo z odstopki pri pozicioniranju obdelovancev. Kljucne besede: adaptivne robotske obdelave, razigljevanje, laserska triangulacija, korekcije napake polozaja, lokalizacija
Jedan od bitnih izazova u daljinskoj laserskoj 3D obradi (RL3DP) je postizanje visoke točnosti jer laser radi po rubovima predmeta koji obrađuje. Ovaj rad prikazuje novi RL3DP sustav s automatskom 3D ...nastavnom funkcionalnošću radi točnog i brzog određivanja prijenosa detektiranih rubova koje obrađuje robot sa 3D skenerom, fiber laserom i izvan aksijalno pozicioniranom kamerom. 3D skeniranje se bazira na laserskoj triangulaciji sa pilotskom laserskom trakom. Eksperimentalni rezultati pokazuju da sustav ima preciznost bolju od 70 μm i 120 μm u bočnom i vertikalnom smjeru u mjernom području od 100 × 100 mm. Vrijeme učenja je 30-puta kraće u odnosu na vizualni postupak. Stoga, takav sustav može značajno smanjiti troškove obrade sa modernim proizvodnim sistemima koji se moraju prilagođavati stalnim promjenama geometrije i funkcionalnosti proizvoda.
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