PMID- 35632290 OWN - NLM STAT- MEDLINE DCOM- 20220531 LR - 20220716 IS - 1424-8220 (Electronic) IS - 1424-8220 (Linking) VI - 22 IP - 10 DP - 2022 May 20 TI - Beam Offset Detection in Laser Stake Welding of Tee Joints Using Machine Learning and Spectrometer Measurements. LID - 10.3390/s22103881 [doi] LID - 3881 AB - Laser beam welding offers high productivity and relatively low heat input and is one key enabler for efficient manufacturing of sandwich constructions. However, the process is sensitive to how the laser beam is positioned with regards to the joint, and even a small deviation of the laser beam from the correct joint position (beam offset) can cause severe defects in the produced part. With tee joints, the joint is not visible from top side, therefore traditional seam tracking methods are not applicable since they rely on visual information of the joint. Hence, there is a need for a monitoring system that can give early detection of beam offsets and stop the process to avoid defects and reduce scrap. In this paper, a monitoring system using a spectrometer is suggested and the aim is to find correlations between the spectral emissions from the process and beam offsets. The spectrometer produces high dimensional data and it is not obvious how this is related to the beam offsets. A machine learning approach is therefore suggested to find these correlations. A multi-layer perceptron neural network (MLPNN), support vector machine (SVM), learning vector quantization (LVQ), logistic regression (LR), decision tree (DT) and random forest (RF) were evaluated as classifiers. Feature selection by using random forest and non-dominated sorting genetic algorithm II (NSGAII) was applied before feeding the data to the classifiers and the obtained results of the classifiers are compared subsequently. After testing different offsets, an accuracy of 94% was achieved for real-time detection of the laser beam deviations greater than 0.9 mm from the joint center-line. FAU - Jadidi, Aydin AU - Jadidi A AD - Department of Engineering Science, University West, 461-32 Trollhattan, Sweden. FAU - Mi, Yongcui AU - Mi Y AD - Department of Engineering Science, University West, 461-32 Trollhattan, Sweden. FAU - Sikstrom, Fredrik AU - Sikstrom F AUID- ORCID: 0000-0001-5734-294X AD - Department of Engineering Science, University West, 461-32 Trollhattan, Sweden. FAU - Nilsen, Morgan AU - Nilsen M AUID- ORCID: 0000-0002-8771-7404 AD - Department of Engineering Science, University West, 461-32 Trollhattan, Sweden. FAU - Ancona, Antonio AU - Ancona A AUID- ORCID: 0000-0002-6247-5429 AD - Department of Engineering Science, University West, 461-32 Trollhattan, Sweden. AD - Physics Department, University of Bari, Via Orabona 4, 70126 Bari, Italy. LA - eng GR - 20170315/Swedish Knowledge Foundation, project AdOpt/ PT - Journal Article DEP - 20220520 PL - Switzerland TA - Sensors (Basel) JT - Sensors (Basel, Switzerland) JID - 101204366 SB - IM MH - Lasers MH - Machine Learning MH - Neural Networks, Computer MH - Support Vector Machine MH - *Welding PMC - PMC9146067 OTO - NOTNLM OT - feature selection OT - laser beam offset OT - laser beam welding OT - machine learning OT - spectrometer OT - tee joint COIS- The authors declare no conflict of interest. EDAT- 2022/05/29 06:00 MHDA- 2022/06/01 06:00 PMCR- 2022/05/20 CRDT- 2022/05/28 01:43 PHST- 2022/03/15 00:00 [received] PHST- 2022/04/25 00:00 [revised] PHST- 2022/05/09 00:00 [accepted] PHST- 2022/05/28 01:43 [entrez] PHST- 2022/05/29 06:00 [pubmed] PHST- 2022/06/01 06:00 [medline] PHST- 2022/05/20 00:00 [pmc-release] AID - s22103881 [pii] AID - sensors-22-03881 [pii] AID - 10.3390/s22103881 [doi] PST - epublish SO - Sensors (Basel). 2022 May 20;22(10):3881. doi: 10.3390/s22103881.