Detekcijski sistem za mikrometrsko in podmikrometrsko lasersko prevrtanje tankih kovinskih folij

magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo

Rok Špan (Author), Peter Gregorčič (Mentor)

Abstract

Vrtanje mikrometrskih in podmikrometrskih izvrtin z laserskim snopom je pomemben tehnološki izziv, ki ga lahko rešimo z detekcijskim sistemom v povratni zanki. V magistrskem delu smo razvili detekcijski sistem, ki nam je omogočal nadzorovanje prevrtanosti tanke kovinske folije in smo ga vgradili v laserski sistem z nanosekundnim vlakenskim laserjem. Postavili smo laserski sistem, ki vsebuje nanosekundni vlakenski laser ([lambda]= 1060 nm), skenirno glavo in optiko (premer snopa v gorišču znaša 13 um). Eksperimente smo izvajali na foliji iz nerjavnega jekla debeline 28 [mikro]m in titana z debelino 32 [mikro]m. Odprtozančni sistem za izdelavo mikroizvrtin smo spremenili v zaprtozančni s pomočjo fotodiode, asferične leče in krmilnega vezja, ki smo ga skozi nalogo zasnovali in razvili. Detekcijski sistem deluje tako, da zbere svetlobo na fotodiodi in s tem zazna laserski preboj, hkrati pa prekine nadaljnje lasersko bliskanje za izvrtano luknjo. S sistemom za detekcijo smo poiskali optimalne parametre za izdelavo izvrtin na nerjavnem jeklu v rangu 1.3 [mikro]m +/- 0.5 [mikro]m in pokazali, da jih je mogoče ponovljivo izdelati. Raziskali smo vpliv polarizacije na obliko izhodne luknje in kontrolirano razširili izhodni premer, s pomočjo zakasnitve določenega števila laserskih bliskov, po detekciji preboja skozi material. Za analizo vzorcev smo uporabili optični mikroskop s petstokratno povečavo, nato pa še električni vrstični mikroskop (SEM), kjer smo luknjice izmerili. Na koncu smo preverili, kolikšna je najmanjša možna razdalja med luknjicami za izdelavo največje možne matrike izvrtin. Ugotovili smo, da je čas za vrtanje ene izvrtine 0.3 ms in 6 min 48 s za matriko 40000 izvrtin/cm2 . Najmanjša izhodna luknja, ki smo jo uspeli izvrtati, znaša 0.8 [mikro]m.

Keywords

magistrske naloge;laserske obdelave;lasersko mikrovrtanje;vlakenski laserji;nanosekundni laserji;detekcija laserskega preboja;laserska ablacija;laserski inženiring površin;

Data

Language:	Slovenian
Year of publishing:	2019
Typology:	2.09 - Master's Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[R. Špan]
UDC:	621.9.048.7:621.7.04(043.2)
COBISS:	16929563
Views:	713
Downloads:	188
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Detection system for micrometer and sub-micrometer laser drilling of thin metal foils
Secondary abstract:	Drilling micrometer and sub-micrometer holes with a laser beam is an important technological challenge that can be solved with a feedback loop detection system. In this master's thesis, we have developed a detection system that allows us to control perforation of a thin metal foil and installed it into a laser system with a nanosecond fiber laser. We set up a laser system containing a nanosecond fiber laser ([lambda] = 1060 nm) , scanning head an optics (the beam diameter in focus equals 13 um). The experiments were performed on stainless steel foil with a thickness of 28 [micro]m and titanium with a thickness of 32 [micro]m. The open-loop system for micro-holes drilling, was transformed into the closed-loop system by using a photodiode, an aspherical lens and a control circuit, which we designed and developed within this thesis. The detection system works by collecting light on the photodiode, thereby detecting a laser-induced breakdown, while interrupting further laser pulses for the drilled hole. With the detection system, we found the optimal parameters for the production of holes in a stainless steel foil in range of 1.3 [micro]m +/- 0.5 [micro]m and showed that they can be reproduced. The effect of polarization on the shape of the output hole was investigated and the output diameter controlled by delaying a certain number of laser pulses, after detecting a brakdown through the material. An optical microscope, with a five hundred times magnification, was used to analyze the samples, followed by characterization with a scanning electron microscope (SEM), where the holes were measured. Finally, we checked the minimum distance between the holes to produce the largest array of perforated holes. We found that the drilling time of one hole was 0.3 ms, while it takes 6 min 48 s for a matrix of 40000 holes per cm2. The exit diameter of the smallest hole we were able to drill equalled 0.8 [micro]m.
Secondary keywords:	laser processing;laser micro drilling;fiber lasers;nanosecond lasers;laser-induced breakdown detection;laser ablation;laser surface engineering;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. Ljubljana, Fak. za strojništvo
Pages:	XXIV, 68 str.
ID:	11217222