Dynamic laser marking

Details Dynamic laser marking Dynamic laser marking

1993-07-28

1997-08-05

Walberg, Teresa L.

Electric heating

Metal heating

By arc

21912169, 21912181, 21912183, 347259, B23K 2608

Patent

active

056539002

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a method and an apparatus for marking a moving body of material using a high energy density beam.
Many products are manufactured or processed on production lines with the product concerned moving continuously from one work station to another until all the manufacturing or processing steps have been completed. Often the marking of the product is incorporated into the production line, establishing a requirement for a device capable of marking the product without adversely affecting the continuous movement of the production line.
One such device in use today is the ink jet marker which is capable of directing a controlled jet of ink onto a moving package so as to produce a desired indicum. Such devices are capable of marking up to 1000 items a minute but require constant attention and frequent overhaul to prevent the nozzle of the ink jet from fouling. Such an overhaul may necessitate the shutting down of the production line, with a consequent loss in manufacturing or processing time. Furthermore, devices of this type consume a large quanitity of materials such as ink and solvent, resulting in them having a significant running cost. Questions have also been raised as to the indelibility of the resulting mark.
Laser marking on the other hand, offers a clean and elegent alternative to ink jet marking and provides the body concerned with a truely indelible mark.
Broadly speaking, current commercial laser marking techniques fall within one of two categories. In the first of these categories a beam of unfocused laser radiation is passed through a mask so as to produce the desired pattern, while in the second a beam of laser radiation is scanned across the object concerned, tracing out the desired pattern.
U.S. Pat. No. 4,758,703 provides an example of a marking technique falling into the first category, and it describes a method of covertly encoding a microscopically visible pattern onto the surface of a moving object. In the method described, the presence of a moving object is sensed and the speed of its approach measured so that at the appropriate moment, when the object passes the laser head, a beam of unfocused laser radiation is directed onto the object through a mask. It is the mask that is responsible for generating the pattern of the marking, and it comprises a mask plate having a cross-sectional area greater than that of the beam and incorporating a matrix of holes which may or may not be obscured. Having passed through the mask, the beam is focused to reduce the size of the pattern produced on the surface of the package, as well as to increase the intensity of the beam. In the particular method described, the intensity of the beam is carefully controlled so that the final pattern is barely etched on to the surface and remains invisible to the naked eye.
The Applicant's own co-pending UK Patent Application No. 9117521.6 provides an example of a scanning method of laser marking and relates to a method and apparatus for providing a body of material with a sub-surface mark in the form of an area of increased opacity to electromagnetic radiation. The method comprises the steps of directing at a surface of the body a high energy density beam to which the material is transparent and bringing the beam to a focus at a location spaced from the surface and within the body so as to cause the localised ionisation of the material. UK Patent Application No. 9117521.6 additionally relates to a body marked in accordance with the said method or by use of the said apparatus.
Although the scanning laser marking technique has the advantage of being more flexible in that the shape of the desired mark may be changed externally without interrupting the operation of the laser to change a mask element, the technique has yet to be used commercially for marking moving bodies because of fears that the resulting mark would be blurred or else "Stretched" in the direction of motion of the body. This fear has to date confined the scanning laser marking technique to applications in which the body to be ma

REFERENCES:
patent: 3571554 (1971-03-01), Baujoin
patent: 3848104 (1974-11-01), Locke
patent: 4049945 (1977-09-01), Ehlscheid et al.
patent: 4063064 (1977-12-01), Saunders et al.
patent: 4088864 (1978-05-01), Theeuwes et al.
patent: 4099830 (1978-07-01), Whittle et al.
patent: 4100599 (1978-07-01), Nally
patent: 4154530 (1979-05-01), Connolly, Jr. et al.
patent: 4160894 (1979-07-01), Stemmler et al.
patent: 4218606 (1980-08-01), Whitman, III
patent: 4283145 (1981-08-01), Miyazawa
patent: 4307282 (1981-12-01), Gappa
patent: 4319122 (1982-03-01), Pope et al.
patent: 4323755 (1982-04-01), Nierenberg
patent: 4338114 (1982-07-01), Brockway et al.
patent: 4338147 (1982-07-01), Backstrom et al.
patent: 4371782 (1983-02-01), Brouwer
patent: 4375025 (1983-02-01), Carlson
patent: 4404454 (1983-09-01), Taylor et al.
patent: 4480169 (1984-10-01), Macken
patent: 4560856 (1985-12-01), Miller et al.
patent: 4564739 (1986-01-01), Mattelin
patent: 4578329 (1986-03-01), Holsappel
patent: 4584455 (1986-04-01), Tomizawa
patent: 4587396 (1986-05-01), Rubin
patent: 4618759 (1986-10-01), Muller et al.
patent: 4626649 (1986-12-01), Dupeyrat et al.
patent: 4626656 (1986-12-01), Ootsuka et al.
patent: 4703166 (1987-10-01), Bruning
patent: 4720618 (1988-01-01), Stamer et al.
patent: 4725709 (1988-02-01), Mattelin
patent: 4742206 (1988-05-01), Dietterich et al.
patent: 4758703 (1988-07-01), Drever et al.
patent: 4769310 (1988-09-01), Gugger et al.
patent: 4791267 (1988-12-01), Yokoyama et al.
patent: 4797532 (1989-01-01), Maiorov
patent: 4803336 (1989-02-01), Myer
patent: 4806727 (1989-02-01), Ruckl
patent: 4808790 (1989-02-01), Ruckl
patent: 4822973 (1989-04-01), Fahner et al.
patent: 4854696 (1989-08-01), Guez
patent: 4874919 (1989-10-01), Bransden et al.
patent: 4906813 (1990-03-01), Gajdos
patent: 4918284 (1990-04-01), Weisz
patent: 4941082 (1990-07-01), Pailthorp et al.
patent: 4952789 (1990-08-01), Suttie
patent: 4956539 (1990-09-01), Uesugi et al.
patent: 4970366 (1990-11-01), Imatou et al.
patent: 4970600 (1990-11-01), Garnier et al.
patent: 4987287 (1991-01-01), Jack
patent: 5021631 (1991-06-01), Ravellat
patent: 5041716 (1991-08-01), Wakabayashi
patent: 5049721 (1991-09-01), Parnas et al.
patent: 5051558 (1991-09-01), Sukham
patent: 5087805 (1992-02-01), Silverschotz et al.
patent: 5109149 (1992-04-01), Leung
patent: 5120928 (1992-06-01), Piliero
patent: 5132510 (1992-07-01), Klingel et al.
patent: 5166505 (1992-11-01), Gorriz et al.
patent: 5168454 (1992-12-01), LaPlante et al.
patent: 5170279 (1992-12-01), Schwartz et al.
patent: 5206496 (1993-04-01), Clement et al.
patent: 5229573 (1993-07-01), Stone et al.
patent: 5229574 (1993-07-01), Stone

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