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- What is LTW? |
It means “laser
transmission welding.” When referring to resin welding, it is also called “laser
welding.” However, as this term also refers to welding using laser, to avoid
confusion, the term “laser transmission welding” is used. |
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- What is ACW? |
It means “absorbance
control welding.” By using this method, laser welding of parts with the same
material and same color is possible. It is also capable of abutting the welding
of plastic as with metal welding. Thermoplastic resin with high transmittance
is suitable for the ACW method. We are now applying for a patent for this
technique and related welding method. |
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- What are the advantages of laser transmission
welding? |
Unlike hot
plate welding, vibration welding, and ultrasonic wave welding, laser
transmission welding is a type of non-contact welding, producing excellent
appearance without burrs. |
As this method is almost free from distortion caused by heat and no vibration is produced, it can be used for welding of thin plastic bonding parts, which require high accuracy. |
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- What are resins (plastics) that can be welded by laser
transmission welding? |
Amorphous
resins including PMMA (polymethyl methacrylate), PS (polystyrene) and PC
(polycarbonate), crystalline resins including engineering plastics like PA
(polyamide), PBT (polybutylene terephthalate) and PPS (Polyphenylene sulfide),
and olefin-based materials including PP (polypropylene) and PE (polyethylene)
can be laser-welded. With the latest technology, it is possible to weld resins
including COP (Cyclo Olefin Polymer) and TPO and TPV (bridged thermoplastic elastomer). |
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- What is eBIND LTW? |
It is a type
of coloring material for the transmission layer in LTW. It appears black to our
eyes, but it transmits a laser beam. Its product form is masterbatch. We offer
a number of products, in particular for crystalline resin. |
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- What is S-type coloring matter? |
S-type
coloring matter is coloring matter for LTW that has been developed leveraging
Orient Chemical Industries’ proprietary technologies. |
To
produce it, a chemical treatment is conducted on an anion-based compound. This
gives properties such as heat resistance, humidity resistance, and sublimation
resistance. Conventional dye-based coloring materials are inferior in these
properties. In addition, pigments have the problem of large energy loss. |
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- What is YAG? |
YAG is an
acronym for Yttrium Aluminium Garnet. YAG laser is excited by a special lamp
with Yttrium Aluminium Garnet crystalline structure, and laser beam is
oscillated. These days, LD-excited YAG laser, whose excitation source is a
semiconductor laser, has appeared. |
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- What is LD? |
LD is an acronym
for Laser Diode and means a semiconductor laser. The semiconductor has an
intermediate resistivity between resistivity of conductor likely to conduct
electricity, and resistivity of insulator unlikely to conduct electricity. The
semiconductor laser oscillates a laser beam by conducting electricity. |
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- What is fiber laser? |
Fiber
laser is a type of solid laser that uses optical fibers as the amplification
medium. When excited light enters a core fiber added with rare earth, light of
specific wavelength is amplified, and it can be extracted as laser light. As it
is possible to amplify light in a very thin core fiber, laser light with high
beam quality can be obtained. |
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- What is the dilution ratio of eBIND LTW? |
For the
standard grade of eBIND LTW series, we recommend a dilution ratio of 15 times.
As the added amount of eBIND is designed in consideration of the optical
characteristics, we recommend that you use eBIND LTW at the recommended
concentration. For example, eBIND LTW-8XXXC will become usable when it is
diluted by 25 to 30 times. |
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- What colors can be used for laser transmission
welding (LTW)? |
For
eBIND, black is currently set as the standard color, but from the technical
point of view, various colors can be used. Orient Chemical Industries, Ltd.
introduced a white-color material that transmits laser at the Nagoya Plastic
Industrial Fair held in November 2003. Orient Chemical Industries, Ltd. holds
patents for the techniques regarding this laser-transmitting white-color
material and its manufacturing method. |
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- What is “master batch”? |
“Master
batch” refers to a high-concentration coloring matter compound consisting of
plastic (resin), a great amount of dye/pigment, and others. This master batch
is designed to provide correct color density when a small amount of the master
batch is added to uncolored plastic. Among the features of the master batch are
that it allows accurate measuring and does not contaminate its surrounding
area. |
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- Can I conduct a welding test using the laser
transmission welding? |
Please
refer to the links to companies related to LTW. Laser welding machines,
monitoring devices for resin welding, laser processing job shops, etc. are
introduced. |
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≪Glossary≫ |
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- What is “visible light (region)”? |
This term
basically refers to light and its region that a person can visually recognize.
The definition of visible light differs from document to document. This is
because recognition capability differs from person to person. The color
difference measurement region by a spectrophotometer is 380 nm to 780 nm. |
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- What is “infrared ray (region)”? |
This term
refers to a region of electromagnetic wave from around 750 nm to around 1 mm.
For LTW, near-infrared ray laser is generally used. Semiconductor lasers and
YAG lasers oscillate lights that have a wavelength in this region. In laser
welding, laser diode (LD) in particular is used, and a long-wavelength laser of
940 nm or greater is excellent in black color transmissivity. |
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- What is “transmittance”? |
In LTW, this
term refers to the ratio between the incoming light (I0) and the outgoing light
(I) when light passes through a plastic transmission layer (thickness). In
other words, it is an index indicating how much light has transmitted through the
layer. Transmittance is generally represented by “t” and obtained by t = I/I0 ×
100. |
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- What is “reflection”? |
In LTW, this
term refers to the ratio between light radiated to the plastic interface area
and reflected light. The higher the reflection is, the lower the transmittance
is, requiring a higher laser output. |
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What is “scattering”? |
In LTW,
this term refers to a phenomenon in which laser light entering the inside of
plastic hits molecules and particles in the medium, and its path changes to
various directions. It has been confirmed that in fillers such as crystalline
resin and glass fiber, laser light expands due to the influence of scattering. |
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- What is “dye” or “solvent dye”? |
In the
field of plastic, “dye” mainly refers to oil-soluble dye (solvent dye) and it
is generally called organic solvent soluble dye. Solvent dye belongs to organic
pigment and refers to a compound soluble (soluble at molecule level) in solvent,
wax, etc. Solvent dyes are used for coloring
plastic such as PS (polystyrene), ABS (acrylonitrile-butadiene copolymer),
PMMA (polymethyl methacrylate), PC (polycarbonate), and PET (polyethlene
terephthalate). As these dyes show migration, their use is limited under thermally-influenced
conditions. |
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- What is “pigment”? |
It
generally refers to a particulate solid that is insoluble in solvent (water,
solvent) or other solutions, and chemically and physically stable. With
pigment, reflection, transmission, interference, and diffraction of light occur
due to its particulate structure and thus its color is felt. Pigments are
divided into organic pigments and non-organic pigments. |
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- What is “carbon black”? |
It refers
to a common black pigment that is produced by putting a compound containing carbon
hydride or carbon in a condition with insufficient air supply (incomplete combustion),
and is used for coloring plastic. Its nomination or properties vary depending
on the raw material or manufacturing method. Carbon black is generally known as
a substance that absorbs all light. |
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- What is “black”? |
When all
visible light is absorbed, a person recognizes its color as black. It is
commonly known that when the three colors yellow, magenta, and cyan are evenly
mixed, black is produced. (Subtractive color mixture) |
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- Same color |
In color
quality control, when color difference is ΔE 0.3 to 0.5, it is generally
treated and managed as the same color. |
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- Color difference |
A
difference of color from the standard color to compare with is expressed as
color difference. A value calculated using the L*, a*, and b* values in CIElab
spaces is expressed as color difference (ΔE). The National Bureau of Standards
in the U.S. sets the color difference value evaluation criteria (NBS unit) as
follows. |
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