U.S. patent application number 13/891791 was filed with the patent office on 2013-11-14 for odor reduction in laser processed material.
The applicant listed for this patent is Preco, Inc.. Invention is credited to Christopher Chow, Brian Lindahl, Daniel B. Miller.
Application Number | 20130299491 13/891791 |
Document ID | / |
Family ID | 49547850 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130299491 |
Kind Code |
A1 |
Miller; Daniel B. ; et
al. |
November 14, 2013 |
Odor reduction in laser processed material
Abstract
The present invention includes methods for treating a
laser-processed material that produces an odor due to the laser
processing. The present method includes treating the
laser-processed material with heat to dissipate the odor from the
material. The method can also include a cooling step after heating
of the laser-processed material. Multiple cycles of heating and
cooling may also be performed to substantially reduce or eliminate
the odor from the laser processed material. The invention also
includes an article made according to the method and apparatus for
laser processing with the produced article having substantially
reduced odor.
Inventors: |
Miller; Daniel B.; (New
Richmond, WI) ; Lindahl; Brian; (Somerset, WI)
; Chow; Christopher; (Lake Elmo, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Preco, Inc. |
Somerset |
WI |
US |
|
|
Family ID: |
49547850 |
Appl. No.: |
13/891791 |
Filed: |
May 10, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61645202 |
May 10, 2012 |
|
|
|
Current U.S.
Class: |
220/62 ;
219/121.67; 432/9 |
Current CPC
Class: |
B23K 2103/34 20180801;
B23K 26/703 20151001; B65D 25/00 20130101; B23K 2103/50 20180801;
B23K 26/402 20130101; B23K 26/702 20151001; B23K 26/38 20130101;
B23K 26/70 20151001; B23K 2103/40 20180801 |
Class at
Publication: |
220/62 ; 432/9;
219/121.67 |
International
Class: |
B23K 26/42 20060101
B23K026/42; B23K 26/38 20060101 B23K026/38; B65D 25/00 20060101
B65D025/00 |
Claims
1. A method of reducing odors from a material, the odor caused by
laser processing, the method comprising heating the material to a
temperature sufficient to substantially reduce the odor.
2. The method of claim 1 wherein the material is a cellulosic,
fibrous or paper based material.
3. The method of claim 1 wherein the material is treated to more
than one cycle of heating and cooling.
4. The method of claim 1 wherein the heating comprises the use of
heat gun, hot plate, heated roller, laser, oven, heat lamp, heated
gas, microwaves or combinations thereof.
5. The method of claim 1 wherein the material is heated above
210.degree. F.
6. The method of claim 1 wherein the material is heated to between
about 210.degree. F. and about 500.degree. F.
7. The method of claim 1 wherein the material is heated to below a
scorching temperature of the material.
8. The method of claim 1 wherein the odor is reduced by at least
90% compared to non heat treated material.
9. The method of claim 1 wherein the heating is performed after
processing by the laser converting system.
10. The method of claim 1 wherein the heating is performed
concurrently with the laser processing.
11. An article comprising material processed using a laser wherein
an odor generated by the laser processing is substantially reduced
or eliminated with heat treatment.
12. The article of claim 11 wherein the article is made from
cellulosic material, fibrous material or is a paper based
product.
13. The article of claim 11 wherein the article has not been
subjected to any odor masking agent.
14. The article of claim 11 wherein the odor is reduced by at least
90% compared to an article subjected to laser processing without
heat treatment.
15. An apparatus for laser processing an article made from a
material, the apparatus comprising: a laser system for processing
the material by burning the material; and a heating system for
heating the material during or after the burning to reduce odor
caused by the burning.
16. The apparatus of claim 15 further comprising additional heating
and/or cooling system.
17. The apparatus of claim 15 wherein the heating system comprises
a heat gun, hot plate, heated roller, laser, oven, heat lamp,
microwave or combination thereof
18. The apparatus of claim 16 wherein the cooling system comprises
fan, air knife, cold roll, cooling plate, or combination
thereof
19. The apparatus of claim 16 wherein the laser system, heating
system and cooling system are operably connected by a
controller.
20. The apparatus of claim 15 wherein the laser system and the
heating system process and heat treat the material simultaneously.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is based on and claims the benefit
of U.S. provisional patent application Ser. No. 61/645,202, filed
May 10, 2012, the content of which is hereby incorporated by
reference in its entirety.
FIELD
[0002] The present invention relates to laser processing of
materials, and more particularly to reduction of odor caused by
laser processing.
BACKGROUND
[0003] Lasers are well-known devices used in many areas of industry
including production of packaging materials. Production of
packaging materials has conventionally been performed by die based
systems. Conventional die based systems require not only large
areas to store the dies, but also time to set a die to run a
particular package configuration. The use of lasers offers the
ability to produce packaging based on a digital format. An almost
endless library of digital patterns can be neatly stored and
organized on computing devices. These patterns are readily
available for loading into laser based systems and can be ready to
begin new production jobs in a fraction of the time that was needed
for a die based system.
[0004] Use of laser-based systems allows companies the potential to
eliminate conventional die based converting, along with the costly
manufacture, maintenance, storage, and changeover costs associated
with dies. While dies may continue to be the tool of choice for a
number of applications, they are not always the best choice. As the
laser industry continues to advance and mature, more and more
applications have and will become laser based.
[0005] One of the advances necessary for this continued growth lies
in the area of reduced post processing odor. While lasers offer a
number of advantages, one of the disadvantages can come in a
lingering odor that may be present post processing or converting.
The odor can be a burnt odor and is undesirable in a number of
applications of the converted materials. A large number of the high
speed laser processing systems are CO.sub.2 based which operate in
the mid infrared region and as such are heat based. The majority of
the residue in laser-processed material is removed during
processing in the form of vapor and particles. However, some can
remain and cause an unacceptable odor. Porous materials can make
this matter worse as odor causing compounds can be trapped in the
porous areas. Paperboard is one such material that is well suited
for converting with the CO.sub.2 laser. Unfortunately, paperboard
can have an unacceptable odor post laser processing. In some areas
of industry this odor is minimal and is tolerable while in others
it is unacceptable.
SUMMARY
[0006] This disclosure includes a method for reducing odors from a
material, the odor having been caused by laser processing of the
material. The method comprises heating the material to a
temperature sufficient to substantially reduce the odor.
[0007] This disclosure also includes an article that was produced
in part by utilizing a laser with the laser processing causing an
odor and the odor having been substantially reduced or eliminated
by heat treatment.
[0008] This disclosure also describes an apparatus for producing an
article that has been processed by a laser with the laser
processing causing an odor. The apparatus comprises a laser system
that processes the material in part by burning and a heating system
for heating the material during or after the burn to reduce or
eliminate odor caused by the burning.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIGS. 1A and 1B are a flow diagrams of a process for odor
reduction in laser processed materials.
[0010] FIG. 2 is a schematic diagram of an apparatus for reducing
odors in laser processed materials.
[0011] FIG. 3 is a schematic diagram of an apparatus for reducing
odors in laser processed materials.
DETAILED DESCRIPTION
[0012] This disclosure relates to reduction of odor in materials
that have been processed using a laser system. Methods of reducing
odor from material that has been processed by a laser are
disclosed. Such laser processing includes cutting and scoring. It
has been found that the odor arising from the use of a laser system
is reduced significantly by the application of heat to the
material. Heat is applied using a variety of techniques. In some
embodiments, one or more cycles of heating and cooling have been
found to be advantageous for eliminating substantially most of the
odor from the laser processed material.
[0013] This disclosure also includes articles made from material,
particularly porous material processed by a laser that are
substantially odor-free. The article can be used immediately after
odor reduction without the presence of the offending odor which is
generated during laser processing. The article is treated by heat
to reduce or eliminate the odor.
[0014] This disclosure also describes apparatus that is used to
reduce odor in and/or eliminate odor from material processed by a
laser. The apparatus includes a heating system to heat the material
for reducing or eliminating the odor. The laser treated material is
heated immediately after being processed by the laser, although the
material may be heated sometime afterwards. Immediate heating can
result in better process efficiencies.
[0015] A cooling step after heating in some situations helps in
further reducing or eliminating the odor by allowing the use of
multiple heating cycles. The act of cooling in and of itself is not
suspected to have any odor reduction affect. The apparatus may then
also include a mechanism for cooling the material after it is
heated for multiple heating cycles.
[0016] The apparatus may also include a laser system that processes
the material with the laser and then immediately heats the
processed material after it has been processed by the laser. The
apparatus may then include a cooling system for cooling the
material immediately after the material is heated. The laser
system, the heating system and the cooling system can be in a
variety of configurations as described herein.
[0017] A laser system or a laser-based system as referred to herein
relates to a system that processes materials through the use of
laser technology. Lasers are used in a variety of ways to produce
packaging for products.
[0018] Many products are packaged in paperboard which is a thick
paper-base material. It is derived from wood pulp and more recently
from recycled waste paper (which also has its origin from wood
pulp). It should be understood that paperboard may be called by
other names, such as cardboard, kraft board, and the like.
[0019] Paperboard is generally thicker than paper (usually over
0.25 mm) and is typically in individual sheets or in a continuous
sheet drawn from a roll. From the paperboard, packaging blanks are
cut and portions of the blanks may also be scored so the blanks can
be bent to form the walls of the package. Certain other portions
can also be scored to form flaps that overlay each other and are
then secured to each other by a suitable adhesive to form the
package.
[0020] In recent years, lasers are being used more to cut and score
packaging blanks. Lasers provide a very efficient method of cutting
and scoring packaging blanks over the old mechanical die systems.
Lasers cut and score through the use of a collimated amplified beam
of light that terminates in a focal point. It is at the focal point
of the beam that cutting and scoring takes place. Intense heat at
the focal point cuts and scores the paper in what can be described
as essentially a burning process. A by-product of burning a
cellulose based material is the distinctive odor of burnt paper. In
many packaging applications, this distinctive burnt paper odor is
not troublesome. However, there are applications in which the odor
is objectionable. One such application is cigarette packaging.
Consumers often smell cigarette packages and expect a distinctive
tobacco aroma. When the package is cut and scored by a laser, the
burnt paper odor may taint the tobacco aroma (as well as the
tobacco flavor itself) and be found objectionable. Such a burnt
paper order would also be objectionable in other applications such
as perfume boxes, scented soaps and the like.
[0021] Lasers have also been recently used to mark (etch) or cut
leather products. (See U.S. published application 2011/0045237)
Again, a distinctive odor is caused by burning leather with a
laser. Leather is a product which has certain desirable olfactory
characteristics. The odor of burnt leather would work against the
desirable "leather smell" that most consumers are familiar with and
desire. This disclosure also encompasses manmade materials that
simulate leather.
[0022] Although cellulose based materials and leather are
specifically mentioned herein, this disclosure encompasses other
materials that can be processed by a laser and because of such
processing a burnt odor is developed and may be found
objectionable.
[0023] Another characteristic of materials that may produce an
undesirable odor are materials that are generally porous materials.
Such materials may also be "natural" materials. A "natural"
material is any product derived from plants or animals. This
disclosure also encompasses materials that are manmade such as
polymeric sheets whether comprising a single polymeric layer or
multiple layers of different polymers which are common in present
day packaging. This disclosure also encompasses cellulose based
packaging which includes a paperboard layer or the like that is
combined with one or more polymer layers or one or more polymer
layers with one or more cellulose based layers. In addition, any of
the aforementioned may include a metallic layer that is coated on
or between layers using well-known techniques.
[0024] The materials appropriate for the present invention can trap
odors when the material is processed by the laser system. Treatment
of the laser processed material by the methods described herein can
remove the odor.
[0025] Methods for processing materials resulting in a product
wherein the odor has been substantially reduced or eliminated are
illustrated in FIGS. 1A and 1B. A first method as illustrated in
FIG. 1A includes step 110 of processing a material using a laser
system. A variety of methods can be used to convert the material
described herein and can be dependent on the specific end use of
the package. The laser system is generally used to process the
material into sizes that can be assembled together to form a
desirable type and size of package.
[0026] Methods to reduce the post-laser processing odor include
step 120 of heating the material processed in step 110. Without
being bound by any theory, it is believed that heating liberates
and or vaporizes or decomposes the residual odor causing components
produced by laser processing that can be trapped in the material.
Heating of the processed material in step 120 can be accomplished
using a number of different techniques. Heating can be accomplished
via radiation, conduction currents, convection currents and/or
chemical applications. Various gases can be utilized to apply the
heat as well. Heat treatment can be performed using heat guns, heat
plates, heated rollers, heated roller laminator, heat lamps, ovens,
microwave ovens and the like. Heat treatment can also be performed
using lasers. Heat lamps and/or lasers sources themselves are also
capable of supplying the heat to the material. Other methods of
supplying heat are also within the scope of this invention. Heating
can involve the cycling of low to high temperatures and/or high to
low temperatures.
[0027] In alternative embodiments, step 110 and step 120 can be
conducted simultaneously as opposed to sequentially. In other
words, the laser-processed materials can be treated with heat
during laser processing as opposed to after laser processing.
[0028] The temperature that the material is exposed to during the
heat treatment can vary. The temperature may be dependent on the
exact material that is used and the length of the exposure to the
heat. It is most important that the material be elevated to an
optimum temperature for most effective odor reduction. Generally,
the material is exposed to temperatures below the scorching
temperature of the material. The temperature can be, for example,
between about 200.degree. F. and about 500.degree. F. For some
materials, temperatures above 500.degree. F. may result in
scorching of the material. In some preferred embodiments, the
temperature of the surface to be treated is between about
300.degree. F. and about 400.degree. F. Temperatures outside this
range are also within the scope of the invention.
[0029] The duration of the exposure to heat can vary based on the
material, the heat source, the heating temperature and the like. In
some exemplary embodiments, the laser processed materials are
exposed to heat between about 5 seconds and 20 seconds to
sufficiently raise the temperature of the material for optimum odor
reduction. With the appropriate heat delivery method the exposure
duration can be kept to a minimum.
[0030] As further illustrated in FIG. 1B, the methods for reduction
of odor may include step 130 of cooling the materials, preferably
after the heating step 120. Cooling in step 130 can be accomplished
using a variety of techniques including the use of fans, air
knifes, cooling plates and the like. Cooling can generally be for
short periods of time sufficient to reduce the temperature of the
material to allow additional heating cycles if deemed beneficial.
Cooling may occur between heating steps as heat dissapates into
ambient from the material. The material can be cooled, for example,
for at least 3 seconds, preferably at least 5 seconds. In some
exemplary embodiments, the heated material is cooled between about
5 seconds and about 60 seconds. The cooling may be directed to only
one surface. Alternatively, the cooling may be directed to both
surfaces.
[0031] The methods for reduction of odor can optionally include
additional steps 120b, 130b, 120c and 130c. Steps 120b and 130b
represent a second cycle of heating and cooling. Steps 120c and
130c represent a third cycle of heating and cooling. In some
embodiments, the materials are exposed to multiple heating and
cooling cycles. In some other embodiments, the laser processed
materials is exposed to at least 2-3 cycles of heating and cooling
are performed to reduce or eliminate the odor. More than 3 cycles
of heating and cooling may also be performed and are all within the
scope of this invention.
[0032] The methods described herein can substantially reduce or
eliminate the odor of materials that have been processed using a
laser system. Testing of reduction of odor is a subjective test as
presently there is no odor detecting equipment. The odor can be
evaluated by subjectively sniffing the material and comparing it to
a reference sample. Preferably, at least about 85 percent of the
odor is eliminated and, more preferably at least about 95 percent
of the odor is eliminated by the methods described herein. In some
exemplary embodiments, about 95 percent to about 99 percent of the
odor is eliminated.
[0033] An apparatus for processing the porous materials is
illustrated in FIG. 2 at 200 and includes units for converting,
heating and cooling systems illustrated as separate units for ease
of explanation but in practice may be integrated together.
Apparatus 200 includes laser system 230 for converting and heating
system 240a for heating the laser treated materials. The apparatus
may also include cooling system 250a. Material 210 is placed on
conveyor 220 in a manner that laser system 230 can process material
210. After processing by laser system 230, material 210 is heated
by heating system 240a and then cooled by cooling system 250a. FIG.
2 also includes a second heating system 240b and a second cooling
system 250b. Material 210 can be treated further by another
heating/cooling cycle by heating system 240b and cooling system
250b. Heating system 240a and 240b may apply heat to one surface of
the material. Alternatively, heating system 240a and 240b may be
configured to apply heat to more than one surface of the material.
Cooling system 250a and 250b may direct cooling to one surface of
the material. Alternatively, cooling system 250a and 250b may be
configured to direct cooling to more than one surface of the
material. FIG. 2 illustrates an embodiment having two heating
systems and two cooling systems to treat the materials to two
cycles of heating/cooling. In some embodiments, additional heating
and cooling systems may also be employed. In other embodiments,
only one heating system (or one heating and cooling system) may be
employed.
[0034] Alternatively, an apparatus may include only one heating
system (or one heating and cooling system) but the material may by
treated to multiple cycles of heating and cooling by the same
heating and cooling system. The processed material is transported
back and forth between heating system and the cooling system for
the desired number of cycles.
[0035] FIG. 3 illustrates another embodiment of an apparatus for
processing materials. Apparatus 300 includes converting, heating
and cooling systems as one unit. Apparatus 300 includes laser
system 330, heating system 340a and 340b and cooling system 350a
and 350b. All of these systems are operably connected by controller
360. Controller 360 can be programmed to operate laser system 330,
heating system 340a and 340b and cooling system 350a and 350b in a
desired manner as material 310 is conveyed on conveyor 320.
Apparatus 300 is shown with two heating and cooling systems.
Apparatus with one heating system and one cooling system as well as
apparatus with more than two heating and cooling system are also
within the scope of this invention.
[0036] The reason why heating the laser processed material reduces
or eliminates odor is not understood and whatever mechanisms or
theories may be implied by this disclosure, the patentability of
this invention should not be held to any such one theory. Factors
considered to be at work include; diffusivity (odor particles
lodged in the material), vaporization (including odor particles
trapped in condensated material), increased oxidation at elevated
temperatures (increased effectiveness of oxygen in the air at
breaking down the odor causing byproducts) and the like.
[0037] The present invention is more particularly described in the
following example which is intended as an illustration only since
numerous modifications and variations within the scope of this
invention will be apparent to those skilled in the art.
Example
Converting Using a Laser System
[0038] Paperboard was converted for use in packaging. A Preco
Flexpro laser system was utilized to convert test samples utilized
for odor reduction experiments. It is comprised of a CO.sub.2 laser
and various optical components, including a multi axis steered beam
galvanometer.
[0039] The test pattern for converting comprised of an array of 43
1.461'' long lines spaced 0.04'' apart. This was centered about a 4
in sample coupon of material. The multi-axis steered beam system
was used to deliver the laser beam. It was set at 100 in/sec and
the laser power was set to cut through nearly 98% of the paper
fibers (.about.150 watts). As no odor detecting equipment was
available the odor was evaluated via subjectively sniffing the
material and comparing it to reference samples.
Heating Method 1
[0040] The laser converted sample was heated with a heat gun then
cooled with shop air. The cycle was repeated 2 times. The heating
involved exposing each flat surface of the sample to heat for a few
seconds until hot. Cooling was accomplished by blowing shop air
across the top and bottom surfaces of the sample for a few seconds
each. The output temperature of the heat gun was measured at about
500.degree. F. The opposite surface of the heat-treated sample
reached between about 310.degree. F. and 360.degree. F.
Heating Method 2
[0041] Alternately, the laser converted sample was heated with a
hot plate to elevate the temperature followed by cooling between
two room temperature "cooling" plates. Again each surface was
heated separately for a few seconds followed by the cooling for a
few seconds. A single heating cycle as well as multiple
heating/cooling cycles, were performed to see the benefits of odor
reduction. As the odor reduction is subjectively evaluated it is
difficult to determine the benefit of the 2.sup.nd cycle. One
heating cycle optimally applied appeared to be sufficient to
provide the desired odor reduction in this method as well as the
others. Exposure to about 400.degree. F. for about 10 seconds
allowed for significant odor reduction without scorching of the
material.
Heating method 3
[0042] A heated roller laminator was used to apply the heat to the
laser processed samples. A Royal Sovereign RSH-380 unit was set at
302.degree. F. setting (warmed up) and run at a speed setting of 4
or 9. Multiple passes were employed to increase effectiveness--1
pass front side one pass back side, repeated for 3 cycles. Some
tests also included air cooling between passes. Wrapping the sample
about the top roller (for .about.30 deg wrap angle) was beneficial
as it exposes more of the material to the elevated temperature for
an increased time.
[0043] All of the methods described above resulted in elimination
of at least about 95 percent of the odor compared to the material
that was not treated with heat.
[0044] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *