On the Cutting Edge with PETG and Lasers
Lasers are growing in popularity
among fabricators working with a
wide range of materials. For plastic
applications in the store fixture and highend
point-of-purchase (P.O.P.) market,
lasers offer speed, flexibility and pinpoint
accuracy, enabling the creation of virtually
any shape to exacting specifications.
Offering exceptional clarity, toughness,
high chemical resistance and excellent
forming capabilities, PETG sheet can be a
valuable companion material to laser cutting.
The material’s unique combination of
properties can reduce fabricators’ overall
cost of operations and increase design
flexibility for retail fixtures and displays
created using lasers.
Despite these advantages, however, there continues to
be a lack of a strong knowledge base between laser equipment
manufacturers, fabricators who use lasers and plastics
suppliers. This has resulted in industry misconceptions
about the compatibility between laser cutting
and PETG sheet.
The following article provides an
overview of the correct laser settings for
cutting PETG sheet, as well as how PETG
sheet and laser cutting can contribute to
a fabricator’s total operational efficiency.
The Right Settings
PETG sheet is an excellent material to
work with in regards to laser cutting.
However, because the material has not
yet been as widely adopted for this technique
as alternative materials,
the fabrication community
has been less informed of
proper PETG laser-cutting
Many lasers have a setting for generic plastic sheet, or
acrylic in specific, which is preset in the system. Using
these system presets can result in less than optimal performance with PETG sheet,
since this material often
exhibits less heat resistance
than other types of plastic
sheet. This can lead many
fabricators to incorrectly
assume that PETG sheet
and lasers are not a workable
Eastman Chemical Company,
producer of Eastman
facilities and with the Auburn University
School of Design to determine optimal settings
for laser cutting PETG sheet. Using
these settings, PETG sheet can be used
with lasers as effectively as other plastics
and can even boost overall efficiency.
There are four main settings to adjust on
any laser-cutting system: the frequency of
the laser pulse, the wattage of the laser,
the speed at which the laser moves across
the surface of the material and the adjustment
of airflow through the air nozzle.
Eastman’s research, gathered during
tests using a 75-watt laser, has shown that
the frequency setting can be the most critical
in terms of successfully cutting PETG
sheet. Adjusting the pulse frequency of a
laser to between 2,700 and 3,000 pulses
per second (pps) is optimal for PETG sheet.
This allows the laser to more evenly distribute
heat across the PETG sheet surface,
preventing burning of the material. To complement
this calibration, air nozzle settings
of 26 – 30 pounds per square inch (psi)
are also optimal, as well as a cutting speed
of about 25 inches per minute. Wattage,
however, did not test as a significant factor
in optimizing settings for PETG sheet.
These settings have shown to efficiently
cut PETG sheet in thicknesses up to 100
mm. In addition, use of a pintable to elevate
the sheet during laser cutting also
optimizes aesthetic results as it can prevent
smoke clouding from occurring.
Smoke clouding can easily be wiped clean
from PETG sheet, but this adds a preventable
step to the process, which can cut
down on overall operational efficiency.
Leaving the protective masking on the
PETG sheet during the laser cutting process will eliminate
surface whitening that may otherwise appear. This will
help assure fabricators provide displays and fixtures with
high quality aesthetics for the store environment.
Enhancing Laser Efficiency
Beyond the fact that PETG sheet can be cut using a correctly
calibrated laser, the material can actually work in
conjunction with this cutting technology to create an overall
Most fabricators invest in laser-cutting equipment to
increase production efficiency through faster cutting,
lower maintenance costs and
greater flexibility. PETG sheet
adds to this drive for overall efficiency
because the material is
tougher than many other types of
plastic sheet. For example, PETG
sheet can absorb over 80 joules
of force during dart impact testing.
Impact-modified acrylic, by
comparison, scores around 30
joules. The toughness and durability
of PETG sheet means that the
material can be downgauged for
POP display and store fixture applications without sacrificing
integrity or durability. This can help to reduce material,
shipping and inventory costs.
The ability of PETG sheet to be downgauged can also
translate into faster laser cutting, as less time is needed
to cut thinner sheet. So, while PETG sheet has less heat
resistance compared to alternate materials, its toughness
actually adds to the speed already gained in a laser-cutting
In addition to downgauging, there are several other
PETG sheet processing benefits that can add to the overall
efficiency of a fabricator’s laser-cutting operation. For
example, laser cutting is often one of many fabrication
processes that a plastic sheet can undergo during the creation
of retail fixtures and displays. For designs calling for
this technique to be used in conjunction
with thermoforming, PETG
sheet can improve thermoforming
cycles by up to 20% and eliminate
the need for pre-drying. Because
PETG sheet is thermoformed at
lower temperatures, a fabricator
also has the flexibility to decorate
with paints, coatings or vinyl prior
Together, these time-saving factors
can lead to enhanced overall
efficiencies and improve the return
on investment on the laser-cutting unit, helping to create
a lower total cost of operation.
Another reason for investing in laser technology is the
design freedom that it offers. Lasers operate from programmable
print drivers with easy to understand graphic
user interfaces (GUIs) that are simple to program, even
with the most intricate designs. This enables a laser to
accurately cut any design that can be printed on paper.
PETG sheet adds to this design versatility both directly
with its laser-cutting compatibility and indirectly through
its own inherent versatility. For example, the material
exhibits uniform distribution during thermoforming, which
can result in deeper draws and more detailed designs. In
addition, surface scratches can be easily removed
with a hot air gun, extending the lifecycle of retail
fixtures and displays
Versatility also extends to end-users. For POP displays
and store fixtures, cleaning on a regular basis
is necessary – a process that can expose plastics to
random aggressive chemical agents. PETG sheet,
however, offers a high level of chemical resistance,
ensuring that end users do not have to worry about
special care instructions.
Adding a laser to a fabrication operation can
enhance production efficiency and design flexibility
to help meet brand owner and retailer demands.
PETG sheet can add to this overall flexibility both in
the shop and for the end-user.
Obtaining a Leading Edge
Investment in new technology is ultimately about
creating competitive advantage. These benefits can
come through greater efficiency or better products
and services. Combining PETG sheet with laser cutting
offers fabricators a rare moment of enhanced
efficiency, improved service and a superior product.
By leveraging Eastman’s research in studying the
interaction of PETG sheet and lasers, fabricators
can achieve this unique combination and gain a
leading edge in the marketplace.
Eastman Chemical Company (NYSE:EMN) manufactures
and markets chemicals, fibers and plastics
worldwide. It provides key differentiated coatings,
adhesives and specialty plastics products; is one of
the world’s largest producers of PET polymers for
packaging; and is a major supplier of cellulose
acetate fibers. As a Responsible Care® company, Eastman
is committed to achieving the highest standards of health,
safety, environmental and security performance. Founded
in 1920 and headquartered in Kingsport, Tennessee.,
Eastman is a FORTUNE 500 company with 2006 sales of
$7.5 billion and approximately 11,000 employees.
Written by Chad Alan Frazier, Technician Associate,
Specialty Plastics Film and Sheet, Eastman Chemical
Company. For additional information, contact Lucy
Stewart, Eastman Chemical Company, P.O. Box 431,
Kingsport, TN 37662, 423-229-4229, E-mail: lstewart@
eastman.com. Web: www.eastman.com.
For more information, Lucy
Stewart, Eastman Chemical Company, P.O. Box 431,
Kingsport, TN 37662, 423-229-4229, E-mail: firstname.lastname@example.org. Web: www.eastman.com.