JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - 45

Manufacturing tools using large-scale additive manufacturing systems

LSAM patented compression wheel follows
the nozzle and fuses each new layer with
the existing ones to produce a solid, strong,
void-free part. Before the material is heated,
the pellets are dried to remove any moisture
and then pneumatically conveyed to the
vertically-mounted extruder. The print head
design consists of three Siemens-controlled
servomotors. One for the extruder, one for
the melt pump and one for the patented
compression wheel. These three servomotors automatically coordinate with machine
motions to maintain a precise bead even
without any program changes.
The LSAM has three "PH Series" print
heads to choose from. The standard PH15
head can print up to 68 kg per hour. The
PH30 head will print up to 136 kg per hour
and the PH50 head will print up to 227
kg per hour. Each print head is capable of
printing at high temperatures for use with
different materials that might require higher
temperatures.
The different print heads will determine the
size of the parts to be printed. The length of
the LSAM can reach beyond 30 metres and
on these longer machines, a higher-output
head might be required to print material
faster as the time before each layer is laid is
important to bonding.
If a tool is big enough that it requires multiple pieces to be printed and put together,
multiple parts can also be printed on the
same machine. For example, for a part that
needs to be broken down to two pieces, it
is possible to print a layer on part one and
then a layer on part two, and then to continue with the remaining layers until the parts

are complete. This could be done because
there is a time limit required between printing layers. Instead of the LSAM just sitting
for that period of time, why not print another part. As long as enough space is kept between each part, the subtractive gantry can
machine each part without ever needing to
move them. If a part ever does need to be
moved, the LSAM can machine reference
points right on the part, so that the parts can
be moved to a different machine or moved
off the current machine and re-installed later.
LSAM subtractive process
The trim or subtractive gantry is a five-axis CNC router system equipped with a
12HP (3,000 to 24,000 RPM) spindle
and a ten-position automatic tool changer. The vertical Z axis stroke is enhanced,
so that the router head can machine from
the print table surface to a point completely over the top of a printed part. The machine is also equipped with an automatic
tool length measurement system and
Thermwood's patented impact-resistant
head. The machine uses Siemens intelligent servo drives throughout, for both
printing and trimming.
Each gantry has its own, free-standing
Thermwood high-performance Q-Core
CNC control for movement. The print gantry also includes an integrated print head
control to manage melt, pressure and metering functions. Special control functions,
not normally part of a CNC control, have
been developed to operate the servo drive
print head and bead compression wheel.
These functions automatically perform

LSAM 3D printed Aerospace Tool

tasks that would otherwise need to be incorporated in the CNC print program. This
simplifies 3D print programming.
The LSAM comes standard with two gantries - an additive gantry that contains the
extruder and printing components, and
a subtractive gantry that contains the advanced CNC router portion. These two
gantries operate independently of each
other and can be run at the same time
knowing where each one is located.
The LSAM system can produce large industrial tooling using thermoplastic composite
materials and a near-net-shape approach
(meaning that the additive head will print
a tool that is slightly bigger than the final
size). The CNC router portion of the LSAM
(or subtractive gantry) trims the tool to the
final shape and size. Traditionally parts
have been made by machining an oversized
blank, removing material to achieve the final shape. Often more material is removed
than what remains. The near-net shape results in much less material to be removed
and thus faster processing times, lower cost
and more efficient use of the material. With
the proper material, it may be possible to
skip the building of a master and go directly to the working mould, saving even more
time and money.
More information:
www.thermwood.com

Thermwood PH50 Print Head Control

No111 March 2017

/ jec composites magazine

http://www.thermwood.com

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World