Direct Metal 3D Printing Enables CEEE to Manufacture Lean and Green Heat Exchanger

Direct
Metal Printing delivers a 20% more efficient heat exchanger through innovative
design for additive manufacturing, produced in weeks not months and with
significantly lower weight

“CEEE’s
heat-exchanger application exemplifies the importance of DMP in the lean
manufacturing space for creating low-volume, high-complexity metal components.
These parts are now performing critical functions under challenging conditions
such as continuous stress, high pressure, repeated use and extreme
temperatures.”

The University
of Maryland’s Center for Environmental Energy Engineering (CEEE) sums
up its quest to deliver innovative approaches to energy conversion in two
words: lean and green.

CEEE is working with Oak Ridge
National Laboratory to develop the next generation of miniaturized
air-to-refrigerant heat exchangers for HVAC and refrigeration applications. For
this project, funded by the US Department of Energy’s Building Technologies
Office1, only one type of manufacturing
could satisfy CEEE’s lean and green mandates: direct metal printing (DMP)
using 3D Systems’ On Demand Manufacturing service.

Greater
efficiency in less time

CEEE provides innovative solutions
and technology transfer to meet industrial research and development challenges.
Sponsors are leading industrial companies and government agencies that pool
research funds to augment direct support from the University of Maryland.

3D Systems On Demand Manufacturing is
the world’s leading provider of unique, custom-designed parts, offering instant
online quoting, expertise in 3D design and printing, and proven manufacturing
services support.

CEEE and 3D Systems teamed to
increase the efficiency of a 1kW heat exchanger by 20 percent while reducing
weight and size. The manufacturing cycle for the heat exchanger has reduced
from months to weeks.

Making it
manufacturable

Heat exchangers are found in modern
economies across the world. Any time heat, cool air or refrigeration are
required, a heat exchanger is likely involved. On a global scale, heat exchange
is a multi-billion-dollar industry touching everything from consumer goods to
automotive and aerospace engineering.

CEEE’s extensive experimental and
theoretical research has led to automated design algorithms for creating unique
shapes for tubes and fins used in heat exchangers. The goal is to reach an optimal
air-side thermal resistance and minimize the size and weight of the heat
exchangers. But, these innovative designs require new ways of manufacturing,
according to Vikrant Aute, director of CEEE’s Modeling and Optimization
Consortium.

“Most of these optimized designs are
simply not economically manufacturable today,” says Aute. “They are too complex
technically with small feature sizes and extremely thin material thicknesses.”

That’s where the unique capabilities
of direct metal printing come into play. With DMP, complexity is free — it
costs no more to create a highly complex design than it does a more simplistic
one.

Direct
Metal Printing, in this case 3D Systems’ ProX™ DMP 320 system,
enabled CEEE to prototype its heat exchanger with non-conventional, variable
shapes that are not possible to manufacture using traditional forming
techniques such as extrusion or stamping.

“DMP allowed us to manufacture highly
unusual tube shapes in the form of a hollow droplet to carry the refrigerant,”
says Aute.

3D Systems On Demand
Manufacturing provided input into the design of the heat exchanger to ensure
that it could be manufactured efficiently.

“The ProX DMP 320 allows us to
deliver open-channel diameters and feature sizes as small as 250 microns in a
reliable and repetitive way,” says Jonathan Cornelus, business development
manager at 3D Systems On Demand Manufacturing. “High pressure and leak-tight
exchanger walls can be built as thin as 200 micrometers, which is a true
game-changer for heat-exchanger applications.”

Better
design in one part

Working together, CEEE and 3D Systems
optimized the heat-exchanger design so it could be printed as a single part
that requires minimal secondary finishing operations. Manufacturing can be
completed in weeks instead of months, enabling CEEE to test designs much
earlier and more often during the research program. The one-part design also
helps ensure greater reliability.

“With conventional manufacturing
technologies, assembly by brazing extremely thin tubes to a manifold is a
painstaking operation with very low reliability when it comes to leakages under
high-pressure conditions,” says Aute. “With DMP technology, no assembly is
required since the part is produced in one continuous operation, no matter how
complex the parts or how delicate the features.”

Besides the ability to handle very
complex parts at no extra cost, the ProX DMP 320 offers other advantages that
fit into CEEE’s lean and green scenario.

Preset build parameters, developed by
3D Systems based on the outcome of nearly half-a-million builds, provide
predictable and repeatable print quality for almost any geometry.

A totally new architecture simplifies
set-up and delivers the versatility to produce all types of part geometries in
titanium, stainless steel or nickel super alloy. Titanium was chosen for the
CEEE heat exchanger project, based on its lack of porosity and the ability to
provide extremely thin, but very strong, walls.

Exchangeable manufacturing modules
for the ProX DMP 320 system reduce downtime when moving among different part
materials, and a controlled vacuum build chamber ensures that every part is
printed with proven material properties, density and chemical purity. The small
portion of non-printed material can be completely recycled, saving money and
providing environmental benefits.

CEEE performed extensive testing on
the new heat exchanger design, using infrared cameras to verify that heat was
dispersed uniformly over the exchanger and that all the narrow, droplet-shaped
exchanger channels were open and functioning fully. Results showed that the
DMP-manufactured heat exchanger performed as expected.

Adding
mean to lean and green

The unique capabilities of direct
metal 3D printers such as the ProX line is rapidly turning DMP from an
experimental prototyping tool into a mainstream production asset for
manufacturers worldwide.

“We are witnessing new applications
and massive improvements for existing projects in upper-end aerospace and
industrial equipment markets, especially in cases where reduced space, low
weight and high efficiency are critical concerns,” says 3D Systems’ Cornelus.

“CEEE’s heat-exchanger application
exemplifies the importance of DMP in the lean manufacturing space for creating
low-volume, high-complexity metal components. These parts are now performing
critical functions under challenging conditions such as continuous stress, high
pressure, repeated use and extreme temperatures.”

Considering the strength and
reliability that defines DMP-manufactured parts, perhaps it’s appropriate to
add “mean” to the virtues of lean and green. That trio of attributes fits very
well in rapidly evolving manufacturing environments where one size rarely fits
all and the need for speed is paramount.

For further information & details please click on : https://goo.gl/JFvfD8

US-DOE Project: http://energy.gov/eere/buildings/downloads/miniaturized-air-refrigerant-… 

CEEE: www.ceee.umd.edu
ORNL: https://goo.gl/uim4Sf

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