Well, photocuring, photosensitive resin based 3D printers acquired
pretty good popularity during the last years. Most people call them "light-curing"
printers or by technical names. In order to better understand relationships
between SLA, DLP, and LCD, representing the three major methods in resin 3D
printing, it would be necessary to take a closer look at them.Indeed, resin 3D printing is one of the oldest 3D printing technologies
which existed almost two years before FDM (Fused Deposition Modeling). The
world's first ever printed technology was Stereo lithography patented in the
year 1986 by Charles W. Hull. Charles W. Hull founded 3D Systems after which it
emerged to be the world's first company focused on 3D printer development. It
is in this area of interest that actually Hull found the file format that was
going global and even up to now, which is still currently in use with the STL
for 3D printing.
SLA
(Stereolithography)
SLA stands
for Stereolithography Appearance. One of the 3D printing ways, SLA, like any
other technology for photocuring, creates a solid object layer by layer. In the
process of SLA, the UV laser acts as a source of light. Scanning cross-section contours
of objects takes place using a rotating mirror. The technology, making and
solidifying the layers one by one, produces the final 3D structure.
Some of
the most important advantages of SLA are a very high degree of precision as
well as quality prints. It achieves very high detail and resolution because of
laser precise movement and extremely minute sizes. However, on account of such
detail in the prints, it trades off printing speed because every layer needs to
be drawn one by one and thus takes more time than any other method would
require.
DLP (Digital
Light Processing)
DLP is the
fastest 3D printing technology that produces photopolymer parts. While the SLA process employs a laser to trace and cure each
layer individually, in DLP, there's a digital light projector that cures the
entire layer of resin all at once. In its process, it builds a part
layer by layer but does so much faster because it cures each layer
simultaneously.
DLP
printing has superior capabilities to create almost photorealistic details in
resin objects. Toy pieces, jewelry molds, dental molds, miniatures, and other
related items are produced through this technology that shines because it cures
an entire layer in one exposure, which is quite significantly faster than a
system of SLA where each layer is drawn by laser in sequence.
However,
DLP printing resolution depends on the area projected. Generally, the less the projection area, the higher will be
the resolution of the printed object. This is because the accuracy directly
depends on the resolution of the projector used. Most DLP systems find their
base in the Texas Instruments' DMD (Digital Micro-Mirror Device) chips.
Therefore, the characteristics of these chips determine not only cost but also
the quality of a DLP printer and resolution of a light source.
LCD (Liquid
crystal display)
In some
contexts, LCD printing technology is addressed as DUP, or Direct UV Printing
new kind of 3D printing technology. Indeed, all types of LCD 3D printers are
actually similar in their functioning principle, which is the use of a smaller
and relatively cheaper LCD screen replacing a DLP projector with an even
partially masked UV light source for illumination of a cross section of the 3D
print. It is realized at the cost of print resolution and printer durability.
Although LCDs are cheaper and thinner, they do not have a more extended
lifespan in comparison with DLP projectors. The theoretical lifespan of new
black and white LCD screens lasts longer than 2,000 hours; this is really quite
an improvement compared to color screens whose lifespan does not go beyond 500
hours. Equally, LCD printing will print at a speed comparable to DLP
technology, the bonus being equipment that is much lighter, and considerably
smaller and less expensive.
CLIP
(Continuous Liquid Interface Production)
Additive
manufacturing's newest frontier, CLIP 3D printing, takes an already impressive
technology to the next level. Carbon and its continuous process have
dramatically sped up production so that CLIP can be very precise. Unlike most
traditional 3D printers, which build objects layer by layer, CLIP 3D printing
uses a special oxygen permeable window to cure a photosensitive resin with
light. This would protect the resin that happens to be in contact with it from
curing while allowing the rest of the resin to continually get light, which
would ensure fast and smooth object formation.So, in the
final analysis, this technology is capable of manufacturing high quality parts
very speedily while offering superior surface finishes and strength.CLIP's
applications range from medical, automotive, and consumer goods and the like,
valued for its speed, accuracy as well as its capability to produce complex
designs. Going ahead, it is likely to take 3D printing technology forward with
maturity.
Comparing SLA, DLP, LCD, And CLIP 3D Printing
Technologies
|
|
SLA |
DLP |
LCD |
CLIP |
|
Technology |
Resin is cured layer by layer with laser |
Use
of a digital projector in the curing of the layers of the resin |
LCD
screen is used for curing resin layer by layer |
Continuous
resin flow with a digital light projector |
|
Resolution |
Details
are very high, up to 25 to 100 microns |
It
will come out with very high details; up to 25 to 100 microns |
50-
100 microns |
25-
100 microns, very high resolution |
|
Speed |
Very
slow as curing is done point by point |
Quite
fast than SLA since it cures the whole layer in one shoot |
Extremely
fast, also cures the entire layer in a single go |
Very
high, continuous print |
|
Material |
Photopolymer
resins |
Photopolymer
resins |
Photopolymer
resins |
Photopolymer
resins |
|
Post Process |
UV
curing and cleaning. |
UV
curing and cleaning. |
UV
curing and cleaning. |
Nearly
negligible compared to others . |
|
Applications |
Prototyping,
models of much detail, dental/medical application |
Prototyping,
jewelry, dental |
Prototyping,
detailed models, small batch production |
Prototyping,
production quality parts, functional parts. |
References