SLA vs DLP vs LCD

Photopolymer or resin 3D printing is commonly associated with delicate, miniature products. After all, using the best resin 3D printers is your best bet when you want to make a small but detailed model.

Currently, resin printers can work according to one of three technologies – SLA, DLP or LCD. Each of the technologies has its own advantages and disadvantages.

Before choosing a 3D printer, you should know which technology is suitable for printing specific products. For example, for a jeweler and a dentist, the main criterion will be accuracy. If you will be printing figurines as a hobby, you’ll want to look at the quality of the surface and cost of consumables.

Let’s go through an overview of SLA, DLP and LCD

SLA vs DLP vs LCD: The Differences

1. SLA

SLA was one of the first patented 3D printing technologies. The technology was patented back in 1986 by Charles Hull. You can find out more about this by reading the History of 3D Printing. Below is also a nice documentary that covers the subject:

DLP and LCD are similar in basic principles to SLA, but appeared much later.

Principle of Operation

SLA printers use photopolymer resins to print models. Resins are light-sensitive polymers that solidify under the influence of a certain spectrum of UV radiation.

A laser beam is used to harden the resin by focusing on particular points with the help of mirrors. The beam sequentially “draws” a slice of the model. Therefore, gradually, layer by layer, the model is printed on the desktop.

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How SLA Technology Work

There are two options for positioning the print bed – top and bottom.

Table Top

Visually, the table top printbed looks like an inverted FDM machine. The model is printed upside down on such a machine. The table moves during printing from bottom to top.

The module with the laser is located at the bottom of the machine, under the bath with polymer. The bottom of the bath is usually made of silicone. The area transmits UV radiation well and practically nothing sticks to it.

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Table Top Printer Model

The table top print bed is the most popular solution for desktop SLA printers.

Table Below

Here, the laser module is located at the top of the printer above the resin bath, and the print bed. During printing, the laser module gradually descends downward, immersed in the resin.

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Under Table Industrial SLA

This arrangement is traditionally used in industrial machines with a large print area. The only inconvenience is that the tray must always be filled with photopolymer. Also, when you change the type of resin, you have to completely drain all the photopolymer and thoroughly wash the bath.

Pros

  • High accuracy. Such a device is not inferior in accuracy to professional jewelry CNC machines.
  • Perfect surface quality. The smallest models look monolithic. The layers are not visible even at high magnification.
  • Large selection of consumables. Due to the growing popularity of resin 3D printing, many specific resins are available. The consumables ranger from soft flakes to resins with increased strength characteristics (for example, there is a very strong, biocompatible photopolymer for the manufacture of temporary dental crowns).

Cons

  • The high cost of a 3D printer. SLA devices are very demanding on the quality of components. As a result, the printers are more expensive than their FDM counterparts.
  • Expensive consumables.
  • Slow print speed compared to DLP and LCD technology.

Print Example

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Cardiac muscle printed on Formlabs Form 3

 

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Rings printed with SLA technology
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Spoon prototype

 

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Butterfly Figurine Printed on Formlabs Form 3

 

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Technical model

 

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Snow shovel prototype. Manufactured on Formlabs Form 3L

Best SLA Printers

Formlabs is one of the leading SLA 3D printer manufacturers. The company’s range includes both small desktop models and professional machines with a large print area.

The printers include:

a) Form 3

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PRICE ON FORMLABS

Specifications:

  • XY Resolution: 25μm
  • Laser spot size: 85um
  • Laser power: One 250mW laser
  • Working area size: 14.5 x 14.5 x 18.5 cm
  • Layer thickness: 25 – 300 microns

This printer is like a small professional machine. Despite its small size, it can easily cope with the most complex models.

Formlabs Form 3L

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PRICE ON FORMLABS

Specifications:

  • XY Resolution: 25μm
  • Laser spot size: 85um
  • Laser power: One 250mW laser
  • Working area size: 33.5 × 20 × 30 cm
  • Layer thickness: 25 – 300 microns

This printer allows you to print large-format models or quickly produce small batches of products.

However, with the advent of faster and more cost effective technology, SLA printers have become less popular. As a result, the printers are mainly used in industries with high requirements for print quality and stability.

2. DLP

DLP technology is based on the principles of SLA. However, instead of a laser, a projector is used as a source of UV radiation.

Principle of Operation

DLP 3D printers use photopolymer resin to print models. However, unlike SLA, the light source is not a beam, but a DLP projector.

DLP 3D printers are significantly faster because the projector used illuminates the entire layer at once. In contrast, with SLA, the laser only illuminates a small area at a time.

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How DLP technology works

The projector is located at the bottom of the printer, under the resin container. The bottom of the container is usually made of transparent, wear-resistant film. The film transmits UV radiation well and nothing sticks to it. Moreover, the film can be easily replaced in case it breaks.

Pros

  • Fast printing. The projector illuminates the entire working area at once. Therefore, the number of models placed on the print bed does not determine the printing time. The printing time is influenced only by the height and thickness of the layer.
  • Medium price segment. Compared to SLA, the DLP 3D printers are much cheaper.

Cons

  • Less accurate. Some DLP printers are inferior in accuracy to SLA devices. This is not visually noticeable on the finished product. However, it can be an unpleasant surprise where models need to be printed in perfect.
  • Possibility of parasitic illumination. Due to the illumination of the entire layer at a time, parasitic illumination of the resin can occur.
  • Projector resource. The projector is the heart of a DLP printer. Be sure to pay attention to the resource of the projector. For example, the projector life of FlashForge Hunter is 50,000 hours.

Print Examples

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DLP printed ring lot

 

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Ring samples printed on FlashForge Hunter

 

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Props for miniatures 28 mm

 

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Jaw mockup made by FlashForge Hunter

Best DLP Printers

The best DLP 3D printers are:

a) FlashForge HunterSLA vs DLP vs LCD 17

AVAILABLE ON TOP3DSHOP

Specifications:

  • XY Resolution: 0.0625mm
  • Print speed: 10mm / h
  • Light source: 405nm LED
  • Working area size: 120×67.5×150 mm
  • Layer thickness: 0.025-0.05 mm

FlashForge is renowned for the quality of its printers, and the Hunter is no exception. The printer is a good “workhorse” capable of solving various problems.

Read the full Flashforge Hunter 3D printer review.

Today, DLP technology is used less and less. Instead, 3D printer manufacturers are opting to produce affordable 3D printers using LCD technology.

3. LCD

LCD is the most recent technology used in photopolymer printers. This technology was designed to be a more affordable analogue of DLP technology, suitable for home users.

The first LCD printers had a number of unpleasant childhood sores (uneven illumination of the working area, etc.). These problems were eventually solved or compensated for.

With the improvement of the technology, LCD 3D printers have been unveiled that produce models with the same accuracy as DLP 3D printers. Most LCD 3D printers are suitable for home use and production tasks.

Principle of Operation

LCD technology almost completely copies DLP. However, instead of a project, LCD 3D printers are fitted with LEDs. Under the bath is an LCD display (similar to the display of a smartphone or tablet). The display is dimmed in some places and lets in light only in the right places.

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How LCD technology works

Since the module with the screen and LEDs is located at the bottom of the printer, the bottom of the resin container is transparent. As with DLP, transparencies are commonly used.

Pros

  • Cheap devices. The use of LEDs in conjunction with an LCD display greatly reduces the cost of a 3D printer.
  • Inexpensive consumables and spare parts.
  • Large selection of 3D printers. You can easily find a model for any task.

Cons

  • Less accurate. Budget models work well for printing miniatures or figurines. However, their accuracy may not be enough for things such as dental work or jewelry making.
  • Parasitic illumination is possible. As in DLP technology, the entire layer is illuminated at once. This can lead to parasitic illumination.
  • The print quality may not be the same throughout the printable area. Since an array of LEDs is used as the UV source, and not a single light source, the work area may be illuminated unevenly. This problem can be solved programmatically or physically.
  • Print speed is lower than DLP. The LEDs shine “weaker” than the projector. Therefore, the exposure time of the layer is slightly longer. However, LCD printers are still faster than SLA units.

Print Example

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Small miniature made with Anycubic Photon Mono

 

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Troll printed on an LCD machine

 

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RC tires made of soft polymer

 

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Castle model made with Phrozen Sonic Mini 4K

 

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Anycubic Photon Zero figurine

 

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Troll printed on an LCD printer

Best LCD Printers

a) Anycubic Photon ZeroSLA vs DLP vs LCD 25

AVAILABLE AT ANYCUBIC

Specifications:

  • LCD display resolution: 854×480 px
  • XY-axis positioning accuracy: 0.1155mm
  • UV wavelength: 405 nm
  • Working area size: 97x54x150 mm
  • Layer thickness: 0.01-0.2mm

This is a budget model aimed at home users.

Read the full Anycubic Photon Zero review.

b) Anycubic Photon Mono X

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AVAILABLE AT ANYCUBIC | AMAZON

Specifications:

  • LCD display resolution: 2560×1620 (2K)
  • XY-axis positioning accuracy: 0.051mm
  • UV wavelength: 405 nm
  • Working area size: 130x80x165 mm
  • Layer thickness: 0.01-0.15mm

Anycubic Photon Mono X is one of the best resin 3D printers for miniatures. Thanks to the LCD display of higher resolution, the accuracy and quality of the finished models have been improved.

Read the full Anycubic Photon Mono X review.

c) Phrozen Sonic Mini 4K

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AVAILABLE ON PHROZEN | AMAZON

Specifications:

  • LCD Resolution: 6.1 “4K Mono LCD
  • XY-axis positioning accuracy: 35 microns
  • UV wavelength: 405 nm
  • Working area size: 134x75x130 mm
  • Layer thickness: 0.01-0.30mm

The Phrozen Sonic Mini 4K has a mono LCD matrix, with high resolution. Therefore, it prints very quickly and accurately.

Read the full Phrozen Sonic Mini 4K review.

d) Wanhao GR1

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AVAILABLE ON TOP3DSHOP

Specifications:

  • LCD Resolution: 6.3 “2K HD
  • XY-axis positioning accuracy: 0.055mm
  • UV wavelength: 405-410nm
  • Working area size: 140x78x200 mm
  • Layer thickness: 35-100 microns

The Wanhao GR1 has an enlarged work area, allowing you to produced many models at a time. Moreover, its special UV-LED matrix ensures uniform illumination.

LCD printers are becoming more popular and replacing expensive DLP and SLA printers. This is, of course, due to their availability of a wide variety of models.

Read the full Wanhao GR1 review.

Scope of Application of SLA, DLP and LCD 3D Printers

Dentistry

Accuracy is very important in dentistry. Even a slight distortion of even 0.1 mm can make the painstaking work of making a crown or prosthesis useless.

SLA 3D printers are used for dentistry because of their high accuracy. Check the models below made by some of the printers.

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Jaw model

 

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Aligner made using 3D printing

In addition to the accuracy of the printer, the choice of material plays an important role. It is necessary to use special resins with a low percentage of shrinkage.

Here are some guides on dental 3D printing:

Jewelry production

The full potential of photopolymer printers is being unleashed in the jewelry industry. In addition to accuracy, detail and perfect surface quality are very important.

Check some of the prints made by the 3D printers.

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Ring made from burnt-out photopolymer

 

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From model to finished product

Previously, such products had to be very painstakingly cut by hand or made from wax on high-precision CNC machines. But now, you can make a digital model and, using a printer and fired resin, quickly produce the required number of products ready for casting.

Prototyping

Resin 3D printers are also used for printing prototypes, making master models, etc. Below are some print examples made using the printers.

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Helmet and other prototypes made on a photopolymer printer

 

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Case prototypes

FDM technology is not suitable for everything. Sometimes, you need to quickly make a mock-up of a future product with a smooth surface. In such a case, professional photopolymer printers can easily cope with this task.

Hobby

Affordable resin 3D printers have become a great help for miniature lovers. It is much easier to model and print a 28 mm figurine of your favorite hero than to make it by hand.

Check the print examples of some of the models made using resin 3D printers.

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Soviet motorcyclist in 28mm scale

 

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“Spare parts” for miniature 28mm

Moreover, large decorative figurines made using resin 3D printers are more accurate than those made using FDM printers. After the LCD printer has finished its work, you don’t have to smoke the model for a long time to smooth out the layers.

For example, check this model of the bust of a girl.

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Bust of a girl

Layout

FDM printers can be used for large and schematic layouts. However, their accuracy is not sufficient for making small parts.

When you have a 3D model, you can quickly make an accurate and detailed model of a building or an entire block.

Here are some print examples made using photopolymer 3D printers.

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Model of the statue of V.I. Lenin

 

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Printed and painted building model

Conclusion

Despite all the advantages of photopolymer printers, there are small nuances that are common to all technologies. These include:

a) Washing the model

After printing, the model must be rinsed from resin residues. The best way is to use an ultrasonic alcohol bath. Depending on your model, you can also rinse it with a glass of isopropyl alcohol and a brush.

b) Additional illumination in the UV camera

After washing, the model must be “re-illuminated” in a UV camera,. Otherwise, the resin will not be strong.

To illuminate the model, you can use a regular UV lamp or a manicure machine. These will cost less than professional dryers, but may take longer for additional exposure. Make sure the lamps are in the correct UV spectrum before purchasing.

c) Strength of polymers

Despite the huge variety of resins, they are still inferior in strength to the plastic filaments used by FDM printers. The exception is some highly specialized resins.

For some people, these nuances can become significant disadvantages. However, despite this, photopolymer printers are used both as home printers and as work machines in various fields.

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