SLA vs DLP: Key Differences & How to Choose the Right 3D Printing Technology

AttributeSLADLP

Attribute

Print resolution

SLA

25 - 300 microns without voxel pixelation

DLP

25 - 300 microns with voxel pixelation

Attribute

Can print larger parts

SLA

Yes

DLP

Attribute

Wide range of material colors

SLA

DLP

Attribute

Minimum feature size

SLA

100 microns

DLP

100 microns

Attribute

Can produce very smooth organic surfaces

SLA

Yes

DLP

Attribute

High-speed printing

SLA

DLP

Yes

Attribute

Has isotropic material properties

SLA

Yes

DLP

Yes

Attribute

Minimum wall thickness

SLA

0.1 to 0.3 mm

DLP

0.1 to 0.3 mm

Attribute

Parts need support structures

SLA

Yes

DLP

Yes

Attribute

Largest print volume

SLA

335 x 200 x 300 mm

DLP

192 x 108 x 370 mm

Table. SLA vs. DLP Comparison

Comparisons on Key Dimensions

SLA and DLP printers are very similar in terms of performance. The key differences lie in SLA printers’ larger print volumes and better surface resolution.

SLA vs. DLP: Technology Comparison

Both SLA and DLP produce parts by polymerizing a liquid photopolymer resin with a UV light source. Both technologies print parts upside down with the build plate slowly moving out of the resin vat and the part thus appearing to grow out of the photopolymer. DLP 3D printers polymerize an entire layer at a time whereas SLA 3D printers scan the cross-section of each layer using a single focused laser. SLA printers can create smoother parts than DLP printers that tend to have a pixelated type effect on complex surfaces.

SLA vs. DLP: Material Comparison

Both SLA and DLP make use of photopolymers that are cured by a UV light. Variants of these photopolymers are available with either short or long molecular chains. Short chains produce stiffer parts while longer-chain polymers make parts more flexible. Photopolymers need to be cleaned in a solvent bath once they’re finished to remove any uncured resin. A post-curing stage using UV light may also be needed to ensure optimal properties.

SLA vs. DLP: Product Applications Comparison

SLA and DLP can both produce highly accurate parts with very fine features. They’re often used to create casting patterns for jewelry pieces or custom dental molds designed to perfectly replicate a patient's dental structure. If parts are to be used in medical or mechanical applications, they generally need to be post-processed to ensure optimal mechanical properties.

SLA vs. DLP: Print Volume Comparison

SLA printers can be built around larger print volumes. This is because the resolution of the print is not affected by the distance from the light source. The narrow laser cures only a single point worth of photopolymer at any given moment. DLP printers, on the other hand, need to have a relatively shallow resin bath as the resolution degrades with distance. The light source needs to be placed close to the layer to be polymerized. Print volume on DLP printers can be increased with the help of higher resolution light sources but this makes the printer significantly more expensive.

SLA vs. DLP: Surface Finish Comparison

SLA and DLP produce some of the smoothest surface finishes of any 3D printing technology. When compared to each other, SLA prints have better surface finishes, especially on complex curved surfaces. An SLA laser will more closely follow a complex curve. DLP printers, meanwhile, will create curves by approximating them with multiple cubic structures. This results in a pixelated appearance on complex surfaces. The effect is only noticeable upon close inspection and in many cases is not visible to the casual observer.

SLA vs. DLP: Cost Comparison

In general, DLP printers are cheaper than SLA printers. A typical SLA printer can cost $3,750 whereas an entry-level DLP printer can cost as little as $500.

What are the Mutual Alternatives to the SLA and DLP?

SLA and DLP are excellent 3D printing styles, but there is another alternative technology that can achieve a similar result:

MJF: Multi-jet fusion is a powder-bed fusion technology. It creates parts by first laying down a thin layer of powder which is heated close to its sintering temperature. Then fusing and detailing agents are placed across the powder in the shape of the part cross-section. Finally, an infrared heat source sinters the treated powder together. This process creates parts with surface finishes that are not as good as SLA or DLP but do come close.

What are the Similarities Between SLA and DLP?

Listed below are some of the similarities between SLA and DLP:

Both SLA and DLP can produce parts with very high levels of accuracy.
SLA and DLP make parts by curing liquid photopolymer materials.
Printed parts from both styles need to be post-processed via a solvent bath and post-curing under a UV light.

What are the Other Comparisons for SLA Besides DLP?

Below is another 3D printing technology that is comparable to SLA:

SLA vs. SLS: Selective laser sintering also makes use of a laser to trace out a part’s cross-section and can achieve excellent resolution. The difference is that an SLS printer uses its laser to thermally fuse thermoplastic particles together instead of the SLA printer’s liquid photopolymer.

What are the Other Comparisons for DLP Besides SLA?

Below is another 3D printing technology that is comparable to DLP:

DLP vs. Polyjet: Polyjet printing is an advanced technology that works by spraying a fine layer of photopolymer onto a build plate. A UV light then passes over the liquid to solidify the layer. Successive layers are then deposited on the top of one another until the part is complete. Polyjet printers have extremely high resolution. They can print parts in many different materials so they can build different properties and colors into various sections of the same part.

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Dean McClements

Dean McClements is a B.Eng Honors graduate in Mechanical Engineering with over two decades of experience in the manufacturing industry. His professional journey includes significant roles at leading companies such as Caterpillar, Autodesk, Collins Aerospace, and Hyster-Yale, where he developed a deep understanding of engineering processes and innovations.