Stereolithography (SLA), Digital Light Processing (DLP), and LCD are three very similar resin 3D printing technologies. They all use photopolymer resins in a resin tank, and cure the resin to form solid 3D printer models. But there are subtle differences to consider when choosing whether to buy a DLP vs SLA 3D printer, or when considering a 3D printing service.
- Don’t forget to check out our ranking of the best resin (SLA and DLP) 3D printers
This article considers the differences between SLA, LCD and DLP. If you want any specific information about these technologies, we have written detailed guides on:
- Our complete guide to Stereolithography 3D printing.
- Our complete guide to Direct Light Processing 3D printing.
SLA vs DLP vs LCD 3D Printing: How they work
SLA 3D printing
Stereolithography is the oldest 3D printing technology, having been commercialized way back in the mid-1980s by 3D Systems. The invention of SLA over 30 years ago marks the inception of 3D printing, which has evolved to change millions of lives today.
SLA uses a laser beam to selectively solidify parts of the resin, stored in a resin tank or resin vat. The laser beam is shone at the bottom of the tank, and is directed by mirrors called galvanometers to the precise area to be cured.
This continues until the layer is completely cured, before the build platform rises up by one layer, and the process repeats again and again until the part is finished.
Great SLA 3D printers include:
- Formlabs Form 3: $3,499 — Available on Dynamism Store here
- 3D Systems FabPro: $2,150 — Available on Amazon here
DLP 3D printing
Digital Light Processing was invented a couple of years later in 1987 by Larry Hornbeck of Texas Instruments — though not for the purpose of 3D printing, but for movie projection, which the technology has wide use in.
DLP 3D printing uses a projector, rather than a UV light laser as with SLA. The projector flashes light onto the entire layer of resin at once, selectively solidifying the part using thousands of minuscule mirrors called DMDs (digital micromirror devices) that direct the projection of light.
These projectors use pixels, with layers consisting of voxels, as with regular 2D or 3D cameras.
LCD 3D printing
More recently, low cost LCD 3D printers have become popular, offering better quality than FDM 3D printers can for the same price. These resin 3D printers use LCD panels using LED lights to cure resin in a similar way to DLP 3D printers.
As with DLP, LCD 3D printing involves flashing entire layers at once to cure resin housed in the resin tank, but LCD printers don’t use mirrors. Instead, powerful LCD panels shine light via LEDs at the model, which the LCD panel blocks off in the areas that are not to be solidified.
The LCD screen only lets the light pass through areas that are to be cured into the finished part, simplifying the process and removing the need for any mirrors or galvanometers.
Great LCD printers include:
- Anycubic Photon Zero: $199 — Available on Amazon here
- Elegoo Mars: $200 — Available on Amazon here
- Elegoo Mars Pro: $277 — Available on Amazon here
Key differences between SLA, DLP and LCD 3D printing
Though SLA, DLP and LCD are largely similar — they both cure resins and operate layer by layer — there are some key differences between them.
- If you buy a DLP or SLA printer, you’ll need a 3D slicer for resin printing. Check out our ranking of the best resin 3D slicers
The biggest difference between SLA and DLP is the difference in method used to cure the resin.
DLP uses a projector, LCD 3D printing uses an LCD screen, and SLA uses a UV laser that traces the dimensions to be printed. DLP and LCD are faster than SLA as they can create entire layers at once, whereas SLA requires manually tracing the dimensions of each layer with the laser.
Another lesser difference but worth noting is that DLP 3D printers usually have shallower resin tanks — the tanks which resin material is stored in during printing. If you’re big on saving money this is an advantage, as this reduces the waste of expensive unused resins.
SLA vs DLP vs LCD: Print Quality Comparison
Resin 3D printing is known for being one of the most accurate and precise 3D printing technologies, and even low cost LCD printers are able to create complex geometries that technologies like Fused Deposition Modeling just cannot match.
Honestly, the print qality of an LCD 3D printer compared to a DLP or SLA 3D printer depends on the 3D printer used. An expensive SLA 3D printer will be far better than a cheap DLP 3D printer, with higher quality components used and better resolutions and precision.
The technologies themselves are similar in their ability to create accurate models, it is the execution that affects quality.
SLA vs DLP vs LCD: 3D Printer Comparison
If you’re choosing between an SLA or DLP 3D printer, what’s best for you depends largely on your printing priorities.
- View our ranking of the best resin 3D printers.
For example, if print speed is a big priority, then absolutely go with a DLP 3D printer as they are on average far quicker.
If you value reliability, go with an established brand known for solid printing such as Formlabs’ Form 3 SLA printer. Again, the technology differences are small enough that it is more based on what you as an individual require, rather than choosing between two technologies.
In the same vein, if you need a printer capable of producing jewelry molds, or models for use in dentistry, pick a printer that specializes in these areas such as an EnvisionTEC DLP printer or a Formlabs SLA printer.
If you’re looking for a cheap printer that can print passable prototypes at home and can accept slightly lower quality, go with an LCD 3D printer such as the Elegoo Mars or AnyCubic Photon S.
- Elegoo Mars: $200 — Available on Amazon here / Elegoo Mars Pro Available for $279 on Amazon here
- AnyCubic Photon S: $350 — Available on Amazon here
- Formlabs Form 3: $3,499 — Available on Dynamism Store here
Some resins may work with both DLP and SLA printers, or with DLP and LCD printers, so there is some overlap. But not always, as though some 3D printer companies allow their machines to be used with any third party resins, some restrict them to only use their branded resins.
The best resins for you ultimately depend on what you’re looking to achieve with SLA, DLP or LCD 3D printing. Basic resins exist for fun, hobbyist 3D printer projects, as well as specialized castable, dental, engineering, or 3D printed jewelry resins.
More industrial and professional quality resins will cost more, and can cost upwards of $100/liter. The most basic resins can cost far less, at around $40, but will not offer the same level of quality, even on high quality resin printers.
We recommend some high quality resins below:
- Recommended SLA 3D printer resins on Matterhackers
- Recommended DLP 3D printer resins on Matterhackers
- LCD 3D printer resins we recommend on Matterhackers
SLA vs DLP vs LCD: Print Speed
Due to SLA involving a laser passing over each area of the part to be solidified, while DLP and LCD can cure whole layers instantly, DLP and LCD are generally faster than SLA printers.
As for which is faster between DLP and LCD, again this depends on the 3D printer you purchase. More expensive resin 3D printers will likely print faster and at better quality, and a $2,500 DLP 3D printer will almost certainly print faster than a $300 LCD 3D printer.
For an extremely fast 3D printer, consider:
- Uniz Slash Plus: $1,999 — Available on Matterhackers here
Overall, the differences between DLP and SLA are minimal, but can be important depending on what you’re looking for in a technology or printer. These differences mean it is best to evaluate printers on a case-by-case basis rather than on the actual technology, to make sure you get what you want. Pick the best 3D printer for you, not the best technology.