3D Slicer

DLP, LCD and SLA are all resin based 3D printing technologies. Our main topic of discussion here will be the differences between DLP and LCD 3D printers. But before delving deeper into the subject, you might be asking what resin based 3D printing is?

Resin 3D Printing - A Rookie's Guide

Resin 3D printing is also known as vat polymerization. All vat polymerization technologies involve a photosensitive resin cured by a light source to produce solid layers and, eventually, whole units. The nomenclature is derived from the fact that  the resin is contained within a vat, or tank, and is cured against a build platform, which slowly rises out of the tank as the part is formed.

This first 3D-printer was named stereolithography apparatus or SLA and used a laser to cure a light reactive resin. So knowing what SLA 3D printing is fundamental to our understanding of how LCD and DLP 3D printing works. It's important to remember that the light source is what sets SLA, DLP, and LCD apart.

SLA uses galvanometer directed lasers, to cure the resin. Galvanometers can be thought of as mirrors guiding the laser beam through the transparent tank bottom to a particular point on the build platform. The resin cures and becomes a hard plastic at the spots where the laser ‘hits’ the resin.

Whereas, Digital light processing (DLP) uses a digital light projector to cure the resin in place of a laser. Images of whole layers are flashed onto the bottom of the vat. Light is selectively guided using a digital micromirror device (DMD). It plays a similar role to the galvanometers used in SLA, but is considerably efficient. Layers generated using DLP printers consist of so-called voxels, the 3D equivalent of pixels. Companies like EnvitionTEC, Atum3D, Rapidshape, and Kudo3D, Sprintray, Miicraft used this technique.

One of the latest developments in resin 3D printing is LCD. It also flashes complete layers at the resin tank, but with the UV light coming from an array of LEDs shining through an LCD, not a projector, unlike the DLP technique. A screen selectively masks redundant pixels, revealing only the pixels necessary for the current layer. As such, no special device is

One of the latest developments in resin 3D printing is LCD. It also flashes complete layers at the resin tank, but with the UV light coming from an array of LEDs shining through an LCD, not a projector, unlike the DLP technique. A screen selectively masks redundant pixels, revealing only the pixels necessary for the current layer. As such, no special device is required to direct the light, eliminating the need of expensive DMD devices.The liquid resin turns into a rigid plastic on the areas where the light ‘hits’. Companies like Wanhao, Anycubic, Sparkmaker, Kudo3D, Creality, XYZprinting, Phrozen, and many more.

Well, how do they compare?

So, we basically covered all the foundations of resin 3D printing. An arduous read you might be thinking but let's now shift our attention to the subject matter at hand. DLP and LCD. What differentiates them? And the one you should be looking at while making a purchase.

Our 2 main points of contention shall be :-

I .  Quality of the print

II . Application and cost comparison

For the veterans here, comparisons will be made on the basis of factors like pixel distortion and price of components.

  1. Quality of Print

DLP

DLP projectors generate the image of a layer by shining a light beam through a lens to a DMD, which then reflects the light beam towards the bottom of the resin tank. Due to this the light beam must spread or expand to cover a much wider area. This increases the probability of wider models having distorted pixels at their edges.

It is important to note that the number of pixels on a DLP projector remains the same irrespective of the area covered by the print. So, smaller and narrower prints have a much higher precision than wider prints done on the same DLP printer.

To help you picture this effect better, let's think of a literal picture or a photo that you’ve taken on your smartphone. As you zoom in on the photo, you notice the sharpness declines or it appears more pixelated. That’s exactly what happens when printing big objects on a DLP printer — they’re “zoomed out”.

That said, you should remember the fact that these devices are produced by several different companies and that distortion is corrected for on more professional devices, which have better quality components. Also, the “pixelation” issue doesn’t necessarily suggest that a DLP printer has poor print quality, only that its resolution is more concentrated for smaller prints.

LCD

LCD 3D printers use an array of UV LCDs as a light source, unlike the DLP ones which use a projector and DMDs.The light from the flat LCD panels is shined parallelly, onto the build area. Because this light isn’t expanded, pixel distortion is considerably lower with LCD printing.

Which means that the print quality of an LCD printer depends on its LCD density. The more pixels it has, the better the print quality.

The one aspect DLP and LCD are both superior to, when compared to SLA, is build speed. As the entire layer is flashed at once, instead of a single point, the two technologies are typically able to produce parts faster.

2.  Application and Cost Comparison

Both DLP and LCD find their uses in the dental (especially in the orthodontic and prosthodontic sectors), jewelry (You would be surprised to know how popular 3D printed jewelry is due to the vast amount of customisations available) and engineering industries, just to mention a few. Hobbyists are also seen using both types of printers. You might be asking what kind of printer suits your needs while being affordable at the same time.

The general trend, looking at market statistics and logistics is that DLP printers are the more expensive, professional machines. LCD, a more recent technology, has so far been seen mostly in affordable, desktop printers. Why are they cheaper? Well yes, you guessed it. It’s because LCD printers don’t use the really expensive DMD technology.

As mentioned earlier, cheaper DLP printers sometimes suffer from minor voxel/pixel distortion. However with a higher budget this wouldn’t be too much of a problem. Because, with higher quality printers comes higher quality hardware, specifically designed to avoid any kind of distortion.

In general, LCD 3D printers use cheaper components than DLP 3D printers, making them a cheaper resin 3D printing solution. This is a great thing because it extends the reach of resin 3D printing to a wider audience of makers.Both DLP and SLA printers use resins, so the cost of printing should be similar. However, we must remember that the cost greatly depends on the manufacturer of the resin and even the printer.

Both DLP and LCD are able to achieve swift and accurate print speeds and showing precise details. But at higher prices, the DLP 3D printers start to trump their LCD counterparts.

So it all boils down to whether you are a professional or a beginner. If you’re the former, someone who needs high detail and fast print speeds,we’d suggest that you look into professional DLP printers. On the other hand, if you’re the latter and are a newbie to the world of resin 3D printing, LCD would be a great choice.

Well that concludes the article, if you thought that the article was too long to read, fear not we’ve compiled here the generic differences between the two for ease of access.

Also Read : Silicone 3D Printing Summarised

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