Your Guide to the Formlabs Form 3L

Form 3L at TCT

Stereolithography has come a long way this past decade. The first stereolithography 3D printers were slow and crude. The technology came about in the 80s by way of Japanese researcher Hideo Kodama. Hideo invented the layered approach to 3D printing we know today, utilising UV light and photosensitive polymers.

The advantage of SLA (the abbreviated term for stereolithography) is the ability to manufacture complex parts to a high quality. Geometrically complex shapes can be made and made well with a high degree of accuracy and precision.

In contrast to FFF (also known as FDM), there are also no visible layer lines. SLA-printed parts have a smooth finish and sharp edges, giving parts a retail-worthy quality fresh from the print bed. Overhangs present little issue with SLA, and supported walls are connected to other structures, so there is little chance of warping.

However, unsupported walls are at a high chance of warping, and they are also at risk of detaching from the print. This gives rise to the need for unsupported walls and structure to be printed quite thick. They may also need a filleted base. This brings a degree of challenge and limitation to the design process.

In fact, stereolithography in its basic form is quite a brutal manufacturing process. The forces exerted on parts are extreme. The way around this is for the printer itself to rely on calibration (which is what the Form 2 does), but really, this plasters over the problem. The real solution is to reduce forces on parts at a hardware and software level, which is where Low Force Stereolithography with the Form 3L comes in.

The Formlabs Form 3L

The Form 3L is Formlabs’ biggest 3D printer to date. It has a build volume that’s five times greater than that of the Form 2 and Form 3, and it utilises a new printing process called Low Force Stereolithography.

Low Force Stereolithography (LFS) is a massive upgrade over regular stereolithography because it boosts reliability, repeatability and print quality. The Form 2 was always a reliable machine, and it could always deliver a reliable and high-quality 3D printing experience, but LFS moves the game on even further with light-touch support structures, allowing finished models and parts to be easily peeled away from the build platform.

LFS is quite easy to explain in two parts, because there are two key components: linear illumination, and a flexible resin tank. Before we get into these, here’s a useful video explaining them:

Linear illumination

What does it do? It creates a perfect, perpendicular curing source.


The Form 3L has a Light Processing Unit (LPU) which delivers linear illumination. The illumination is accurate and highly precise, with this process transforming the layer of liquid resin into a solid layer. The illumination is controlled via an optic system that contains a system of lenses and mirrors. The laser beam is directed through the optic system, passing through a spatial filter before reaching the platform.

The perpendicular aspect comes from a parabolic mirror which keeps the laser perpendicular to the build plane for uniform prints. There’s also closed-loop calibration which uses optical sensors to continuously correct for scale and power. This reduces the need for human intervention.

Flexible resin tank

What does it do? It drastically reduces peel forces and enables light-touch support structure.

Flexible resin tank

Inverted SLA introduces peel forces that affect the print as it separates from the surface of the tank. So, the Form 3L has a flexible resin tank that bows gradually as the part is lowered, which reduces the pressure on parts and allows for light-touch support structure.

By drastically reducing peel forces, the flexible resin tank increases both print success rate and repeatability, for a better 3D printing experience.

The improvements light-touch support structure brings to the 3D printing experience are game-changing. It means you can quite literally twist and snap support structure from any part with a 100% clean edge. Parts pop free from support structures easily, giving designers more time to focus on design and creation. It also means a new platform for more advanced materials and applications (greater part complexity, geometries, etc.)

Other upgrades and tech

The Form 3L isn’t just an enlarged version of the Form 3 – it is, in fact, an even more capable machine.

The biggest upgrade are the two 250mW laser units, whereas the Form 3 only has one 250mW laser. This makes the Form 3L twice as powerful. Adding a second laser was absolutely necessary because of the Form 3L’s larger build volume, but in spite of that, the Form 3L also builds models a little faster.

The Form 3L also has an air-heated print chamber – the Form 3 has one too, but the Form 2 doesn’t. This temperature control system works in addition to the self-heating resin tank, to provide a more stable environment for your creations.

Build volume and specifications

The Form 3L’s build volume is 30 x 33.5 x 20cm (11.8 x 13.2 x 27.,9 in).

The Form 3 has a 14.5 × 14.5 × 18.5cm (5.7 × 5.7 × 7.3in) build volume.


This makes the 3L’s build volume five times greater than the Form 3’s. It is 69% greater on the X axis, 79% greater on the Y axis and 13% greater on the Z axis. This makes it the printer of choice if you want to create large, functional models.

Printer specs at a glance (Form 3):

– Material support: All Formlabs resins
– Layer resolution: 25 – 300 microns
– Build volume: 30 x 33.5 x 20cm (11.8 x 13.2 x 27.,9 in)
– Interface: 5.5-inch touchscreen display
– Connectivity: Wi-Fi, Ethernet, and USB

In addition to being able to print the complete Formlabs resin library, the Form 3L is also compatible with the Formlabs Colour Kit. This enables you to add pigment to any Formlabs resin. There are 16 colours to choose from, enabling you to 3D print models and parts in a solid colour to cut down on the need for painting and post-processing.

colour kit

The key differences between the Form 3L and the Form 3 are the 3L’s larger build volume and two laser units. The key differences between the Form 3L and the Form 2 are the technology and size – the Form 3L has a build volume that’s five times greater than that of the Form 2, and it utilises Low Force Stereolithography, whereas the Form 2 utilises Stereolithography. Low Force Stereolithography is newer and superior in every aspect.

Here are the Form 3L and Form 3 next to each other:


Interface and usability

The Form 3L has an in-built 5.5-inch touchscreen with a 1280 × 720 resolution. It’s bright, crisp, responsive, and the software is easy to use.

When you first turn the 3L on, the screen guides you through the setup process with a walkthrough. This gives you the opportunity to bond with the machine and get to know how the interface looks and responds to commands.


Workflow is managed using PreForm for PC or Mac. This is Formlabs’ proprietary print management software. In our opinion, it is one of the best out there because it puts all the most important stuff in one place. It’s also one of the cleverest programs out there, because it can auto-repair broken meshes and assign the correct print settings according to what it sees. This can catch things you miss and make life easier.

Managing your prints with PreForm is easily done, and in many cases, the program will do all the hard work for you by automatically setting up print layout, orientation, and supports, without any human intervention. Of course, you still have the final say though. The program simply offers a guiding hand, based on what it sees.

Importantly, PreForm is in the cloud, which means you can manage the print process from anywhere with an internet connection. It needs to be downloaded to a computer to operate, though. It’s available for PC or Mac.

What’s in the box?

The Form 3L comes with the following equipment as standard:

– Form 3L 3D printer
– Form 3L Resin Tank
– Form 3L Build Platform

Interested in buying one? Perhaps you want more than one? The Form 3L is available for pre-order. It’s estimated to begin shipping in Q1 2020. For sales or to find out more about the Form 3L, you can contact our team by email at or by calling 01765 694007.

All images in this article are credited to Formlabs