Formlabs: Basic process architecture and methodology

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Formlabs: Basic process architecture and methodology

Over the past few years a lot of 3D Printer manufacturers have wowed the Indian market with their state-of-the-art 3D Printers. Formlabs is one such company reviving the 3D Printing industry with its desktop Stereolithography printers. Formlabs’ Form 2 is a very compact desktop Stereolithography (SLA) machine that delivers an industrial grade output for the 3D Printed parts. In order to appreciate Formlabs’ SLA process, one has to acquaint themselves with the traditional Laser-Stereolithography (SLA) process, first.

Laser-Stereolithography process architecture

Although both the processes work on Stereolithography technology, the methodology of printing the parts is different. A Form 2 3D Printer mainly comprises of a vat of resin material, a build platform and a laser energy source. A typical SLA system has the laser located at the top of the machine whereas the build platform is situated at the bottom. In a Formlabs SLA system, it’s just the other way round with the build platform situated at the top of the printer and the laser at the bottom. As a result, the models are oriented upside-down on the build platform. Hence Formlabs is also, at times, referred to as Inverted SLA.

Formlabs SLA process architecture. Image Courtesy: Formlabs

The process starts by lowering the platform into the resin vat. Then, the laser selectively cures the resin material and the platform is raised for the wiper to agitate new layer of resin in place. During this process, the build platform performs a “peel” process that literally peels off the part from the PDMS surface of the resin tank. If the peeling forces are too large, it may damage the print and the machine. Thus, part orientation plays an important role is Formlabs SLA. We will address part orientation and support structure generation in detail in the next article.

 

During printing, the internal temperature in maintained at around 31˚C. We, at Chizel, have observed that the machine takes quite some time to raise itself to that temperature. This has a lot to do with the ambient temperature where the machine is being operated. One important consideration is to keep the machine away from direct sunlight. The Form 2 comes with an amber colored cover that protects the resin from curing due to ambient UV light. The Amber cover is made up of high strength PC material.

Another important aspect Formlabs has catered to is in maintaining the resin level. The Form 2 has two demarcations on the resin vat. One corresponding to a minimum level, and the other corresponding to maximum. If at any given point in time the resin level falls below the minimum mark, the printer automatically starts letting in the resin from the material canister into the resin tank until it reaches the maximum mark. Also, if the resin level drops in the canister, the same is intimated to the user via a notification. Thus one doesn’t have to constantly monitor the resin levels.

Resin tray with demarcations for resin levels

After the print is completed, the parts are taken out from the build platform. These SLA parts in their raw form are soft and mushy and need post-processing to give them the required strength. As a part of post-processing, they are immersed in a solution of isopropyl alcohol (IPA). IPA hardens the part and cleans any residual resin left on it. The parts can then be polished and painted to any desired color and finish.

Now that you are acquainted with the basic architecture and process methodology of Formlabs SLA, let’s deep dive into part orientation and support structure generation principles.

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