Building 3D printers is complicated. Many different systems (optical, mechanical, electrical, and chemical) need to work in harmony to create high-precision 3D prints on your desktop. The more systems that have to work together, the more opportunities there are for things to go wrong.

This post is the first in a series where we’re documenting the process we went through to ship our latest creation, the Form 2. This is one of the most critical moments developing any complex piece of hardware — connecting and testing all the subsystems.

A look inside the Form 2 desktop 3D printer

Engineered for Precision, Designed for Reliability.

We learned a lot designing and manufacturing the Form 1 and Form 1+. One of our biggest goals in developing the Form 2 was to drastically increase quality and reliability. From the first drafts of the system architecture in late 2014 to the first machines that will ship from the manufacturing line in a few weeks, everything was created with one goal in mind: reliability.

An early prototype render of the Form 2 design

Design Verification Testing

“The product is guilty until proven innocent” — Bill Drislane

When building a complex product, it’s critical to identify issues as early in the prototyping phase as possible.

You wouldn’t have a final product to test, but you can start working on the subsystems. In fact, if you wait until you have your final product assembled to start your testing process, you’ve waited way too long.

Slide from the first Design Verification engineering all-hands meeting ca. mid-2014

Component Lifetime Testing

We want to make sure that all of our components live a long, happy life. To get there, we designed tests that pushed every major component to its physical limit. Each of the 50+ components that make up the Form 2 3D printer were put through the equivalent of 36 months of regular operation. This meant over 2 million cycles of machine parts sliding, turning, peeling, hoisting etc. All of our components had to survive this endurance test before they were considered for the next step in integration: subassemblies.

Laser Focus

At the heart of stereolithography 3D printers are its lasers. The Form 2 has a 250mW precision laser that traces an optical path through the printer, curing layers of photopolymer resin.

Laser testing jig — testing burn-in and lifetime

Lasers are integral to the SLA 3D printing process; our optical systems have to undergo the most critical tests. First, we tested the optical power of the lasers. To be able to simulate thousands of hours of printing in a shorter period of time, lasers are run at higher than normal temperatures. In development and in production, we run a beam profile of every single laser. We use cameras and sensors specially designed to analyze and record laser spots to ensure each beam meets the right size, shape, and high power metrics.

Inspecting the laser spot size after printing

Precision Galvanometers

One of our most ambitious efforts in building the Form 2 was to design and manufacture our own custom galvanometers. These are the very precise, rapid-response motors that guide the laser during the printing process.

We built our own custom galvanometers — no easy task.

For the Form 2, we needed a level of precision and reliability that we couldn’t find in off-the-shelf galvanometers, so we had to take on the challenge of building our own. Though galvanometers are relatively simple in terms of function and part count, the real work is in ensuring that the design is reliable and manufacturable. Design validation testing was an integral part of the development process.

In the galvanometer tests, we studied pointing accuracy, precision, and stability. Our tests exposed lasers and galvanometers to operational conditions beyond what they will ever experience in a printer. During these tests, we drove the components at higher powers, faster speeds, and high temperatures for hundreds of hours while monitoring their performance.

Testing one of the first batches of Formlabs-built galvanometers

Lifting & Sliding

The Form 2 has a few critical moving parts; the build platform that raises and lowers during the build process (also known as the z-stage), and the sliding peel and wiper mechanisms. We expect both of these subsystems to see a lot of use, so we wanted to test for their longevity.

We developed test rigs that ran on “infinite loops” to identify when these components would fail. Both the z-stage and the slide assembly performed so well that we eventually stopped the test after 4 continuous months and over 2 million slide cycles. That’s equivalent to over 500km (310 miles)!