Desktop 3D printing has matured from its humble beginnings of not much more than a glue gun on a rudimentary X-Y-Z translation stage to a wide range of beautifully engineered machines, driven by amazingly smart software. These machines turn out high precision plastic parts at relatively low cost and high levels of repeatability.

The first is a milling machine that mills out copper clad fiberglass. These milling machines cut traces down to 10 mils (0.010") and are limited by the tendency of the copper to delaminate, not by the accuracy of the machine.

The second approach is an additive process that uses inkjet technology to “print” conducting and insulating inks onto a substrate material. The biggest challenge here is the material science involved in developing conductive inks. The fundamental problem is that the conductivity of conductive inks are is not as high as that of copper. This requires the traces to be thicker and they need to be applied in multiple layers, slowing the process down.

The next step in the conventional process is the creation of custom stainless steel masks that cover everything except for the points at which the components touch conductive pads on the PCB. The mask is aligned over the board and solder paste is applied using a squeegee technique. This process has a higher upfront cost to create the mask, but once you have it, it’s easy to apply solder paste to many boards.

On the desktop, the process is totally different, but the result is much the same. Rather than spending the time and money to create custom masks for every iteration of the PCB, solder paste is applied by a syringe controlled by what is effectively a 3D printer. Instead of depositing plastic, it deposits dabs of solder paste.

In a traditional process, pick and place machines rapidly peel components off of reels and, using a combination of computer vision and robotics, they place the components on the solder paste already applied to the boards. The machines run at a blistering pace and make for mesmerizing

YouTube videos

.

On a desktop machine, the process is much the same, although the lower mass of desktop machines limits the accelerations of the head and therefore the rate of components that can be placed. This is an area where 3D printing has made a big impact: low cost and high precision mechanical components which support these movements along with software which handle the surprisingly complex properties of high accelerations with high precision are now widely available. Add open source computer vision modules like

OpenCV

and the barriers to entry come down even further. Desktop pick and place machines will likely never reach the speed of their conventional counterparts. But they don’t need to. If you’re only building a few boards at a time, shaving seconds off each board doesn’t really matter.

The final step in the conventional process involves a conveyer belt which drives through a long oven. Heat from the oven melts the solder paste and adheres the components to the PCB. These ovens can handle a high volume of boards and provide a controlled temperature profile to avoid damaging the boards and the components.

On the desktop, a few different approaches are used. Some ovens, like the NeoDen

T-962A

are basically miniature versions of industrial reflow ovens. However, some systems take a page from the desktop 3D printing playbook and utilize heated print beds. The

Voltera

and the

Squink

fall into this category heating the plate on which the PCBs are fabricated to reflow the solder. Ultimately, either approach works fine, and as long as the heating profiles are within the envelopes set by the component manufacturers, you’ll get good results with both.

There’s not yet a consensus about whether desktop electronics manufacturing machines should specialize in one of these steps or if a single machine can reliably perform all four steps. Both approaches are being tried and it’s too early to tell which approach will succeed in the long term. The chart below displays the current players in this space and which steps of the process they handle.

2006: MakerBot Cupcake 2015: MakerBot Replicator Rostock MaxV2 Printrbot PlayThese machines are playing an increasingly important role in the world of electronics prototyping and low volume manufacturing. They are easy to set up, provide fast results, and enable rapid iteration. Today, conventional electronics manufacturing and assembly (fabrication of printed circuit boards and soldering components onto the board) takes place in four steps, using expensive capital equipment that can run into the millions of dollars. These steps are now being replicated on desktop machines costing less than 10 thousand dollars. Some of the steps are being done in a completely new way on the desktop, and some are exactly the same, just on a smaller scale.Traditionally, PCBs are created by a photolithography process that deposits copper traces on thin layers of fiberglass. These layers are stacked, drilled, and cut into final shapes. Photolithography requires expensive mask making and industrial chemicals which require large capital equipment investments in excess of a few million to 10 million dollars. PCB Fabrication PCB Fabrication There are two approaches to fabricating PCBs on the desktop, and both are entirely different from the conventional approach. Othermill Othermill Cartesian Co. Argentum Voltera Stainless Steel Solder Paste Spreading Solder Paste Conventional Pick and Place Machine Desktop Pick and Place Machine, NeoDen TM240A Conventional Reflow Oven NeoDen T-962a Desktop Reflow Oven

The current trend of desktop electronics manufacturing is to replicate the four steps of conventional electronics manufacturing on the desktop. However, there’s room to rethink all of the assumptions of conventional electronics manufacturing from scratch, especially as devices are becoming smaller and the distinction between the electronic and mechanical elements are blurred.

Voxel8

is taking a novel approach here, eschewing the entire circuit board and integrating the network of conductive traces into the 3D printed plastic enclosure itself. LPKF is driving forward the

Laser Direct Structuring (LDS) process

which uses a combination of lasers and a chemical process to “paint” conductive traces onto injection molded plastic, negating the entire need for a traditional printed circuit board. On the wearable front, Google’s

Project Jacquard

is integrating conductive threads into clothing. By rethinking the assumptions of conventional electronics manufacturing, lots of doors open up to newer, smaller manufacturing machines.