Time for a second 3D printer within the lab

I’d guess at the moment most electronics R&D labs have an 3D filament (FFF/FDM) printer for the engineers to make use of. These printers have turn into very helpful for issues like creating 3D fashions of a PCB meeting to test it for match into an enclosure. It’s possible you’ll be printing out the enclosure so you possibly can create a full working prototype. If wanted, you could possibly additionally create customized knobs, handles, insulating washers, and many others. However alongside along with your product components, FFF printers are additionally helpful for creating numerous instruments and fixtures for the lab similar to:

Each occasionally, the printer can mean you can clear up an engineering downside.

Not too long ago I wanted to enhance reception for an ultrasonic receiver, so I rapidly modified an present small parabolic dish designed to carry the receiver. This improved the ultrasonic sign reception by 9 dB.  As helpful because the FFF printer is, it might be good to have just a little higher printing decision to construct a number of issues that the FFF printer has a tough time producing.

In the previous couple of years, the low-cost resin printer has been refined to the purpose of being a must have in a lab. It may possibly print all of the gadgets above however with a decision that’s roughly 10x higher than an FFF printer. That might not be a giant deal for a scope probe holder or for a cable organizer, however there are some things that want the improved decision. Let’s take look nearer have a look at resin printers and a few the helpful issues it may well print.

LCD-based resin printers (typically known as a masked stereolithography equipment, or MSLA) have lately advanced and improved within the lower-priced area. Now for lower than $400, you may get a printer able to creating fashions with a Z (vertical) decision of 10 µm and an XY decision all the way down to 25 µm (for reference, printer paper is about 100 µm thick). This very high-quality element measurement opens up the likelihood for creating new components that may help in digital product growth and prototyping. Not solely are new and higher printers being launched, however a gradual stream of recent resins is consistently arriving. These should not simply new colours, however resins with numerous mechanical properties similar to improved power, extra flexibility, translucent, clear, static dissipating, and many others.

Now let’s have a look at a few examples the place these printers can be helpful. One space to be explored is the creation of small bed-of-nails check fixtures. A bed-of-nails check fixture can be utilized for board testing, programming onboard gadgets, board monitoring throughout debug, or just holding a PCB securely whereas on a lab bench. A bed-of-nails check fixture consists of a block of non-conductive materials with an indentation within the form of the PCB to be inserted. Throughout the indentation, there are usually spring-loaded probes, often called pogo pins, inserted into comfortable becoming holes within the block. The holes, and due to this fact the probes, are precisely aligned in order to create {an electrical} contact to the underside of the PCB at a selected place on the copper. (There can be a bed-of-nails check fixture on the highest, creating comparable contact on the highest of the PCB.)  These pins are additionally electrically related on the backside of the block, to some digital tools and to energy with the intention to ship alerts and monitor alerts, voltages, and currents on the PCB. To help in PCB alignment throughout the check fixture, there are usually two stainless-steel pins inserted into the fixture that align with holes within the PCB.

3D modeling software program may very well be used to mannequin the indented block together with all of the holes for pins, any holes for a latch mechanism to carry the board down, in addition to the legs and a cable entrance gap. Some modeling software program, Autodesk’s Fusion 360 for instance, can pull in a PCB design so the required holes for pogo and alignment pins may be simply situated and created within the block. The newer cheap LCD-based resin printers are able to making a clear 100 µm gap within the meeting and with some high-quality tuning of the slicer, a 50 µm gap must be possible. With these clear and correct holes, no drilling must be required. Word that FFF printers may be used, however because of its decrease decision, the minimal sensible gap is round 2 mm. This will work for much less dense PCBs.

Our buddies at Autodesk have created a video for us demonstrating the best way to design a bed-of-nails utilizing Fusion 360:

One other space that resin printers can excel is within the creation of optical gentle pipes. Many functions of sunshine pipes require a customized design to ship the LED gentle to a entrance panel. This will imply numerous bends or a number of pipes as one half for displaying assorted indicators. Creating gentle pipes has been tried utilizing FFF printers and clear filament with less-than-optimal outcomes. This resulted in both poor gentle transmission or important submit processing involving slicing and sharpening. However with resin printers, creating customized gentle pipes turns into very doable. Any configuration of sunshine pipe may be simply created in 3D modeling software program and by following a number of finest practices (such utilizing inner reflections within the design when bending). The sunshine pipe can be configured with information pins, snap match tabs, and even threads. Resin for the sunshine pipes is offered in away from translucent colours. 

Determine 1 reveals some easy gentle pipes that we’ve designed utilizing Fusion 360 and printed utilizing a Creality Halot One Plus resin printer. These gentle pipes have been designed for steering gentle from a 5 mm through-hole LED. (Downloads for the recordsdata for these gentle pipes can be found right here.) I’m at the moment experimenting with versatile resin printed gentle pipes that might be simpler to assemble into an enclosure. If profitable, I’ll submit them on the identical thingiverse web page.

Determine 1 Easy gentle pipes 3D printed utilizing a Creality Halot One Plus resin printer.

Word in Determine 1, there are two gentle pipes which might be nonetheless connected to helps which might be usually required to realize a profitable print. This can be a good time to notice that resin printing requires submit processing, the place FFF typically doesn’t, apart from eradicating helps. And as famous above, submit processing includes a cleansing operation, eradicating helps, after which curing.  None of those steps are tough nor take very lengthy however could be a bit messy.

Designing and printing the sunshine pipes in Determine 1 solely took a number of hours, so your subsequent undertaking received’t want to attend for weeks, or longer, for prototypes to check your gentle pipes for match, type and performance.

A few caveats for resin printers: the construct measurement tends to be smaller than FFF printers. Additionally, as acknowledged above, the resin may be messy and may have good air flow. Uncured UV resin mustn’t come into contact with pores and skin or eyes. UV curing usually requires a UV curing station, though outside publicity to daylight will remedy the half. 

As you possibly can see, two printers are higher than one, and I consider within the close to future all labs can have each FFF and resin printers. Then subsequent will come the metallic printers and hopefully, sometime, somebody will work out the best way to construct a printer that that makes a multilayer PCB from scratch.

Damian Bonicatto is a consulting engineer with a long time of expertise in embedded {hardware}, firmware and system design. He holds 30 patents.

Phoenix Bonicatto is a contract author.

Associated content material