Prototyping what was once impossible

Case Study: Prototyping The Impossible

One of the coolest things in modern rapid prototyping is the ability to build (what was) impossible.  Now the 3D printing complex parts and features are the things we could only dream of previously.  Now they are so easy.  Best of all, the parts are completely functional, not just for show.

Years ago, we used fragile prototypes (early SLA) to show concepts and generate better processes.  It was game changing, but mostly in understanding, not for production.  Even now as abilities evolve, most prototyping continues to represent things to produce in traditional ways - like injection molding, casting, forging or machining.  For these processes, impossible features are still a constraint.

While that is still the lion's share, there are more and more places where 3D printing complex parts brings the impossible into production.  It is slowly taking over.  This is particularly true where budgets are large (ex. military aircraft), or volumes are small (ex. custom machines).  So, that is why we are here today.

Gotta Love Prototype Day

For a new custom machine we are building, the once impossible features come in handy for creative 3D printing complex parts.  The process for custom machines often includes development phases where the original ideas don't pan out.  That is most true when dealing with irregular parts or actions where we can't predict behavior.  As we work with them, we gain understanding, which leads us to improve the processes.

Blended multifunction 3D Printing Complex Parts in MJF prototypingThat is exactly the case with some of these parts.  After learning by doing on the custom machine, the product taught us what to expect, and how to handle it.  The solution brings some changes in the machine, as well as new thinking about some key parts.

The part shown here is a cool example.  Originally it was a welded steel tube - straight, simple, easy - with a sensor port on the side.  Changes for improved machine function require a side flow port and a long entry sensor tube.  Yes, the part has a lot going on, but we can 3D print complex parts, so why not make this all into one part with MJF (Multi-Jet Fusion) so it is totally functional?

And there it is.  Works like magic.

From a construction perspective, there is nothing impossible in this part, yet building without 3D printing is so much more of a chore.  Prototyping makes it quick, easy and much less expensive than fabrication.  That's a big plus.

3D Printing Complex Parts Makes Impossible, Possible

Another part comes to life easily.  Again, when convoluted shapes are the need, 3D printing complex parts makes features that are impossible with most methods, easy.  The part spirals around a motor body (see photo below), and includes slots to capture the bands.  On the inside, in the flow areas, ribbing and slots come in perfect - just like the artistic 3D Cad model.  (While the intention is not art, it does have an artistic flair.)

The fun part?  These complex features make assembly and setup a breeze, and they function so perfectly.  They add a pretty simple function into the machine where space is tight.  By allowing the flow to spiral around the motor it gives access at the point of need, and clearance for other component motion.

Artistic, Prototyping Impossible Features.Easy InstallationThe material is superb, and this will function with the machine for years to come.  It is strong enough, and stable enough to perform the duties long term.

Add this to the "Why do we make prototypes" list.  These are full production tools, but we call them prototypes because they exist only once, and the build is 3D printing complex parts.

We will add impossible features as a powerful advantage for using the rapid technologies of "3D Printing".  On the one hand it is amazingly complex, and on the other, it is so simple.

Think about how we could make similar parts if 3D Printing was not around.  To our thinking, this is a lot more complex to make with sheetmetal or other plastics.  How would you make it?

For this application, prototyping the impossible is the Elegant Solution.

Easily Complex

For the aircraft industry, military aircraft in particular, we have created some really crazy molds to make complex parts.  Some large, some small.  Today, those crazy molding skills are not as needed.  When it comes to complex parts, now we just print them with whatever details they need.  The surface finish is not as good, and there are other visual deficiencies, but 3D printing complex parts really changes the game.

It is so easy to make some areas thicker, some thinner and never worry about the mold shrink, draft release, or other traditional mold issues.

Are they as strong?  That is a trick question. Information from vendors varies a little, but most say the MJF parts approach 75% of full molded plastic strength.  Some post processing is required for the numbers, but in general, these parts are really tough.

So, No, the material is not as strong, but add a little in the right places, then yes, it is. You can manipulate part design to easily add material where needed, while thinning other areas where the extra material is not needed.

MJF also has some properties that are valuable in a other ways.  It is quite abrasion resistant, manifest because it doesn't like sanding or files.  This resistance makes it great for some places where other materials won't work as well.  It also makes them hard to finesse for fitting parts together.

Fear No Impossible Prototype Parts

I admit, using the word "Impossible" with "Prototyping" leads to a misnomer.  Nothing is truly impossible with any of these parts.  While they are pretty cool, they are nothing like the crazy prototypes others have made.

Quick 3D Printing Complex PartsIn the past it was much more involved to create such features, and in most cases, building parts similar is a fabrication assembly.  More to the point, if these rapid prototyping methods were not available, we would use a different thought process entirely for these areas of machine design.  It would not be as elegant, that is for sure.

That said, these methods certainly do allow complex geometry to come to life quickly and easily.  And, I might add, fairly cheaply.  Many use it in artistic presentation, and others as show-n-tell.  Yet, as we see it here, these 3D printing complex parts are great for functional features.  This machine is in production.

The example here is a for a custom machine, yet the process is product development.  The product is the machine, and thus as we discover better ways, we rely on 3D printing complex parts to solve problems - FAST.  To us, it is all part of the excitement in engineering.

Getting Them Made

Please note:  the MJF process and the strengths and uses above are not from a home style 3D printer.  Home printers have a place, and I have no doubt, as technology advances, better things will come as a reality.  But, not quite yet.

For these kinds of parts, we recommend hiring a prototyping facility.  They know their machines, and they can produce such parts in just a couple days.  I think these were 4 days - which includes quoting and express shipping.

There are plenty of providers who make prototypes, but watch carefully.  Prices vary a lot.  Maybe they quote less when they are slow, and more if they are full?  I don't know.  Check around.

For further reading, here is another build method to fit a different need.

Good Luck as you build with 3D printing complex parts.  See you next Prototype Day!

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