FUN-damentals of 3D printing

This article will have super fun info, on the basics of 3D printing

3D printing has actually been around for a hot minute — way longer than I’ve been alive 😉. Your knowledge of 3D printing is probably that it can print out some pretty dope superhero figurines. Spoiler: it can do cooler things than print Spiderman.

3D printing, aka additive manufacturing, is powerful. I’ll explain the *pizzaz* in a sec, but let’s take a second to throw it back to whenever Michelangelo was alive, carving the “David”. David wasn’t always iconic. In fact, at one point David was pretty square… literally …(I hope people got the joke).

more rectangular but you get my point

And Mickey-B was just chipping away the block of cement until he created the desired David. This approach wastes tons of materials and also takes a long time.

David looks concerned AF

Subtractive manufacturing is not in.

3D printing will transform everything. It will use less time, money and materials. Just to dip your toes in some applications…

• temporary housing during disasters
• Food printed customized to your exact nutritional needs
• Fixing heavily damaged forensic evidence (e.g. bones)
• Medical devices, prosthetics and machinery parts
• Furniture because shipping takes too long

…

We always jolt around with fun phrases like “creating the future” , 3D printing is literally doing that.

Let’s talk about how.

The name 3D printing is a bit of a fraud. 3D printing is just 2D printing over and over again. #exposed

In order to “3D” print something we have to first…

1. Design it (duh) into a 3D model
2. Slice the model (break it down into 2D layers)
3. Print each of the 2D layers on top of each other (using a printing technique)

There are 7 different 3D printing techniques.

Let’s start with a fun one:

Vat Photopolymerisation (VPP)

Woahhh BIG word.

Vat = container

Photo = light

Polymer = large molecule with many repeated subunits (called monomers)

E.g., [ so so so so so so so so so so so so so] is a polymer (a large chain of repeated “so” units).

Photopolymer = polymer that changes properties when exposed to light

So Vat Photopolymerisation works by starting with a container (vat) of liquid photopolymer resin. We also have a laser.

When the laser hits the resin, it hardens (also known as curing). Otherwise, it stays liquid.

Think of one of the fun pillows that change colours based on how one’s hand pushes the sequins.

We can draw fun shapes! The hand is like the UV laser, and the pillow is like the resin, it has one of two states (silver or pink… or really liquid/solid).

VPP works by creating the desired shape of a layer (by curing), and stacking all the layers.

As the printer hardens each layer, there is a platform that moves, exposing a new layer.

The liquid hardens because the light activates the monomers (subunits of polymer material) to create unbreakable bonds. This makes the material solid forever, aka thermoset. If you tried to melt the material back down to the liquid resin, it would burn.

The machine uses a laser + mirror, to cure the material (orange) and add it to the 3D part (blue)

There are different VPP machines, which vary based on the light (hardening) source used.

• SLA uses UV
• DLP uses light bulbs
• CLIP uses UV and Oxygen PS. CLIP is super fancy and cool. It’s 25–100X faster than traditional methods, article coming soon.

TL;DR — Vat photopolymerization takes a liquid material and uses light to harden liquid layer into a specific shape, then stacks many layers.

Material Jetting

MJ is similar to Vat photopolymerization, except it doesn’t use a vat of liquid; it exposes the polymer a few hundred drops at a time.

It can also use more than one material. VPP starts out with all its material in a bucket (vat). But MJ continuously adds materials as it’s printing.

In printing, ‘cured’ means that a non-solid material is solidified. Material jetting sprays some liquid material, and then use UV or another light to cure the material, creating a new layer.

Let’s pretend water turns into an ice cube when a laser is shot at it (literally the opposite of what would happen but just pretend).

A material jetting printer would have a platform, and it would spray droplets of water onto it. Simultaneously, there would be a laser, selectively turning the water into ice (curing it). Once enough water has been cured, the platform moves down, and we repeat:

1. Spray material + cure using laser
2. Move platform downwards (to make room for the new layer)

The Blue parts are the UV light (to cure) and the inkjet (where the material liquid drops come out)

MJ is awesome at quick prototyping, with tons of details. It’s also called photo plastic printing,(Ah! Photo again… because it uses light to create different plastics.)

Binder Jetting

Binder jetting uses liquids to join powders, and turn them solid.

Steps:

1. Lay powder on the base
2. selectively drop a binder (glue/liquid), on the parts of the powder that we want hardened
3. repeat

Similar to how VPP uses light to turn liquid solid. This time, we’re turning powders solid with a liquid.

It’s one of the only printing processes that doesn’t use heat, which helps make the objects stronger.

The power bed moves down, so more layers of powder can be added on. Inkjet printheads dispose the “binding” material.

Power bed fusion

Instead of fusing powder with liquid, power bed uses heat (or lasers) to fuse powders. Note: this technique is mainly used for 3D printing metals

A heat source selectively heats powders until they’re hardened to the desired shape.

Steps:

1. Set layer of powder
2. Use thermal energy to fuse some powders (the unfused powders are removed after the printing process)
3. repeat

The diagram is identical to binder jetting, except instead of liquids it’s a laser 😎

Material Extrusion

The most common type of 3D printer is a Dused Deposition modeling (FDM) machine. It’s the concept of stacking icing, but with other materials instead.

This printer uses a nozzle to warm and pour out materials and then they solidify.

Directed Energy Deposition

This one just looks cool. It’s like Material Extrusion but 10x cooler. It has a fancier nozzle.

As the material is seeping of out the nozzle, there’s a laser, which uses thermal energy to add a new layer to an object.

The material (Labeled as powder)travels to the spout, and as it seeps out, the laser joins the party, which helps build a new layer.

In action 🚀… bob the builder would be jealous ;)

Sheet Lamination

3D printers combine a bunch of 2D printed layers. Sheet lamination combines thin sheets into 3D objects.

While stacking sheets, the printer uses a laser to put it in the correct shape.

So the steps are

1. Add a new sheet
2. Use a laser to shape the sheet
3. Repeat

WOW, so you’re basically all set for all the main types of 3D printing and how they work. This technology is changing the way the world is being built.

To recap:

1. Vat photopolymerization = using a light to cure (solidify) a vat(bucket) of liquid resin (pre-solid material)
2. Material jetting = using light & droplets of liquid jetting to print
3. Binder jetting = using a liquid (glue) to cure powders
4. Power bed fusion = using thermal energy to cure powders into metal
5. Material extrusion = icing approach of melting a material, disposing of it in a nozzle, and then letting it solidify
6. Directed energy disposition = material extrusion but with more thermal energy
7. Sheet lamination = stacking many thin sheets together

Using these methods we can 3D print medical supplies, space stations and fabrics… the opportunities are endless 😍

Stay tuned for more content on CAD software, 3D printing projects, 3D printing materials & applications.

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