In this project, I am going to give you a basic introduction to 3D printing pens and how to use them.

What is a 3D printing pen?

A 3D printing pen is like a handheld 3D printer. It uses the same kind of heating element and extruder that you would find on a desktop 3D printer. But instead of being controlled with computer software and motors, you guide the printer head by hand.

How Does it Work?

Like all 3D printing devices, a 3D printing pen works by heating a plastic filament to its melting point and forcing it through an extruder tip. This is very similar to how a hot glue gun works; the melted plastic is very soft and can be fused onto a surface or worked into any shape that you want. Once the melted plastic leaves the tip, it cools quickly. After a few seconds, the plastic hardens and holds whatever shape you have worked it into.

What Can You Do With a 3D pen?

These pens effectively allow you to draw with plastic. You can work the plastic into just about any shape and apply it to most surfaces. You can use it to add raised decorative designs to everyday objects. With practice, you can even make 3D drawings in empty space. These pens can also be used to modify and repair other 3D printed objects.

Project Steps

Select a 3D Printing Pen

There are several different types of 3D printing pens to choose from. Most of them follow the same basic design, but they all vary slightly in their features. When selecting a pen you should consider things like “What filaments can it use?”, “Are the temperature and speed settings adjustable?”, and “What accessories are available?” Here is a quick comparison of some of the more popular models.

3Doodler Cost: $99; Filament: ABS and PLA; Speed Settings: 2 speeds; Accessories: Interchangeable tips, stand

3D Air Pen Cost: $70; Filament: ABS; Speed Settings: 1 speed

3D Simo (Only available in Europe, Japan and South Korea.) Cost: $100; Filament: ABS, PLA, WOOD, HIPS, LAYbrick, Bendlay, Flexi; Speed Settings: Digitally Adjustable; Temperature Settings: Digitally Adjustable

3D Printer Pen (available in the Netherlands.) Cost: $88; Filament: ABS, PLA and HIPS; Speed Settings: 2 Speeds; Temperature Settings: Digitally Adjustable

Yaya 3D Pen Cost: $120; Filament: ABS; Speed Settings: 2 Speeds

CreoPop Cost: $119; Filament: uses light-sensitive photopolymers instead of melting plastic; Speed Settings: 1 speed; Temperature Settings: No heating elements. Polymers set with UV light; Accessories: Rechargeable Battery with USB charger

Other Models Currently in Development: 3Doodler 2.0; 3DFormer; Lix Pen

Set Up Your Pen

Before you can start printing, you need to do a few things to set up your pen.

Power On: Start by connecting the power supply to your pen and turning it on.

Select a Filament: Then select the filament that you want to print with. Make sure that your pen is designed to print with this kind of filament.

Select the Temperature Setting: If your pen is designed to work with different filaments, select the temperature setting that is appropriate for the filament that you are using. Wait a moment for the pen to heat up; most models will have an indicator light to tell you when it is hot enough to use.

Insert the Filament: Slide the filament into the filament input port. If you are inserting a previously used piece of filament, trim the end with a pair of scissors so that it is flat — this helps to prevent jamming. Once the filament is set all the way down into the pen, press the extrude button. You should feel the internal motor start to pull on the filament.

Select the Speed Setting: Select the fast setting and press the extrude button until the melted filament starts to come out of the tip of the pen. Then you can adjust the speed setting based on what and how you are printing.

Making 2D Sketches

The easiest kind of project to start with is using your pen to make 2D sketches out of plastic. This may sound like an odd application for a “3D pen,” but these sketches are different — you can pick them up off the paper when you are done.

First, select a nice clean surface to draw on. Paper works fairly well for this. You can also use a printed drawing as a stencil. You can find lots of stencils online.

To start a sketch, extrude a small bead of plastic onto the paper. This will be the initial anchor point. Then draw a line by slowly moving your pen across the paper while extruding plastic.

Keep the tip of the pen close to the paper so that the melted plastic is pressed onto the paper before it has a chance to cool. The hotter that the plastic is when it makes contact with the paper, the better it will stick. You want the whole line to be well adhered to the paper because many filaments will shrink as they cool and this can pull the plastic off of the paper and distort the shape.

At the end of a line, stop extruding plastic, but do not move the pen. Wait for few seconds to allow the plastic on the paper to cool. Then pull the pen away. This will leave a small point of plastic sticking out where the tip of the pen was. You can smooth these out by gently touching them with the side of the tip. The tip will remelt the point of plastic and squish it back into the line.

When you want to connect two lines, pause at the point where the lines meet. This will allow the heat from the tip to partially remelt the first line and make a stronger connection.

When your sketch is completed, gently peel it off of the paper. You can now use a knife or a pair of scissors to carefully trim off any rough edges. After doing this, if you feel that the lines of your sketch are still a little too rough, you can stick it in a toaster oven for a few minutes. Set the temperature to just above the melting point for your filament (320°F/160°C for PLA , 225°F/106°C for ABS). This will partially remelt the plastic and soften up the edges.

Assembling 3D Objects From 2D Sketches

The simplest way to make a three-dimensional object with a 3D printing pen is to assemble it from several two-dimensional sketches. As an example, I am making a simple Warren truss bridge.

Start by sketching out each of the sides. I used a stencil to help me keep the sides even.

Set the bottom piece in the middle of your work surface. Then hold up the first side piece next to it. Apply a small bead of plastic at points where the pieces come together. Locations with more exposed surface area are easier to stick together. I connected them at the corners of each triangle. If you want a stronger connection, you can apply a new line over the whole corner where the two pieces come together. Do this for each side piece of the model. Lastly, attach the top piece in the same way.

Once the overall shape is holding itself together, you can go back and add drops of plastic to reinforce any weak areas. To give the model a more finished look, go back and trim off any points that are sticking out with a pair of scissors or wire cutters. I do not recommend putting a three dimensional shape into a toaster like you might do with a two dimensional sketch, because the shape will probably warp.

Creating Freehand 3D Objects in Space

The ability to make freehand drawings is space is probably the most celebrated feature of the 3D printing pen. It is also the most difficult. Making drawings in empty space is extremely difficult. You will need to practice quite a lot before you can make nice shapes like the ones that you see in the advertisements. So don’t be discouraged if your first attempts don’t look very good.

To begin a 3D sketch, you need to start with a solid anchor point. Make a large dot of plastic on the paper. Then slowly lift the pen into the air while extruding at the slow speed. You need to move your hand at the same speed that the extruder pushes out the plastic.

To make a straight line, hold the body of the pen in line with the plastic and very gently pull on it. A small amount of tension will keep the line of plastic straight while it cools. When you reach the point where you want the line to end, stop extruding plastic and hold the pen still for a few seconds. The plastic needs to cool and resolidify before it can support its own weight. You can help the plastic to cool more quickly by gently blowing on it or by having a small fan pointed at your work area. Once the plastic has hardened, pull the pen away. The melted plastic in the nozzle may leave a small point or trail off in a string from the pen. You can just trim this off with scissors or wire cutters.

Making a curved line is more difficult. Again, start by making a thick bead on the paper to use as an anchor point. Lift up the pen from the paper while extruding at the slow speed setting. Move the pen in the direction that you want the plastic to initially go as if you were making a straight line. Once you have extruded about an inch of plastic, stop. As the plastic begins to cool you need to move it into the appropriate shape. You can speed up the cooling process by gently blowing on the plastic or by having a small fan pointed at your work space. Once the first bit of plastic has been worked into the appropriate shape, extrude another inch and shape that section. Continue this process until you have completed a large section. You will eventually need to create another anchor point because there is only so much weight that one point can support.

When you want to join two pieces of plastic, hold the pen at the junction for a few seconds. This will allow the heat from the tip to partially remelt the first piece and fuse the two sections of plastic together.

The most difficult part of creating freehand sketches in space is working at the right speed. You need to move your hand at the same speed that the extruder puts out the plastic, or else it will sag. You have to move the pen around to shape the plastic as it is cooling, so you need to intuitively know how quickly the plastic will cool and solidify. This takes a lot practice to get down.

Modifying and Repairing Other Plastic Objects

3D printing pens can also be used to modify and repair other plastic objects. The melted plastic that comes out of 3D printing pen can bond to most surfaces, but it bonds most effectively to other thermoplastics. The heat from the tip and the melted filament is able to melt the surface of the other plastic and fuse the two plastics together. This works especially well if the surface being modified is the same type of plastic as the filament.

Because of this, a 3D printing pen is ideal for modifying and repairing other 3D printed objects. If you have an object that was created on a desktop 3D printer, you can use the pen to add details to it. The pen is able to move around and print in any orientation. This lets you do things that would be impossible for a fixed-axis printer.

You can use the pen to repair objects that are cracked or chipped. Just hold the tip of the pen close to the surface. Then, extrude a small amount of plastic directly into the crack. Use the tip to work it into crack and then smooth it out. Wait long enough for the heat from the pen melt the surface. Any repairs that you make will not look perfect, but they will strengthen the object and make it more functional.

Look for everyday objects that are made of the same material as your filament. For example, ABS is used in Legos, Monitor/TV cases, coffee makers, cell phone cases, and most computer plastic. ABS is often labeled with recycle code #9 or ABS.

Legos are particularly fun to work with. You can add decorative details to your play sets, or give your Lego figures custom hair. You can make your own free-form pieces that will attach to the blocks. You can even use it to permanently fuse pieces together.