- No products in the cart.
24 Nov 3D Printed Animatronic Eye Mechanism
Print Your Own Animatronic Eye Mechanism
Our challenge was to design a 3D printable version of the animatronic eye mechanism. Obviously we would need some non printed parts, such as a couple servos and some nuts and bolts, but everything else could be 3D printed. By choosing a range of Polymaker filaments, you can create a very efficient system, with each individual part working beautifully alongside the next. The result is a captivating set of life like eyes.
In this article, We’ll explain how to print and assemble your very own animatronic eye mechanism. All .STL files are available at Polymaker’s Thingiverse account. Watch the Eye Mech in action Above or on our YouTube Channel. There is also a step by step tutorial video and assembly video at the end of this article or alternatively you can watch them on our YouTube Channel. The design of this mechanism is dedicated to desktop extrusion based 3D printing, so all parts have been designed with quick & easy printing in mind. There are two servo motors which control the movement of the eyes and two pivots which copy and transfer the energy synchronising the eye movement. One servo for controlling the X movements (left and right) and another servo for controlling the Y movements (up and down).
To get the full range of movement out of the servos and extend their lifetime, We decided to use a ball bearing to transfer the energy to both eyes. In this set up one servo is located right behind the eye and is directly driven by the motor. To enable both eyes to move in tandem, the second eye is linked indirectly and the power is transferred through a connecting rod and a bearing. By using a bearing, it greatly reduces friction and ensures that the energy is transferred in a linear motion. The design of the Pivots has allocated space to encompass the 13mm bearing. Simply pause your print when the print at 80% completion, then drop the bearing into the gap and resume your build. Wait until enough plastic is built up around where the bearing is going before inserting the bearing. This will minimise the chance of your printer getting damaged by the nozzle dragging over the bearing during a travel movement. Once the print is finished you should have a well secured bearing in your 3D printed part.
The PolyFlex couplings that link the conrods to the eyes are the secret behind the eye mechanism. Only a flexible material can be used for this part. The part is designed to be flexible in every direction much like a universal joint, while still strong enough to push, pull and manipulate the eyeball accordingly. However, the flexibility of this part is vastly affected by the infill chosen when printing. In the end we were printing the coupling at 0% infill with 2 shells which we found to be a perfect balance between flexibility and stiffness. Any more infill on the coupling and it started to drain power from the servos whilst limiting the range of movement. Any less shells and the part would delaminate at the stress points. Its the shape of the coupling which provides the flexibility and an internal structure to stop it collapsing in on itself.
For added effect the eyeball was printed with three different colours changing the filament at increments to create the colours of an eye. For the base of the eye I used white PolyMax this is 85% of the print. As the white is reaching the top of the hemisphere, I paused the print to change the filament to PolyPlus translucent blue and then again to PolyPlus black to create a pupil for the final 4 or 5 layers (99%).
Once all the components are printed you can start to assemble your rig. Start by inserting the long M4x45mm bolt through the 4mmØ stack in the corner of the board and secure it with a nut. Then screw another nut on top and leave it floating half way up the thread. This nut will be used as a shelf to match the height of the servo when levelling off your mechanism. Then repeat this step with the shorter M4x25mm bolt in the corresponding hole. After this step bolt the sockets onto the board using the M3x12mm bolts and M3 nuts. Next bolt the servos into the board, note how the X servo is bottom mounted and the Y servo is top mounted. You may have to shave a small support of plastic off the bottom mounted servo to allow it to lay flat against the board. Make sure the orientation of the servo is correct. The centre of the servo arm should line up directly behind the socket. The Y Servo is bolted through the top of the board. There is a small notch to allow the wires to pass through the board, this should also help with orientation. Once the servos are mounted in the board, plug in the wires and turn on your remote control. This will zero the servos and set them in their natural resting position. Make sure the trim on your R/C is also centred as you can use this to make fine adjustments on the rig when assembled. After zeroing the servos, choose the four armed servo arm and orientate the servo arm so it runs parallel with the edges of the board.
Next start assembling the 3D printed parts. Insert the pins and ball into the back of the eyeballs. If you are struggling to fit the pins into their slots, try gently heating the tip with a hairdryer or heat gun before inserting, this should help the plastic soften and ensure a tight tolerance for a glue free tight fit. Twist the couplings onto the pins and assemble all the conrods, pivots and servo arm extensions. These all bolt together with the M2 bolts and the printed parts push fit together. Once you have all the pivots, conrods and eyes assembled, you can mount them onto the board. Start by clicking the balls into their sockets and then screw the servo arm extensions onto the servos. Now adjust the floating M4 nuts so that your pivots and servos are at the same height from the board, the conrods and board should also be in parallel. Secure the pivots with another M4 nut on top of the bearing and your eye mechanism is now assembled. Plug your servos and battery into your transmitter, turn on the R/C and make minor adjustments with the trim to centre the eyes. If your eyes are slightly askew, pull or push the couplings and pins until both eyes are synchronised.
Now your seemingly inanimate plastic 3D printed parts spring to life! Hopefully this introduction into animatronics can inspire you to design your own mech, or improve on my design. To follow the step by step tutorial and assembly of this project, either view the videos below or visit our YouTube Channel