3D Printed Kinetic Sculpture

While browsing the internet, I came across something called “kinetic sculpture”. After watching some fascinating designs on the internet, I decided to make one for myself.

Whereas, a kinetic art may be powered by the energies of wind, liquids, magnets, motor etc. Most of the sculptures that I saw were powered by controlled release of energy from a spring. But it needed to be cranked up again, once the energy of the spring was exhausted.

I wanted to make a kinetic sculpture which:

1. Could be mostly 3D printed.

2. Is powered by a motor.

3. Has variable rotation speed.

4. Looks good even in static condition.

The sculpture is mostly 3D printed, except for the bearings, screws and nuts. It is driven by a motor (which was removed from a broken CD drive) using belt (rubber band) interface. The motor is powered by a 9V battery. The battery is replaceable. I used a PWM speed controller to achieve variable motor speeds. The sculpture diameter is 500mm approximately.

Tools and equipment’s

3D printer

Soldering iron

Wire cutter

Allen key 4mm

Screw driver

Consumables

PLA filament (500gm approximately)

M8 threaded bolt 100mm long (1 no.)

Bearing (603-2z – 1no.)

Bearing(6301z – 2nos.)

M5x20 socket head screw (2 nos.)

M5 nut (2 nos.)

Super glue

9v Battery

PWM speed controller

Wires

Flat head drywall screw (4 nos.)

For 3D designing, I used “Sketchup” and for slicing the stl files, I used “Cura”.

Initially I designed only the sculpture, assuming that the sculpture would rotate on the 8mm bolt. But it was a mistake to not plan the whole idea beforehand. Which is explained later in the instructable.

I created separate STL files for different parts of the sculpture, and printed them separately.

Each part has very small area of contact with the other part. Hence, I had to design a template which would hold the sculpture together, once glued. The template also acted as a guide to achieve the shape as desired from the design.

Parts of first sculpture were glued onto the template using super glue (any Cyanoacrylate glue) to create 1 leaf and subsequently 8 leaves of first sculpture.

CAUTION: Please wear gloves while handling the glue, as you might glue your fingers accidentally. I had a tough time while doing this activity.

NOTE: Ensure to put enough glue while joining parts, also between the edges and at the corners as shown in the image. You don’t want the sculpture to fall apart while rotating.

The leave's were then joined to the central circular part to complete first sculpture. Similarly, the second sculpture was completed.

NOTE: 1. While putting the second sculpture together, it should be remembered that the templates and central circular part are to be glued in opposite direction to the first sculpture.

2. Somehow the super glue and PLA material react, to produce a whitening effect on the surface of the glued parts. In order to avoid this, you may use other type of glue, or simply clean the whitened surface using a brush and some oil (I used coconut hair oil). It works very well.

After completing both the sculptures, I tried inserting them on the 8mm bolt and rotated them manually. The sculptures started to wobble badly. This is when I realized that I should have planned everything thoroughly beforehand. Then, I had to introduce bearings in my design.

A two piece bearing housing was designed. Wherein, one piece fits firmly inside the bearing and then screwed onto the bolt. While the other piece holds the bearing on the outside, which will be further glued to the sculpture. The outer piece was designed with a groove which would act like a pulley for belt drive mechanism.

One bearing holder was affixed on the front side of first sculpture, while the other was affixed on the rear side of the second sculpture.

NOTE: The bearing and bearing holders have to be fixed onto the bolt initially. Then the sculpture has to be inserted on-to the bolt, to glue the holder and sculpture together. This ensures that the bearing holder is almost exactly at the centre of the sculpture.

This step includes designing, printing and assembly of

• The bevel gears and
• The motor drive.

But i separated them out in order to accommodate for the images and for better understanding.

Since only one motor was used to drive the 1st sculpture, Some mechanism was required to rotate the second sculpture in opposite direction at same speed.

This was realized using three bevel gears. Wherein, one bevel gear was affixed to the centre of each sculpture (on the opposite face to that of the bearing holder). The third bevel gear was attached on the bolt at 90 degrees w.r.t. the sculpture face which acted as an interface between the two sculptures. Third bevel transferred power from the first to the second sculpture and thus rotate the second sculpture in opposite direction.

For smooth rotation of the interface bevel, I used “603-2z” bearing. Designed an attachment to mount the interface bevel on the bolt. The attachment was fastened to the bolt using M5x20 socket head screw and nut.

Designed a two-piece motor holder. Wherein, one piece is screwed onto the 8mm bolt and the second piece slides onto the first. The second piece is held in place using M5x20 socket head screw and nut.

NOTE: The motor depicted in the above image, was the initial choice. This motor didn’t work as desired, therefore, I changed the motor to the one shown in the next step.

After integrating the sculpture and bevel gear on the bolt, I found out that the length of the bolt was short. It wasn’t long enough to be mounted on the wall.

Unfortunately, I didn’t have another bolt longer than this. So, I had to design an attachment to elongate the bolt. Also the assembly had to be dis-assembled and assembled again after fitting the attachment. The designed attachment was screwed onto the 8mm bolt.

I used a 9volt battery, a motor from a discarded CD drive, PWM (Pulse width modulation) circuit and few wires for the drive mechanism circuit. I bought the PWM circuit online.

Connections to the motor are soldered while the connections for 9V battery are snap-in type, and the PCB has a terminal block.

A housing for battery and a PCB holder were also designed and printed.

The whole sculpture assembly was integrated on the 8mm rod. This was to be mounted on the wall using a wall mount bracket.

The bracket was affixed to the wall using four “flat head dry wall screws”. The battery housing was glued to this bracket and the PCB holder was glued on top of the battery housing.

After mounting the bracket, whole assembly along with the bolt was screwed in the wall bracket hole. This step completes the making of the “Kinetic sculpture”.

NOTE: 1. Insert the belt for belt drive before mounting the sculpture on the wall mount bracket.

2. Rotary switch of the PWM PCB already had a toggle function to turn the motor On & OFF. Hence there was no need for a separate toggle switch.

That’s it….

It took me quite a few days to complete the whole thing. Hit a few roadblocks. But after watching it function and create the illusion. I think it was worth it.

If you wish to make a similar Kinetic sculpture, I have provided the stl files below.

But I think I made a complicated design by trying to create something different. Which in turn increased the efforts and time required. A simple and rather better design can be created (I will try and create some, but not so soon). Of course you can avoid the mistakes that I did by planning the whole idea beforehand if you wish to make something different.