3D printed GearBox

Greetings, everyone!

I'm excited to introduce my newest creation—a 3D-printed gearbox!

In order to prepare for an upcoming kinetic sculpture project, the objective of this project was to construct a functioning gearbox with two output shafts that spin in opposing directions.

To generate spur gears, we installed an addon or extension in Fusion360 called GF GEAR GENERATOR. The gears are then organized so that they can output two shafts, each of which rotates in the opposite direction.

We have utilized 3D printing for the gearbox's body and even the gears themselves.

About electronics, we created a driver board from scratch up using an H-bridge configuration paired with a microcontroller that regulates the motor's rotation. The microcontroller and motor are powered by an inbuilt lithium cell, which is yet another component of the driver.

Originally, I intended to combine the gearbox and kinetic sculpture into a single part, but it would have been too lengthy, so I split the articles into two: one for the gearbox and one for the kinetic sculpture. The gearbox construction process is the primary subject of this article.

Materials Required

These were the materials required in this project:

• Custom Circuit (provided by Seeed Studio Fusion)
• IP5306
• 10uF 1206 SMD Capacitors
• USB Port Type B micro
• 1uH Inductor SMD
• Li-ion cell
• Li-ion cell 18650 Cell holder
• Right-angle Push Button
• Indicator LEDs SMD 0805 Package
• 1K Resistor
• 10K Resistor

Design

Using the GF Gear Plugin, which will be explained in the Gear Setup Step, we first generate gears to begin designing the model.

Following the creation of gears, we constructed a three-layer enclosure around them. The top layer encloses all of the gears in place and has an opening that outputs the rotation produced by gear sets, while the middle layer is the layer onto which we fastened all of the gears using M6 bolts.

The small-gear DC motor, whose shaft is attached to gear A, is also located in the midlayer.

The bottom layer provides a stable foundation for the gearbox and holds the circuit.

We separated the three layers using specially made spacers, and we have fastened them all together with M6 bolts that are 75 mm long.

We used an Ender3 printer with a 0.5mm nozzle, 50% Gyroid Infill (for strength), orange PLA for the three layers, and black PLA for the gears and spacers. We exported all three layers, together with the gears and spacers, into a mesh file and 3D printed them.

Gear Setup

Two sets of gears are used in the model; one set rotates in a clockwise direction, while the second set rotates counterclockwise. Spur gears make up both sets, which were all produced using Fusion360's GF GEAR plugin.

Gear D from one set and Gear A from the other set are connected in the two sets; we modeled both sets so that Gear D can be placed on top of Gear A. Both gears revolve in the same direction because Gear A is attached to the motor.

GEAR SET 1-CLOCKWISE

Set 1 contains the Main Gear A, a 10-teeth spur gear with a 4 mm modulus. The modulus here is the size of the gear teeth.

In order to accommodate Gear D, we have modeled a holder that sits atop Gear A and functions similarly to a key socket.

Gear B, which is the same size as Gear A but is only modeled to transfer rotation from Main Gear A to Gear C, comes next in Set 1. This is the Idler gear, or gear B. The idler gear's main job is to transfer motion from gear A to gear C; it does not alter rotational speed or direction.

Gear C, a 15-teeth, 4mm modulus gear with a shaft in the center, is the rotation output gear. Out rotation will be transferred via this shaft.

Gears A, B, and C revolve in clockwise, counterclockwise, and clockwise directions, respectively.

This setup is useful for maintaining the same rotational direction between the input and output gears while transmitting motion over a distance. It is commonly used in various mechanical systems to manage space constraints and achieve desired mechanical advantages.

GEAR SET 2-ANTICLOCKWISE

In Gear Set 2, we have only two gears, Gear D and Gear E.

Here, Gear D serves as the input gear, receiving rotation from the lower Gear A that it is fitted onto. Gear D can be placed on top of Gear A to fit in position since it has a slot in the middle. The clockwise direction of rotation is the same for both Gear D and Gear A.

Gear D transfers rotation to gear E, which rotates in a counterclockwise direction.

Gear C from Set 1 and Gear E are positioned on top of each other and share the same rotational axis; Gear C rotates in a clockwise direction while Gear E rotates counterclockwise.

Circuit Construction

Regarding the circuit for this project, we created a custom board that uses a 3.7V 2000mAh Li-ion cell as the power source and an XIAO SAMD21 M0 microcontroller to drive a simple H bridge setup made with four N channel Mosfet AO4406. We utilize the IP5306 Power Management IC, which has low cut, high cut, and fuel indication functions, to properly charge and discharge the cell.

Additionally, we attached two indicator LEDs to the XIAO's GPIO D2 and D3. These LEDs will be used in code to inform the user of the motor's rotation; the first LED will illuminate if the gears are turning clockwise, and the second LED will illuminate if the gears are turning counterclockwise.

Let's have a closer look at the H bridge we have constructed.

Four A04406 N-channel Mosfet ICs, which were available in the Soic8 package, are utilized in this. The microcontroller controls the Mosfet's gate.

The Mosfet is marked in the schematic as Q4, Q5, Q3, and Q6.

We placed a DC motor between the mosfets. Basically, we can regulate the motor polarity, which causes it to vary its spin depending on which mosfet configuration is being operate, by setting up the H bridge and regulating the current flow by turning on the mosfet's gate.

We finalized the schematic and created the board file by following the dimensions from Cad model.

The USB Type C port, switch, CON2 JST connection, and lithium cell holder were all positioned on the top side of the board, while all of the SMD components were positioned on the bottom.

Seeed Studio Fusion Service

After finalizing the PCB, we exported its Gerber data and sent them to Seeed Studio Fusion for samples.

An order was placed for Red Solder mask PCB.

PCBs were received in a week, and their quality was super good considering the rate, which was also pretty low.

Seeed Fusion PCBService offers one-stop prototyping for PCB manufacture and PCB assembly, and as a result, they produce superior-quality PCBs and fast turnkey PCBAs within 7 working days.

Seeed Studio Fusion PCB Assembly Service takes care of the entire fabrication process, from Seeed Studio Fusion Agile manufacturing and hardware customization to parts sourcing, assembly, and testing services, so you can be sure that they are getting a quality product.

After gauging market interest and verifying a working prototype, Seeed Propagate Service can help you bring the product to market with professional guidance and a strong network of connections.

PCB Assembly Process

• Using a solder paste dispensing needle, we apply solder paste to each SMD component pad to begin the PCB assembly process.
• Next, we added all the SMD components in their place using a ESD Tweeser.
• The circuit was then placed on the Reflow Hotplate, which heats the PCB from below to the solder paste melting temperature. All SMD components are connected to their pads as soon as the PCB reaches the solder paste melting temperature, which is typically 200° C.
• Turning the Board over, we started the THT Components assembly by first placing the Lithium ion cell holder using a solder iron.
• Next, we solder the pads to secure the other THT components, such as the switch, JST connection, and USB Type C port, in their proper locations.

Power Source

We utilized a 3.7V 2000mAh Li-ion cell as the power supply, which was connected to the lithium cell holder in the proper polarity.

After pressing the ON button and the device turns on, we measure the output voltage with a multimeter and observe that it is 5.1V, indicating that the circuit is working.

CODE and DRY RUN

We attached an XIAO M0 microcontroller to the circuit and uploaded the code below to see if it worked or not.

The JST wire connector for the motor is then inserted into the circuit JST connector.

const int motorPin1 = 0; // Pin connected to H-bridge input 1
const int motorPin2 = 1; // Pin connected to H-bridge input 2
const int ledCW = 3; // Pin connected to LED for clockwise direction
const int ledCCW = 4; // Pin connected to LED for counterclockwise direction
void setup() {
pinMode(motorPin1, OUTPUT);
pinMode(motorPin2, OUTPUT);
pinMode(ledCW, OUTPUT);
pinMode(ledCCW, OUTPUT);
}
void loop() {
// Turn motor ON in one direction (clockwise)
digitalWrite(motorPin1, HIGH);
digitalWrite(motorPin2, LOW);
digitalWrite(ledCW, HIGH); // Turn on CW LED
digitalWrite(ledCCW, LOW); // Turn off CCW LED
delay(3000); // Wait for 3 seconds
// Change direction (counterclockwise)
digitalWrite(motorPin1, LOW);
digitalWrite(motorPin2, HIGH);
digitalWrite(ledCW, LOW); // Turn off CW LED
digitalWrite(ledCCW, HIGH); // Turn on CCW LED
delay(3000); // Wait for 3 seconds
}

This code controls an H-bridge motor driver to turn a motor in clockwise and counterclockwise directions for 3 seconds each. LEDs indicate the direction of the motor's rotation, with ledCW lighting up for clockwise and ledCCW lighting up for counterclockwise.

The system is turned on and the motor begins to spin in a single direction after the power button is pressed. After three seconds, it reverses course for an additional three seconds, repeating the cycle.

Now that the circuit is operational, we may proceed with the gearbox body assembly procedure.

GEARBOX CONSTRUCTION Process: MID SECTION

• Let us begin with the midsection assembly, which starts with the DC gear motor being inserted into the Gear Motor Holder part.
• The motor stopper, a tiny part that holds the motor in place, is then used. It is tightened with two M2 screws on the midsection.
• The Gear A is now attached to the motor shaft.

MID SECTION: GEAR ASSEMBLY

• Now that we have the gear assembly, we put the first set of gears—which contained gears A, B, and C—into position first, followed by set two, which included gears D and E.
• We install the top layer part, which has openings for the input and output gears as well as for Gear B, to secure all of the gears in place.
• To keep Gear B in place, we fastened it with an M6 bolt.
• We attached the 3D printed spacers from the four sides, which would be positioned between the middle and top layers. M6 bolts were used to put them in place.

BOTTOM SECTION: CIRCUIT ASSEMBLY

On the Bottom layer, we position the circuit and secure it in place using Three M2 Screws.

GEAR ASSEMBLY & BOTTOM SECTION ASSEMBLY

• First, we connect the JST wire connector of the DC motor to the JST connector on the circuit to begin combining the Mid Gear assembly and the bottom layer.
• After attaching the 3D-printed spacers to the M6 bolts, we positioned the bottom layer and used four M6 nuts to secure it.
• The gearbox assembly is finished.

RESULT

The finished product of this build is a functional Gearbox 3D. Made from scratch, we used only 3D-printed gears in this build, and since there is tolerance between the gear and the body, they operate smoothly. No bearings were needed. Bearings for individual gears can be used to smooth things out and reduce the frictional losses, but that is a topic for a later update.

For now this project is working and can be totally powered by the onboard lithium cell.

WHAT'S NEXT?

What we will be doing with this gearbox is mounting a kinetic sculpture to the top of it, which will be mounted on a wall. Kinetic sculptures are works of art that use motion and balance to create dynamic and eye-catching pieces. In this case, we are using two blades with a unique pattern; two of them are ready, and one is mirrored of the other.

One blade will be attached to the clockwise rotating shaft, and another blade will be placed to the counterclockwise rotating shaft. Two blades moving in opposite directions provide an intriguing pattern that is visually euphoric.

The next project will be a brief tutorial on how to construct a kinetic sculpture using the gearbox built in this article.

For now, this project is finished and needed no further revision.

All the details regarding this project, including files, are attached, which you can download.

Leave a comment if you need any help regarding this project. This is it for today, folks.

Thanks to Seeed Studio Fusion for supporting this project.

You guys can check them out if you need great PCB and stencil service for less cost and great quality.

And I'll be back with a new project pretty soon!