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Fan Cheng
Fabrication details of automatic welding manipulator

Published on:2020-04-27

Manufacturing details of automatic welding manipulator: < br > Step 1: Design

At first I saw that many professional projects could not be implemented because of their complexity.
Then I decided to make my products inspired by other projects, so I used Google sketch up 2017 pro. Each component is assembled adjacent to each other in a specific order, as shown in the figure below.
Before assembly, I have to test the parts and select the appropriate soldering iron, which is guided by drawing the virtual finishing project.
These drawings show the actual finishing life, size, shape and correct size of each part to select the appropriate soldering iron.

Step 2: electronic parts

1. Stepper motor 28byj-48 with drive module ULN2003
2.Arduino Uno R3
3. Mg-90s miniature metal gear servo motor
4. I2C serial LCD 1602 module
6. Jumper
7.Step down Module
8。 Micro servo motor metal gear

Step 3: operation and installation

During my work, I encountered some obstacles, and we must announce it.
1。 The arm is too heavy to be fixed by a small stepping motor. We will fix it in the next version or laser cutting and printing.

2. Because the model is made of plastic material, the friction of the rotating base is very high and the movement is not smooth.
The first solution is to buy a larger stepping motor that can withstand weight and friction. We redesigned the base to adapt to the larger stepping motor.
In fact, the problem still exists. The larger motor does not fix it, because the friction between the two plastic surfaces next to us cannot adjust the percentage of the pot. The maximum rotation position is not the maximum current that the driver can provide. You must use the technology shown by the manufacturer, where you can measure the voltage while turning the potentiometer.
Then I completely changed the base design and installed the servo motor with metal gear with gear mechanism.

3。 Voltage
Arduino board can be powered by DC power jack (7 - 12V), USB connector (5V) or VIN pin of circuit board (7-12V). By supplying voltage through 5V or 3.3V pins to bypass the regulator, we decided to buy a special USB cable that supports 5V voltage or any power supply.
Therefore, the stepper motor and other components only need 5 volts to ensure that the parts are free from any problems. We fix the step-down module.
The step-down module is a step-down converter (step-down converter), which is a DC to DC power converter to step down (boost the current at the same time) from its input (power supply) to its output (load), while maintaining a stable or voltage.

Step 4: modify

After some modifications, we changed the design of the model by reducing the arm. As shown in the figure, the size of the servo motor gear and make appropriate holes.
When testing the servo motor, the weight was successfully rotated 180 degrees correctly, because its high torque means that the mechanism can bear heavier loads. How much rotational force the servo mechanism can output depends on the design factors - power supply voltage, shaft speed, etc.
It s also good to use I2C because it only uses two pins. You can put multiple I2C devices on the same two pins. For example, you can have up to 8 LCD backpacks + LCD on two pins! The bad news is that you have to use the hardware I2C pin.

Step 5: soldering iron base or holder

Fixed with metal gear servo motor to bear the weight of soldering iron.
servo. attach(9, 1000, 2000);
servo. write (constrain (angle, 10, 160)) ;
At first, we encountered an obstacle, that is, motor vibration and vibration, until we found a tricky code to limit the angel.
Because not all servos have a complete 180 degrees
So we wrote a test to determine the location of the mechanical limit. Use servo Write microseconds instead of servo Write I prefer this because it allows you to use 1000-2000 as the basic range. Many servo systems will support ranges beyond 600 to 2400.
So we tried different values to see where you got the buzz that tells you you ve reached your limit. Then you can only keep within these limits when you write. You can use servo Set these limits when attach (pin, min, max).
The Arduino function is useful for finding the true range of movement and ensuring that the code does not attempt to exceed the end point.
The following is a link where you can purchase USB soldering iron:
Mini 5V DC 8W USB power welding stylus + touch switch bracket

Step 6: coding

Arduino usage Library

The environment can be extended by using libraries, just like most programming platforms. The library provides additional functionality for sketching, such as using hardware or manipulating data. Use libraries in sketches.