An automatic sorting machine performs the task of sorting components according to their sizes and materials and it can be done individually as well as simultaneously with or without human interaction depending upon its application.
Automatic Sorting Machine Using Conveyor
In this automated era, automatic sorting is highly needed in almost every industry. Its main objective is to reduce human efforts and time that can ultimately raise its efficiency. However, the perfect sorting machine is still in progress which should be flexible and compatible in design.
An automatic sorting machine is a part of the Material Management System (MMS) and is widely used in industrial applications.
Objectives of Automatic Sorting Machine
There are three main objectives of an automatic sorting machine.
- The first task is to distinguish among the three types of material (wood, plastic, and metal) by using proximity sensors.
- The second task is to sort the objects concerning their heights at three different levels and send them to their specific compartment by using a pushing mechanism (conveyer belt, pneumatic cylinder, and PLC).
- The third task is to maintain a small time interval between input materials.
Construction of Automatic Sorting Machine
An automatic sorting machine consists of
- Belt conveyor
- Pneumatic cylinders
- Pneumatic system
- Direction control valves
- Proximity sensors
- A PLC for automation of the system.
The complete phenomenon of sorting and pushing mechanism by using a conveyer belt, sensors, and pneumatic cylinders is shown in the figure. It works on the principle of detection of material type using sensor technology and pushes it to its destination with the help of double-acting pneumatic cylinders.
A belt conveyor system makes use of thermoplastic belt material due to its many advantages such as being lightweight, cost-effective, easily available, and are ideal for several industries such as food handling, textile production, etc. The belt conveyor system is powered by using an electric motor.
Two double-acting pneumatic cylinders along with proximity sensors are used and mounted at one side of the conveyor belt. These cylinders are powered with the help of a pneumatic system and are controlled with the help of 5/2 direction control valves.
To control the movement of air actuators, compressed air has to be regulated, controlled, and reversed with a predetermined sequence. Pressure and flow rates of the compressed air to be controlled to obtain the desired level of force and speed of air actuators.
The function of the directional control valve is to control the direction of flow in the pneumatic circuit. DCVs are used to start, stop and regulate the direction of airflow and to help in the distribution of air in the required line.
The proximity sensors are non-contact type sensors used to detect and determine whether the object is metallic or non-metallic. Collectors are placed in front of the pneumatic cylinders to collect their respective items.
And finally, a PLC is used to control all the elements in the system by using the program installed in the PLC. There are many types of PLC available in the market like Siemens PLC, Mitsubishi PLC, Allen Bradley PLC, Delta PLC, and many more.
Working of Automatic Sorting Machine
The working mechanism comprises of objects passing through the conveyer belt and their detection according to their size and material and sorted into the assigned boxes through a pneumatic system.
- The system is powered ON and the items are fed on the conveyer belt.
- Once an item arrives on the conveyer belt, proximity sensors i.e. inductive sensor, capacitive sensor, and photo reflective sensors detect the item and differentiate among the construction material of the object (metal, wood, and plastic).
- According to the material of the object, the objects are sent to their respective containers by pushing them using a pneumatic cylinder that will be operated by using a PLC.
Sorting and Pushing Mechanism
The sorting mechanism customs the conveyer belt for the transportation of the objects from source to target. The conveyer belt is powered by a 24V Switching Mode DC Power Supply.
It is essential to note that the automated belt moves the object to detection position by dynamics of the running motors using sensor signals fed in PLC for processing.
Detection of Objects using Sensors
Detection of an object through a proximity sensor may rely on light, sound, vision, or electromagnetic field.
The first sensor placed in our system to sense the presence of the arriving object is an Inductive Sensor. It is a non-contact sensor, performing the task of differentiation of metallic and non-metallic objects. The inductive effect aids in the recognition of metals.
The arrival of the metallic article on the belt causes the dampening in the amplitude of the oscillator present in the inductive sensor. The rise and fall in the amplitude of the oscillator cause change in the output of the sensor.
Next, capacitive sensors are placed. The capacitive proximity sensors can identify metallic as well as non-metallic objects irrespective of their form. Whether the article is solid, liquid, or powdered, these sensors would be able to perceive them.
Conclusion of Automatic Sorting Machine
This work proposes an efficient MMS for multi sorting of three different objects (wood, plastic, metal) by using PLC and proximity sensors. The proposed algorithm shows 100% accuracy in the identification of material with minimal time intervals.