Conveyor Belt
Developed for the MTE 100 Design project, we designed a conveyor belt that would separate a set of 3 package types. the mechanical assembly was designed on AutoCAD and the logic was developed on a NoCode software
General Design
The conveyor system is made up of 3 zones. The main conveyor belt, the 3 sorting zones, and the 3 buffer zones. The system starts at the boxing zone where the models are boxed into 7 - 7/8 x 7 - 7/8 x 7 - 7/8 and 3 - 15/16 x 3 - 15/16 x 11 - 13/16 inch boxes.
The main conveyor belt is made up of two conveyor belt pulley rollers and one idler to provide tension as seen in Figure #. The belt is made of SBR rubber and the main structure including the belt bed is constructed using 1.5 x 1.5-inch black anodized aluminum extrusion. The system spans a length of 239 inches with a belt width of 12 inches. The conveyor system is also outfitted with limit laser sensors beside each piston and safety laser sensors along the edges of the system. Together assembled according to the diagram below, the main conveyor system is made.
The sorting zone is a special section within the conveyor system consisting of a sorting piston. The piston is composed of 8 track-roller carriages allowing for smooth linear motion, and the structure is fully composed of 1.5 x 1.5-inch aluminum extrusion. The piston is powered by a separate motor connected to a rack and pinion system. With the rack fastened to the aluminum extrusion, the spinning pinion will convert the rotational motion of the motor to the linear motion of the piston. The piston head is sized 9 x 12 inches and can extend over 17 inches making it capable of pushing the box onto the buffer zone.
The buffer zone is composed of 23 separated 2-inch diameter free-running rollers. The use of free running rollers here allows for the boxes to travel over the required 5 feet, but it further allows for the boxes to slow down to a complete stop by the time it arrives at the shipping dock.
Logic Design
As the box enters the first scanner, it is scanned for its type via the barcode scanner. The Cheerio model and any unknown box continues along the conveyor belt for about 5 feet until their laser sensor. Once the laser is cut, the belt will halt temporarily, and the piston will extend to push the box onto the buffer zone. The laser will be placed at right end of the sorting zone to allow for proper box placement. The cheerio and unknown boxes are stopped in front of the first two sorting zones respectively.
The goat figurines continue along the main conveyor belt to the second scanning stage where they are scanned for their orientation. The goat figures in the upwards orientation stop at the piston and the sideward orientation continues along the conveyor belt to its destination.
Controllers and Actuation
Motor Controller
The FDC 3260T Brushed DC Motor Controller from RoboteQ was chosen for the belt motor due to its power output, I/O ports, temperature management, Safe Torque Off feature, and chain linking capability. With a maximum output of 60 volts, it can effectively control the DPP 680 Brushed Motor within its functional voltage range of 24 - 60 volts. The motor controller's current output of 40 amps continuous and 60 amps max exceeds the motor's requirements. It offers 8 analog inputs, 4 digital inputs, and 6 max pulse inputs for sensor integration, and communication ports such as Ethernet, USB, RS232, and RS485 for enhanced capabilities. The controller's heat generation necessitates temperature maintenance, aided by its conduction plate and thermal throttling. Safe Torque Off enhances safety by reducing motor torque during excessive force situations, while the CANbus port facilitates connection with up to 127 microcontrollers, enabling communication between the belt and piston controllers.
Brushed Motor
For the design of the conveyor belt system, the DPP680 Brush Motor from ElectroCraft was chosen due to its peak torque, velocity, sealed ball bearings, dynamically balanced armatures, and replaceable brushes. The motor's torque value of 77.68 newtons per meter ensures sufficient force for transporting objects over a distance of at least 20 meters and a load of 300 kilograms. With a maximum velocity of up to 1000 revolutions per minute, the motor can effectively power the system's rollers at various speeds. Sealed ball bearings in the motor prevent contamination and heat buildup, enhancing its durability. The motor's dynamically balanced armatures counter vibrations, maintaining structural integrity. Additionally, the motor's feature of replaceable brushes addresses the issue of wear and damage caused by continuous use, minimizing downtime and replacement costs.
Vision Sensor
For the vision component capable of reading barcodes and QR codes in the conveyor system, the chosen sensor is the Keyence 1D/2D Code Reader SR-2000. This reader was selected for its ability to scan both 1D and 2D codes. Key specifications include its reading distance, where a range of 100 mm to 2000 mm allows flexible placement at a distance of 1 meter from the conveyor system, ensuring a wide field view for effective scanning. The SR-2000's communication speed options (9600, 19200, 38400, 57600, or 115200 bps) enable swift data transmission, enhancing continuous conveyor flow. With a CMOS image sensor, the reader efficiently converts light waves into electrical signals for barcode interpretation. Vibration resistance within the 10-50 Hz range suits the conveyor's operational frequencies, and a voltage rating of 24 VDC +- 10% ensures safe and suitable power distribution. The reader's mounting bracket, compatible cables, and Ethernet connections facilitate integration into the system, while aluminum extrusions hold it securely above the conveyor for top-down scanning.
