I. Introduction
The large-scale production of electronic products has driven the booming development of SMT (Surface Mount Technology), and the widespread use of pick-and-place machines has further demanded the standardized packaging of SMD (Surface Mount Device) electronic components. The process of placing SMD components onto carrier tape and then encapsulating them with cover tape is commonly known as tape and reel packaging. Because tape and reel machines are easy to control, earlier tape and reel machines were controlled by a relay-based control system.
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Semi-automatic tape feeding machine
Later, as the price of PLCs and microcontroller control boards decreased, more and more tape and reel machines adopted the control method of PLCs or microcontroller boards + ordinary buttons. However, microcontroller control boards are often perceived as simple and unstable, so more tape and reel machine manufacturers still use PLCs. Later, some manufacturers replaced the buttons with touch screens, which greatly reduced the number of buttons on the tape and reel machine control box panel and made wiring much easier. The above describes semi-automatic tape and reel machines, which require manual feeding. Later, fully automatic tape and reel machines appeared, overcoming the high cost and instability caused by a large amount of manual feeding. Of course, fully automatic tape and reel machines also have disadvantages; they cannot be packaged for every product, only for specific products.
Fully automatic tape and reel machine
II. Electrical Components of a Tape and Tape Machine
The main control components of a semi-automatic button-type taping and packaging machine include:
1. A belt conveyor motor, usually a speed-regulating motor, but stepper motors are also used.
2. One pressure solenoid valve, two cutter head solenoid valves, and one main solenoid valve.
3. Temperature of the two cutting heads.
Signal input section:
1. A start/stop button and a foot pedal start/stop button are connected in parallel.
2. A cutter head lifting button.
3. A three-way selector button for continuous/inching/venting.
4. One counting sensor and one material control sensor.
5. A pressure button.
6. Two thermocouple sensors.
The main electrical components include:
1. One PLC (I/O points required to be greater than 8/4).
2. Two temperature controllers.
3. One speed-regulating motor.
4. Four solenoid valves.
5. Two solid-state relays (temperature controllers), one general-purpose relay (speed control motor), and one main air switch.
6. A counter (this can be omitted if a touchscreen is used instead).
7. Two fiber optic sensors (one for counting, and one for material control).
III. Explanation of the working process and key points of the tape and reel machine
After the electrical and pneumatic connections of the tape and reel packaging machine are made, if heat sealing is used, raise the blade to the appropriate temperature and adjust the carrier tape and air pressure. Use manual or automatic feeding equipment to place the SMD components into the carrier tape, and the motor rotates to form the cover tape into the carrier tape.
The carrier tape is pulled to the encapsulation position, where the cover tape is on top and the carrier tape is on the bottom. Two heated blades press down on the cover tape and carrier tape, causing the cover tape to seal the SMD component opening on the carrier tape, thus achieving the purpose of SMD component encapsulation. Then the take-up reel winds up the encapsulated carrier tape.
Some are not heat-sealed, but cold-sealed. Cold sealing means that the cover tape and carrier tape can be bonded together without heating; in this case, the cover tape must be adhesive. Before packaging, the carrier tape generally passes through two sensors: one for counting and one for material control. Material control detects whether any components are missing from the carrier tape. If a missing component is detected, the tape machine motor immediately stops, and the cutter head moves to the upper position. The counting sensor is usually made of optical fiber and requires a fast response speed to avoid missing counts. The counting sensor can count the edge holes of the carrier tape or the formed grooves. Counting edge holes requires conversion back to obtain the correct SMD count. Since ordinary optical fiber sensors cost two to three hundred yuan, some manufacturers simply use Omron's groove-type photoelectric sensor. A gear is installed on the edge hole of the carrier tape, and a shaft drives another gear. The teeth of the latter gear are used to sense the groove-type photoelectric sensor. In this way, as the carrier tape moves forward, it drives the gear to rotate, thus counting the edge holes of the carrier tape.
There are three normal operating modes for the tape and reel machine: continuous, inching, and degassing. Continuous and inching modes can be selected by adjusting the feeding speed. Degassing is generally used during cold sealing, in which case the two cutters are required to press down, but the pressure is less than that of heat sealing. Because the cover tape itself is sticky, it is only necessary to combine the cover tape and the carrier tape together.
The above describes the basic functions of a semi-automatic tape and reel machine. A fully automatic tape and reel machine also requires an automatic feeding section. The feeding section typically uses a stepper or servo motor to drive a rotating robotic arm. A suction nozzle is mounted under the arm to place SMD components from the feeding position onto the carrier tape. This requires the PLC to have pulse output functionality. The feeding and unloading section is usually designed for specific applications. If the SMD components are reversible and can withstand normal vibration, a vibratory feeder can be used for unloading. If they are polarized and in tubular form, such as some ICs, a repositioning mechanism can be used to arrange the ICs one after another at the suction position. When an SMD component is placed onto the carrier tape, the motor pulls the carrier tape forward one position. This requires the motor to have rapid start and stop capabilities. A speed-regulating motor with brakes can usually achieve this, but sometimes a stepper motor is used.
If a touch screen is used in a tape and reel machine, not only can the panel be simplified, but the time the cutter head spends in the upper and lower positions can also be adjusted according to the speed of the cutter head cylinder.
IV. Application of V80 PLC in Tape and Tape Machines
Because tape and reel machines are easy to control, the requirements for PLCs are high cost-effectiveness and stability. Devison Technology's V80 series M16DT-DC PLC has been used in tape and reel machines since 2005, and has been widely adopted in push-button type, touch screen type, and fully automatic tape and reel machines. Due to its ease of programming, high-speed pulse output capability, stable hardware, and high cost-effectiveness, the V80 PLC is highly favored by customers.
