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Vacuum nozzle and grippers-Types of feeders-PCB

Date:2017年2月27日 15:35

Vacuum nozzle and grippers-Types of feeders-PCB

Vacuum nozzle and grippers

 

Vacuum nozzles are commonly used for handling all the components during the placement operations. There are a variety of vacuum nozzle sizes for different component sizes. For handling small components, positive pressure is often supplied in addition to vacuum at the moment of placement so that the component would be completely release from the nozzle.

In addition to vacuum nozzles, mechanical grippers could be required for handling of some odd-shaped parts. Self-centering mechanical grippers allow simultaneous pickup and automatic centering without the need for a vacuum. A pair of tweezers-type grippers would hold the part while centering it along one axis. However, there are some disadvantages with self-centering mechanical grippers: it is possible that the gripper edges could have contact with epoxy or solder paste. In addition, extra space is required between the components to accommodate the grippers.

Types of feeders

 

Feeders are used to feed components to the moveable pick-up mechanism of placement machines. Feeders move individual components to a fixed location and also assist the pickup head in removing components from their packaging. As the flexibility and placement rate of systems has increased, so have the demands made on the component feeder systems. A high product mix and correspondingly small batch sizes result in frequent feeder changing. Quick feeder changeover is required in order to minimize machine down-time, so feeders must be designed for fast replacement. Here are some of the common types of feeders.

Tape & reel feeders

Tape and reel feeder is the most commonly used feeder design. Tape-on-reel feeders are loaded with a reel, which is placed onto a reel-reception. The peel-off carriage pulls the reel tape forward until the next component is in the pick-up position. When the sensor indicates that the component is at the pickup position, a holder moves down and locks-down the tape. Tape feeders are most suitable for placing large quantities of identical small components. Tape feeders come in a variety of sizes and can be used for Small-outline integrated circuits (SOICs) and plastic leaded chip carriers (PLCCs). The main disadvantage of the tape format is the inability to recycle the empty tapes. Especially in the case of small chip devices, the tape waste material weighs several times more than the packaged components. Moreover, there is additional cost for placing small inexpensive components in tape.

Stick feeders

Stick feeders are designed for components packed in linear sticks (small ICs issued in low volumes). Components are moved to the pick-up location by gravity or vibration. It feeds any ordinary SOP, SOT and PLCC which are packaged in stick form. Due to the various possibilities of adjusting the size of the lane, the feeder can easily be adapted to many different component types.

 

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Keywords for the information:custom pcb design  Vacuum nozzle and grippers PCB  Types of feeders-PCB