1 . The meaning of the placement rate

The so-called placement rate refers to the ratio of the actual number of devices mounted to the number of suction in a certain period of time. The number of total abandonment , refers to the number of suction errors, identification errors,slices and missing, etc., and the recognition errors are divided into two types: device size error and device optical recognition. Whether it is a small machine, a medium machine, a main machine, or a medium speed machine or a high speed machine, they are mainly composed of a device storage device, an XY table, a mounting head, and a control system. The placement head is the core and key components of the placement machine. The placement head generally has a fixed head and a rotating head. The fixed head is generally arranged in a long position, ranging from 2 to 8 and can be taken at the same time or separately. It is also rotated in the horizontal plane and rotated in the vertical plane.

A: device suction /nozzle suction height switch

B: θI rotation (±90’)

C: device optical identification

D: device attitude detection θ2 rotation (±90’)

E: Mounting device / nozzle height switching

F: θ3 rotation (±180′-θ) nozzle origin detection defective product exclusion

G: nozzle conversion

H: nozzle number detection according to the placement machine pickup

The entire process of placement, from the perspective of equipment, in the correct setting of the nozzle pick-up height, the position of the nozzle and the relative position of the feeder, the main factor affecting the placement rate of the equipment is in the pick-up position. According to the production information intelligence of equipment statistics, its impact accounts for more than 80% of the total influencing factors. The reasons are: the feeder on the device storage device, and on the other hand, the nozzle, about 60% influence in the feeder, about 40% is caused by the suction nozzle pollution.

2 .The influence of the feeder The influence of the feeder is concentrated on the abnormal supply.

The drive mode of the feeder is motor drive, mechanical drive and cylinder drive. Here, the mechanical drive is taken as an example to illustrate the effect of the feeder on the placement rate:

1): The driving part is mechanically driven to drive the feeding mechanism by the cam main shaft, and the search arm of the feeder is quickly tapped, and the ratchet wheel connected with the connecting element is driven to advance by one distance, and the plastic wheel is driven at the same time. The take-up reel removes the plastic cap from the braid and the nozzle is lowered to complete the pick-up action. However, due to the high-speed access of the feeder to the feeder, after a long period of use, the pawl of the feeder is seriously worn, and the pawl cannot drive the plastic strip of the take-up reel to be normally peeled off, so that the nozzle cannot complete the pickup work. Therefore, the feeder should be carefully inspected before installing the braid. The feeder that has worn out the pawl wheel should be repaired immediately. If it cannot be repaired, it should be replaced in time.

2): Deformation of the feeder structural parts due to long-term use or improper operation of the operator, the pressure belt cover, thimble, spring and other moving mechanisms are deformed, rusted, etc., resulting in the device being biased, the vertical piece or the device is not absorbed. Therefore, it should be inspected regularly, and problems should be dealt with in time to avoid a large amount of waste of the device. At the same time, the installation of the feeder should be correctly and firmly installed on the platform of the feeding department, especially the equipment without height detection of the feeder, otherwise it may Causes damage to the feeder or equipment.

3): Poor lubrication maintenance of the feeder is easy to be ignored, but regular cleaning, and lubrication are essential tasks.

3 . The influence of the nozzle

The nozzle is also another important factor affecting the placement rate, the cause is internal and external.

1): Internal reason:

On the one hand, the vacuum negative pressure is insufficient, the mechanical valve on the head is automatically converted before the nozzle is taken, and by blowing air into the vacuum adsorption, which generates a certain negative pressure. When the part is sucked, the negative pressure sensor detected value is within a certain range, the machine is normal,or abnormal. Generally, the negative pressure at the pickup position to the placement nozzle should be at least 400mmHg. When the negative pressure of the large device is above 70mmHg, the filter inside the vacuum pump should be cleaned regularly to ensure sufficient negative pressure; At the same time, the working state of the negative pressure detecting sensor should be checked regularly.

On the other hand, the filter on the placement head and the filter on the nozzle are blackened due to contamination of the surrounding environment or the air source is contaminated. Therefore, the filter should be replaced regularly. Generally, the filter on the nozzle should be replaced at least once every half month. The filter on the placement head should be replaced at least once every six months to ensure smooth airflow.

2): External causes are pressure relief of the air source circuit, such as rubber tube aging, cracking, aging of seals, and wear of the nozzle after prolonged use, and on the other hand due to adhesive or external environment dust, especially the large amount of waste generated after the cutting of the tape-wrapped components ,and causes the nozzle to block.

Therefore, due to the cleanliness of the nozzles, the pick-up of the nozzles is monitored daily, and the suction or the pick-up is poor. The mouth should be cleaned or replaced in time to ensure a good condition. At the same time, when installing the nozzle, it must be ensured that the installation is correct and firm, otherwise the nozzle or equipment will be damaged.

Still not finished ,will update after .Thanks .