User-Manual-of-NeoDen4-PNP-machine.pdf - 第50页

45 5.5 Placement failure analy sis an d troubleshooting Placement failure a nalysis Whether Pick and Place mac hine can run normall y or no t, which will d irectly imp act o n produ ction quality and volume. To make the …

5.4.2 Maintenance of device

Check below points daily

(1)

Please check below before turn on the machine

a. Temperature and humidity: temperature range 20℃～26℃, humidity range 45～70％.

b. Working environment: please keep air fresh to avoid corrosive air in.

c. Make sure there’s no obstacle on dual rails or the whole working area.

d. Make sure camera lens is clean, no dirty things.

e. Make sure no obstacles around the head nozzles.

f. Please check whether nozzle is dirty or out of shape and adopt relevant cleaning measure or

change new nozzle.

g. Please check whether feeders are well installed, and keep feeders clean.

h. Please check whether the air hose is well connected with machine.

(2)

Please check listed below after turn on the machine.

Error tips will show on the monitor if the machine work abnormality.

a. Check the monitor screen whether display normally after system starting working. Check

emergency switch whether could work normal.

b. Check the placement head whether could return to the original place.

c. Whether have abnormal noise when placement head move.

d. Check negative pressure whether in normal range or not.

e.by the way checking PCB’s transmission on dual rails to know whether sensor is still work fine.

Check below points monthly

a. X, Y axis--please make sure no abnormal noise when placement head move.

b. X, Y motor--please make sure motors working well, no abnormal heating appearance.

c. Nozzle--please check nozzle whether up down flexibly, not bent, check the suck surface whether

level.

d. Air hose--check the air hose and connector, make sure hose is fine without broken, abrasion or

air-leak etc.

e. Negative pressure--check all nozzles’ negative pressure. If abnormal, please clean nozzles.

f. Positive pressure--check whether they’re normal.

g. Optical axis--please check whether it is covered dusk. Please keep it clean and lubricated.

h. Operation button--check each button to make sure they are well-worked

i. Connector--check if well-connected of the air connector and air hose.

5.5

Placement failure analysis and troubleshooting

Placement failure analysis

Whether Pick and Place machine can run normally or not, which will directly impact on production

quality and volume. To make the machine run properly, we must fully understand the structure and

characteristics of the machine, master every kinds of failure patterns of manifestation, reason and

troubleshooting methods. Finding problems and reasons in time and timely troubleshooting can help

ensure efficiency of the machine during working.

（1）

Common failures

a. not start boot failure

b. head doesn’t move

c. fail to feed forward a board

d. Pick failure

e. Place failure

（2）

Main reasons of failure

a. transmission systems-driven PCB and head movement transmission system and the

corresponding sensors.

b. Air Route-Air pipe, nozzle

c. Nozzle size not suit to the component

d. No info in Footprint library

e. Irregular component

f. Incorrect values setting of component’s heights or pick height

（3）

placement troubleshooting

Failure patterns of manifestation, Reasons, troubleshooting methods

head doesn’t move

Solutions:

a. Sensor is poor connected or short-circuited. Please wipe off the dust or lubrication on

sensor or even exchange a sensor

b. Longitudinal sensor or sensor poor connect or short circuit, check and repair the transmitter or

add too much lubricating oil on sensor-clean the sensor

c. Rails fail to advance the board feed forward after uploading the PCB

Solutions:

a. The rails belt gets loose or broken, need to be adjusted or exchanged.

b. The rails drive motor doesn’t work.

c. Nozzle can’t pick up component

d. Pick up position offset

e. Components fall down during moving

Solutions:

a. Nozzle had been wearing or become aging, the crack causes leakage. - replace with a new nozzle

b. The nozzle’s bottom surface is uneven or get suck by solder paste or other dirt Please wipe it

off and use cleaning needle to clean the nozzle

c. Current nozzle size is not suit to component, change another one

d. Surface uneven on the component, replace with a qualified one

e. Component is sticking to the bottom tape;

f. Burrs on tape hole stuck component;

g. Component’s pin gets stuck in the corner of the den;

h. Gap between components and tape package hole is not big enough, uncover the plastic tape and

upside down to check if the components can fall down or not.

i. Plastic adhesive tape is too sticky or flimsy and then cannot be unfolded. Or plastic adhesive tape

has been tearing down from edge side.

j. Pick up position offset. Actual Feed box is offset from Feeding center, check X, Y, Z data and do

reprogram.

Placement offset

Solutions:

a. Programming issue (some components’ positions are inaccurate), amend the coordinates; If all

components are offset, please modify fiducials.

b. The components’ thickness setting errors, modify components information on Footprint Library

c. Pick height is too high that causes components being dropped. Please reset the Pick Height value

d. Pick height is too low that causes slide problem during placement

e. High speed issue. Lower the speed to achieve a more accurate rotation and placement effect.

5.6

Related issues during solder paste printing process

(1)

Stencil Printing Technology

Screen printing technology refer to using ready-made stencil, directly contact to the printer in a

certain way, make the solder paste evenly flow on the stencil and then leak into the mesh through

the holes. When getting the stencil away, solder paste had been covered to the printed circuit board

solder graphics, corresponding, thus complete the solder paste printing on the PCB.

(2)

Inspecting of solder paste printing

Printing process is one of the key working procedures to ensure the quality of surface mounting.

According to the statistics, under the premise of guaranteed quality about components and PCB,

correctly PCB design, 70% of the surface quality problem caused during printing process. In order

to ensure the quality of SMT assembly, it is necessary to strictly control the quality of the solder

paste printing. The amount of solder paste printing requirements are as follows: