User-Manual-NeoDen-IN12-Reflow-oven.pdf - 第22页

21 other suitable carriers t o place the soldered PCB. *It is not recommended to open the incubator when it is not necessary. If it must be opened, the incubator must be supported by a support rod before the next work ca…

heating speed

Decrease transfer speed and temperature

Excessive fines

Top layer temperature out of limit

Reduce top heat and increase bottom zone

temperature

Tin balls

Due to dry too fast

Decrease transfer chain speed and temperature

Solder pasting is unqualified or PCB re-

paste

Use PCB after cleaning and drying

Flux coking

Over heating

Add transfer chain speed, lower temperature

Components

wrong position

PNP wrongly, the tin on the solder pad is

irregular or asymmetrical, drying too fast

causes airflow to blow components

Check place position

Check the shape and thickness of tin

Lower transfer chain speed and temperature

Tin bridging

Misposition

Check position

Tin migration

Moist overtime

Increase the belt speed

Lower pre-setting temperature

Solder skips

The solder paste is not enough on pad,

the unevenness of the micro-component,

the PCB coplanarity problem

Thickened tin paste coating

Try to make the solder on the pad even

Check component pin stability

PCB over heat

Heating speed too fast

Decrease transfer chain speed and temperature

Analysis on the cause of the solder joints not shining

In the SMT soldering process, customers will have requirements for the brightness

of the solder joints. It is often just a subjective consciousness of the customer. We

can only get the conclusion of the brightness through comparison. Because there is

no standard for the brightness of the solder joints; roughly speaking, the reasons

for the non-bright solder joints are as follows:

1. There will be difference between the solder paste with or without silver.

Customers should explain their soldering requirements to the supplier when

choosing solder paste.

2. The tin powder in the solder paste is oxidized.

3. The flux in the solder paste has an additive that causes a matting effect.

4. After soldering, there are rosin or resin residues on the surface of the solder

joints, which is a phenomenon we often see in actual work. Especially when

choosing rosin-type solder paste, although rosin-type flux will make the solder

joints slightly brighter than no-clean flux, the presence of its residues often affects

this effect. It is more obvious in larger solder joints or IC foot parts; if it can be

cleaned after soldering, I believe the gloss of solder joints should be improved.

5. The preheating temperature of reflow soldering is low, and there are non-volatile

residues on the surface of the solder joint.

The main reasons for solder joints not full are as follows:

1. The activity of the flux in the solder paste is not enough, and the oxidized

substances on the PCB pads or SMD solder joints are not completely removed.

2. The moisture retention of the flux in the solder paste is not good.

3. PCB pads or SMD soldering positions have serious oxidation.

4. During reflow soldering, the preheating time is too long or the preheating

temperature is too high, cause the failure of flux activity in the solder paste.

5. If the solder paste has not been fully stirred or the flux and tin powder have not

been fully fused. If, there will be insufficient tin on some solder joints.

6. Reflow zone temperature too low.

7. Insufficient amount of solder paste at the solder joint.

9.2 Precautions

*Keep a certain distance of more than 100mm when PCB size exceeds 100mm.

*If the PCB length is longer than the ESD tray, the ESD tray needs to be replaced by

other suitable carriers to place the soldered PCB.

*It is not recommended to open the incubator when it is not necessary. If it must be

opened, the incubator must be supported by a support rod before the next work can be

carried out.

*The upper cover and incubator can only be opened after the bottom caster is lay down.

*The power board and control board should not be touched when the power is on.

*The change of chain speed will affect the plate surface temperature, so after adjusting

the chain speed, be sure to retest the plate surface temperature curve, and adjust the

temperature setting according to the actual test results.

9.3Machine maintenance

♦Replace the filter element assembly regularly

Support Rod

keep distance of

more than 100mm

The filter assembly needs to be replaced regularly, and the service life of the filter

assembly is 8 months (depending on the service frequency).

The following is the replacement tutorial. Prepare the filter assembly and a cross

screwdriver before replacement;

Replace the left filter assembly: remove the fixing screw of the left wind shield

and take down the left wind shield --> remove the screw of the left concave and

take down the left concave --> remove the fixing screw of the left filter cover

and push out the left filter cover to the right --> push out the filter installation

chamber and the filter assembly to the right together --> replace the prepared

filter assembly and install it in the reverse order of disassembly

Replace the right filter assembly: remove the fixing screw of the right filter

cover, push the right filter cover out to the right -- > push the filter installation

chamber and the filter assembly out to the right together --> replace the

prepared filter assembly, and install it in the reverse order of disassembly

Right filter cover

Left filter cover

Left concave

Right concave

Left wind shield

Filter installation chamber

and filter assembly

Filter installation chamber

Filter assembly

Filter (front)

Filter (back)

Carbon fiber cotton