1. Whether the wave soldering machine track is horizontal
If the track is not parallel to the work, the whole set of mechanical transmission device installed in a tilted state, that is to say, the whole set of mechanical operation tilt. Then due to the uneven force everywhere, will make the friction of the parts of the force becomes bigger, which will lead to the transportation of jitter. In severe cases, the drive shaft may break due to excessive torque. On the other hand, because the tin tank needs to be in a horizontal state to ensure the level of the wave before and after the level, which will make the PCB in the wave over the left and right ate tin height inconsistency. Step back even if the track can be tilted to make the height of the wave before and after the track to match the height, but the tin tank will certainly appear before and after the end of the height inconsistency, so that the tin wave in the flow out of the nozzle after the impact of gravity will be in the surface of the wave of tin cross-flow. Transportation jitter, the wave is not stable is the root cause of bad welding.
2. Wave soldering machine level placement
Wave soldering machine level is the basis of the normal work of the whole machine, the machine before and after the level of the direct decision track level, although you can adjust the track screw rack leveling track, but may make the track angle adjusting screw due to the front and back end of the force is not uniform and lead to the track lifting and lowering is not synchronized. In this case, adjust the angle, ultimately leading to inconsistent height of the PCB board immersion tin and resulting in poor soldering.
3. Wave soldering machine tin tank level debugging
The level of the tin tank directly affects the height of the wave before and after the wave, the low end of the wave is high, the high end of the wave is lower, but also change the direction of the flow of tin wave. Track level, body level, tin tank level is a whole, any one link of the failure will affect the other two links, and ultimately will affect the quality of the entire furnace soldering board. For some simple PCB design, the impact of the above conditions may not be significant, but for the design of complex PCB, any one of the subtle links will affect the entire production process.
4. Wave soldering flux
It is composed of volatile organic compounds, easy to volatilize, easy to generate smoke when welding VOC2, and promote the formation of ozone on the surface, becoming a source of pollution on the surface.
a. Rosin type, based on rosin acid.
b. No-clean type, solid content of not more than 5%, halogen-free, flux extension should be greater than 80%, no-clean flux most of the halogen-free activator, so its activity is relatively weak. No-clean flux preheating time is relatively longer, preheating temperature should be higher, which is conducive to the PCB into the solder wave before the activator can be fully activated.
5. Wave soldering guide width
The width of the rail can affect the quality of welding to a certain extent. When the rail is narrow, it may lead to PCB board downward concave, resulting in the whole piece of PCB immersed in the wave when the two sides of the tin ate less tin ate more in the middle, easy to cause the IC or row of bridges generated by the seriousness of the PCB board will be injured or cause the edge of the chain claw walking jitter. If the gauge is too wide, in the spray flux will cause the PCB board chattering, causing the PCB board surface components shaking and misalignment (except AI plug-in). On the other hand, when the PCB through the crest, due to the PCB is in a relaxed state, the buoyancy generated by the crest will make the PCB in the crest surface floating, when the PCB out of the crest, the surface components will be due to the external force is too large to produce the de-tinning bad, resulting in a series of poor quality. Under normal circumstances, we take the chain claw to clamp the PCB board after the PCB board can be smoothly pushed back and forth by hand and no left and right shaking of the state as a benchmark.
6. Wave soldering transportation speed
Generally speaking, we say that the transportation speed of 0-2M/min adjustable, but taking into account the wetting characteristics of the components and the smoothness of the solder joints off the tin, the speed is not the faster or slower the best. Each type of substrate has an optimal soldering conditions: appropriate temperature activation of the right amount of flux, the peak of the appropriate wetting and stable desoldering state, in order to obtain good soldering quality. (Too fast or too slow speed will cause bridging and false soldering)
7. Wave soldering preheating temperature
Soldering process preheating conditions is a prerequisite for good or bad soldering quality. When the flux is evenly coated to the PCB board, need to provide the appropriate temperature to stimulate the activity of the flux, this process will be realized in the preheating zone. Leaded soldering preheating temperature is maintained at about 70-90 ℃ between, and lead-free flux without cleaning due to the low activity needs to be at high temperatures in order to activate the activity, so its activation temperature is maintained at about 150 ℃. To ensure that the temperature can meet the above requirements and maintain the component temperature rise rate (2 ℃ / within), the process is located in the time of about 1 minute and a half. If more than the limit, may make the flux activation is not enough or coking inactivity caused by poor soldering, resulting in bridging or virtual soldering. On the other hand, when the PCB from low temperature into high temperature if the temperature is too fast may make the PCB board deformation and bending, preheating area of the slow warming of the PCB due to the rapid warming of the PCB resulting from the stress caused by the deformation of the PCB can be effectively avoided to weld the poor generation.
8. Wave soldering furnace temperature
Oven temperature is the key to the entire welding system. Leaded solder in the 223 ° C - 245 ° C can be wetted, while lead-free solder needs to be between 230 ° C - 260 ° C to wet. A tin temperature that is too low will result in poor wetting, or poor fluidity, bridging or poor soldering. Too high a tin temperature will result in severe oxidation of the solder itself, poor fluidity, and serious damage to the copper foil on the surface of the component or PCB. Due to the differences between the set temperature of each place and the measured temperature of the PCB board surface, and soldering by the component surface temperature limitations, leaded soldering temperature is set at about 245 ℃, lead-free soldering temperature is set at about 250-260 ℃ between. At this temperature PCB solder joint brazing can achieve the above wetting conditions.
Features of NeoDen ND250 wave soldering machine
Heating Method: Hot Wind
Cooling method: Axial fan cooling
Transfer Direction: Left→Right
Temperature Control: PID+SSR
Machine Control: Mitsubishi PLC+ Touch Screen
Flux tank capacity: Max 5.2L
Spray Method: Step Motor+ST-6