Flux Frequently Asked Questions and Answers
Is there a lot dirt on the PCB board after welding?
- The preheating temperature is not preheated before welding or the preheating temperature is too low (when ending, the time is too short).
- The walking speed is too fast (FLUX failed to fully volatilize).
- The temperature of the tin furnace is not enough.
- It is caused by the addition of antioxidant or antioxidant oil in the tin liquid.
- Too much flux coating.
- The foot of the component and the plate hole are disproportionate ( the hole is too large) to raise the flux.
- During the use of FLUX, no thinner was added for a long time.
Is it big smoke and smelly?
The problem of FLUX itself
- Resin: If you use ordinary resin, the flue gas is large.
- Solvent: This means that the smell or pungent smell of the solvent used by FLUX may be large.
- Activator: large smoke and pungent smell.
The exhaust system is not perfect.
Electricity connection, leakage (poor insulation)?
1. The PCB design is unreasonable, the wiring is too close, etc.
2. The quality of PCB solder block film is not good, and it is easy to conduct electricity.
On fire?
- The wave furnace itself does not have a wind knife, resulting in too much flux coating, which drips on the heating tube during preheating.
- The angle of the wind knife is not right (so that the flux is unevenly coated on the PCB).
- There are too many adhesive strips on the PCB, which ignited the adhesive strips.
- The walking speed of the board is too fast (Flux is not completely volatile, and Flux drips) or too slow ( the heat temperature of the board surface is too high).
- Process problems (the PCB board is not good and the heating pipe is too close to the PCB).
Is the solder joint too bright or not bright?
- This problem can be solved by selecting bright or matting FLUX);
- The tin used is not good (for example, the tin content is too low, etc.).
The colour of Flux
Some colourless and transparent FLUX add a few photosensitive additives. It changes colour after light, but does not affect the welding effect and performance of FLUX.
Split, tin beads?
- Low preheating temperature ( FLUX solvent is not completely volatile);
- The speed of walking the board has not reached the warm-up effect;
- The inclination of the chain is not good, there are bubbles between the tin liquid and the PCB, and the bubble bursts to produce tin beads;
- Improper operation method when the hand is soaked in tin;
- Wet working environment.
2. Problem with PCB board
- The board surface is wet, not fully preheated, or moisture is produced;
- The hole design of PCB running gas is unreasonable, cause air between PCB and tin liquid;
- The PCB design is unreasonable, and the parts are too dense, causing air.
Short circuit?
1.Short circuit caused by tin solution;
- Continuous welding occurred but not detected.
- The tin solution does not reach the normal working temperature, and there is a “ting wire” bridge between the solder joints.
- There is a slight tin bead bridge between the solder joints.
- Continuous welding is the bridge.
2. PCB problems:
For example: the solder mask of the PCB itself falls off, resulting in a short circuit.