Printed Circuit Board Assembly or PCB Assemblyas a hobby is slowly gaining popularity. Many welding enthusiast find it challenging to put together electronic micro components. However, despite constant practice, many welders still commit errors during the soldering process which becomes a waste of time, effort and money. Hence, our experts at pcbnet.com have made a list to help you identify the most common mistakes done when soldering circuit board assemblies and how to remedy them.
• Heat-exposed joints
A lot of craftsmen, especially newbies apply too much pressure when soldering a PCB. A lot of heat during welding can result to a burnt joint. An overheated joint happens when excessive heat is applied to a solder that hasn’t melted completely. The problem is characterized by hard to clean, scorched flux around the hole.
Use a scraping tool or a small knife to gently remove the burned flux in and around the hole. Apply a small amount of isopropyl disinfectant to a cotton bud or toothbrush and thoroughly clean the area so you can weld it again.
• Disturbed Joint
A disturbed joint is a solder that was not allowed to cool and solidify properly. The piece appears in frosted, coarse, or crystallized state.
Heat the joint again and place the PCB assembly on a rack and place the rack in a shelf so it won’t be moved.
• Cold Joint
A solder that didn’t melt completely creates a cold joint which appears uneven or bumpy. These joints are weak and break easily so they must be redone immediately. Excessive solder is another cause for getting a cold joint thus, it advisable to have accurately measured raw materials prior to welding to avoid mishaps.
Repair a cold joint by pre-heating an iron solder then directly applying it to the fuse until it is liquefied.Weed out extra solder using the iron tip.
• Inadequate Wetting (SMT)
Applying high temperature on pins instead of the solder pads results in insufficient dousing. The solder did not flow freely on to the pad thus creating surface remainders.
Heat the solder pad initially with the iron tip. Then apply additional solder material onto the original one and let them melt and mix until they flow freely.
• Inadequate Drenching (pad)
Unclean PCB assembly or animproperly heated pad creates uneven joints. Inadequate Drenching means that the lead was melted well but was not able to sustain its contact with the pad.
Apply heat on the joint until it dissolves onto the solder pad. Use the tip of the hot iron to get the right temperature.
• Insufficient Wetting
When a pin is not heated properly and solder wasn’t able to melt through, it produces an incomplete pin joint that looks like protruding match sticks.
Apply heat on both the pin and the pad using the warm iron tip and put additional welding material. Make sure that the solder melts completely so it can cover the pad surface.
• Incomplete Solder Joint
A solder- starved joint is one that has very little solder material in it. A bond may be formed but this poorly built joint may crack overtime.
Reheat the fuse and put more bonding agent to form a solid joint foundation.
• Excessive Weld
Too much solder material may appear durable but its ability to connect electrical transmission is unreliable. A deformed joint may or may not manifest a malfunction so it’s better to avoid them altogether.
Eliminate extra solder by picking it out with a heated iron tip or if there is a huge amount then you can use a solder wick or solder-sucker to do the job.
PCB assembly is definitely not an easy task, so even if it can be done at home, most people would prefer to order and purchase from a reliable supplier instead, like pcbnet.com.Our welders have years of experience ensuring top quality printed board products.
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