What's the best way to clean a misprinted PCB?

During stencil printing, circuit boards are periodically misprinted due to clogged apertures, stencil out of alignment, solder paste rheology shifts and other issues. Stencil misprints are defined as

1. A-Side Misprint: Initial print out of alignment with no components previously placed
2. B-Side Misprint: A-Side was successfully printed and components placed and soldered. The subsequent process of printing the B-Side results in the solder paste being out of alignment resulting in a B-Side misprint

Companies commonly address the misprint by either hand wiping the misprinted side of the circuit card and/or cleaning the misprint in a stencil cleaning machine.  The method of hand wiping the misprinted side of the PCB is not recommended as solder paste can be trapped in the solder mask defined channels and through-hole vias - this can be seen in the image above.
The best approach is to clean the misprinted circuit board using an automated cleaning process that provides programmable wash, rinse and dry steps. Production cleaning systems remove both wet solder paste and reflowed flux residues while meeting quality and yield objectives. To capture the wet solder paste, innovative collection and filtration systems safely capture and contain solder spheres from being sprayed onto production assemblies. Additionally, the containment and filtration systems prevent raw solder paste from entering the rinse water streams.

The printed circuit board should be cleaned as soon as possible after the mis-print to achieve the best results.

SMT PCB Stencil Cleaning Machine:

Machine Description：
SME-800 is a high quality aqueous detergent stencil cleaning machine which used to clean solder paste stencil, red glue stencil, red glue cooper stencil, mis-print PCB, large size PCBA.
The total process--aqueous detergent clean, water rinse, hot air dry are complete just in one wash chamber. The Unique 4 fixed cleaning spray rods, 4fixed air knives and stencil move back and forth design makes the machine stable, reliable and super cleaning result.
Machine Features：
1.Suitable to clean SMT stencil ,cooper mask, resin mask, misprint PCB and large size PCBA
2.The unique 4 spray rods and 4 air knives fixed and stencil moves clean mechanism, more stable. quick and efficient to clean remaining solder paste ,red glue and flux on SMT stencil ,cooper mask, resin mask, misprint PCB and PCBA.
3.The unique real-time aqueous detergent filtering system is right for precise stencil cleaning.
4.State of the process is visible through a large observation window.
5.Real-time measure DI water resistivity and monitoring cleaning effect.
6.The remaining detergent in the pump and pipes are blown off by compressed air and flow back to cleaning tank. This function saves detergent up to 50%.
7.Can used as PCBA cleaning machine to clean PCBA up to 800mmx800mm
8.English color touch Panel operational interface, PLC procedure control, cleaner temperature,  clean time , rinse time and rinse times ,clean temperature, hot air dry time and temperature,  resistivity can be set and monitored as required.

Machine Spec：

Item	SME-800 Spec
Max Stencil Size	L800 x W800 x H40(mm)
Liquid tank	60x2pcs
Clean time	2~5min
Wash time	1~3min，
Dry time	3~5min
Rinse times	1~99time
Clean detergent	Aqueous detergent
Rinse water	DI water（water）open-loop or close-loop
Dry method	High pressure hot air dry
Detergent heat temp	0~60℃
Hot air dry temp	0~90℃
Clean heat power	9KW
Rinse heat power	9KW
Hot air heat power	6KW
Clean/rinse filter	0.45um
Resistivity range	0~18MΩ
Power	AC380V,50/60HZ,28KW
Machine size	L1300xW1400xH1950（mm）

Keywords:

SMT Reflow Oven, Lead free Reflow Oven, Reflow Oven Manufacturer, LED reflow oven, PCB Reflow Oven, Nitrogen Reflow Oven, Dual Rail Reflow Oven, China Reflow Oven, wave soldering machine, Dual Rail Wave Soldering Machine, Nitrogen Wave Soldering Machine, Wave Soldering Machine Manufacturer.

Flason Electronic Co.,ltd provide a full SMT assembly line solutions, including SMT Reflow Oven,  Wave Soldering Machine,  Pick and Place Machine,  SMT Stencil Printer,  SMT AOI SPI Machine,  SMT Reflow Oven,  SMT Peripheral Equipment,  SMT Assembly line,  SMT Spare Parts  etc any kind SMT machines you may need, please contact us for more information: wechat whatsapp:+8613691605420, Skype: flasonsmt, Email: sales@flason-smt.com
FAQ
1) This is the first time I use this kind of machine, is it easy to operate?
There is English manual or guide video that show you how to use machine.
If you still have any question, please contact us by e-mail / skype/ phone /trademanager online service.
2) If machine have any problem after I receive it, how can I do ?
Free parts send to you in machine warranty period.
If the part is less than 0.5KG, we pay the postage.
If it exceeds 0.5KG, you need to pay the postage.
3) MOQ ?
1 set machine, mixed order is also welcomed.
4) How can I buy this machine from you? ( Very easy and flexible !)
A. Consult us about this product on line or by e-mail.
B. Negotiate and confirm the final price , shipping , payment methods and other terms.
C. Send you the proforma invoice and confirm your order.
D. Make the payment according to the method put on proforma invoice.
E. We prepare for your order in terms of the proforma invoice after confirming your full payment.
And 100% quality check before shipping.
F.Send your order by air or by sea.
5)Why choose us ?
A. Gold supplier on Alibaba !
B. Trade assurance to US$54,000 !
C. Best price & Best shipping & Best service !