Didn't Your prototypes turn out as expected?
Who would have thought that skipping an important step of quality inspection during manufacturing could lead to faulty products? But fear not, for I am here to save the day with my advice.
So, let's get down to business and talk about the importance of quality inspection for prototype manufacturing. First and foremost, it's crucial to ensure that the final product meets the specified requirements and is functional. Without proper inspection, you may end up with a batch of prototypes that are nothing more than expensive paperweights.
The solder bridges does not look too nice on this picture, doesn't it?
A client reached out us, they had issues during the production of a small batch of prototypes from a Chinese Manufacturer, leading to functional devices not being produced. Couple of devices were working and couple of them are not. Some of them was working for couple of days then, for a sudden, they were producing different kind of weird issue. After optical inspection, we realized quickly, the problem was traced back to poor soldering caused by improper stencil printing.
Oh, yay! Look at these shots, it's just perfect. The pads have exactly the right amount of solder to ensure a proper connection to the board. I mean, who needs a proper connection anyway when you can just experience the joy of weird issues?
To maintain consistent and reliable quality, during the manufacturing process, it is recommended to have a comprehensive checklist that is checked at each start of production. This will ensure the stencil printing is performed perfectly, contributing to the overall success of the process. Here is a reference that should be taken during prototyping:
Use proper cutouts for critical parts of the stencil to have proper amount of paste applied to the pads. Having too small cutout could lead to small amount of paste printed to PCB.
Clean the stencil after each board to remove any residue and ensure a clean surface for the next print. Leaving paste on the stencil could cause less paste printing to the next board.
Inspect and clean the cutouts before applying solder paste to prevent any debris from interfering with the process.
Provide support to the board to avoid bending of the stencil and maintain its stability. Bent stencil could lead too much paste printing and bridges on your board.
Stretching the stencil is essential for consistent and even spread of paste.
At start of production examine the amount of paste on each board to ensure consistency and mark any boards with too little paste for documenting purposes.
Perform 100% AOI or MOI (automatic or manual optical inspection) of the critical components after soldering and mark any boards with non-proper solder.
Do proper documentation of the manufacture.
In conclusion, the moral of the story is this: don't be like the manufacturer mentioned in the the article and make sure to include quality inspection in your prototyping process. Trust me, you'll thank yourself later.
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