![]() ![]() Solder paste is placed inside a jar and put into the solder paste mixing machine. Solder paste can be mixed using a Solder paste mixer. To ensure consistent viscosity, the solder paste needs to be mixed. When stored, the viscosity of the solder paste can change as solder particles with a high specific gravity settle at the bottom of the jar. ![]() However, when the solder paste needs to be used, we can not just use it straight out of the tub. Refrigeration ensures that the solder paste maintains its properties for a longer period of time and thereby increase the shelf life of solder. I incrementally add to it as I find the time, but unfortunately it's currently far from done.Solder paste is usually stored in a refrigerator when kept over a long period of time. I wrote it from scratch instead of stealing content from PCB reviews on the internet. The following are some things to consider. There are many PCB review tip lists on the internet. Whether it is obvious or not, the person who designed the schematic shouldn't be the only person that reviews the schematic, same with the person that laided out the PCB shouldn't be the only person that reviews the PCB. Make sure the package for the part number matches with the package that was used on the PCB layout. If you have the time, do a full BOM review, make sure every part number is correct and orderable. Print schematic to paper, get some yellow hilite pens, then choose one net connection at a time on the schematic, then follow the trace on the pcb, decide if it's ok or not, then draw a yellow line over the entire net on the sheet of paper, choose next net and repeat until done. This is very time consuming, and should be done as a team effort. If you have the time, you should do a net by net comparison review between the schematic and PCB too. Someone should do a full schematic review to look for any high-level engineering design problems. Simple example to get point across (not saying you must use this format): * _.pdf Make this group of PDF files part of what is included in your review package. Seriously, don't be a lazy fool that downloads the datasheets from distributors or random internet website!!! Rename every PDF file name using some common file naming method, and use a naming scheme that benefits your group the best. ![]() If a PCB costs $10 each, then not the same level of monetary risk as a PCB that costs $500 each.īefore starting any review, someone should download the latest PDF datasheet for every part from the original manufacturer website. The more expensive the PCB, the more time you should spend on reviewing things. You have to determine how deep you want to go. To do a full comprehensive review takes a lot of time. I typically turn off everything, then turn-on board border and drill holes, then turn-on only one copper layer and look at it, then turn it off, then turn on the next copper layer, then after done with all layers just turn on the top copper layer plus top silk screen and look at them as a pair then turn top layers off, then do the bottom copper layer with bottom silk screen. Make sure you generate gerbers, then use a gerber viewer to look at one layer at a time. ![]() There is a lot of validation work that you can do internally BEFORE sending it out. RF, PLC, CAD, HW Startups, Robotics, Microcomputing, DIY Audio, DIY Gear, DIY, Mindstorms, ASM, EE Books, Product Design, LabVIEW, Breadboard, RTLSDR, Manufacturing, Electronic Circuits.īefore sending out a board, your team should have an internal review to catch "easy to find" mistakes, which allows you to fix the schematic and/or PCB until you feel it's worth asking a 3rd party to review it.
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