Re: How to evaluate or ciertify 0402 parts| 19 September, 2000
1.Make a program that mounts rows of 0402 parts one after the other with spacings 0.3mm or 0.2mm (to check your machine repeatability) taking the parts from four different feeders(this is a must if you have turret machine). Place rows of 0402s at 0 degrees and lines with 0402s at 90 degrees (of course with double sided adhesive tape). 2.Check for missing parts or misalignments and what kind of components are mounted worse (capacitors or resistors). 3.Check your machine info after the test, you should expect >99.70% mounting rates. 4.Make sure your machine can handle the recognition of this components (shape & height) usually height measuring(pick up error) is the biggest problem with resistors. 5.When mounting a real PCB you can have spacings up to 0.3mm with the 0402s are mounted this way --> ||||||| (many cell phones use this)and up to 0.5mm if mounted this way -> - - - - - or any other way. 6.Just one more advice: do not trust vendors specs, you have to evaluate by yourself.