They are present on 99% of orders and depending on the content of the questions in the worst cases, can add lead time or cancellations, if not resolved in timely manner. We strive to improve tooling time and help meet delivery dates by advising our suggestions in EQ documents and using the customer feedback, to help reduce EQ for future revisions, or similar part numbers.
But what if the customer does not want reduced EQ’s?
On two recent customer visits, I posed this question, and both answered that they like to receive EQ’s as it gives them a positive feeling that data has been reviewed thoroughly. This combined with a copy of the working Gerbers, reassures our customers that no changes have been made to the original design, without their permission
So, what are the limits to an acceptable and unacceptable EQ?
Often, EQ’s can be avoided if easy to understand manufacturing drawings or text documents detailing the minimum requirements for manufacturer, are included in the data packs. Also consider taking EQ’s and implement the fixes in the next revisions or on similar part numbers, especially if you intend to use the same manufacturer.
Let’s look at some common occurrences of EQ and how these can be reduced or removed. First example is board markings. Locations, how it shall be marked and what the markings should contain i.e. UL, manufacturer logo, date code etc, should be a simple instruction on the drawing or text file
Another example is stack ups, clear information regarding material type, copper and dielectric thicknesses combined with any impedance requirements should all be present in the manufacturing data. Allow for some room for adjustment from your suppliers as you will not get the same stack up, material type and impedance results from all manufacturers.
Last example is solder mask, thicknesses, clearances and dam sizes. Often there are numerous EQ’s regarding these and again the simple fix is to make drawing notes accurate to the design. If you don’t have time to do this at design stage, be prepared to make the time to answer when the EQs arrive
Contact us if you want further advice on how to reduce the number of EQs on your designs.
