Reduce BOM Lines or reduce BOM cost? How to make production cheaper? [closed]

Question

We are designing a product that will hopefully sell many thousand units, and now I am at the stage of specifying what parts to use.

We require three inter-board connectors, one with 10contacts and two with 4 contacts. Instead of using two different sizes, we can just use three of the ten contact connectors. The ten contact connectors cost 30% more than the four contact connectors at volume. So the obvious choice is to spec for two different parts on the BOM.

But more BOM lines increases the PCBA assembly cost, and increases the inventory of components we have to hold.

What has the greater effect on unit cost, reduced BOM lines, or reduce BOM cost?

Answer 1

The obvious answer to your question is that it really depends on a number of factors. You have to weigh the cost per part versus the cost per BOM line to determine the most cost effective approach.

On thing that can be said though if you are working on BOM line item minimization is to first concentrate your attention on those lines with the lowest part costs. This will almost assuredly be first in the SMT resistor category followed closely by the low capacitance valued SMT capacitor category. The biggest gains will come here. Think seriously if you have 10K and 12K resistors if you can have both lines be the same value....even if that ends up being that you end up specifying 1% resistors for both line items.

Answer 2

If these parts are hand-placed, the build cost impact of 2 different part numbers is probably small. If they are machine placed, reel sizes may mean it is irrelevant (3 identical reels, or 1 plus 2).

Unless you can make cost savings by buying in bulk, you are optimising the wrong part.