This is a summary post aimed at providing some guidance to newcomers in the electronics assembly field on methods for analyzing the solderability of BGA (Ball Grid Array) solder balls. Workingbear decided to write this after seeing someone ask about this topic in an online forum. Some of the content might overlap with topics already covered in previous blog posts.
Workingbear recently received questions from readers about electronic component soldering leads turning yellow or showing discoloration (purple, blue, etc.) after going through the reflow oven. Why do the leads of components discolor after reflow? Does this discoloration affect product functionality? And how should we handle discolored components or assembled PCBs? Let’s dive into these questions for this article.
This is a answer to a question from a community member asking about plastic quality control. The question was: “Can we rely solely on MI (Melt Index) values to monitor the quality of plastic resins? And does an increase in MI indicate plastic property degradation?” Many people believe there is no direct correlation between MI values and cracking in plastic products.
When discussing whether using re-grind resin in plastics leads to degradation, Workingbear sought advice from industry experts. Most professionals agreed that it does cause degradation. However, opinions on whether MFI values can reliably indicate the presence of re-grind resin are divided within the industry. The conclusion? It’s uncertain but worth considering. Below is a summary of the information compiled by Workingbear.
It’s an open secret in the plastic injection molding industry that re-grind resin is often added during injection. Some manufacturers even claim that, given the current competitive environment and cost-cutting pressures, it’s impossible to make a profit without using some re-grind resin. Plus, they argue it promotes recycling and aligns with today’s emphasis on environmental sustainability. However, from a quality perspective, adding re-grind resin introduces risks of reduced strength and increased brittleness in the structure of plastic products.
