Standard of Excellence: Finding and Developing Future Leaders in Manufacturing
Global Sourcing Spotlight: Navigating the Variables of Holiday Schedules in Global Sourcing
Nolan’s Notes: Soldering Technologies
BOOK EXCERPT: The Printed Circuit Assembler’s Guide to... Encapsulating Sustainability for Electronics, Chapter 2
July 3, 2024 | I-Connect007 Editorial TeamEstimated reading time: 1 minute
The following is a brief excerpt from: The Printed Circuit Assembler’s Guide to... Encapsulating Sustainability for Electronics
By Beth Turner, MacDermid Alpha Electronics Solutions
Chapter 2: Application Overview
There are many important things to consider when applying an encapsulant. This chapter is an overview of the application process, we will cover many of the terms and definitions found on a technical data sheet and discuss the primary considerations for each of the process stages. It is worthwhile considering some of the terms and definitions found on a technical data sheet to understand how the different liquid, mixed system, and cured property values can dictate the method chosen to apply materials.
Storage
It is important to store liquid encapsulants according to the manufacturer’s specification to ensure shelf lives are achieved. Single component materials require external energy sources to initiate the curing reaction; heat-cure systems should be stored in cool, often sub-ambient temperatures; UV-cure systems should be stored in blackout containers to prevent premature curing. Partial curing can increase the viscosity and cause small gelatinous clumps to form in the liquid system; this can cause problems during the application, for example, blocking valves and lines in dispensing equipment. Some liquid encapsulants are sensitive to moisture; it is important to keep such encapsulants stored in airtight containers. In addition to the problems above, moisture contamination can also cause unwanted side reactions during the cure process that can lead to undesirable bubbles and voids.
The Liquid Properties
When asked, “What is the viscosity,” the short answer is, “It depends.” Most encapsulants in their liquid state exhibit non-Newtonian flow and thus viscosity is not a single number. Viscosity is dependent on a variety of factors, including temperature, shear rate, time, and volume. Rheology profiling could be a more useful tool to understand liquid flow properties.
It is also important to understand the density of the material to convert between the weight and volume mix ratio, but also to understand the weight contribution an encapsulant will have, to a PCBA or unit.
Share on:
Suggested Items
GB200 Rack Supply Chain Requires Further Optimization, Peak Shipments Expected Between 2Q25 and 3Q25
12/18/2024 | TrendForceAs the market closely follows the progress of NVIDIA’s GB200 rack-mounted solution, TrendForce’s latest research indicates that the supply chain requires additional time for optimization and adjustment.
Liquid AI Raises $250M to Scale Capable and Efficient General-purpose AI
12/16/2024 | Liquid AILiquid AI announces a Series A round of financing with AMD Ventures as strategic lead.
Compal, ZutaCore Collaborate to Showcase Groundbreaking Waterless Two-Phase Liquid Cooling Server Solutions at SC24
11/25/2024 | Compal Electronics Inc.Compal Electronics, a global leader in server innovation, has partnered with ZutaCore®, a leading provider of waterless direct-to-chip two-phase liquid cooling (2P DLC) solutions, to introduce a series of groundbreaking server solutions.
Unlocking Advanced Circuitry Through Liquid Metal Ink
10/31/2024 | I-Connect007 Editorial TeamPCB UHDI technologist John Johnson of American Standard Circuits discusses the evolving landscape of electronics manufacturing and the critical role of innovation, specifically liquid metal ink technology, as an alternate process to traditional metallization in PCB fabrication to achieve ever finer features and tighter tolerances. The discussion highlights the benefits of reliability, efficiency, and yields as a tradeoff to any increased cost to run the process. As this technology becomes better understood and accepted, even sought out by customers and designers, John says there is a move toward mainstream incorporation.
Jabil Introduces New High-Performance, Purpose-Built AMD and Intel Servers Optimized for AI, FinTech, and Cloud Applications
10/14/2024 | BUSINESS WIREJabil Inc. announced that it is expanding its server portfolio with the J421E-S and J422-S servers, powered by AMD 5th Generation EPYC™ and Intel® Xeon® 6 processors.