The implications of non-compliance with new environmental regulations are serious and can affect many areas of business, including manufacturing, distribution and marketing.
The use of lead and other hazardous substances in electronic components is of increasing environmental and political concern, and new international regulations - including the Waste Electrical and Electronic Equipment (WEEE), Reduction of Hazardous Substances (RoHS) and End-of-Life Vehicle (ELV) regulations – are making content compliance and process compatibility critical business issues for component manufacturers and sub-assemblers.
Make compliance a high-profile business issue
Many established systems and corporate infrastructures will be affected by the migration to RoHS-compliant manufacturing. However, recent surveys indicate that the majority of RoHS-aware personnel are those with operational rather than management responsibility.
Designing a roadmap that addresses the business and supply chain issues associated with the transition involves the evaluation of procurement, logistical, manufacturing, rework, communication, and information technology processes.
Smaller companies may opt to delegate responsibility down the supply chain. This approach is the least expensive, but exposes the company to the greatest risk, both in terms of potential legal damages and market share losses.
Ideally, responsibility for organizing a compliance team and implementing the transition roadmap should lie at the senior management level. The compliance team should include supply chain/purchasing managers, risk managers, manufacturing managers, design managers, and information technology managers.
In some organizations, outsourcing the conversion program to a third party is often the most practical solution. The third-party partner provides services that reduce organizational risk and allow companies to test homogenous products, monitor supply chain partners, and search for RoHS-compliant suppliers.
Communicate with the supply chain
Managing product life cycles, developing migration strategies, requalifying materials, and complying with distributor and OEM customer requirements may require a new level of documentation and data management. Obtaining and consolidating material declaration information for all components, comparing it against legislative and corporate standards, and disseminating this information up and down a complex supply chain is critical to maintaining compliance, improving operational efficiency, and ensuring customer satisfaction.
Many global suppliers of electronic components and assemblies have already notified their suppliers that they will require delivery of RoHS-compliant components well in advance of the RoHS and WEEE deadlines in order to meet their own targets. This proactive approach helps manufacturers consolidate design changes, qualify replacements and identify general risks in new bills of material (BOMs).
Identify and track compliant components
Due to the higher temperatures and tighter process windows required by lead-free processing, compliant and non-compliant parts must be segregated. While component suppliers are beginning to supply information on their part numbering and marking schemes, there is a lack of consistency. The Joint Electron Device Engineering Council (JEDEC) has released a marking standard for lead-free components, JESD97, which governs only the issue of lead in solder and termination finishes.
Some manufacturers have added a compliance-identification logo and Moisture Sensitivity Level (MSL) to bulk packaging labels, but will not change the device part marking. Others have added a finish ID mark to the device part mark. Each component manufacturer must be contacted and each component qualified, identified and tracked within the manufacturing process.
Identifying compliant components with a unique part number is of particular importance to electronic distributors, who are also responsible for compliance and visibility of non-compliant stock. One of the most disturbing practices that electronic distributors see is the release of new lead-free modifications to existing parts, without new part number assignments. According to the member suppliers of the National Electronic Distributors Association (NEDA), the confusion resulting from this practice is likely to disrupt the electronics supply chain and significantly increase operating costs for all parties.
Evaluate components and assemblies
Many RoHS-compliant component finishes are available to the industry and are being used successfully in electronic assembly operations. However, each manufacturer must evaluate cost, reliability and manufacturability with compliant alloys, due to factors such as higher melting temperatures.
Higher soldering temperatures also affect PCBs and other components with plastic coatings. Common problems include interfacial delamination, popcorn-induced cracking and warping. Temperature tolerance for these parts must be identified, and replacement components procured, if necessary.
As more component suppliers develop components with pure tin or high tin content alloy finishes in order to meet the new directives, the “tin whisker” reliability problem has increased. This condition occurs when tin reacts with copper containing alloys and begins to grow tiny dendrites known as whiskers. This poorly understood phenomenon poses a serious reliability risk to electronic assemblies. The risks associated with tin whiskers can include short circuits, metal vapor arc and damage resulting from broken whisker debris and contamination.
The International Electronics Manufacturing Initiative (iNEMI) has formed several tin whisker test, modeling and user group projects to investigate why whiskers form and methods for controlling them. Experimental test results and interim recommendations for RoHS-compliant finishes are available on the iNEMI website at www.inemi.org/cms.
Evaluate manufacturing processes
The use of compliant finishes and solders requires higher reflow temperatures. Most component manufacturers are using the 260ºC reflow profile considered by iNEMI as the benchmark. Numerous RoHS-compliant solders are available today, some of which are in common use. However, the component manufacturer should characterize variations in the intended solder under varying process conditions. Because lead-free solder typically requires higher temperatures and longer process durations, each component must be tested to ensure that the device is able to maintain its integrity under these conditions.
Evaluate repair and rework processes
Rework is complicated by the fact that compliant solder alloys do not wet or wick as easily as the Sn/Pb solder. Nevertheless, successful rework methods (both manual and semiautomatic) have been developed with compliant solders for all types of components, and most of the rework equipment for Sn/Pb can still be used for the new solder. Bottom line
Developing a transition roadmap is essential to ensuring a successful transition to RoHS and WEEE compliance. Several departments figure into multiple stages of the product life cycle and
