Archive for the ‘Soldering Supplies’ Category
Lead Free Reflow Profile Chart
Monday, August 17th, 2015Lead Free RoHS Information
Friday, August 14th, 2015Which are the exceptions to the RoHS and WEEE directives?
There are a lot of exceptions to the RoHS and WEEE directives. In order to be sure if one or more exceptions apply to the end product or sub product the directive needs to be consulted carefully. In general the military, air and space electronics are exempt. Some Medical devices are also exempt. Alloys with Pb concentration above 85% are equally exempt.
Where can I get up-to-date web information on WEEE and RoHS directives and progress?
Getting up-to-date information is critical to your company’s transition roadmap. A good place is the web and the following website contains updates originating from the TAC (Technical Adaptive Committee) for the RoHS. The website www.dti.gov.uk/sustainability contains copies of the WEEE and RoHS Directives but also the latest minutes of the TAC meetings. Another useful website in reference to the WEEE directive which includes the EU’s perspective is www.europa.eu.int/comm/environment/waste/weee_index.htm.
What are the new IPC-1066 and IPC-1085 Documents and how can they help you in the RoHS-Lead-free transition?
These IPC documents were issued in January 2005. The IPC-1066 is titled “Marking, Symbols and Labels for Identification of Lead-free and Other Reportable Materials in Lead-free Assemblies, Components and Devices” is a document detailing ways to identify components with lead-free finishes, but it can be expanded to board finishes and solder used for assembly. A letter system from e1 to e9 will identify the various lead-free finishes. This document will be used primarily by component manufacturers in the identification and labeling of lead-free components. This document should be used to train procurement, inventory control and production personnel, so as to create an awareness of the component finishes intended to be soldered. The IPC-1065, Material Declaration Handbook details the hundreds of other controlled chemicals restricted in electronic assemblies and also details approved test methods for their detection. It will be useful if a RoHS banned substance must be tested for.
What are the labeling requirements to indicate RoHS product compliance?
The RoHS Directive doesn’t require any specific label to be put on assemblies or box builds. Although some companies have designed their own label and some are using it, by law it is not necessary. Any product entering the European market will be assumed to be RoHS compliant. The same applies to the lead-free logo; it too is not required. Some manufacturers are using their logos to indicate the product is lead-free but this is usually for marketing purposes.
Do I need Material Declarations for my finished product?
A Material Declaration showing compliancy for your product is not required by the EC law. However, if a product entering the European market is intercepted and found to be non-compliant to the RoHS after July 1, 2006, it will be important to demonstrate that a company has done all that is possible in insuring compliancy. Material Declarations or data from each component used in the assembly will then be required. Keeping Material Declarations for each individual item used in a build is important and can show good due diligence has been exercised. A close relationship with suppliers is essential.
What are the main elements required from a Material Declaration Form for my components, boards, wiring, etc.?
The essential elements a Material Declaration must contain are as follows:
Compliancy to European RoHS Directive banned substances,
Free of Polybrominated Biphenyls and Polybrominated Diphenyl ethers flame retardants, can be found in some plastic molding compounds and laminates
Temperature maximum limits for a lead-free soldering process
New Moisture Sensitivity rating for lead-free assembly
The key is to insure banned substances are not present, but also that the parts are lead-free process compatible. Lead-free soldering when using SAC alloys will require hotter thermal profiles. To insure reliability close attention must also be placed on the maximum temperature the part can see but also the impact of moisture.
What is the definition of “lead-free”? Is there an allowable threshold limit?
The EU RoHS directives defines 0.1 wt% (1000ppm) as the threshold for lead per homogeneous material if not intentionally introduced (i.e. each material prior to soldering).This is defined as a limit for each homogenous material, i.e. component lead, lead plating, glass fibres, plastic moulding, solder, pad finish etc. It is NOT defined at 0.1% by mass of the finished product, or circuit board.
Pin Holes: Pin holes often appear on the surface of solder joints. How are they formed?
Friday, August 14th, 2015Pin holes are formed as a result of moisture entrapment. All that is required is a tiny amount of moisture. When the solder comes in contact with the through-hole, component lead, wire or whatever is being soldered, the water boils and it forms a gas bubble that will either escape or be trapped as the solder solidifies
Sn60 vs. Sn63: When is the use of one of these two alloys more appropriate than the other?
Friday, August 14th, 2015The Sn60Pb40 has a plastic range and puts down a slightly thicker coating of solder. Sn60 is often preferred for lead tinning and other solder coating applications. Sn63Pb37 is eutectic and as such has no plastic range. Generally it flows better than the Sn60 and is the preferred alloy for wave soldering and surface mount applications.
Lead-Free vs. Leaded Solder
Thursday, July 30th, 2015The Restriction of Hazardous Substances directive is more commonly know in the electronics industry as RoHS. The RoHS directive is aimed at restricting the use of 6 hazardous materials in the manufacture of electrical and electronic devices as follows:
• Lead (Pb)
• Mercury (Hg)
• Cadmium (Cd)
• Hexavalent Chromium (Hex-Cr)
• Polybrominated Diphenyl Ether (PBDE)
• Polybrominated Biphenyls (PBB)
RoHS 1 is closely linked with the Waste Electrical and Electronic Equipment Directive (WEEE // 2002/96/EC) which sets guidelines for the recovery, collection and the recycling of electrical goods to solve the problems associated with tremendous amounts of toxic waste.
The effect of these two initiatives have had on the electronics industry varies greatly depending on the target sales market and the end use of the product. The overall supply chain from individual components to bare printed circuit board manufacturing has shifted from a predominantly tin-lead alloy based market to one that caters almost exclusively to lead-free finishes. The result has been limited supply, and in some cases, complete elimination of tin-lead plated components. This has, in effect, forced manufacturers to make design and process changes on products that were traditionally tin-lead based.
The primary difference between lead-free and tin-lead solders, from a desoldering, repair and rework standpoint, is the temperatures required to form a proper inter-metallic bond. For the most widely used tin-lead alloys such as Sn60 Pb40 or more commonly Sn63 Pb37 (eutectic), the melting point is 361° (183°). The most commonly used lead-free alloy, Sn96.5 Ag3.0 Cu0.5, commonly referred to as SAC 305, has a melting point of 422° F (217° C) to 428° F (220°). The resultant increase in melting point will have the effect of reducing the overall process window and can change the traditionally accepted appearance of the finished product.
Prior to the implementation of the RoHS and WEEE directives, the use of tin-lead solder was widely accepted and it’s reliability was exhaustively tested and it’s appearance easy to inspect. Virtually all electronics assembly were designed to withstand manufacturing with the commonly known tin-lead solder and the temperatures that they require. Further, virtually all specifications written for the compliance of electronic assemblies in the military, government and consumer markets were written with the same tin-lead alloy in mind.
Today the use of lead-free solder alloys that comply with the RoHS and WEEE directives are in wide use and while segments of the electronics industry continue to perform reliability and life-cycle testing on complete RoHS and WEEE compliant assemblies and manufacturing processes, the use of individual lead-free components and board finishes is commonplace.
The Process Guides contained herein will reference the common tin-lead (Sn63 Pb37) and lead-free SAC 305 (Sn96.5 Ag3.0 Cu 0.5) alloys.
What is RoHS?
Thursday, July 30th, 2015First adopted by the European Union, The Restriction of Hazardous Substances Directive (RoHS 1 // 2002/95/EC) limits the use of certain hazardous substances used in the manufacture of various types of electrical and electronic equipment. The EU adopted these restrictions in February 2003. This directive restricts, with exceptions, the use of six hazardous materials. The hazardous materials that RoHS aims to control are Lead, Cadmium, Mercury, Hexavalent Chromium Polybrominated Diphenyl ethers and Polybrominated Biphenyls. RoHS 1 is closely linked with the Waste Electrical and Electronic Equipment Directive (WEEE // 2002/96/EC) which sets guidelines for the recovery, collection and the recycling of electrical goods to solve problems associated with tremendous amounts of toxic waste.