Archive for the ‘Lead Free’ Category

OrmeSTAR Ultra

Saturday, September 12th, 2009

OrmeSTAR Ultra is a new surface finish which has recently been introduced into the market. I read about this finish in a press release published at www.pcb007.com I am currently managing the installation and qualification of the chemical process at Electropac Co., Inc. located in Manchester NH USA. Their URL is www.electropac.com This shall be the first installation in the United States in a production environment. Ultra is classified as an Organic Metal-based Nanofinish and can be considered a Green process. More information is available from the manufacturer of OrmeSTAR Ultra at www.enthone.com The OrmeSTAR Ultra fact sheet can be downloaded from Enthone or through the link below… (more…)

Immersion Silver Storage and Handling

Sunday, August 2nd, 2009

Printed circuit boards that are coated with immersion silver must be handled with care and stored properly. The shelf life of immersion silver is typically 12 months. Properly stored boards protected from the environment can far exceed that limit. The following considerations must be taken into account in order to preserve the solderability of the finish. (more…)

Immersion Silver

Saturday, August 1st, 2009

Immersion silver is a solderable surface finish applied to the bare copper of a printed circuit board. The role of the immersion silver is to prevent the copper from oxidizing. When soldering to a board with immersion silver a copper-tin intermetalic alloy is formed. The silver is absorbed into the solder joint. Immersion silver is applied as a last operation. It is common for it to be applied to individual boards in piece or pallet form after the parts have been removed from the process panel. This minimized handling contamination and visual defects to the plated surface.

Immersion Silver has the following advantages… (more…)

When to apply ENIG.

Saturday, August 1st, 2009

ENIG (Electroless Nickel Immersion Gold) is applied to the bare copper of a printed circuit board during the fabrication process. When in the fabrication process should be a concern to the contract manufacturer or OEM responsible for assembling the components onto the bare board. If a fabrication drawing states that the printed circuit board shall have SMOBC (Solder Mask Over Bare Copper) then ENIG must be applied after the application of solder mask. There are some exceptions to the rule. (more…)

ENIG (Electroless Nickel Immersion Gold)

Friday, July 31st, 2009

There are many benefits to Electroless Nickel Immersion Gold (ENIG). The first benefit is a very flat and level surface to solder to. This makes ENIG ideal for fine pitch surface mount devices. Another benefit is that the nickel strengthens the structure of the plated through hole. There are some drawbacks to ENIG. ENIG is an unforgiving process. Once the coating is applied there is no going back. Techniques that could be used to remove the finish are also damaging to the copper. Tight chemical and process controls need to be in place at printed circuit board manufacturers in order to provide a quality coating of ENIG per IPC-4552. Defects with the ENIG plating process may not be discovered until (more…)

Why can’t I use FR4 with Lead Free Soldering.

Saturday, January 17th, 2009

You can build a printed circuit board and solder it through a lead free soldering temperatures. It is not advisable! I know some designers that use standard FR4 for lead free soldering applications. The designs are simple single and double sided boards. The companies that they work for have done the due diligence to prove out their design and manufacturing process. On moderate to complex designs they specify lead free soldering compliant laminates in place of FR4. The compliant laminates are much more expensive than standard FR4. They made the upfront investment system by doing the testing and evaluating to save money down the road. They know what they can get away with and have the test data to prove it. However, the results are specific to their designs and their assembly process. When in doubt, play it safe and specify lead free soldering compliant laminate. In order to justify the cost of the more expensive laminate you need to understand what happens to the material at high temperatures.

The main challenge faced by a laminate system is (more…)

RoHS vs. Lead Free Assembly

Saturday, January 17th, 2009

It is easy to mis-interpret the relationship between RoHS and Lead Free Assembly. Lead Free Assembly has been around for decades in limited applications. RoHS came about when the European Union passed a directive known as WEEE. WEEE or Waste of Electrical and Electronic Equipment (2002/96/EWG) regulates the end of life disposal and recycling of electrical waste. The legislation states that producers are responsible for waste and financing its collection. Users from private households should be allowed to recycle products free of charge. To reduce recycling costs the restricted or banned materials, manufacturers are striving to remove these substances from their product. This is where RoHS comes in.

RoHS or Restriction of Hazardous Substances (2002/95/EWG) prohibits the use of the following substances: (more…)