Dear industry colleagues,
Not infrequently off line e-mail arrives which is often both illuminating and thought provoking. The following material is from one such message, in this case, from a contract manufacturer who has some posed some technical and logistical questions regarding conversion to lead-free that are likely being faced by most if not all contract assemblers.
I received permission from them to post the following for general comment. Please consider this a "from the trenches" request from an individual on the front lines.
Comments, suggestions or ideas relative to the points made should preferably be posted on the forum, however, if you prefer, I can take your comments off line and forward them to the sender.
Thanks in advance for sharing your thoughts/comments.
Kind regards to all,
Joe
"1. As a contract manufacturer, we have many customers with many designs, and many different component part numbers. It is not clear who will be responsible for identifying which components can handle the longer hotter reflow cycles or wave process. I am sure the burden will be shared as some customers will request the change and others may accept the change.
2. I am not as concerned about the bare board materials as I am about the individual components. For each component, the reliability and functionality needs to be reviewed -- especially components that are Moisture Sensitive Devices as those have been qualified under the 63/37 reflow melting temperatures.
3. Identifying, Categorizing, and Separating inventories for customers with lead-free vs. not lead free is going to be a logistical nightmare. Keep in mind, if there is no legislation in the US and some of our customers are happy with the current alloy they will have no reason to change and CM's will need to keep inventories straight.
4. Many companies have a difficult time keeping No-Clean and Water Soluble chemistries from being mixed -- Imagine if we need to keep Lead-Free No-Clean and Lead-Free Water Soluble chemistries away from the Leaded No-Clean and Water Solubles?
5. Equipment -- A second Wave machine will be needed, center support rails on the reflow ovens will be needed to support the PCB's that sag under higher heat, increased machine maintenance will be needed, and imagine how the cost of electricity will go up along with the cost of increased AC! What about Nitrogen -- We'll probably need to add that with the board finishes and higher temps. How will X-ray work without Lead? How will Vision systems work as the reflectivity of the solder joints change?
This just touches the tip of the iceberg.
I suppose what confuses me the most is the cost. Is the cost of this all justified? Has anyone done a cost/benefit analysis?
I am also confused when I hear that Silver is one of the elements used in one of the more promising alloys. Is the risk and high toxicity level associated with mining and refining silver far less than the toxicity of the lead that ends back up in the ground (where it started in the first place?)
And what about the guy who dumps his battery on the side of the road so he doesn't have to pay $5 to get rid of it properly?
Well, I suppose that's enough for one night. It was kind of fun to be on the soap box for a few minutes and relieve some of the stress about what might become inevitable."