Exploring Alternatives to RoHS Restricted Substances in Electronic Components

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In summary, the Restriction of Hazardous Substances Directive is a list of substances that are to be avoided when possible during manufacturing. There are alternative substances and processes which help during the design / manufacturing phase for electronic components, but there may not be a suitable alternative for keeping the physical integrity of the part from diminishing due to using a sub-standard alternative.
  • #1
dingpud
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Restriction of Hazardous Substances Directive...

As most of you know, there is a list of restricted hazards which are to be avoided when possible during manufacturing, designing, etc...

The list for the ROHS via a recent search through wikipedia.org list the following:
1. Lead
2. Mercury
3. Cadmium
4. Hexavalent chromium (Cr6+)
5. Polybrominated biphenyls (PBB)
6. Polybrominated diphenyl ether (PBDE)

What alternative substances and processes exist which help during the design / manufacturing phase for electronic components? Purchase Orders are starting to impose restrictions stating that RoHS substances may not be used. One problem with that is there may not be a suitable alternative to keep the physical integrity of the part from diminishing due to using a sub-standard alternative.

If anyone has any experiences that they would be willing to share, I am sure many of us could benefit. I am getting ready to enter into this problem, and will report any failures / successes that I come across.

Best to all...
 
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  • #2
We went through this at my company over the past couple of years. In general, the RoHS parts require higher temperature soldering processes (less/no lead), and that is the biggest re-qualification issue. If folks have specific questions, post them here, and we'll try to help out in answering them.
 
  • #3
Within the coming months, I am definitely going to have some questions. Is there an issue with allowing a thread to go on for a while without any replies, then post a reply a couple weeks or a month later?

I was reading a thread where someone pointed out that old threads should not be reinitialized.

thanks,
 
  • #4
dingpud said:
Within the coming months, I am definitely going to have some questions. Is there an issue with allowing a thread to go on for a while without any replies, then post a reply a couple weeks or a month later?

I was reading a thread where someone pointed out that old threads should not be reinitialized.

thanks,

No worries. That's why I stickied it. I'll try to find a good reference or two, and post the links for general info as well.
 
  • #5
Does anybody have any good suggestions / experience with brands and/or compositions of lead-free (reduced?) solder for manual soldering? I did some stuff with silver solder years and years ago which I found nearly impossible to work with, and I remember popping a number of pads on the (home etched) PCB I was using at the time. I was just starting out at the time, so I imagine that probably had a hand in things, as well.
 
  • #6
MATLABdude said:
Does anybody have any good suggestions / experience with brands and/or compositions of lead-free (reduced?) solder for manual soldering? I did some stuff with silver solder years and years ago which I found nearly impossible to work with, and I remember popping a number of pads on the (home etched) PCB I was using at the time. I was just starting out at the time, so I imagine that probably had a hand in things, as well.

No suggestions on brands, but I'd stongly suggest investing in a Metcal soldering iron. They're a bit more expensive than the traditional Curie point temp-control soldering irons, but they are amazing at how well they control the tip temperature, and how they handle such a wide range of soldering (fine SMT all the way up to big lugs and things). They use RF heating of the tips.

http://www.okinternational.com/
 
  • #7
Falling in line with the RoHS topic, when you do in fact have an item, say solder, and you need to get a lab to do the inspection to find out what the composition of the solder is, who do you use?

Going through one of those wonderful quality audits and it has been mentioned that we need a third party inspection of our solder to match the spec sheets the vendor provides. Any suggestions, and any guesses on how much that costs.
 
  • #8
dingpud said:
Falling in line with the RoHS topic, when you do in fact have an item, say solder, and you need to get a lab to do the inspection to find out what the composition of the solder is, who do you use?

Going through one of those wonderful quality audits and it has been mentioned that we need a third party inspection of our solder to match the spec sheets the vendor provides. Any suggestions, and any guesses on how much that costs.

I ran this by our RoHS specialist, and here is his response:

The are many analysis labs out there. Any lab that has X-ray fluorescence (XRF) is suited to do testing down to the ppm level or go/no-go. Trace Labs back east was the lab that we used for the majority of our testing which was only done on our proto runs in leadfree process.

In the production environment and after we converted to RoHS, we have avoided going down the road of testing by making sure that our contract manufacturer (CM) specified/documented which solder type and supplier they were using. I believe we were able to get our CMs to even use the same suppliers (there are only a few major ones out there). We also made sure that our boards on built on lead-free lines to prevent any potential Pb contamination. At the component level and PCB level we control the AVL (approved vendor list) and we have RoHS Cert documention for each component down to the supplier level.

If the custumer is using a CM who is building leadfree and non-leadfree assemblies on the same line, there there is a potential problem there with contamination and testing would be a good idea. If this testing is going to be frequent, they should consider buying a portable XRF detector. Better yet, if their CM is still mixing leadfree and non-leadfree builds, they should consider finding a CM who has a dedicated lead-free line.
 
  • #9
you may want to add beryllium to your list. the oxide is used as a thermal conductor sometimes and is extremely toxic.
 
  • #10
Proton Soup said:
you may want to add beryllium to your list. the oxide is used as a thermal conductor sometimes and is extremely toxic.

Sorry, I didn't understand your post. Do you mean that the RoHS initiative has added beryllium to their list and we should be aware of it, or do you mean it's something that we should think about independently of the RoHS initiative? I honestly am not that up on it all myself, and use our in-house expert for this stuff.
 
  • #11
berkeman said:
Sorry, I didn't understand your post. Do you mean that the RoHS initiative has added beryllium to their list and we should be aware of it, or do you mean it's something that we should think about independently of the RoHS initiative? I honestly am not that up on it all myself, and use our in-house expert for this stuff.

i'm not familiar with RoHS, just mentioning another hazard some may run into. probably rare and only seen by defense applications and such. sorry if this goes outside the scope of this thread.
 
  • #12
Something that I realized a little while ago, but forgot to post, is that some contracts have a specific requirement RoHS components are not to be used. The reasoning for this is the TIN whiskers which can form on the leads of components causing them to break.

http://en.wikipedia.org/wiki/Tin_whiskers

Certain jobs allow you to be exempt from the RoHS stuff, so beware of that. A real pain in the butt is that some vendors have switched to RoHS compliant parts, but don't tell everyone that they have, kept the same part numbers...so an inventory nightmare potential...
 
  • #13
What is your industry, customer type, and customer location? There are exemptions that you may be entitled to follow if you use BGA packages, press-fit connectors, or other devices where lead is still required for proper assembly and long term reliability.

You will still face supply chain issues as vendors change to tin-only interfaces with the same part numbers. For the critical parts many have chosen to change their part number because they understand the danger of mixed stock.
 
  • #14
I noted that you specifically mentioned "electronic components" rather than assemblies - in light of that, almost all electronic component manufacturers have been offering RoHS compliant parts for some years now; some haven't changed manufacturing part numbers - can be a nightmare in this respect. There is a general consensus that they don't last as long as traditionally made lead-based components, but it also depends on your application. Medical devices and military applications are exempt (category 8 and 9) - there are more, but hey. The directive mainly concerns itself with the broad umbrella of consumer products.

If you meant electronic assemblies, we have had excellent results using SAC 305 (96.5 Sn/3.0 Ag/0.5 Cu). It takes some getting used to, but reliability is good as long as the process of heating, soldering and cleaning is followed.

Hope that helps somewhat.
 
  • #15


I've been working very closely with Microsoft and Motorola and since the advent of ROHS more manufacturers are going back to the use of tin. Tin in leaded solder does not pose a problem, but whith the deletion of lead we were seeing some odd things happening, namely Tin whiskers . We were surprised to find how fast these crystalline structures grew and obviously it posses a serious threat, for thay are conductive. We have even reported crystalline growth in lead free solder, needless to say about a recall we had with hard drives that had tin in the outer covers that when the structures grew on the inside of the drive, well need i say more! The problem has been serious enough that NASA had to pull all 52 of the flight computers out of the shuttle because of this, some whiskers were up to 18mm long! So sometimes the cure is worse then the illness. http://nepp.nasa.gov/whisker/
 
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  • #16
I haven't been able to get an update from my RoHS PE (we're both hammered at work, sorry), so I'll unstick this thread until there is new info.
 

1. What is RoHS and why are alternatives necessary?

RoHS stands for Restriction of Hazardous Substances and is a regulation that restricts the use of certain hazardous chemicals in electronic and electrical equipment. Alternatives are necessary to reduce the potential harm to human health and the environment from these substances.

2. What are some examples of hazardous substances restricted by RoHS?

Examples of hazardous substances restricted by RoHS include lead, mercury, cadmium, hexavalent chromium, and certain flame retardants. These substances can have negative impacts on human health and the environment if released into the environment.

3. How do RoHS type alternatives differ from traditional alternatives?

RoHS type alternatives are specifically designed to replace restricted hazardous substances in electronic and electrical equipment. They must meet certain criteria, such as being environmentally friendly and functionally equivalent to the restricted substance, in order to be considered as a viable alternative.

4. Are there any drawbacks to using RoHS type alternatives?

One potential drawback of using RoHS type alternatives is that they may be more expensive than traditional alternatives. This is because they often require more research and development to ensure they meet the necessary criteria and are safe to use.

5. How can I ensure that the RoHS type alternative I am using is compliant?

To ensure that the RoHS type alternative you are using is compliant, it is important to check for certifications or labels from regulatory bodies, such as the European Union's CE marking for RoHS compliance. You can also consult with the manufacturer or supplier for information on the alternative's compliance and safety measures.

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