Environment ■■■■■■

What are the issues with lead?
·Lead is a component in solder (37%).
·More and more PCB’s are being produced using more and more solder.
·More and more PCB’s are being disposed of in landfills.
·Agencies are concerned that lead can leach from landfills into ground water.
·Lead free is less then 0.1%TW

Lead-free Dates
Pb-free is not the only issue
·Increased power consumption
·Air pollution from Pb-free solder
·Health issues for operators
·Higher running cost, N2 etc etc
·Other “dangerous” Alloys offered
·Long term reliability
·Level playing field

Application of Solder
Primary causes of environmental impacts
  ·Energy consumption during assembly
  ·Dross formation
  ·Flux
Conducted testing to determine reflow energy consumption (kW-h/g solder)
  ·Steady reflow oven operation
  ·Throughput kept constant
  ·Energy normalized by mass of solder (avg. 2.5 g/board)
Wave solder testing to be conducted
  ·Protocol currently under development

Test Vehicle Spec’s for Reflow Testing



Reflow Test Profile Characteristics



Solder Application Data
Energy Consumption during Reflow Testing

Air Pollution and Health Issues
·A rise in temperature of 30-40oC will give
·10 times higher reactivity in the chemicals
·Higher reactivity will create faster and more powerful reactions on the ingredients in the flux.
·Powerful chemical reactions will crack the substances into smaller parts
·Low molecular substances and a high number of small particles are formed
·We can show that a higher number of particles are formed in lead-free soldering compared to Pb / Sn soldering and hand-soldering

Air Pollution and Health Issues


Test results in 6 particle sizes

Lead-free solder gives of 250 % more particles in the size from 0,5-3,0 microns

What particles are the most dangerous ones ?

End-of-Life Stage
Potential environmental impacts of electronics at end-of-life depend on disposition and location
  ·Landfill
  ·Incineration
  ·Recycle or reclaim
  ·Overseas recycling/disposal
Impacts for each method will be determined, weighted for actual disposition based on research
Sensitivity analysis will be used to show spectrum of possible impacts

EOL Disposition of WEEE
Surveyed federal and state sources, select municipalities, recyclers
  ·Most states uncertain; some federal and state data available
  ·Assumed distribution for incineration and land-filling
    14% incinerated
    77% land-filled
  ·9% of WEEE recycled (EPA 2002)
    50-80% of which is shipped overseas

Impacts from Land-filling of WEEE
Impacts will depend on several variables:
  ·Location of landfilling (U.S. vs. other)
  ·Leachability of solders
  ·Fate and transport of metals through the environment and resulting human exposure
Leachability testing is being conducted
  ·Results of previous testing inconclusive
  ·PWB’s will be tested, as well as with land-fill leachate
  ·Testing conducted by Uni. of Florida

Lead Free Components will be the issue on your SMT Line first!
  ·Many of our users are getting lead free parts or being advised that lead free parts will soon be shipped (many customers are not knowing they are getting lead free parts, are you?)
  ·What component terminations will you get supplied?
  ·What issues will you see on your SMT line?
  ·What do you need to change in your thermal process?
  ·What does your staff need to learn?


  The following terminations will be used on lead free parts:
  ·Silver Ag
  ·Palladium over Nickel Ni/Pd or Ni/Pd/Au
  ·Gold or Gold over Nickel Ni/Au
  ·Pure Tin (White Tin) Sn
  ·Pure Tin over Nickel Ni/Sn
  These 5 Finishes need to be understood in great detail to get a good yield in your factory
  Silver Ag:
  Silver is a by-product of lead and like lead it has good wetting characteristics
  Silver has no normal Oxides, it tarnishes like your silver wear at home (black in colour) and it is hard to remove
  The same as Tin, Silver has been around in the Electronic Industry for over 50 years and is safe and has “NO RISKS” apart from possible silver migration
  Palladium:
  Contact angle data for Ni/Pd and Ni/Pd/Au finish components was higher than for Sn/Pb.
  Lead pull data was lower for Sn/Pb finish components compared to Ni/Pd and Ni/Pd/Au.
  Lead pull failure mode analysis showed the Sn/Pb components failed within the solder. In most cases with Ni/Pd and Ni/Pd/Au components the solder was pulled completely from the pad.
  Wetting balance test results showed that the Sn/Pb components took longer to pass the T0 line then the Ni/Pd or the Ni/Pd/Au finish.
  Gold or Gold over Nickel Ni/Au:
  Generally has a Nickel (Ni) Barrier under the Gold (Au)
  However pure Gold is also possible
  Like Gold flash PCB’s (which is just a other word for Ni/Au Nickel barrier under the Gold plating) you need to understand that Gold flows in to the solder like water and if you have too much gold going in to the joint, you have gold in-brittlement. Also if all gold flows into the solder joint and you are left with Nickel it will be very hard to solder as Nickel does not wet well at all
  Remember the “Black nickel days”, similar issues can / will be seen
  Pure Tin (White Tin) Sn:
  Many of you need to understand that Tin is not a good wetting alloy
  Without any Nickel barrier under the tin termination you will find it very difficult to get any wetting at all
  For this reason they have a plated nickel barrier
  Try to avoid pure tin finishes as tin whiskers will also be an issue on top of the wetting problem
  However these components are normally much cheaper
  Pure Tin over Nickel Ni/Sn:
  These components have a nickel barrier under the tin finish, this will help in the soldering process with wetting as well as the tin whisker issue
  The thickness of the nickel barrier, in relation to the tin layer is important, this information is near impossible to get from suppliers, sometimes they don’t even tell you if there is a nickel barrier under the tin plating
  Please ask for component specifications which have this information
  Pure Tin over Nickel Ni/Sn:
  These components are very common and many suppliers will use this termination technology
  However it is not necessarily the easiest to solder but with the right tools and correct education of your staff it is possible to process them
  Keep in mind the new lead free shapes of solder fillets
  
  What issues will you see on your SMT line?
   · Lower solder fillets in some cases less than 25%
   · Pillowing or even Tombstoning effect
   · De-wetting, black nickel, alloy 42 is bad
   · Tin oxides mixed in with the flux residue
  What do you need to change in your thermal process? If we have HASL PCB’s and Ni/Sn terminations on some components
  Tin melts at 232 deg C and not at 179 or 183 deg C like the solder cream we use
  The Nickel barrier acts as a heat sink and the thickness of it will effect the heat sinking also.
  Tin does not wet as well as Sn/Pb
  More heat is needed, which also will give you more time above the melting temperature

Additional options needed to make Lead-Free technology work!


 

Expected problems



Visual inspection







What solutions do we offer?
  Lead-Free profiles in our machines look like this


Fact 1:Oxygen free soldering has many advantages and opens up the process window for you
  ·In reflow soldering, all of you would use an Inert atmosphere if it would be for free. Why?
  ·It stops the solder particles, pads and component leads from re-oxidizing
  ·It reduces/eliminates surface tension on the molten solder
  ·It broadens the process window for a no-clean soldering process. It improves the wetting speed and increases the wetting force.
  ·Due to this it reduces bridging and gives very shiny, strong and reliable solder joints
Fact 2:Final temperature of “ALL“ components exactly defined by temperature of the vapour
  ·In reflow soldering, all of you have a heat source which is at least 20 to 30 deg C higher than your product peak temperature. Why?
  ·Your peak Temperature also has in many cases a 6 or more deg C Delta T. Why?
  ·Due to the heating method and nature, this is unavoidable.
  ·What does this mean? With a 183 deg C cream you have a peak of 215 to 225 deg C and a heat source temp of 250 deg C
  ·In condensation soldering with 200 deg C “Galden” you have a peak temperature on all components of 200 deg C and also a heat source temperature of 200 deg C. This means nothing is more than 17 deg C above the 183 deg C and leaves room for the Pb free soldering process.
Concept:Asscon manufactures condensation reflow systems based upon the facts presented
  ·Heating of components is independent from shape, colour, mass and mass arrangement
  ·Oxygen free solder process (including Preheating) without using inert gas
  ·Final temperature of ?ALL“ components exactly defined by temperature of the vapour
  ·Pre-selection of temperature gradient during heating process
  ·Automatic selection of the peak temperature
  ·Blowhole free soldering due to vacuum technic
  ·Minimal temperature difference between components
  ·Optimal technology for lead free soldering process
  ·Lowest risk of damage compared to all other soldering
Products:Besides soldering, the equipment we manufacture should fulfil other major demands
  ·Third party certification on the process
  ·Good uptime of the machines: over 98% due to a well designed concept
  ·Safe, continuous and trouble free operation
  ·Easy to handle and to install, mobile
  ·All systems are for Lead free operation, only approved system for Pb free at Siemens and Bosch
  ·Less strain on the Environment due to better efficiency and new technology
  ·Already many users in Europe. Ask us for a list of their names
Market:“YOU” – the market wants effective solutions with future technologies and the right quality/price ratio
  ·Asscon offers the best solution in Reflow soldering when it comes to making the best connections.
  ·Compared to other brands the quality/price ratio of Asscon products is much better, especially when we take running cost in to consideration.
  ·Closer track spacing, more advanced component packages and smaller solder powder particles as well as Pb free will make Inert soldering “a must” in your soldering process.
  ·A lower skilled labour force will be a factor in our manufacturing environment. How and who in your company can fine tune your SMT line when all this will be a reality.

Asscon VP under vacuum vs. normal reflow system
  On the right you see a set of pictures given to Asscon by a VP6000 Vacuum soldering system user

  Top picture from before the Asscon machine was installed, using a normal convection nitrogen reflow oven

  Bottom after they installed the Asscon VP 6000 machine


  
  Normal Reflow Soldering and Condensation Soldering with Vacuum
  Paste: SnAgCu
  

  Normal Reflow Soldering and Condensation Soldering with Vacuum
  Paste: SnAgCu
  
  Vacuum-Soldering by different Pressure Parameter
  Paste: SnAgCu,