Friday, 24 January 2014
In every PCB Assembly line, there is a fallout of PCBs which are assembled and then fail at the end of the line. It is proven over time that very few of the PCBs have failed because of the chipset.
Causes of failure could be the following :
Causes of failure could be the following :
- The raw PCB could be faulty
- There could be a paste problem, causing a short or an open
- There could be a silicon problem but this is rare. Brand new components straight from the factory are really well tested, and very few are faulty.
When a PCB fails it is shifted to a debug area, here the fault is diagonised, repaired and then the PCB is re-tested. At this stage if the PCB passes it is shipped as normal, but in case if it fails again; it goes back round the debug loop. At the debug area each time the component is removed and replaced by a new one. After three attempts the PCB is often classed as unreliable and scrapped.
As the product life cycles are becoming shorter, the debug technicians are given less time to learn a new product, due to this it takes up the probability to wrongly diagonise the fault and this could lead to an increase of "end of line" failures. These failed boards as they have gone through the debug process atleast one time, the chipset have endured one reflow cycle, sometimes more if it has gone through the debug process multiple times. However if the PCB has been through 2 reflow cycles to assemble it, then the big components which are usually the most valuable have had only one reflow cycle, the second one.
Looking at the standards laid out by component manufacturers - ICs are termed good for three reflow cycles. Many of the failed PCBs as described above have had one reflow cycle. The solution to achieve savings by having the components re-used, and also fall within the component manufacturers standards is using the IC RESCUE process which is a safe component recovery method. Moreover after the components are safely recovered, the components are electrically and mechanically tested
Why is the above solution a practical approach?
These components which are within manufacturers specifications and tested, therefore trusted can be :
- Put onto a new assembly
- Used in a debug area to repair a failed assembly
- Used in field return repairs in the future
- Sold in the market place as refurbished but "Zero Hours" good component
Wednesday, 8 January 2014
Over the past 15 years the electronic industry has been moving away from lead solder due to environmental, health and safety issues. This has reached a point where a vast majority of ICs are only purchased in lead-free format. To enable this transition, lead-free solder was introduced, but the only catch with lead free solder was that it wasn't as good as leaded solder, for instance it melted at a higher temperature than lead solder.
But certain high reliability industries were made exempt from moving to lead-free, as they were operating in important environments and at the time it was unknown how exactly lead free solder would hold up or perform in harsh conditions. Certain examples are :
Military / Defence - Missiles could be stored long term and then used, due to these extended timelines and the nature of its use it had to be 100% operational, so a risk could not be taken of the solder being lead free as no data was available regarding its long term effects.
Aerospace - Due to the G-force, height, pressure that the aircraft come under, it was as important from the safety standpoint that the aircraft system not to fail mid flight. Lead free solder as with Military / Defence had not proven itself yet to be as robust for harsh environment.
Automative - Due to high heat, vibration and safety issues; critical electronic systems in cars such as braking systems and airbags were also exempt.
Due to such changes in regulations where most of the other sectors had moved on lead free solder, many IC manufacturers have stopped producing leaded parts, they were producing just lead free parts. One factor that hit High reliability industries was that although high reliability parts cost more than commercial versions, in many cases the small volume consumption of these parts in lead form did not justify setting up a separate line to make a lead version of the component, therefore the high-reliability industries often struggle to find their ICs in the lead format.
Often they would have to buy them in lead free format and convert them to lead format, there is no credible and safe way to do this for BGA other than Retronix - IC Rescue Process, it is the only process that does not use any reflow cycles to achieve alloy conversion and therefore meets the IC manufacturer's specifications. Another issue that keeps the industry restricted at times is that they rely on tried and tested technology especially for missiles, aircraft control systems as they know it works.At time technology used by certain IC manufacturers for making certain components become obsolete and they stop making the parts altoghether, high reliability industries will end up buying a bulk of components with total guess work anticipating future requirements.
So the issues that they could face are :
- They may only buy in lead free format which would have to be converted to Leaded version
- They may not be able to find the ICs at all.
- A component is needed which has been out of production and obsolete.
- Forced to buy large volumes of ICs, this could lead to component packages being broken open, a few are used and the rest become exposed leading to oxidisation and solderability problems.
Each of the problems can be solved and can save high reliability industries from having to spend too much time and effort on the ICs, contact us using this link - http://www.retronix.com/contact-us or email us on firstname.lastname@example.org
Do visit our website : http://www.retronix.com
A few interesting videos on our processes -
Thursday, 5 December 2013
Retronix is changing.
With the efforts being put in, we have the right processes, the right people and we are at the cusp of a great opportunity to present Retronix as being evolved into a sharp, efficient and a quality service provider.
Retronix is undergoing a change in branding with the philosophy we believe in and for the future of this company.
Retronix provides services to highly important sectors such as Military, Aerospace, Oil&Gas, big OEM's and IC manufacturers therefore our message to our customers will be ruled by the following four values:
CONSISTENCY : Signifying control and repeatability
INNOVATION : Signifying customised solutions and flexibility in our services
QUALITY : Signifying excellence and value
PRECISION : Signifying accuracy and care
We aim to make Retronix as a one word definition for the above four values and every step of the way Retronix will reflect these values.
We take the first step today with a slight change in the logo tagline
Wednesday, 20 November 2013
The philosophy of the Retronix IC recovery process is built around industry standards, adopted by the largest IC manufacturers. For them, when you are soldering ICs to PCBs, temperature and time are your enemy. The higher the temperature, and the longer the profile, then the more likely damage is to be caused. Think of passing your wet finger through a candle flame, no damage. Then think about holding it there for a minute! IC Manufacturers state (as a rule) no more than 3 or 4 reflow cycles should be carried out on an IC, but up to that number is fine:
Micron - "The maximum number of reflows is defined as three...product guarantees may be invalidated" (Ref 1.)
Xilinx - "Pg.11 JEDEC STD-20 compliant Packages capable of withstanding high reflow temperature rating (245 C-260 C) for 3 reflow cycles" (Ref 2.)
INTEL - "Many BGAs (including Intel BGAs) are rated for 3 reflow cycles" (Ref 3.)
Intel specifies two more points which are relevant, in the above referenced document, point 18.104.22.168 specifies, that the profile goes above 154 deg. after approx 1.9 minutes, and does not come below 154 deg. again till about 6.4 minutes. So it is above that temperature for approx. 4.5 minutes, moreover some profiles are even longer than this.
Keeping the above standards in mind, the Retronix IC Rescue process is different and unique as it manages to stay within all the stated manufacturers specifications, much shorter in terms of temperature and time, safe and well below stated reflow profiles.
Following comparison shows the traditional method to the Retronix method, and how the Retronix IC recovery method is changing the landscape of the component recovery market.
The first time the component goes onto a PCB it has gone through a reflow profile, therefore the count starts from 1.
As can be seen from the comparison above:
The Retronix IC Rescue method is well within the manufacturers specifications, the process is automated, controlled and completely safe.
Additional benefits of Retronix IC Rescue method include an automatic wash which makes sure each IC is clean, a mechanical test to verify functionality, including curve trace test, key functional test and memory test. A solderability test and XRF test to verify composition of leg or ball.
Watch a video on the IC recovery process:
For more information on the reflow profiles and on our IC recovery process do contact us and we will be happy to set up a meeting to discuss more on this process - (Click Here)
E - email@example.com, firstname.lastname@example.org
Know more about IC Rescue -http://www.retronix.com/ic_bga_recovery
Tuesday, 1 October 2013
A customer was experiencing a high failure rate, during accelerated life testing on one of their PCBs. The same fault was causing the problem each time.
The problem was of cracking solder joint(s) on a Leaded Chip Carrier (LCC) which was soldered directly on the PCB. It was discovered that the LCC created a lot of heat, with no space under the component to dissipate the heat. The thermal imbalance between the IC and the PCB caused the solder joint to fail.
To fix the problem Retronix fitted Plastic Core Solder Spheres (PCSS) to the pads, which don't collapse.The PCSS created enough 'standoff' between the IC and the PCB which allowed the heat to dissipate. Also having the exact same spheres on the exact same pads also guaranteed the RF inductance on the part.
This solution reduced the failure rate on the PCB by a factor of 10, eliminating the issue as a weak spot on the component.
E - email@example.com, firstname.lastname@example.org
Know more about Application Specific Balling and Reballing -http://www.retronix.com/application-specific-balling-and-reballing
Tuesday, 24 September 2013
A lot has been talked about the problem of tin-whiskering and the way it could lead to problems in different electronic components. This could especially lead to big problems if the electronic components are deployed in high reliability environments such as avionics, and harsh environments such as oil rigs deployed deep sea; where failure is not an option.
But what are Tin Whiskers?
Tin whiskers are electrically conductive, crystalline structures of tin that sometimes grow from surfaces where tin (especially electroplated tin) is used as a final finish.
What are the mechanisms by which Tin Whiskers form?
The mechanisms by which tin whiskers grow has been studied for many years. But unfortunately no single, widely accepted explanation of this mechanism has been established. But there are certain agreed factors in tin whisker formation. Tin whisker growth is primarily attributed to stresses in tin plating; the stresses may be from various sources which include :
- Residual stresses in the tin resulting from the plating process.
- Electro deposited finishes are considered most susceptible due to stresses built into the finish as a result of the plating process.
- Formation of intermetallic compounds especially within the tin grain boundaries.
- Compressive stresses such as those introduced by torquing of a nut or a screw.
- Bending or stretching of the surface after plating
- Scratches or nicks in the plating introduced by handling.
What are the commonly reported characteristics of Tin Whiskers?
The vast disparity in the observations reported by different experimenters is evidence of the complications associated with understanding and controlling tin whiskers. The following provide a very basic overview of some of the observed characteristics of tin whiskers.
Whiskers may be straight, kinked, hooked, or forked. Their outer surfaces are often grooved. Some growths may form as nodules or pyramidal structures.
All of the above characteristics have been known to cause problems, for example causing a short circuit in a satellite leading to blacking out of several important services. Therefore it is very important to understand tin whiskers and work on a solution that leads to tin whisker mitigation. A solution that has worked for mitigation for tin whiskers is re-tinning of components.
E - email@example.com, firstname.lastname@example.org
Know more about Re-Tinning -http://www.retronix.com/alloy_conversion_re-tinning_rohs-compliant