Weller Soldering Tip #6 (0)
Posted 3 July, 2008 in Technical Articles
Confirm that the manufacturer’s recommended soldering temperatures match the range of temperatures that are required in the application. One additional suggestion is to try and lower the operating temperature of the tools, even if the soldering dwell time is lengthened by several seconds. This will also assist in extending tip life; 90° F lower in temperature can improve tip life by more than 50% when no other variables are introduced.
Is Halogen-Free Part of the Future? (0)
Posted 1 July, 2008 in Industry News
It’s been almost two years since the birth of RoHS and now some people are pushing to add more hazardous substances to the list of restricted materials, and halogen is one of those substances but it doesn’t come without any great debate.
Some say that just like the hazardous materials listed under RoHS, halogen-free electronics should also be part of the environmental trend to go green. But others disagree and say that halogen in electronics doesn’t affect our environment either way.
According to Tim Jensen in his Halogen-Free blog, the industry seems to have defined halogen-free as being less than 900ppm of bromine (Br) and 900ppm of Chlorine (Cl).
Right now there aren’t any laws that require electronics companies to manufacture halogen-free products, but many companies including large corporations such as Intel are slowly going in the direction of halogen-free.
The other source of confusion for this topic is the difference between halogen-free and halide-free. I’m obviously not qualified to describe the detailed difference between the two but if you love chemistry and are interested in knowing the details, read Jensen’s blog article about the differences between Halogen-Free and Halide-Free. But here’s the cliff notes version of the differences. A halogen means fluorine, chloride, bromide, iodine or astatine is present. On the other hand, a halide is a compound that contains a halogen.
You’re probably wondering where halogen is used in the electronics industry. Well, as it turns out, halogen can be found in many flame retardants such as brominated flame retardants and polyvinyl chloride which is more commonly known as PVC. Halogen-free advocates believe these flame retardants (that contain halogens) are bad for both our health and the environment once the electronics have been thrown away, recycled, etc…
I’m sure this is just the beginning of the halogen-free debate as well as the question of other substances that could be considered hazardous. Here’s some more information if you’re interested.
· IPC has an informative site on halogen-free and brominated flame retardants
· Here’s an general article on Eco-Friendliness from GreenerComputing
· Apple’s environmental policies
· Intel’s lead-free and halogen-free policies
· Dell’s stance on brominated flame retardants
Weller Soldering Tip #5 (0)
Posted 26 June, 2008 in Technical Articles
When using pre-tinned devices and HASL (Hot Air Solder Leveling) or OSP (Organic Solderability Preservative) on PC Boards, using a very active rosin core solder is not necessary. Using a high activity level flux works well on heavily oxidized metals such as bare copper or other non-tinned or non-plated metals, but is not readily suggested for standard electronic assemblies. Use a flux that is designed for the metals that are being joined and keep the activity level to a minimum to help extend tip life.
Missed Weller’s first four tips?
Common Sources of ESD (0)
Posted 23 June, 2008 in ESD News
If you are reading this, you probably have an idea of what ESD is. But do you know the common sources for ESD? There are three, human body ESD, machine ESD and charge device ESD.
I would imagine that human body ESD is thought of the most when the term ESD is mentioned, and rightfully so because humans probably cause the most ESD damage. Human body ESD is when a human transfers the electrostatic discharge to a part that is static sensitive. Some of the most damaging human errors include ungrounded employees walking around with static sensitive items such as PCBs, employees not wearing appropriate gloves or finger cots and employees walking around with ESD sensitive parts in open bags, bins, totes, etc… Human body ESD can be avoided with the use of a heel/sole ground or wrist strap; both are relatively inexpensive.
Machine ESD is the second cause of ESD damage. This source of damage is caused when an ungrounded part (conductive or dissipative) such as a machine or tool comes in contact with an ESD sensitive part. The solution to this problem is to simply ground the machine part, tools, etc…
The final source is charged device ESD. This type of ESD takes place when a part or device develops a charge and then comes in contact with a conductive item. Once the two parts touch there is a fast discharge which ultimately damages the ESD sensitive part. Ionizers are useful in this situation as they neutralize new charges and prevent build up of charges. Reducing movement of a part within the facility and having one common ground also helps combat charged device ESD.
Other things to keep in mind when protecting your ESD sensitive parts:
- Make sure your ESD bags and containers are not too old. Many materials lose their ESD protection over time.
- Have an ionizer? Make sure both emitters are working and make sure there is an equal balance of positive and negative ions.
- Store ESD sensitive parts in the appropriate containers. I know it seems like common sense but it’s important.
Weller Soldering Tip #4 (0)
Posted 19 June, 2008 in Technical Articles
Fluxes containing a “high solids content” are one of the largest contributors to surface contamination, which leads to the blackening or charring of fluxes on a soldering iron tip. This in turn, can cause a tip to be rendered useless in a matter of hours, if not minutes. If proper research is done, solder manufacturer’s technical data sheets or MSDS sheets will indicate the % of solids. Extremely high temperatures will also accelerate the surface contamination process.
RoHS Compliance Costs a Pretty Penny (0)
Posted 16 June, 2008 in Industry News
RoHS (Restriction of Hazardous Substances) has been around for almost two years now. If you are not aware, RoHS is the ban on six substances (lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ether) in electronics equipment in the European Union.
According to an article on Purchasing.com, RoHS has cost the electronics industry over $32 billion, and that’s just getting started. It’s estimated to cost around $3 billion just to maintain compliance with RoHS.
Here are some things to keep in mind with RoHS:
- The cost of RoHS will continue to increase. With the possibility of adding more substances and getting rid of exemptions, compliance will just become more costly.
- About 29% of companies say they lost sales because of RoHS.
- On the more positive side of things, RoHS helped many companies reorganize by improving their supply chain process and reevaluating their product lines; some companies have even reported increased market share.
- Many electronics companies are reporting more inventory than usual. This is probably because many companies had to carry both RoHS compliant and non-RoHS compliant goods and now they are stuck with the non-RoHS compliant items.
The article on the cost of RoHS is pretty interesting, regardless of your involvement with RoHS.
Weller Soldering Tip #3 (0)
Posted 12 June, 2008 in Uncategorized
Many solder manufacturers recommend that the wire cored solder should not be applied directly to the soldering tip. This is mainly in part due to the aggressive nature of the flux formulations used in the core. However, the tip has to constantly be "tinned." Therefore the solder must be applied to the tips working surface to protect it from surface oxidation and contamination. Check with the solder manufacturer for a material that is compatible with hand soldering.
Types of Air Ionization (0)
Posted 9 June, 2008 in Technical Articles
While personal grounding with items such as wrist and heel straps is usually the first step in static control, air ionization is a step that complements static control programs when grounding is not possible or when more protection is needed.
There are two basic ways of creating ions (ionizing). The first is alpha ionization or nuclear ionization. Alpha ionization uses a nuclear source such as polonium 210. The alpha particle (polonium 210) collides with air molecules and bumps electrons off the air molecules. The molecules that lose electrons become positive ions and the neutral air molecules capture the loose electrons and become negative ions. Alpha ionizers are beneficial because of the fact an equal number of positive and negative ions are created; everything in the work area is neutralized to zero.
The second method is corona ionization and this is what type of ionization we are talking about when we refer to AC and DC. Corona ionization is electrically based. In this method of ionization, ions are created by applying high voltage to a sharp emitter point which creates a high positive electric field. The electrons from the air molecules are attracted to the sharp point. The molecules that lost electrons are now positive ions and are repelled from the point. A similar thing happens with the high negative electric field except neutral air molecules pick up the electrons which ultimately create negative ions and are pushed away by the negative electric field.
Unlike alpha ionization, corona ionization usually doesn’t provide a completely balanced number of positive and negative ions.
The first type of corona ionizers is AC (alternating current) ionizers. AC ionizers use one emitter to produce both positive and negative ions; this is what makes AC ionizers unique. This is also beneficial because if one emitter becomes disabled, the balance of positive and negative ions will not be affected. The fast AC cycle produces an almost continuous stream of both positive and negative ions; therefore, rapid and thorough neutralization of charges is assured.
Steady State DC (direct current) is another type of corona ionizer. This ionizer uses separate positive and negative power supplies that run simultaneously to create bipolar ions. SSDC ionizers produce a high ion current because both emitters are continuously producing positive and negative ions. This type of ionizer is often used in rooms where low offset voltage is needed.
The last type of corona ionizer is Pulse DC. Pulse DC is the latest development in corona ionization and it is more demanding and complex compared to other ionizers when it comes to operating requirements. These ionizers are similar to SSDC in the fact that separate positive and negative power sources are used but with Pulse DC, the positive and negative emitters alternate. This alternating creates clouds of both positive and negative ions which mix together and create the pulse effect. Pulse DC ionizers can be used in a low airflow environment and the rate of the pulse can be adjusted based on the work area.
One thing to keep in mind with DC ionizers is that if one emitter fails, you may have an imbalance of positive and negative ions.
Need help choosing an ionizer?
Weller Soldering Tip #2 (0)
Posted 5 June, 2008 in Technical Articles
Use temperatures between 315-371°C (600-700°F) for Sn63Pb37 and 371-427° C (700-800° F) for Lead-Free alloys. Temperatures higher than 725° F can and will shorten tip life in most cases. Temperatures below 371° C (700° F) can increase tip life by as much as 50 % when compared with temperatures higher than 399° C (750° F).
Missed soldering tip #1?
Dr. Lasky Talks About The Latest Issues With Solder Products (0)
Posted 2 June, 2008 in Industry News
About a month and a half ago we had an interesting guest blog post about RoHS2 written by solder expert Dr. Ronald Lasky. Dr. Lasky is very knowledgeable when it comes to RoHS, RoHS and WEEE (among other things), so it’s always a pleasure to hear what he has to say.
I found a video interview with Dr. Lasky on Rick Short’s blog. The interview is a little long (over 8 minutes) but it’s definitely worth watching because of Dr. Lasky’s insight into the future of electronic assembly materials including the hot topic of halogen-free.
The video is easy to watch and listen to. Both Dr. Lasky and the interviewer are very conversational.
The link to the interview:
http://realtimewith.com/pages/show.cgi?rtwsid=10&st=10&c=11&v=366
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