February 2008

What is RoHS anyway?

by Andy on February 25, 2008

Lead Free RoHS Compliant Marking Tape I’m sure many people have seen the term RoHS and aren’t really sure what it is or what it stands for. If you are unfamiliar with RoHS, read the brief overview below to learn about RoHS and why it’s important.

RoHS is short for Restriction of Hazardous Substances. RoHS started in the European Union and restricts the use of specific hazardous materials found in electronic products.

All electronic products sold in the European Union after July 1, 2006 must be free of lead (Pb), mercury (Hg), cadmium (Cd), hexavalent chromium (CrVI), polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE).

The reason these substances are banned is because they are hazardous to the environment, including landfills. Another reason for the ban is because of the potential hazard for those manufacturing or recycling electronic products that contain one or more of the above six substances.

Right now there isn’t a federal ban on the substances in the United States, but some states have banned several of the substances. For instance, in 2003, California passed the Electronic Waste Recycling Act which bans the sale of electronic products (after January 1, 2007) that contain more than the stated amounts of the following substances, .01% of cadmium, .01% of hexavalent chromium, .01% of lead and .01% of mercury.

As with most legislation, there are criticisms. One of those most common complaints is that some believe the product’s quality is compromised because of the material restrictions. The high cost to comply is another criticism, especially for small businesses.

If your state doesn’t already have a ban on the sale of electronics with hazardous substances, be on the lookout for a future change in the law.

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What ESD Bags Should I Buy?

by Andy on February 18, 2008

The options are almost endless when it comes to ESD bags on the market. Some of the more popular bags are anti-static bags, static shielding bags and moisture barrier bags. Many of the bags come in different variations and size; which bag you choose depends on your need.

Anti-Static bags are almost exactly like

poly bags.These bags are made with an additive in the material so the anti-static properties of the bag will never wear off. While anti-static bags will not protect what is inside the bag from an electronic charge, they will not build up a charge either.Because of this, an anti-static bag is generally used in a situation where the part being placed in the bag is not particularly ESD sensitive but some of the items it may come in contact with are ESD sensitive.

Static shielding bags are another common type of bags. These bags are made to hold items that are ESD sensitive. They are made up of a multi-layered material which includes a specialized layer to reduce static build-up. Part of the layer is made with aluminum which keeps the charges out of the bag and creates a Faraday cage. A Faraday cage is an enclosure made of a conductive material that blocks out electrical fields. An example of a common Faraday cage is an elevator. Depending on the material used to construct the elevator, cell phones may not work because the elevator is blocking out the signal needed to send or receive phone calls.

Both anti-static and static shielding bags have options for both open top and zip-top.The open top bags are sealed with a heat sealer or folded and secured with either tape or an ESD label.The zip-top bags cost more but have a closure of their own which is similar to a freezer or sandwich bag.

Moisture barrier bags, also known as Dri-Shield bags, are designed to keep items safe from not only ESD but also moisture, radio frequency interference (RFI) and electro magnetic interference (EMI).These bags are very similar to the static shielding bags with the exception of a thick single layer of metalized material or multiple layers of the metalized material.This addition makes it more difficult for the bag material to “breathe,” which means moisture doesn’t transfer through the bag as easily. The added thickness is what shields magnetic and radio interference.

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The Weller WES51 vs. the Hakko 936-12

by Andy on February 11, 2008

The Weller WES51 soldering station and the Hakko 936-12 soldering station are often compared when it comes down to buying a new soldering station. Below are some basic facts about each model.

Weller WES51 Soldering Iron

Weller WES51:

-Temperature: adjustable 350°F – 850°F within ±9°F

-50W, 120 V input (line voltage) and 24 V output

-Automatic shutoff after 99 minutes to prolong station and tip life

-Works with Weller ET series tips

-Cordless temperature lockout prevents temperature from getting higher than specified for board or component

-Non-burnable silicon rubber cord attached to iron

-Iron design reduces fatigue

-Comes with power unit, soldering iron, iron holder with sponge and ETA tip

Hakko 936-12 Soldering Station Hakko 936-12:

-Temperature: adjustable 392°-896°F within ±1.8°F

-60W, 24V

-Lock screw prevents accidental temperature changes

-Compact unit

-Compatible with lead-free solder

-Comes with station, ESD safe iron (Hakko 907), tip (Hakko 900M-T-1.6D) and iron holder with sponge

- accommodates large, medium or small irons

Both the WES51 and the 936-12 are ESD safe, have slim handled irons for comfortable use and both stations have a heater/sensor combination for rapid heat-up and recovery.

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Knockout Punches: The Perfect Hole

by Andy on February 4, 2008

Greenlee Slug Buster Many people in and out of the electrical industry often search for a tool that will cut holes in metal both accurately and quickly, while leaving smooth edges. An ideal tool for the job is a knockout punch.

Punches do their job well and are easy to use. Typically there are three parts to a hole punch. There is the punch itself, which actually does the cutting, then there is the die, which is placed on the opposite side of the metal for the punch to be pulled against, and lastly there is the draw stud, which is used to pull the punch and die together in order to cut the hole.

Once you have determined what size hole you need and it’s desired location, simply drill a pilot hole in the center of the area. When drilling your pilot hole, be sure that it is big enough to pass the punches draw stud without it binding. The draw stud should be inserted through the die and then through the pilot hole. The open side of the die should be facing the metal. Once the draw stud has been inserted through the pilot hole, you will need to thread the punch onto the other end, with the cutting edges toward the metal, until both die and punch are snug to the metal. Now that you have your punch in the desired position, simply use a ratchet wrench to tighten the two sides together. As the draw stud is tightened with the ratchet wrench, the die and the punch are pressed together to cut a perfect circle in the metal.

You have several options when it comes to choosing a type of knockout punch to purchase. First you have to choose from a standard knockout punch or a Slug-Buster knockout punch. A standard punch keeps the waste or slug from the hole intact while a Slug-Buster punch will split the slug in half while cutting the hole. The benefit of a Slug-Buster punch is that the waste is easier to remove from the die when it is in two pieces.

A new punch line Greenlee has introduced is the Slug-Buster SC self-centering punches. These punches will not only split the slug in half like the normal Slug-Buster punches, but will also align themselves on the pilot hole, saving you time and ensuring accuracy. Greenlee has even created a detailed Slug-Buster SC demonstration video so that you can see these new and improved punches in action.

The second deciding factor is whether you want a manual knockout punch or a hydraulic punch driver. The manual punches are driven by a ratchet wrench that pulls the punch through the metal. Hydraulic punches are usually pricier than manual knockout punches but these punches can develop up to 11-tons of hydraulic force, depending on the specific hydraulic driver used, to make fast, easy punches.

Greenlee is a company known for making both quality manual and hydraulic punches.

All-Spec now stocks several Greenlee punch kits, including the 735BB, the 737BB and the 7238SB.

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