"Tool time" in rework: expect the unexpected: common tools can be put to good use during rework.

Most people are familiar with the types of tools and equipment used in circuit board rework--from hot-air rework systems costing thousands of dollars to solder fountains, solder pots and microscopes. But you might be surprised to discover that the tools that our rework technicians use most often are simple, inexpensive items--often costing pennies--that were not designed with rework in mind!

The most common tool for our rework technicians is the classic X-ACTO[R] knife. The knife is a simple, inexpensive tool used by craftsmen the world over. Our techs use the knives for every conceivable operation, including cutting, preparing, scraping and removing residue. They even use the different surfaces and edges of the blade, such as the back or the tip, for different operations.

Another simple tool that you see our operators using are round wooden sticks. Our techs are constantly sharpening, shaping and modifying the tips of their sticks for various uses. A sharpened point may be used to apply tiny dots of epoxy, coloring agent or solder mask; or, a stick can be cut into a fork shape to move jumper wires around. The wood is soft and will not scratch or mar the surface of the board. The sticks are disposable and inexpensive; they do not contaminate or conduct electrostatic discharge (ESD).

Another group of tools found in the rework operator's arsenal are, believe it or not, dental tools. While specialized hand tools have a long tradition of working on teeth, they are also perfectly suited to circuit board rework. Made of high-grade stainless steel, dental tools hold a good edge, are sturdy and strong, dean easily and are designed to complement the manual dexterity of a skilled operator. From scraping and cleaning to reforming bent leads, dental tools are ideal for rework because they allow access to tight areas.

Moving to more familiar turf and larger tools, we must take a moment to mention soldering irons, the tool most often associated with the rework process. While books could easily be written on the subject, remember one key point: You need to have a powerful, top-of-the-line soldering iron when conducting rework. The current sophisticated and expensive circuit boards demand a level of temperature control and available power only found in higher-end soldering irons; do not cut corners or expense when making this purchase.

Manual tools are obviously not the only type of tools used. Rework often demands the use of power tools for grinding and drilling. Three primary types of power tools are on the market. The first consists of a motor with a flexible drive shaft that drives a handpiece with a chuck for interchanging bits. Such powerful tools have a lot more power than is usually needed when working with circuit boards. Also, the handpiece is difficult to control because it is connected to a spinning and vibrating drive cable.

The second general type of power tool has the motor encased in the handpiece itself. While these tools are more versatile and suited for delicate operations than the first type, they are nonetheless somewhat bulky and difficult to get into tight areas because you hold the entire motor and power supply in your hand. Weight and vibration can also contribute to operator fatigue and inaccuracy.

The only type of drill that we use is the third type, referred to as a micro-drill. Similar to a dental drill, the tool was not originally designed for rework, but it is ideal for it. The drill's power source sits on the workbench and is connected to the handpiece by a telephone-style power cord. The handpiece is slender and fairly lightweight, easy to hold and manipulate. The micro-drill has high revolutions per minute (RPM) speed, and its considerable power and flexibility give the operator tremendous freedom. A variety of cutting tools can be used with the micro-drill, but the most common type is the carbide ball mill.

On the high end of rework products, we find the milling machine, something that one would expect to see in a machine shop rather than in a rework department. Is the machine overkill? Not really, we have three in our rework area. The high precision inherent in a milling machine is essential for routing, drilling, cutting slots, trimming and other procedures where tolerances are tight.

Many other familiar and unfamiliar products find appropriate use in the rework department for simple and complex tasks. The important thing is to be creative and keep an open mind. Remember, for every type of rework task, no matter how simple or how difficult, a solution is out there somewhere, just waiting to be found!

Jeff Ferry is president of Circuit Technology Center, Haverhill, MA; [phone]; www.circuittechctr.com.