Keeping Your Edge: Diamond Tools

Diamond tools require proper care to ensure that it performs as needed. Unlike the graphite electrodes in EDM machines, diamond tools tend to be expensive.  Premature replacement of the tools can cost a company plenty of money. Knowing about the best practices with regards to caring for diamond tools is crucial to maximize the profitability of the operation.

Caution must be taken when handling the tools. Although diamond is high resistance to wear, placing the cutting tip of the tool on hard surfaces can have long-lasting effect on its sharpness and cutting ability.  This is especially true when dealing with tools that have been used very recently and are still very hot. The pressure from the weight of the tool can cause the binder that holds the diamond particles suffer deformation and effectively blunting the tool.

In cleaning the tools, make sure to use the right cleaner. Some cleaners are too acidic and can damage the tool. Check the pH and other properties of the cleaner to ensure that it is suited for cleaning diamond tools.

Another things to keep an eye on is overheating as extreme heat can damage both the binder and diamond particles. Lengthy cutting operation that generates extreme heat requires the use of coolant to keep temperature under control.

Using diamond tools on high-carbon steel and alloys can cause a reaction between the diamond particles and carbon from the work piece. This molecular structure of the diamond particles can get altered, turning it into soft graphite.

EDM, Graphite Electrodes, and Quality of Finish

Many expected the use of EDM or electrical discharge machining to dwindle at the turn of the century due to the development of new machining technology. More than a decade has passed since the prediction but EDM remains in use and preferred by many workshops. 

The reason for this staying power is the lower cost of operation, reliability of EDM machines that allowed them to stay in very good condition, and quality based on the experience of the operator. A newer technology might offer far better potential in terms of quality but until an operator is able to master its operation, that potential will remain as is.

Graphite electrodes have also made EDM machines for applications that are more than just rough cutting. The graphite used for electrodes in sinker EDM have varying grades. The type of grade determines the quality of finish.

Fine grade graphite electrodes are made of particles with sizes between 11 to 20 microns. These electrodes are primarily used for roughing in large cavities in work pieces. The finish is very crude and will require further polishing down the line. Polishing equipment like diamond tools can be used for improving the quality of the work piece right after the EDM process.

The superfine grade graphite electrodes feature particle sizes between 6 to 10 microns. These electrodes are used for creating cavities that larger details. The quality of finish is still very crude will require polishing.

The ultrafine and angstrofine grade graphite electrodes are the ones used for finishing applications. Ultrafine grade features particle sizes of less than 5 microns while angstrofine have submicron particles. These are used for creating intricate details with very high quality finish.

Explosive Forming

Both machining and metalworking operation change that size and shape of a material. Whereas machining mostly use cutting processes, metalworking relies on heat and pressure. There are various types of metalworking operations. One of them is explosive forming.

In explosive forming, small controlled explosions create shock and pressure that are used to shape metals. The explosive which is usually a mixture of gas is detonated over the metal  that is placed on top of a die. The forces from the explosion forces the metal into the die and spread it evenly over the die's surface. The same forces can cause plastic deformation which can strengthen the metal.

There are two main methods used for explosive forming. The first one is the standoff method wherein the explosive is placed from a prearranged distance from a metal work piece. The energy from the explosion is transmitted to the metal either through air, water or oil. The second explosive forming operation is the contact method wherein the explosive and the work piece are in direct contact with each other. The explosion produces a very high amount of pressure, forcing the metal into the die.

Explosive forming was first used in aerospace applications in the 1960s and has been in use ever since. This metalworking operation offered several advantages.  It maintains precise tolerance and eliminates the need for time-consuming and often costly welds. The quality of the finished work piece is dependent upon the die. A high quality die is always going to product high quality results.

Unlike other metal working methods, explosive forming requires less tooling which an greatly affect the cost of an operation.