When deciding whether or not to use EDM tapping, there are several things to consider. These factors include Speed, Hole depth, Electrode, and Dielectric liquid. Using the proper combination of these factors will give you the best results. However, you should remember that these factors may vary depending on the application.
Hole depth
EDM tapping is a versatile process for forming very small holes. The electrodes used for this process can be ranging from 0-80 millimeters in diameter. The electrodes can be made of graphite, brass, or copper. The electrode material used should be chosen based on the particular material, and the electrode type used should be compatible with the material being tapped.
The electrode feeds through a threaded bushing that keeps the electrode in place and sets the pitch. Custom EDMs are equipped with a split nut design so that they can accommodate different diameters of threads. The lead nut’s collapsible collar locks the electrode in place and the lead nut’s internal threads. There are also auto-set orientations and thread matching, and the depth can be controlled using a mechanical stop or a programmable servo unit.
Compared to conventional tapping, EDM taps have the advantage of not creating any chips or long ribbons. Conventional tapping can distort thin bottom walls, and this can lead to material cracking. This is especially true for threaded blind holes made from exotic alloys.
Electrode
Electrode tapping is a key step in the EDM process. The taps used are made of different materials and come in various sizes, including 3 inch and 6 inch. These electrodes are also available in orbiting and non-orbiting designs. In addition, they are available in metric and inch sizes.
Several manufacturers produce electrodes for EDM tapping. Most electrodes are available in catalog items and some suppliers can fabricate custom electrodes to meet your specifications. Standard electrodes are six inches long and five inches threaded and have a center hole for pumping dielectric fluid. Most electrodes are manufactured with a gap between 0.002 and 0.006 inches, which will provide an even spark gap and minimize spark generation. Likewise, orbiting electrodes are also manufactured undersized to fit into the tap-drilled hole.
A conventional EDM die-cutting machine can perform the process of threading. The threaded electrode 15 is driven into the workpiece hole and a guide plate is attached to it. When the power is turned on, the dielectric fluid is supplied to the electrode. The electrode is then tapped using a circular guide plate.
Dielectric liquid
Dielectric liquid can be used in different EDM processes, and some studies have shown that mixing powder with the dielectric fluid can improve the process and surface quality. These studies varied the concentration of silicon powder and flushing flow rate, and the effects on the final surface were determined by morphologic analysis and surface quality indicators. One study performed by Jeswani (1981) involved the use of a 4 gm/L fine graphite powder and found that the MRR and electrode wear ratio decreased by 60% and 15%, respectively.
The selection of a dielectric liquid is not an easy process, and a number of factors must be considered. The extent of metal removal and electrode wear are two obvious factors, but other factors may be more subtle. When choosing a dielectric liquid, it is important to consider the amount of impurities in the fluid and how these affect the dielectric performance.
Dielectric liquid is a fluid that is used in EDM processes to control the temperature of the electrode. The electrical discharge causes the material to become extremely hot, and the dielectric fluid helps in cooling the metal during the machining process. The most common process is wire EDM, which is conducted through a thin copper or brass wire that acts as an electrode. The dielectric liquid used in wire EDM is usually deionized water.
Speed
The speed of EDM tapping is controlled by the amount of current flowing through the tool. In this process, the tool moves along a path close to the workpiece and may even touch it. The material on the tool’s surface is removed by the current, leaving behind small craters. Depending on the technology employed, these craters may be nanometers-size for micro-EDM operations, or hundreds of micrometers for roughing operations.
The EDM-Bohrmaschine 10 consists of an upper and lower element. These elements are connected to a rotary drive unit 13 and a Gleitbahnbewegungsteil 70. The Gleitbahn Bewegungsteil 70 is the driving mechanism of the EDM-Bohrmaschine.
The EDM process is primarily used in the mold and toolmaking industry, but is increasingly used for prototype and production parts. The electrode used in the EDM process is typically made of graphite, copper tungsten, or pure copper. The workpiece is then machined by feeding the electrode onto a vertical ram. In many cases, the electrode is curved.
