Science — CrossRef. Appl Phys Lett — CrossRef. A selective review. Rev Adv Mater Sci 44 4 — Nanotechnology 25 32 — CrossRef. Scripta Mater 66 8 — CrossRef. Mater Today Proc 4 2 — CrossRef. This may involve a slight adjustment, or several operations carried out on it. An example of this is a recent project we undertook for a client who had a complex 4 axis conventionally machined aluminium component.
Work Carried Out: For this project the client had very detailed specifications regarding the sharp corners and pocket depths required. To carry out this type of work, conventional machining would not have been sufficient.
You can see the process followed with this project and the various stages of it from the photographs included as well as a video demonstrating our use of the AD35L Sodick Spark Eroder. This piece of technology can accurately and effectively spark erode an Aluminium component as well as other materials such as Carbide, Inconel, Titanium and Bronze. We were able to complete the work on the aluminium component to the customers specifications.
We were also able to provide the client with a quick turnaround time. However a simple rule is that if the material can conduct electricity it can be machined using either wire or spark erosion. The only other thing to consider is — has the material or part been coated, often a coating will impair electrical continuity.
Used when the safety of copper is desired, but it provides much better wear resistance. Also used in the EDM machining of carbides and refractory metals cobalt, molybdenum, etc. When mixed and sintered with the element tungsten, copper shows a marked increase in resistance to wear. This is due to the high melting point of tungsten. Silver Tungsten. Used where the high conductivity of silver is desirable As the name suggests, this material is also very expensive, about five times the cost of copper tungsten.
It is obviously only for very specific applications. Tungsten will EDM very slowly when compared with other metals. It is very expensive compared with other alloys, and is limited in the sizes available. Due to the difficulty in machining tungsten, electrodes are usually supplied pre-formed. Its most common application would be small hole sparking operations. Advantages: Low cost, high strength, suitable for most spark erosion machines, good for entry-level or inexperienced operators, spark eroded mirror finishes can be produced, wire erodes easily, few housekeeping problems.
Disadvantages: difficult to grind, burrs produced, slower EDM metal removal rates, higher wear. Straight Graphite. These are commercially available in many grades. The density and the grain size will be a key factor in its performance and cost. If the application does not require a good finish or fine detail, then satisfactory results can be obtained with cheaper graphite.
If these are the primary considerations then a material with small grain size and high density should be the choice. As a general rule in choosing graphite, for improved wear resistance and surface finish — then the finer the grade of graphite required. Infiltrated Graphite. A mixture of superfine copper particles in a graphite matrix can used in specific applications where good machinability of the electrode is desired a complex shape , but with the forgiveness of copper in marginal cutting conditions deep slots, poor flushing.
The greater the percentage of copper, the lower the chance of arcing, due to its higher conductivity. However a proportionately greater degree of wear will be incurred, and the metal removal rate will also decrease slightly. Due to its expense, in comparison with straight grades, careful consideration must be given in its selection. Advantages: High strength, good machinability, high metal removal rates, and excellent wear resistance. Disadvantages: High cost, lower degree of safety in difficult machining conditions, dust from machining, wire erodes more slowly than metals.
Of course, every application is different and must be individually evaluated. Details to be considered are: How much material must be removed, and what is the surface finish required? What is the electrode raw material costs? How Many electrodes will be needed, and how difficult will it be to construct them? What about redressing? The electrode material selection process should start with the consideration of five important factors:.
Metal Removal Rate. This is the amount of material removed in a given period of time; most commonly measured in cubic millimetres per minute.
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