General Tip: Clean and demagnetize the work piece
As part of preparation, a work piece should be thoroughly cleaned and fully demagnetized before Wire EDM operations. You should clean fluids, coolants, oils, and debris off all of the parts. Be sure to also clean any threaded or counterbored holes, because...
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How do you accurately measure and probe the center of EDM drilling electrodes?
Verifying and finding the center of an EDM drilling electrode can be a delicate and troublesome task, especially as the electrode diameters become smaller (0.5mm / 0.020” Ø or smaller). To find the center of a tube electrode, utilize a table ball within the machine’s...
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Common electrode materials for electrical discharge machining in a sinker EDM with oil-based dielectric
When choosing an electrode material, you must consider many factors. The usual first decision is, should you choose a metallic or non-metallic electrode? Depending on the material to be removed, this can be as simple decision. Carbides and sintered metals require more...
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Can the same electrode reduction undersize amount be used for all electrodes?
A proper answer requires a detailed look at the overall EDM operation. The practice of using a standard electrode reduction amount is very common, but it might not yield the best Accuracy or Machining Speed results. Pros of using a common electrode undersize:...
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Can I use graphite or copper-graphite electrode materials to machine tungsten-carbide?
While graphite materials can be used to machine carbide materials, it is not the best method. One of the reasons is the extremely high electrode wear rate. Burning with a fine-grain graphite, such as DS4 or POCO-3, will lead to 50-60% electrode wear when used to...
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Back to Basics (3/6): Wire EDM Machine Basics
Wire EDM machines use a small, traveling wire electrode to machine complex shapes, which are always through cavities (the wire must pass completely through the workpiece). Machines are capable of cutting and re-threading the wire automatically, which greatly...
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Back to Basics (2/6): The EDM Machining Spark
When you see an EDM in operation, it can appear that there are hundreds or even thousands of bluish-white sparks simultaneously discharging. But in fact, an EDM creates only one spark at a time. Each spark is precisely generated and controlled by advanced adaptive...
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Back to Basics (6/6): EDM Metallurgical Characteristics
All EDM machining is a thermal/heat process that can alter or change the structure of the machined workpiece. Early EDM technology thermally damaged materials as a result of not controlling the discharge spark energy precisely enough. The resulting metallurgical...
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Back to Basics (1/6): EDM Beginnings
The EDM (Electrical Discharge Machining) process utilizes short bursts or pulses of electrical energy to erode and machine conductive materials. The process can be thought of as machining with lightning bolts, called sparks. The number and power of each spark can be...
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Back to Basics (5/6): EDM Drilling Machine Basics
As highlighted in the first lesson, there are three main types of EDM machines: Wire EDM, Sinker EDM, and EDM Drilling. In this segment, we’ll focus our attention on EDM Drilling. EDM Drilling Machine Basics EDM Drilling machines, which are commonly referred to...
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Back to Basics (4/6): Sinker EDM Machine Basics
Sinker EDM, also referred to as Ram EDM, uses electrodes machined from graphite or copper to shape the workpiece. Typically found in die/mold component manufacturing, a Sinker EDM raises and lowers (sinks) the electrode along the workpiece. Regardless of the name you...
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The Most Effective Methods for Holding and Retaining Slugs
There are several different techniques for holding and retaining material slugs. These methods will vary based upon the material type and size of the slug. It is important to have a slug management plan in place before machining begins, as it is imperative to prevent...
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Surface Finish Comparison
There are several different surface finish scales commonly being used. Typically, µmRmax (Ry), µmRa, µinRa, are the scales in use. Following is a helpful Surface Finish Comparison Chart that provides values for several different finish scales.
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What are the best cleaners to maintain my Wire EDM machine?
Proper maintenance and cleaning of Wire EDM equipment is key to achieve reliable and repeatable cutting results. Use the mildest possible, yet most effective cleaner. All cleaning chemicals need to be used sparingly within the machine. It is best to apply cleaners to...
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Is there an easy way to test the condition of my sinker dielectric oil?
Depending on the fluid’s type, make and age, the easiest way to check the condition of your sinker dielectric oil is to ask the fluid manufacturer to perform a dielectric strength test. If you are using a standard petroleum-based di-electric fluid, the oil’s useful...
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What characteristics should be examined when comparing wire types? (Part 1 of 2)
There are several key characteristics that should be evaluated when evaluating a new wire type or brand. 4 Main Wire Characteristics CleanlinessWire memory and threading capabilitiesCutting performanceVariation of the wire by batch A previous article reviewed...
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Understanding Sinker EDM Gear Form Machining
In an earlier Expert’s Corner (Understand Wire EDM Gear Form Machining – EDM Today Summer 2017), gear and involute geometry were examined along with the methods and capability that can be produced by Wire EDM. In this issue, we’ll explore Sinker EDM Gear Form...
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What characteristics should be examined when comparing wire types? (Part 2 of 2)
This is a great question that applies to both plain brass and coated wires. When comparing wires, several characteristics and attributes should be examined, especially when trying the first spool of a new wire brand or type. Price alone is not a good...
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Quality is Key: Drilling Electrodes and the EDM Drilling Process
Physical variables of EDM drilling electrodes (fast hole tubes) can have a significant impact on process and performance. Oftentimes, these are only discovered when it’s too late, i.e., during machine operation. But it is critical for a successful EDM Drilling...
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Selecting a magnetic chuck for a sinker EDM machine
Magnetic chucks are typically specialized for EDM applications. They are sealed differently than those used for grinding machines, as the oil and debris from the EDM process can damage and seize up the typical ON/OFF magnet levers. Several magnetic chuck manufacturers...