First and foremost, machine selection is a huge part of operational efficiency in EDM. Depending on the application, moldmakers can choose from wire, drilling, sinker or some combination of the three.
Wire EDM: Choose a machine with the latest cost-saving features. For example, some machines have an operational mode that minimizes wire consumption by slowing down the wire feed. The right wire EDM can also help manufacturers save on energy and consumables, with features that control and optimize dielectric fluid volume and pressure, pump and filter operation, and resin consumption.
Drilling EDM: Moldmakers should look for machines that combat hole tapering—otherwise known as bullet nosing. To avoid this common problem, machines must not only use high-quality electrodes, but also feature a power supply with a low unload voltage—ideally less than 35 volts. This maintains a high speed, but reduces wear and tear on electrodes. The right type of dielectric fluid can also combat bullet nosing. Try tap water with the appropriate additives instead of de-ionized water.
CNC sinker EDM: These are ideal for cavity and rib machining, and as with wire EDM, selecting the correct machine is the key to productivity. Features such as c-axis, lateral servo, high-speed jump and state-of-the-art power-supply technology can reduce electrode wear and improve productivity. CNC sinkers with high-speed spindles can also perform the same job as an EDM drilling machine, but at a much smaller hole diameter and with more precision.
When it comes to purchasing any type of EDM, remember to consider its control technology. Many machines now have sophisticated software that incorporates 3-D modeling, which can significantly improve ease-of-use and operator efficiency.
When it comes to operational efficiency in EDM, machine selection is critical. Based on the type of application, molders can choose different tools such as sinker, wire and drilling machines. When choosing a wire EDM, it is best to pay attention to the latest cost-saving features. For instance, some of the machines are known to have operational mode that assists in reducing wire consumption by reducing the rate of wire feed. Choosing the best wire EDM is also vital in saving energy and consumption as they have features that assist in controlling and optimizing the filtration and pump operation.
Another thing mold makers need to pay attention to when choosing the right EDM machine is the whole tapering capabilities. One way of avoiding the problem, an EDM machine must be designed to use high quality electrodes and have a power supply with a low unload voltage. This helps in maintaining a high speed and reducing wear and tear on electrodes. Using the right dielectric fluid is vital in combating bullet nosing. Mold makers can also add the right additives to tap water instead of using ionized water.
Another thing con consider when searching for EDM machines is the ease of maintenance. Keeping your machine in good shape is vital. This means that when it endures damage, you need to find ways of fixing it. The ease of maintenance will depend on the type of locker you choose. When searching for the right EDM Machining, it is best to know the types of EDM available in the market. It is worth noting that there are three type of EDM operations; wire EDM, sinker EDM and small-hole EDM. Sinker EDM, for instance uses an electrode that is fabricated into a unique shape. The reverse of the shape is then imprinted. A sinker EDM uses a servo contour mechanism to monitor and maintain continuous sparking during the process. The best part of sinker EDM is that they are extremely accurate. They are most effective when parts need tight tolerances. They are also known to be versatile as they use parts of different sizes.
When looking for an EDM machine, you will find a wire EDM Machining. Like the name suggests, it uses a wire as the electrode. The wire used is spun between two reels during machining. The whole process is computer controlled, thereby improving efficiency. A wire EDM is best used for cutting delicate shapes effectively and efficiently. They are an idea for making contours and sharp corners.
Now that you understand the steps to follow when searching for the right EDM machine and the types available in the market, it is best to know the steps to follow when searching for the right EDM machine manufacturer. First, you may want to check the quality of the EDM machines of the manufacturers. When you choose the best quality, they will serve you for many years without having to replace them. Lower quality will only last for a few years. The difference in the quality of machines is in the quality of the materials used in making them.
EDM or Electrical Discharge Machining is a manufacturing process that is based on the controlled erosion of conductive materials using an electrode. It was first achieved in the 40s, but has developed into one of the most precise and high-quality metal removal processes available. EDM machines are generally used to achieve very complex shapes in extremely hard metals such as tungsten carbide, titanium, and hardened tool steel alloys.
How does EDM work?
There are two types of EDM machines: Die Sinker and Wire EDM. The operation of both is based on the same principle.
An electrical spark is created between the workpiece and a charged electrode using dielectric fluid as the media to control the flow of current. The CNC-controlled machine brings the two electrodes close enough to ionize the gap and superheat the surfaces of the workpiece and electrode.
Once the necessary temperature is achieved, discharge occurs and the material is vaporized. Once the material removed the generator will shut off for a short period of time allowing the vaporized particles to be flushed away in the dielectric fluid. This process repeats itself over and over again at frequencies of approximately 100,000 times per second during rough machining cycles.
In the case of Wire EDM, the role of the cutting electrode is fulfilled by a precisely manufactured brass wire ranging in diameter from 0.0005” to 0.013”. The wire is guided through the workpiece using precision diamond dies at both top and bottom of the workpiece. Sinker EDM typically uses a custom machined electrode made from various materials such as Graphite (carbon), Copper or more exotic materials such as Copper Tungsten.
Why is an EDM ideal for die/mold applications?
The manufacturing of highly tailored dies and molds call for extreme accuracy. As they feature demanding design points such as sharp internal corners, narrow slots, deep ribs and other intricate shapes. There is no other tool that can achieve the high-precision machining required for the man
The need for more modern, innovative Electrical Discharge Machine (EDM) drilling technology in hole-making operations have arisen due to the demand for smaller, deeper, and more accurate holes made as quickly and reliably as feasible.
Here are some pointers on choosing an EDM machine that can assist your company in meeting these objectives.
Look for operational efficiency:
Machine selection is essential when it comes to EDM operating efficiency. Depending on the application, molders can use various equipment, including sinkers, wire, and drilling machines.
When selecting a wire EDM machine, it is important to consider the most recent cost-cutting features. For example, some machines have an operational mode that helps reduce wire consumption by slowing down the wire feed rate.
Choosing the best wire EDM machine is also important for reducing energy consumption and saving money since they offer features that help manage and optimize filtration and pump operation.
Ease of use and reliability:
Look for an EDM machine that is quick, dependable, and easy to use. It should drill exceedingly tiny holes while maintaining high surface finish quality and accuracy at larger depths. In light of some of today’s applications, it’s critical to find a system that could drill a 15 mm deep hole which is 0.20 mm in diameter in tough steel while simultaneously drilling a cooling hole of 2.5 mm in diameter 250-mm deep in mold steel, all with minute size and straightness variations from the entrance to exit.
Ease of maintenance:
Another factor to consider when looking for EDM machines is how easy they are to maintain. It’s critical to keep your equipment in good working order. This implies that you must figure out how to repair it if damaged. The sort of locker you pick will determine how easy it is to maintain.
Types of EDM machines:
When looking for the correct EDM Machine, it’s important to understand the different types of EDM on the market. Wire EDM, sinker EDM, and small-hole EDM are the three types of EDM activities to be aware of.
Sinker EDM, for example, makes use of an electrode that has been manufactured into a certain form. After that, the reverse of the shape is imprinted. A servo contour mechanism is used in a sinker EDM to monitor and ensure continuous sparking throughout the operation.
Supper high-pressure coolants:
Uneven wear increases the probability of a drilling electrode to “wander” off-center, resulting in crooked and slanted holes rather than straight ones. Supper high-pressure coolant/flushing systems assist in averting this scenario by reducing wear and contributing to the production of straighter holes that can be held closer to size from top to bottom.
For example, a 200 mm-deep hole drilled using a digital generator-equipped EDM system with a 1 mm electrode would vary in size from top to bottom, generally less than 0.025 mm.
In EDM, the electrode and workpiece are immersed in a dielectric fluid. The produced electric spark erodes or cuts the workpiece to remove material and achieve the designed geometry. The movement of the electrode is controlled by CNC programs, and there are a few key concepts you need to understand to ensure the process functions well.
Discharge gap
In order to generate sparks between the electrode and the workpiece, there must be a gap, sometimes called “discharge gap”, which is typically in the 0.005 – 1 mm range. If the electrode and the workpiece are in contact, then sparks are not produced. This gap and the movement of the electrode are controlled by a servo mechanism on the EDM system.
Electrode wear ratio
This ratio corresponds to the volume of material lost from the tool electrode divided by the volume of metal removed from the workpiece. Sometimes it is represented by the percentage of mass loss of the tool divided by amount of work.
Removal rate
The speed at which the spark removes material from the workpiece. Typical mass or volume units are used to quantify it ([g/min] [mm3/min]).
Polarity
In order to apply voltage between the workpiece and the electrode, one must be positive, and the other negative. It’s common to use the term “positive polarity” or just “polarity” when the electrode is negative and the workpiece is positive. A “reverse polarity” setup is when the electrode is positive, and the workpiece is negative. We highly recommend familiarizing yourself with your combination of electrode/workpiece materials to determine the best settings and process parameters for your application. The polarity can impact the material removal rate, “electrode wear ratio” and surface roughness, which in turn produces wear, speed and stability effects.
One of the most significant advantages of EDM is that it can be used on all materials as long as they are conductive. It allows for shapes and depths that are hard to achieve with other methods. However, when it comes to selecting the best EDM machine, it boils down to several factors.
For starters, the type of design you want to create should guide you on the type of EDM machine you need. Additionally, the type of machine that best suits your project will be determined by the material you are cutting, the kind of precision you want to achieve and the surface finish desired. Wire EDM machines are known for delivering greater precision if you want to make precise incisions on a thick piece of metal or alloy. The splits and contours from this machine are unachievable with other methods.
If you want a machine that combines reliability and precision and your work has blind holes or cavities (molding), Sinker or RAM EDM is the best choice. This type of machine delivers a smoother surface and exact finish details. Lastly, the Drill EDM machines are best suited for projects that involve making precise and small holes on a work piece. The bottom line is; there is no one-size-fits-all criteria for selecting the type of EDM machine that is right for you. It all depends on the material you want to cut, the precision you want to achieve, and the type of finish you desire
As we see with most machines, there are varying types of EDM tools. Before looking at some of the tasks they can handle, it makes sense to explore the two types that currently exist:
Conventional EDM
A metal die is used as an electrode to produce a distinctive shape. That electrode is then impressed deep into the material that needs to be formed. This creates a negative impression of the unique shape and results in a mold. Conventional EDM machines also go by many other names, including sinker EDM, die sinking, cavity-type, volume, and ram EDM.
Wire EDM
A thin, heated wire is used as an electrode with hard diamond guides in place to hold the wire steady and stable. The taut wire is then used to cut through the material. While the wire doesn’t touch the surface of what it’s cutting – the electrical discharge does – the system still unspools new wire automatically to keep cuts smooth and seamless.
Both types of machines can be used to cut or shape incredibly tough materials such as tungsten, titanium, hardened steel, and other carbides. Traditional tools, especially blade-based, are woefully inefficient for cutting a lot of these materials.
Sometimes when you’re choosing what manufacturing method to use, the requirements for dimensions, materials, and specifications make conventional production processes too expensive. Milling, turning and drilling to machine a block with openings and chamfers that will hold bearings or other components is complex and difficult. Of course, you can cast parts, but the up-front cast molding investment only makes sense when fabricating parts in high volumes.
What if you’re working on a prototype in its early design stages and you only need to fabricate only one or two parts? Milling and turning take a lot of time and waste a lot of material, but electrical discharge machining services (EDM) can be a more efficient solution. EDM is a manufacturing process where material is removed from a workpiece by applying a series of current discharges between two electrodes separated by a dielectric bath liquid.
I think the current EDM devices have become very powerful and more intelligent, which makes operators feel very easy to operate