EDMカットワイヤー：ワイヤ放電加工完全ガイド

What is Wire EDM?

Affectionately termed Wire Electrical Discharge Machining (Wire EDM) or simply wire cutting, the process relies on electrical discharges to cut precisely through electrically conductive materials. The procedure utilizes a slender brass or copper wire electrode that functions as the cutting tool. In contrast to conventional machining techniques, wire EDM does not require the tool to come into physical contact with the workpiece, a restriction that constrains precision in intricate shape formation and strict tolerance control.

The process functions by generating a directed electrical arc between the wire electrode and the workpiece, which sits immersed in a dielectric fluid. The spark sheds minute particles from both the wire wire and the workpiece alike, permitting exacting cuts that can attain tolerances of ±0.001 mm.

History of Wire EDM

Wire EDM technology first appeared in the 1960s as a logical advance of traditional EDM methods. The earliest wire EDM systems were produced in Switzerland and Japan, as manufacturers identified the need for more exacting cutting techniques to deal with intricate geometry. Significant momentum gathered for the technology in the 1970s and 1980s, spurred by the advance of computer numerical control (CNC) systems toward greater sophistication.

Wire EDM evolved chiefly in response to the aerospace and automotive sectors’ demand for high-precision components with intricate internal geometries. Initial machines were constrained by their wire-feeding mechanisms and low-performance power supplies, a limitation that contemporary wire EDM systems have largely overcome.

How Does Wire EDM Work?

Within the wire EDM process, a number of critical elements function in concert:

Wire Electrode System: A slender wire—exhibiting diameters of about 0.02–0.3 mm—is continually fed through the workpiece. Functioning as a single electrode in the electrical circuit, the wire performs this role.

Power Supply: A regulated electric current provokes sparks at the interface between the wire and the workpiece, thereby producing temperatures up to 20,000°F at the discharge point.

Dielectric Fluid: The workpiece is immersed in deionized water or another dielectric fluid, where it assists in flushing away eroded debris and preserves the electrical insulation between the sparking electrodes.

CNC Control: Computer-controlled systems steer the wire trajectory and adjust cutting parameters, maintaining precise geometry and uniform quality.

The process commences as the wire is threaded through an opening in the workpiece. When electrical discharge takes place, minute particles are eroded from both the workpiece and the wire. As the wire feeds steadily forward, it continually delivers a newly exposed cutting edge, while the CNC machine directs its path to attain the intended shape.

Types of Wire EDM

There are a number of types of Wire EDM machine determined by their configuration and capabilities:

Two-Axis Wire EDM: Simple machines that make simple tasks with cutting straight vertical shape, these are used in applications with simple designs and prototyping applications.

Four-Axis EWM: Fancy machines that allow making tapered cuts and any three dimensional shapes by moving the upper and lower wire guides independently.

Multi-Axis Wire EDM: Top of the line machines contain more rotary axes, which make it possible to produce complex curved surfaces and complex shapes.

Submerged Wire EDM: In the machines, the whole workpiece is immersed and the dielectric fluid. This will offer excellent surface finish and exact tolerances.

Traveling Wire EDM: The wire is used continuously through the cut and eliminates the possibility of wire breakage which also leads to longer cutting cycles.

Advantages of Wire EDM

There are so many advantages associated with Wire EDM use in precision manufacturing:

Extraordinary Accuracy: Tolerances of +/- 0.001 mm are easily precisely accomplished with some applications being even stricter.

Complex Geometry Capability: The process has the ability to make an intricate internal feature, sharp corner and complicated contour, which is not doable by traditional machining.

Sound Tooling: There is no need of a mechanical tool wear as there is no physical contact between the cutting tool and the workpiece.

Great Surface finish: Surface finish is accomplished with extremely low requirements of post processing, typically Ra 0.025 or below.

Material Hardness Independence The process is capable of cutting any electrically conductive material irrespective of hardness such as hardened tool steels and special alloys.

Stress-Free Cutting: by the non-contact method, there are no mechanical pressures that lead to part deformation or cracks.

Disadvantages of Wire EDM

Although very useful, occasionally wire EDM is limited:

Limitation by Materials: The electrically conductive materials can only be processed (excluding plastics, ceramics, etc.).

Slow Cutting Speed: The procedure is relative slow as compared to the conventional machining especially when it comes to thick sections.

Higher operating cost: Operating cost is increased due to the consumption of wire, power and due to maintenance.

Surface Integrity Scrutiny: This process has a thermal aspect that may result in a heat-affected zone and residual stress on certain materials.

Starter Hole: Most of the cuts will take an added step in the pre-hole drilling.

Experienced Operator Considerations: The best results are achieved by trained operators who know how the cutting parameters interact in an intricate manner.

Wire EDM Applications

Wire EDM is present in a variety of industries because of its accuracy:

Automobile Industry: Manufacture of fuel injectors, transmission parts, and high precision engine parts with tight tolerance.

Aerospace Manufacturing: Turbine blade production, components of landing assembly, and complex geometry of any structures.

Production of Medical Devices: it involves making surgical tools and equipment, implants and precision components used in medical equipment.

Electronics Industry: Manufactures connector parts, semi-conductor manufacturing equipments and finely-made electronic cases.

Tool and Die Making: Making stamping dies, forming tools, injection molds and metal forming molds.

Development of the Prototypes: Complex parts are rapid prototyped in order to test and validate them prior to complete production.

Common Wire EDM Materials

The electrical conductive materials which can be processed by Wire EDM are varied:

Tool Steels: These consist of D2, A2, O1 and the different hardened steels often applied to tooling.

Stainless Steels: Stainless steel (different by various grades) in corrosive resistance.

Titanium Alloys: Titanium alloys that are aerospace grade improvement and need quality machining.

Aluminum Alloys: Soft and hard aluminum alloys to be used in lightweight.

Copper Alloys: Copper alloys are available with brass, bronze and bare copper that is utilized in electrical applications.

Exotic Materials: Inconel, Hastelloy and other superalloys that are applied in high temperatures.

Carbide Materials: Tungsten carbide and other hard products used in cutting tools and wear products.

Factors Affecting Wire EDM Process

A number of parameters affect wire EDM performance and quality:

Wire material and diameter: Different cutting properties and surface finishes are provided by brass, copper and coated wires.

Power Settings: Voltage, current and pulse duration influence the speed and surface quality of the cut.

Tension on the wire: The correct tension on the wire prevents breaking of the wires and is accurate in cutting.

Dielectric Flow: Sufficient flushing keeps away the debris and ensures good cutting conditions are maintained.

Workpiece Thickness: Thicker parts need modified settings and could have constraints of cutting speed.

Material Properties: Electrical conductivity, Thermal conductivity and M.P affects process parameters.

Wire EDM vs Conventional Machining

When comparing the wire EDM to customary methods of machining, it is important to note that it has a number of specific uses and benefits:

Precision: Wire EDM can obtain higher dimensional tolerance as well as the surface quality than the majority of traditional machining processes.

Complexity: Wire EDM works well with creations of internal features and complex geometries that are torturous or impossible to create on conventional tooling.

Tool Life: Wire EDM does away with the problem of tool wear found in the typical machining of hard materials.

Set up: Wire EDM can in many cases provide reduced set up and fixturing time on complex part

Material Removal Rate: M complexity When dealing with simple geometry, conventional machining normally provides a faster material removal.

Pricing factors: wire EDM can be less expensive in low-volume high-precision work.

Wire EDM vs Other EDM Processes

Wire EDM has some major differences with other EDM processes:

Ram EDM Ram EDM/Wire EDM: Wire EDM has superior surface finish, dimensional accuracy, whereas ram EDM is more suited to cavity routing and scrap forming complex three dimensional shapes.

Small Hole EDM: When using Wire EDM a starting hole must be created whereas in small hole EDM one is created as part of the process.

Micro EDM: Wire EDM is used with larger types of features and micro EDM interests only in very small geometries.

Flexibility: Wire EDM is best suited at through-cuts and profiling, whereas other EDM processes are great at cavity removal and work requiring fine features.

Cost of Wire EDM

Costs of wire EDM have a number of factors involved:

Capital Investment: Wire EDM machines are a major capital outlay and depending on capabilities will vary in cost from hundreds to millions of dollars.

Operating Costs: Continuous operational costs include wire, power and dielectric fluid.

Labor Prices: The advanced quality of the technology implies that highly experienced operators and programmers receive high wages.

Maintenance Needs: Wiring feeding systems, power styles and filtration methods should be maintained regularly which adds to the expenses.

Cost Per Part: In complex geometries in the perfection application where value is being sought in the manufacturing technique, wire EDM may be favored against other manufacturing techniques.

Return on Investment: The possibility to make parts that otherwise will need several operations or will not be fabricated at all often pays off the investment.

結論

Wire EDM is one of the most important technologies which are used in the field of precision manufacturing today, and its advantages compete and even in some cases exceed those of conventional machining techniques. It can develop intricate geometrics to the highest level of accuracy and thus this technology is essential in the industries which demand the stringent standards of precision.

We use some of the best wire EDM technology coupled with our extensive manufacturing base to produce precision mold components at the best standards where nobody can match. We are experts of wire EDM cutting, and since we also focus on the quality and precision of our work, our clients obtain components that they were not expecting.

Further development of the technology such as the ability of speeding the cut and producing a better quality of surface finish as well as increasing automation makes the wire EDM relevant to future manufacturing uses. Due to the increased accuracy and more complicated geometry requirements that the industries continue to seek, wire EDM will be an important technology to continue the objective of wire EDM.

To manufacturers who are evaluating wire EDM as a source of their precision components, the cost of the investment in this technology frequently pays itself in the form of enhanced quality, less secondary work, and the capability to produce shapes that could not be made in any other way. Wire EDM provides the precision and the ability that manufacturing needs when applications require accuracy.