Sep.2023 02
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What is WEDM
Introduction
Wire cutting is a shortened term for Wire Electrical Discharge Machining (WEDM), which refers to a machining method.
Details

Wire cutting is a shortened term for Wire Electrical Discharge Machining (WEDM), which refers to a machining method.

It developed based on the foundation of electric spark piercing and shaping. It involves using a moving metal wire (such as molybdenum wire, copper wire, or alloy wire) as the electrode wire and generating pulsed electrical discharge between the electrode wire and the workpiece to produce high temperatures, causing the metal to melt or vaporize and create a cut, thereby cutting the workpiece.

Main Applications:

  1. Mold machining.
  2. Machining parts with microstructures.
  3. Machining complex-shaped parts.
  4. Machining hard and conductive materials.
  5. Prototyping of new products.
  6. Cutting precious metals.

Main Features: Wire EDM machining has its own characteristics compared to traditional machining methods like turning, milling, and drilling:

  1. It uses a 0.03-0.35 millimeter metal wire as an electrode, eliminating the need for specific shapes, which saves on electrode design and manufacturing costs.
  2. Regardless of the workpiece material's hardness, it can process conductive or semiconductive materials, with minimal electrode wire wear and high machining accuracy.
  3. It is suitable for small batch, complex-shaped, single-piece, and prototype part machining with short processing cycles.
  4. In wire EDM, the electrode wire does not directly touch the workpiece, resulting in minimal workpiece deformation, and the electrode wire and fixtures do not need high strength.
  5. Water-based emulsion is used as the working fluid, reducing costs and fire hazards.
  6. It is not suitable for machining simple-shaped, large batch parts or non-conductive materials.

During the machining process, common problems and their possible causes may include:

  • Visible wire marks on the workpiece surface:

    1. Loose or vibrating electrode wire.
    2. Unbalanced movement of the worktable, causing excessive vibration.
    3. Improper adjustment of pulse power supply parameters.
  • Wire vibration:

    1. Loose electrode wire.
    2. Reduced precision of bearings due to prolonged use, causing wear on guide wheels.
    3. Increased impact and jumping of guide wheels during wire drum reversal.
    4. Bending of the electrode wire.
  • Whining noise and lack of smooth rotation of guide wheels:

    1. Large axial clearance of guide wheels, which should be adjusted.
    2. Ingress of working fluid into bearings; clean the bearings with gasoline.
    3. Reduced precision of bearings and wear on guide wheels; replace bearings and guide wheels.
  • Wire breakage:

    1. Aging and brittleness of the electrode wire; replace the electrode wire.
    2. Overly tight electrode wire and severe wire vibration; adjust the electrode wire.
    3. Inadequate supply of working fluid.
    4. Incorrect selection of workpiece thickness and electrical parameters.
    5. Large clearance in the wire drum reversing mechanism; adjust it.
    6. Exceeding the travel position of the wire drum; check the limit switch.
    7. Oxidation on the workpiece surface; remove it.
    8. Inclusion of non-conductive impurities in the workpiece; replace the material.
  • Loose wire:

    1. The electrode wire is installed too loosely.
    2. The electrode wire has been in use for too long, leading to looseness; re-adjust it.
  • Burn marks:

    1. Incorrect selection of high-frequency power supply parameters.
    2. Inadequate or contaminated supply of working fluid; adjust the fluid supply or replace the working fluid.
    3. Insensitivity of automatic frequency adjustment; check the control box.
  • Inaccurate workpiece precision:

    1. Loose guide rails, increased gap between the lead screw nut; adjust them.
    2. Vertical precision of guide rails does not match; adjust it.
    3. Large clearance between transmission gears; adjust them.
    4. Malfunction of the control cabinet or stepper motor failure; repair it.
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