Ø What should you do if you have a problem and troubleshooting with EDM machine?

Trouble	Phenomenon	Cause	Check item/Solution
1. Wire breaking	①Breaking near feed plate	- Feed plate in friction	Check the feed plate and replace it periodically.
		- No striking of water from the feed plate nozzle	Clean the feed plate nozzle and check water pressure.
	②Breaking near wire guide	- Dirty wire guide	Perform periodic maintenance.
		- Excessively strong holding force of the wire guide	Make adjustment for optimal holding force.
		- Misaligned wire guide	Reset positioning accuracy.
	③Breaking when idling	- Poor wire hooking	Check wire hooking position.
		- Wire winding crossed	Replace or wind off wire.
		(tangled, passing beneath another)
	④Breaking immediately after the start of cutting or within 5 mm	- Air mixed in the cutting liquid (breaking in air)	Degrease and wash the object subject to cutting, as cutting conditions are very strict.
		- Tilted object subject to cutting	Check water pressure of machining liquid.
			Start cutting after plumbing.
2. Error of cutting accuracy	①Shaping defect	- Insufficient pressing force of wire guide and positioning error	Adjust pressing force of wire guide and position.
		- Insufficient wire tension	Properly set wire tension.
		- Large fluctuation in ambient temperature	Remove material distortion (stress).
		- Non-uniform cutting materials	Erroneous plumbing of wire.
		- Improper offset	Clean and maintain guide dies and associated components.
3. Error of surface accuracy	①Rough surface	- Mismatched cutting conditions (non-uniform electric discharge)	Increase wire transfer speed.
	②Wire mark on cutting surface	- Insufficient wire tension	Increase cutting speed.
4. The guide wheel is noisy	① Guide wheel problem	- Wrong installation position of guide wheel	The guide wheels need to be on the same plane when installing
		- Wear of guide wheel bearings	Long-term use of bearing wear is serious
	② Diamond guide question	- Guide wear	Replace with a new guide
5. High noise of wire drum motor	① Coupling problem	- Damaged motor coupling	Replace with new coupling
	② Motor	- Internal noise of the motor	Replace with a new motor

Ø After a period of time, the efficiency of the wire-cutting machine is low. How do we solve this situation?

1.        The selected processing parameters are unreasonable- select appropriate processing parameters for different materials and workpiece thicknesses. Please note that the processing efficiency will decrease when the current is small.

2.        The concentration of the cutting fluid is inappropriate- keep the concentration of the cutting fluid at 11-12.5%.

3.        The deformation of the workpiece will cause an unstable discharge state during the machining process, especially the dressing-control the deformation.

4.        Slow trimming speed-will reduce the relative processing volume of each cutting. If the trimming speed is increased, the offset of the main cutting can be reduced by 0.005mm-0.01mm.

Ø Abnormal noise of wire cutting motor：

1)   When changing the left and right movement direction, the coupling or the fixed pin is damaged: at this time, please carefully observe the reason and replace the loose fixed pin to restore the large area tight fit;

2)    The sound of foreign objects inside the spool is mainly caused by small metal particles or molybdenum wire ends entering the spool. As long as it is not removed by the dynamic balance adjustment screw inside the spool, it can be operated as usual, and the small metal particles or the end of the molybdenum wire can be quickly operated.

3)    For abnormal noise of the toothed belt or gear, check whether the toothed belt or gear is excessively worn and replace it in time. If the occlusal gap is improper, adjust the occlusal gap in time

4)    Excessive load force from the wire tube to the lead screw causes friction or impact sound, which will quickly cause damage to related parts. The abnormal phenomenon in this part should be stopped and carefully searched until it is eliminated.

5)    The fan blade of the wire cutting wire drum motor or its own dynamic balance.

Ø Working of a Wire EDM

A thin, electrically charged wire is held between two mechanical guides. This forms the tool electrode, while the workpiece to be cut is at the other electrode. Voltage is applied on both these electrodes and slowly increased, which forms an electric field between the two electrodes. When this becomes greater than the strength of the dielectric, the latter breaks down thus allowing the current to flow between the two electrodes. This produces sparks and helps cutting the required material from the workpiece, and this happens quite rapidly. So, the charged wire and the workpiece never come in contact with each other, and there are no physical cutting tools to cut the workpiece. This helps cutting of small, complex, and intricate parts with huge precision and accuracy. By far, this is the most efficient method for all good conductor materials.

Ø Benefits of Wire EDM Machining

Certainly, the wire EDM machining has an edge over traditional machining techniques. This method is known to deliver far superior results than even laser cutting. Although, one may have to invest more than what is required for most traditional methods, you get a good return on investment, and it turns profitable in the long run. Apart from being cost effective, wire EDM machining offers many benefits. Here are some of them:

v Precision and quality: Fine precision and quality in cutting can be achieved using the wire EDM method, no matter how hard the metal.

v Tolerance: High tolerance levels of about +/- 0.0002 inches can be achieved using this process.

v Cutting small and complex shapes: Usually, cutting small objects can be difficult, and to form extremely complex shapes with an equal amount of precision is just as challenging. This method, however, enables you to make complex and small shapes as required of the workpiece.

v Suitable for cutting fragile objects: Some fragile and delicate workpieces may get damaged if traditional methods are used. However, this method avoids any contact with the object at all, and hence there is no physical pressure applied. Hence, it decreases the possibility of damage to the workpiece.

v Minimal infrastructure: The space and infrastructure required for this method is minimal. Additionally, it is cost effective.

v High Speed: You can cut metals into the required shape at a reasonably high speeds and multiply your production volume. Also, the quality remains intact with no place for burring or distortion of metal workpieces. This enables prototyping, which can save costs in the long run and add to the business profits.

Ø What Kinds of Materials can be Cut Using the Technique?

The machining is suitable for materials that conduct electricity. There are wide range of materials that are compatible with wire EDM machining. A few among them are

v   Steels

v   Super Alloys

v   Aluminum

v   Brass

v   Copper

v   Tungsten

v   Ceramics

v   Carbon graphite

v   Carbon steel

v   High alloy

v   Inconel

v   Hast alloy

v   Titanium

v   Kovar

Ø What are the Advantages of the Machining Technique?

When it comes to wire EDM machining, advantages are plentiful. A few pros that contribute to the popularity of the technique to cut the aforesaid expensive materials include;

v   The method can be reliably used to cut odd angles, sharp corners, contours, cavities, and external or internal tapers, among other cuts.

v   This computer- and robotics-controlled technique can cut extremely hard, challenging and exotic materials by eliminating burrs and metal distortions.

v   Little or no polishing, heat treatment or cleaning is required after the machining process.

v   With minimal setup time required, the technique can cut the same intricate part over and over again with the same accuracy and with a quick turnaround.

v   Precision and high-speed of wire EDM machines can also be utilized to produce tiny holes, which is challenging to obtain using other cutting techniques.

Ø What are the Components of a Wire EDM system?

Although available in several models, all kinds of EDM machines have the following components in common.

v   Computerized Numerical Control (CNC)

v   Power Supply

v   Mechanical Section comprises of worktable, workstand, taper unit, and wire drive mechanism.

v   Dielectric System

Ø What Kinds of Finishing the Machining can Achieve?

Usually, wire EDM machining can render smooth, yet matte finish or similar to a surface ground finish to the work piece.

Ø What are the Personal Safety Precautions to be taken during the Machining Process?

The machining process can be dangerous in case if you don’t pay attention to some basic safety precautions. Stringently follow the guidelines below throughout the process.

v   Do not touch the component being cut during the process

v   Do not touch the wire when it is in operation

v   Rectify immediately in case any leakage of deionized water from the machine

v   Use rubber gloves and protective shoes throughout the process

v   Refrain from wearing conductive ornaments like watch and gold

Ø Who uses Wire EDM?

Wire EDM machining is employed largely to get delicate and specific cuts or imprints on the workpieces. It helps to form deep holes, hard tapping, whilst also helping to remove broken taps. The machining is largely depended on to create several parts for use in aerospace, automobile, medical industries, among several others. The following are a few parts that are usually machined using the technique.

v   Miniature Parts

v   Internal Gear

v   Titanium Needles

v   Power Generation Turbine Blades

Ø What’s the difference between a stepper and servo?

The basic difference between a stepper and a servo-based system is the type of motor and how it is controlled. In a servo-based system, there is constant signal feedback from the encoder (or motor) to the servo drive. This feedback tells the servo drive exactly where it is within its move. Thus, the servo drive can adjust its power output, as needed, to complete the move. The servo is much more powerful, has quicker acceleration time and more precise positioning.

A stepper-based system runs on an open loop meaning it sends out the number of pulses to the proper axis to get to the programmed location. Because of their simplicity, steppers are less expensive than servos and are the most affordable solution to producing CNC motion. They have the limitation that, if overpowered, they can lose synchronization with the computer controlling their motion. But when configured correctly, they will produce great cuts on a consistent basis. All FANCH machines that come with steppers are programmed to specific specs to ensure that they never lose synchronization at any point so that you can load your CNC router day after day without a second thought.

Ø Do I need to learn a programming language like G Code to operate an EDM machine?

No, you don’t. The design software titles available today allow you to design your files, import pictures and drawing graphics, manipulate them and the software will in turn generate the code that the machine will use to cut out your parts.