MEW 117 July 2006

[Raymond HodgesParticipant @raymondhodges20973]

[Raymond HodgesParticipant @raymondhodges20973]

Hello Electronic Experts

In the MEW 117 July 2006 there is an artikel called "A Simple Spark Erosion Machine" is there someone out there who can scetch me a stripboard Circuit, not a PCB, for the Oscillator only, The Electrode Circuit is OK.

I have tried to do this myself but i aam not proficient enough.

Or can anyone recomend a computer program which can do this.

I can't use a PCB scetch because i dont have the fascility to make a PCB.

Thank you in advance

Ray

[Jeff DaymanParticipant @jeffdayman43397]

Regarding use of a solenoid oscillator mechanism on an EDM (from a 2011 thread I posted):

Any solenoid driven EDM machine I have seen has problems with burning accurate to size, and seems slower than other machines. The movement of the electrode when accelerated rapidly by a solenoid and spring is unpredictable and unless the equipment is heavily built the electrode will move all over the place. If you are just burning out a tap this inaccuracy is fine, but if you are trying to make an accurate hex or square hole for example, it is no good.

I have built and run successfully the Ben Fleming design EDM machine. It uses a simple resistor capacitor (RC) circuit for burning with a DC gearhead motor and leadscrew drive for the electrode holder. The electrode movement is controlled by a comparator which monitors the gap voltage and backs up the electrode if any shorting starts. The circuit does use 2 ICs but they are NOT microcontrollers and stepper motors are not used. These factors make Ben's EDM easy to build electrically and mechanically and like I said it works well and is fairly fast burning. I did make some mods due to some component tolerance problems with my set of scrounged / surplus electrical parts but many other people have reported successful builds of the machine around the world as is to Ben's book description. He supports questions and problem solving from builders via a Yahoo forum online. His EDM does not have a solenoid system or steppers – because you do not need them for simple reliable EDM.

 

By the way, the most important factor for successful EDM I have found is flushing. Not to much, not too little, and things go well. High pressure is not required but good flow is. A diesel fuel transfer pump is what I am using for my flushing pump, with a bypass valve on the outlet to vary flush flow at the job. Capacity of pump is 30 litres per minute. Works great and is rated for light oils. I am using industrial EDM dielectric fluid which locally is only a few more dollars than kerosene, doesn't smell, and is designed for the job, so it is not a surprise that it works great.

JD

[Raymond HodgesParticipant @raymondhodges20973]

Thank you Jeff for your advice

I also have the Ben Fleming Book and PCB but find this far too complicated for my level of electronic knowledge.

I have built a resistor capacitor power section which works well enough for me, but i am trying to separate the solenoid controll from the Burning circuit.

The Oscillator i have mentioned is a simple Solenoid controller the ,Feed motor controll will follow.

Ray

[Raymond HodgesParticipant @raymondhodges20973]

Is there no one who can help

[AndyPParticipant @andyp13730]

Ray,

I am sorry I can't help with a stripboard layout although having looked at the circuit it doesn't look impossible and my ignorance of most things electronic is legendary. I couldn't build that without being given ratings for the resistors and types and ratings for the capacitors which I suspect an electronics whizz would say is obvious but it isn't to me.

I built a simple spark eroder which works well enough for me using a scavenged solenoid (washing machine valve |I think) and a microswitch arranged so that it removed the power from the solenoid at the top of its travel. The circuitry for this is separate from the spark power, it may have been based on the one mentioned in the article to which you refer.

If it would help I can dig the device out from under the bench and see how I wired it all up.

Andy

[Michael GilliganParticipant @michaelgilligan61133]

Ray,

I've just had a quick look at the circuit diagram:

It would be difficult to do a tidy stripboard layout without knowing the physical size and style of the components [particularly the capacitors] that you are using … Therefore, I would suggest that you buy the components first.

That said; the board layout could be greatly simplified by hard-wiring several of the resistors onto the terminals of the switches.

MichaelG.

[Raymond HodgesParticipant @raymondhodges20973]

Thank you Andy

that sounds like a good idea it may be even simpler than using an oscillator.

Michael thank you for your help,

i have all the components and have already built this particular oscillator, but unfortunately it fried the IC, thats why i'm looking for someone to scetch me a wiring diagram to see where i went wrong.

Ray

[AndyPParticipant @andyp13730]

Ray,

It is definitely simpler but maybe not better.

I have created an album called spark eroder with some photos of the device and a circuit diagram, the squeamish and safety conscious should probably avoid looking

Andy

[Les Jones 1Participant @lesjones1]

Hi Ray,
Are you sure that you did not apply more than 12 volts to the circuit. (The NE556 absolute maximum voltage rating is 18 volts.) Can you post a picture of the track side of the board and a few of the top site so it is possible to follow the path of wires. If you have made any errors it should be possible to spot them.

Les.

[Raymond HodgesParticipant @raymondhodges20973]

Les

I have sent you an email.

Andy i have had a look at your spark eroder, well you cant get much simpler than that, amasing.

Thank you

Ray

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