@edmguru, great work, keen to do one myself and while I follow most of what you have done, the z axis control eludes me, I know many others have asked but a schematic of your system would really be helpful, even a hand drawn one photographed.
@EDMguru it is great to see this video. I too am a tool maker/machinist of similar age. 30 years ago I made plastic injection molds. A friend had a molding shop where he let me use his old EDM to sink cavities now and then. It was old enough that it likely used simple electrics like you show here. Over the years I have developed some expertise in electronics and have always thought it should be relatively easy to reproduce the old technology EDMs for small jobs. It appears you have just proved this! I am very interested in doing what you have done here. It has been so long since I have used EDM that I don't remember most of the details of how the electronics work. Thank you for posting this! Do you know about when you may be posting the stepper motor version?
Thank you for your feedback. The D.C. motor version is indeed the easiest way to build a commercial grade E.D.M. as the control side mainly uses off the shelf parts. The stepper motor version however is, by the way they work, more complicated and has a lot more wiring (at least 10x more) also I’m using a custom built controller (no comparator as such) which in tests is very stable, and as a bonus, has the provision to build in an anti arc circuit (basically it switches off the power gen on potential arc forming low voltage sparks). Unfortunately at the moment it’s down to the weather (machine is in an outbuilding) and motivation as to when the new machine will be finished, also I don’t know if I should use the machine column slide or bolt on a new ball screw slide for the z axis? Either way it’s probably going to be a few months yet.
Thank you for your feedback. Unfortunately the machine drawings and design only exist on lots of hand drawn sketches and in my head. Also the machine, as shown in the video, no longer exists as it was dismantled and the parts modified and reused for the new build stepper motor EDM with anti arc circuit which is looking, so far in tests, to be a real game changer for the EDM home builder.
The electrode shouldn't touch the work piece at all it works simply by Ohm's law. Basically as the required burn plasma level is reached, the output voltage from the power generator (which is shunted through a high wattage output resistor) drops, which also causes the speed controller via a voltage divider to change its voltage control reference point either up or down and so change the motors direction.
@@edmguru9056 this is a little confusing to me. what I figured was happening was the voltage was essentially full (100v I assume) at the electrode because the open circuit makes essentially an infinite resistance - meaning there is no voltage drop across the resistor. once the arc is established the plasma (as it becomes hotter and hotter) conducts more and more, making the resistor a bigger and bigger contributor to the resistance of the circuit, eventually limiting the current to your desired value. this way you don't just have a massive thunder instead of the tiny arcs that are ultimately desired (we're assuming ideal power supply here). I think what you're saying is that once the arc is established, the motor will sense the current through the shunt and subsequent voltage divider, and then that does something (like keep it from plunging in further). but since the current is always limited, how can you ever know whether you're arcing, or simply shorting due to contact? does the motor just go down slowly by default, but pull up every time there is current flowing and that increased distance is what breaks the arc? or does the motor just stop moving once the first arc strikes? thank you once again, and for taking the time to respond
Thank you for your feedback I’m sorry this reply has taken so long but your second comment was filtered out as likely spam for some reason. I’ll try to describe how the machine works if I can. The power supply to the power generator is via an isolation transformer (not shown in the video) which has an output of 70 volts ac. Once rectified this gives the 100 volt dc supply for the power generator which is just a basic amplifier design with 3 (could be more depending the number of power settings you require up to the output power of your transformer) individually switched on power outputs through separate high wattage resistors and their value determines the output Amps. The total output Amps is therefore just a resistor in parallel calculation as each stage is switched on if that makes sense. The speed controller is an off the shelf part and it controls the z axis position via a voltage divider from the power generator output using Ohm’s law. Basically as the required burn plasma level is reached (half open voltage), the output voltage from the power generator (which is shunted through the high wattage output resistor) drops, which also causes the speed controllers built in speed control to change its voltage control reference point, and so the speed and direction of the dc motor changes. It might be worth taking a look online about how the control of these machines work which will explain better if that helps.
Revised: I would think by the reduced voltage across the spark gap. With e.g. 50% duty cycle and 20V across an arc, that averages 10V. With 50% duty cycle and 0..1V across a short, that's 0..0.5V. At the high frequency, no way can the motor respond that fast so it's averaged. The resistors limit the maximum average current; in an RC machine this would include the charging current to the capacitors but I don't see any caps in the power supply so this is not an RC machine; just the edge of what is presumably an IGBT? and power resistors with fan. When an arc establishes (ionization breaks down the dielectric, or (undesirable) the electrode touches), current flows and there's an arc. The arc erodes the metal (or, if touching, maybe spot-welds it). The oscillator drive turns off power, bringing the voltage down below the level that maintains ionization; the dielectric becomes insulating again. Flushing the metallic debris out of the gap is important here.
Thank you once again for your safety concerns regarding EDM. I agree that these machines can be dangerous if safety precautions aren't taken. Also this is a pulse EDM and doesn't have the capacitors you mentioned as they are used in RC type EDM.
Thank you for your feedback. I never bothered with a schematic for the power generator as it’s just a basic amplifier design with 3 (could be more depending the number of power settings you require up to the output power of your transformer) individually switched on power outputs through separate high wattage resistors and their value determines the output Amps. The total output Amps is therefore just a resistor in parallel calculation as each stage is switched on if that makes sense. It’s pretty basic and easy to build if you know how amplifiers work.
that looks great, meanwhile im working on a mosfet pwm driven one after building the robert langlois version running on a arduino mega to controll the step motor. do you plan to sale the plans to build one ? that would be great.
Thank you for your feedback. There’s no need to use an Arduino Mega or any code to control the z axis and burn of an EDM as it can all be done by voltage feedback from the electrode via a voltage divider, but having said that, ultimately it is the way to go just like manufacturers of commercial EDM machines do. This is because if you know exactly where the z axis is at any given time you don’t have to wait for a voltage feedback control to work so you can have incredibly fast z axis travel speeds without fear of the electrode hitting the work piece, which is what’s required for the flushing “pump” action when using deep thin web electrodes etc. There’s no plans to sell any schematics just yet as I’m near completing the build of my new EDM which has now been upgraded to 30 Amps output and has a basic fuzzy logic control which helps to “blur” the transition between the z axis down/ pause/ up control point which adds to burn stability and there’s an anti arc circuit which simply turns off the power generator on all the very low and potentially arc forming pulses, which could be a real game changer for the DIY EDM builder. All this new build has been done without using any pc or code but the downside is that the wiring gets complicated and ends up looking like a rat’s nest so coding is something I’ll have to learn one day.
@@edmguru9056 I´m using a arduino mega with the intention to program the burn to stop at a predefine depht without using glass scales or a stopper. it´s kind of hybrid r/c pwm. here it is ruclips.net/video/3v9KojQ7RMw/видео.html
Hello EDMguru! Thanks for your video, and the inspiration it provides. In the early 1990's I built Robert Langlois' EDM using the relaxation oscillator power supply. I used an old office typewriter carriage roller slide for the electrode feed, with stepper motor drive. Nowadays stepper motor drives are much simpler with commercially available equipment! My machine has seen considerable use over the years, but it is SLOW! Hence my interest in your equipment built, primarily, with commercial building blocks. Would you be willing to provide a simple block diagram of the arrangement for your equipment? And a brief description of the DIY power supply? I suspect that many here, including yours truly, would greatly appreciate it. Thank you kindly for your efforts! Greetings from Wolfgang
Thank you for your feedback I never bothered with making any drawings of the machine as it was an easy build but it is something that I’ll do one day. At the moment I’m still working on the new, more advanced stepper motor version. The power generator is just a basic amplifier design with 3 (could be more depending the number of power settings you require up to the output power of your transformer) individually switched on power outputs through separate high wattage resistors and their value determines the output Amps. The total output Amps is therefore just a resistor in parallel calculation as each stage is switched on and in my case it was 3.5A, 7A and 10A if that makes sense.
@@edmguru9056 hello brother Can you please make a detailed tutorial type video of this machine Because I want to make it but I don't have enough knowledge about electronics and circuits Please make a detailed tutorial.
I think the title holds the answer to all our questions. "the fastest, cheapest and easiest....COMMERCIAL grade spark erosion machine..." Unless the word commercial actually applies to the quality/power of the device, it sounds like this is going to be a 'for profit' project. Nothing wrong with that... but might be worth considering when asking "can you make the pcb files/BOM etc available?" Am I near the mark there, EDMGuru?
Thank you for your feedback. The term “commercial grade” in the title sentence refers to the quality of the end result compared to other homebuilt machines I’ve seen online and not to “for profit” as you say but if the new design mosfet power generator, once tested, works even better than my amp based transistor version then I might consider making it a “for profit” venture, but then again I doubt that there is much of a market for an EDM considering how much CNC machining has evolved for home use over the years.
Anyone building this: please look into electrical safety first, including what it takes to stop your heart. Not saying not to do it; saying do it _safely_, so it stays fun! High voltage DC will override the millivolt-level signals from your nerves and brain: hit the right polarity, and your muscles will contract and not let go until they run out of ATP and oxygen. You won't have anything to say about it. Touching with the back of your hand or finger will make you luckier; contracting muscles will tend to pull your hand away, rather than causing you to grip a conductor until your muscles run out of oxygen and ATP. High voltage DC will make and maintain arcs; switches that aren't rated for it are not rated for it for good reason. AC arcs are much easier to extinguish. Make sure there's no high voltage before or while you are touching anything; be suspicious; did that switch or relay **REALLY** open? What happens if that gets bumped? Practical jokers have no place around HV DC.
Thanks for your feedback. Good safety information. I agree that you have to be careful around high voltage, and I always recommend wearing rubber gloves when using spark erosion machines, also these machines are fitted with a volt meter so that you can see if and when there’s voltage present at the electrode.
Scott W, No need to be panic High voltage DC (pulse or not ) not as dangerous as high volt AC. Your body is full of polarize molecules which AC can pass easier. Imagine those molecules flip back and forth 50-60 time a second. And I have tested the DC(100V) myself for 30-40 times, the worst made my finger numb for ten seconds. I make a machine similar to this but also with 250VDC ignition ( Ignition voltage limit current to a few tenth mA). This machine is not more danger or less danger than a commercial one. Most likely dangerous of this machine come from a fire from burning of an EDM fluid.
I would caution anyone that builds this from what I can see it does not appear that you have any isolation from the power main feed line. This is a SERIOUS safety issue. Should someone get a cross the electrode to ground there could be major issues including death due to electrocution.
Thank you for your feedback. Actually there's no need to worry as the power generator is supplied via an isolated transformer which is unfortunately not shown in the video. This transformer has an output of approx 70 volts AC.
@@edmguru9056 ...which gets turned into what voltage DC, about 100 VDC? 30..50V and up is considered dangerous, AC or DC. Notice how many switches are not rated above 24..32 VDC; it's much harder to break a DC arc because the AC line reverses polarity slowly enough for ionization to extinguish much more easily. DC causes muscles to contract. If you are lucky, and touching with the back of the possibly-contracting hand instead of the front will make you luckier, they will pull away from the voltage source. If not, you may not be able to let go of the conductor, because the millivolt signals from your brain cannot out-shout tens of thousands of millivolts from the external source. Depending on the level of contact; dry skin is less conductive and safer than wet and salty / ionizable. Not saying not to do this; saying take reasonable precautions. Treat it as potentially lethal -- keep your fingers away -- until your voltmeter (which you checked against a known voltage, yes the battery hasn't died, it's on Volts and it's working) tells you the voltage has dropped. Maybe add some red indicator LEDs with about a 20V Zener; if the LED is on it's at 24..100? VDC and you don't touch it.
Thank you once again for your safety concerns regarding EDM. I always recommend the wearing of rubber gloves when using EDM. Also the machine has a built in voltmeter which shows when voltage is present at the electrode which is only when the machines switch is actually set to the spark position.
So, let´s rephrase... U made EDM out of: -a power-source (100V / 3,5A to keep it simple) -a dc-motor/controller-unit -a PWM-signal-generator (DutyCycle, Hz, both selectable) -a voltage-divider ... With the information given here, well, sorry, but I don´t see it... If the signal-gen turns on+off a high-speed mosfet, thus controlling the power-source, it´d make more sense, but the mosfet would also need its own driver. None such was mentioned... And I understand, that some natural "triggers" that occur during each cycle (for example: the required burn plasma level is reached), can be exploited, in order to change the motor´s direction, but still, I dont see the connection to the motor-controller, or at least, to the voltage-divider... I beg you for for more information. How do the parts come together ??????? What is that motor-controller made of ?????? Is there any additional parts, that weren´t mentioned in the Intro ??????? Thanks anyway I guess, but as is, the video doesn´t inform more, than a clickbaity video would... I mean, it´s obvious that it works, and that it even works very well... But if someone would come up to you, telling you, he invented an EDM-machine by using an arduino, a mosfet, a donkey, and the tail-feathers of a himalayan male chicken, how would you feel??? You´d be sure thinking, that this person makes jokes on you, right???
Thank you for your feedback, The power generator used on the EDM was a transistor type based on an audio amp design but modified for a square wave pulse input which was provided by a “bought off the shelf” square wave frequency generator so no driver ic is required. The pulse frequency generator and the transistor type power generator are both shown at the start of the video. The voltage divider is fitted after the output current limiting resistors so that once the spark erosion process starts, due to Ohm’s law, the voltage at the electrode and in the divider will drop and this voltage drop is used to automatically control the D.C. motor controller. The motor controllers direction control works by using an input voltage which is either higher or lower than a fixed internal reference voltage, so the input voltage from the voltage divider can control the burn position of the electrode automatically. No other parts are used or are necessary although if you add a potentiometer to the voltage divider, you can manually adjust the output voltage, and set the electrode plasma burn voltage level which is handy for different spark conditions. The output current is set by switching in power resistors in parallel. My videos are not fake or click bait and I never personally ask anyone to like, subscribe or contribute financially in any way so I have nothing to gain from any of my content. I've always said that building an EDM is easy to do (there's nothing "magical" about them) and this type of “Easy-Peasy” EDM machine works simply by Ohms law and is very easy and cheap to build; also I’m surprised that no one else, now or in the past, has thought of using this way to control an EDM before?
@@edmguru9056 This sounds great...!!! I´ve read your answers to several comments, and I couldn´t figure out how it all worked, but I was really interested, And I finally can follow you... And the motor control sounds really unique !!! I´ll write again, when I understand it better...
@edmguru, great work, keen to do one myself and while I follow most of what you have done, the z axis control eludes me, I know many others have asked but a schematic of your system would really be helpful, even a hand drawn one photographed.
@EDMguru it is great to see this video. I too am a tool maker/machinist of similar age. 30 years ago I made plastic injection molds. A friend had a molding shop where he let me use his old EDM to sink cavities now and then. It was old enough that it likely used simple electrics like you show here. Over the years I have developed some expertise in electronics and have always thought it should be relatively easy to reproduce the old technology EDMs for small jobs.
It appears you have just proved this! I am very interested in doing what you have done here. It has been so long since I have used EDM that I don't remember most of the details of how the electronics work. Thank you for posting this!
Do you know about when you may be posting the stepper motor version?
Thank you for your feedback.
The D.C. motor version is indeed the easiest way to build a commercial grade E.D.M. as the control side mainly uses off the shelf parts.
The stepper motor version however is, by the way they work, more complicated and has a lot more wiring (at least 10x more) also I’m using a custom built controller (no comparator as such) which in tests is very stable, and as a bonus, has the provision to build in an anti arc circuit (basically it switches off the power gen on potential arc forming low voltage sparks).
Unfortunately at the moment it’s down to the weather (machine is in an outbuilding) and motivation as to when the new machine will be finished, also I don’t know if I should use the machine column slide or bolt on a new ball screw slide for the z axis? Either way it’s probably going to be a few months yet.
nice start ... one axis and proof of concept is done ... now for the x and y axis' then one can get into more complex shapes such as curves
Do you plan to show more details about the circuit? Seams to be a quite nice and simple solution. Good job!
Thank you for your feedback.
Unfortunately the machine drawings and design only exist on lots of hand drawn sketches and in my head. Also the machine, as shown in the video, no longer exists as it was dismantled and the parts modified and reused for the new build stepper motor EDM with anti arc circuit which is looking, so far in tests, to be a real game changer for the EDM home builder.
so you just limit the current with resistors and switch the 100v on and off?
how do you detect a short circuit when the electrode touches?
thank you!
The electrode shouldn't touch the work piece at all it works simply by Ohm's law. Basically as the required burn plasma level is reached, the output voltage from the power generator (which is shunted through a high wattage output resistor) drops, which also causes the speed controller via a voltage divider to change its voltage control reference point either up or down and so change the motors direction.
@@edmguru9056 this is a little confusing to me. what I figured was happening was the voltage was essentially full (100v I assume) at the electrode because the open circuit makes essentially an infinite resistance - meaning there is no voltage drop across the resistor. once the arc is established the plasma (as it becomes hotter and hotter) conducts more and more, making the resistor a bigger and bigger contributor to the resistance of the circuit, eventually limiting the current to your desired value.
this way you don't just have a massive thunder instead of the tiny arcs that are ultimately desired (we're assuming ideal power supply here).
I think what you're saying is that once the arc is established, the motor will sense the current through the shunt and subsequent voltage divider, and then that does something (like keep it from plunging in further).
but since the current is always limited, how can you ever know whether you're arcing, or simply shorting due to contact? does the motor just go down slowly by default, but pull up every time there is current flowing and that increased distance is what breaks the arc? or does the motor just stop moving once the first arc strikes?
thank you once again, and for taking the time to respond
Thank you for your feedback
I’m sorry this reply has taken so long but your second comment was filtered out as likely spam for some reason. I’ll try to describe how the machine works if I can.
The power supply to the power generator is via an isolation transformer (not shown in the video) which has an output of 70 volts ac. Once rectified this gives the 100 volt dc supply for the power generator which is just a basic amplifier design with 3 (could be more depending the number of power settings you require up to the output power of your transformer) individually switched on power outputs through separate high wattage resistors and their value determines the output Amps. The total output Amps is therefore just a resistor in parallel calculation as each stage is switched on if that makes sense.
The speed controller is an off the shelf part and it controls the z axis position via a voltage divider from the power generator output using Ohm’s law. Basically as the required burn plasma level is reached (half open voltage), the output voltage from the power generator (which is shunted through the high wattage output resistor) drops, which also causes the speed controllers built in speed control to change its voltage control reference point, and so the speed and direction of the dc motor changes.
It might be worth taking a look online about how the control of these machines work which will explain better if that helps.
Revised:
I would think by the reduced voltage across the spark gap. With e.g. 50% duty cycle and 20V across an arc, that averages 10V. With 50% duty cycle and 0..1V across a short, that's 0..0.5V. At the high frequency, no way can the motor respond that fast so it's averaged.
The resistors limit the maximum average current; in an RC machine this would include the charging current to the capacitors but I don't see any caps in the power supply so this is not an RC machine; just the edge of what is presumably an IGBT? and power resistors with fan.
When an arc establishes (ionization breaks down the dielectric, or (undesirable) the electrode touches), current flows and there's an arc. The arc erodes the metal (or, if touching, maybe spot-welds it). The oscillator drive turns off power, bringing the voltage down below the level that maintains ionization; the dielectric becomes insulating again. Flushing the metallic debris out of the gap is important here.
Thank you once again for your safety concerns regarding EDM.
I agree that these machines can be dangerous if safety precautions aren't taken. Also this is a pulse EDM and doesn't have the capacitors you mentioned as they are used in RC type EDM.
Interresting, thanks - Is there a schematic for your high voltage switcher?
Thank you for your feedback.
I never bothered with a schematic for the power generator as it’s just a basic amplifier design with 3 (could be more depending the number of power settings you require up to the output power of your transformer) individually switched on power outputs through separate high wattage resistors and their value determines the output Amps. The total output Amps is therefore just a resistor in parallel calculation as each stage is switched on if that makes sense. It’s pretty basic and easy to build if you know how amplifiers work.
@@edmguru9056 Thanks 👍
Nice work, you I have made a RC EDM machine but not fun. now trying to make a pulse EDM if you have circuit diagram please give a link thanks
that looks great, meanwhile im working on a mosfet pwm driven one after building the robert langlois version running on a arduino mega to controll the step motor.
do you plan to sale the plans to build one ? that would be great.
Thank you for your feedback.
There’s no need to use an Arduino Mega or any code to control the z axis and burn of an EDM as it can all be done by voltage feedback from the electrode via a voltage divider, but having said that, ultimately it is the way to go just like manufacturers of commercial EDM machines do. This is because if you know exactly where the z axis is at any given time you don’t have to wait for a voltage feedback control to work so you can have incredibly fast z axis travel speeds without fear of the electrode hitting the work piece, which is what’s required for the flushing “pump” action when using deep thin web electrodes etc.
There’s no plans to sell any schematics just yet as I’m near completing the build of my new EDM which has now been upgraded to 30 Amps output and has a basic fuzzy logic control which helps to “blur” the transition between the z axis down/ pause/ up control point which adds to burn stability and there’s an anti arc circuit which simply turns off the power generator on all the very low and potentially arc forming pulses, which could be a real game changer for the DIY EDM builder.
All this new build has been done without using any pc or code but the downside is that the wiring gets complicated and ends up looking like a rat’s nest so coding is something I’ll have to learn one day.
@@edmguru9056 I´m using a arduino mega with the intention to program the burn to stop at a predefine depht without using glass scales or a stopper.
it´s kind of hybrid r/c pwm.
here it is ruclips.net/video/3v9KojQ7RMw/видео.html
Hello EDMguru! Thanks for your video, and the inspiration it provides. In the early 1990's I built Robert Langlois' EDM using the relaxation oscillator power supply. I used an old office typewriter carriage roller slide for the electrode feed, with stepper motor drive. Nowadays stepper motor drives are much simpler with commercially available equipment!
My machine has seen considerable use over the years, but it is SLOW!
Hence my interest in your equipment built, primarily, with commercial building blocks.
Would you be willing to provide a simple block diagram of the arrangement for your equipment? And a brief description of the DIY power supply? I suspect that many here, including yours truly, would greatly appreciate it.
Thank you kindly for your efforts! Greetings from Wolfgang
Thank you for your feedback
I never bothered with making any drawings of the machine as it was an easy build but it is something that I’ll do one day. At the moment I’m still working on the new, more advanced stepper motor version. The power generator is just a basic amplifier design with 3 (could be more depending the number of power settings you require up to the output power of your transformer) individually switched on power outputs through separate high wattage resistors and their value determines the output Amps. The total output Amps is therefore just a resistor in parallel calculation as each stage is switched on and in my case it was 3.5A, 7A and 10A if that makes sense.
@@edmguru9056 hello brother
Can you please make a detailed tutorial type video of this machine
Because I want to make it but I don't have enough knowledge about electronics and circuits
Please make a detailed tutorial.
🎉
I think the title holds the answer to all our questions. "the fastest, cheapest and easiest....COMMERCIAL grade spark erosion machine..." Unless the word commercial actually applies to the quality/power of the device, it sounds like this is going to be a 'for profit' project. Nothing wrong with that... but might be worth considering when asking "can you make the pcb files/BOM etc available?" Am I near the mark there, EDMGuru?
Thank you for your feedback.
The term “commercial grade” in the title sentence refers to the quality of the end result compared to other homebuilt machines I’ve seen online and not to “for profit” as you say but if the new design mosfet power generator, once tested, works even better than my amp based transistor version then I might consider making it a “for profit” venture, but then again I doubt that there is much of a market for an EDM considering how much CNC machining has evolved for home use over the years.
so we need more tetails how to make one .. like that new one you saying
Anyone building this: please look into electrical safety first, including what it takes to stop your heart. Not saying not to do it; saying do it _safely_, so it stays fun!
High voltage DC will override the millivolt-level signals from your nerves and brain: hit the right polarity, and your muscles will contract and not let go until they run out of ATP and oxygen. You won't have anything to say about it. Touching with the back of your hand or finger will make you luckier; contracting muscles will tend to pull your hand away, rather than causing you to grip a conductor until your muscles run out of oxygen and ATP.
High voltage DC will make and maintain arcs; switches that aren't rated for it are not rated for it for good reason. AC arcs are much easier to extinguish.
Make sure there's no high voltage before or while you are touching anything; be suspicious; did that switch or relay **REALLY** open? What happens if that gets bumped?
Practical jokers have no place around HV DC.
Thanks for your feedback.
Good safety information. I agree that you have to be careful around high voltage, and I always recommend wearing rubber gloves when using spark erosion machines, also these machines are fitted with a volt meter so that you can see if and when there’s voltage present at the electrode.
Scott W, No need to be panic High voltage DC (pulse or not ) not as dangerous as high volt AC. Your body is full of polarize molecules which AC can pass easier. Imagine those molecules flip back and forth 50-60 time a second. And I have tested the DC(100V) myself for 30-40 times, the worst made my finger numb for ten seconds. I make a machine similar to this but also with 250VDC ignition ( Ignition voltage limit current to a few tenth mA).
This machine is not more danger or less danger than a commercial one.
Most likely dangerous of this machine come from a fire from burning of an EDM fluid.
I would caution anyone that builds this from what I can see it does not appear that you have any isolation from the power main feed line.
This is a SERIOUS safety issue.
Should someone get a cross the electrode to ground there could be major issues including death due to electrocution.
Thank you for your feedback.
Actually there's no need to worry as the power generator is supplied via an isolated transformer which is unfortunately not shown in the video. This transformer has an output of approx 70 volts AC.
@@edmguru9056 ...which gets turned into what voltage DC, about 100 VDC? 30..50V and up is considered dangerous, AC or DC. Notice how many switches are not rated above 24..32 VDC; it's much harder to break a DC arc because the AC line reverses polarity slowly enough for ionization to extinguish much more easily.
DC causes muscles to contract. If you are lucky, and touching with the back of the possibly-contracting hand instead of the front will make you luckier, they will pull away from the voltage source. If not, you may not be able to let go of the conductor, because the millivolt signals from your brain cannot out-shout tens of thousands of millivolts from the external source. Depending on the level of contact; dry skin is less conductive and safer than wet and salty / ionizable.
Not saying not to do this; saying take reasonable precautions. Treat it as potentially lethal -- keep your fingers away -- until your voltmeter (which you checked against a known voltage, yes the battery hasn't died, it's on Volts and it's working) tells you the voltage has dropped. Maybe add some red indicator LEDs with about a 20V Zener; if the LED is on it's at 24..100? VDC and you don't touch it.
Thank you once again for your safety concerns regarding EDM.
I always recommend the wearing of rubber gloves when using EDM.
Also the machine has a built in voltmeter which shows when voltage is present at the electrode which is only when the machines switch is actually set to the spark position.
Homebuilt: I can see why you r worry. His machine is a direct treat to yours.
So, let´s rephrase... U made EDM out of:
-a power-source (100V / 3,5A to keep it simple)
-a dc-motor/controller-unit
-a PWM-signal-generator (DutyCycle, Hz, both selectable)
-a voltage-divider
... With the information given here, well, sorry, but I don´t see it... If the signal-gen turns on+off a high-speed mosfet, thus controlling the power-source, it´d make more sense, but the mosfet would also need its own driver. None such was mentioned... And I understand, that some natural "triggers" that occur during each cycle (for example: the required burn plasma level is reached), can be exploited, in order to change the motor´s direction, but still, I dont see the connection to the motor-controller, or at least, to the voltage-divider... I beg you for for more information. How do the parts come together ??????? What is that motor-controller made of ?????? Is there any additional parts, that weren´t mentioned in the Intro ??????? Thanks anyway I guess, but as is, the video doesn´t inform more, than a clickbaity video would...
I mean, it´s obvious that it works, and that it even works very well... But if someone would come up to you, telling you, he invented an EDM-machine by using an arduino, a mosfet, a donkey, and the tail-feathers of a himalayan male chicken, how would you feel??? You´d be sure thinking, that this person makes jokes on you, right???
Thank you for your feedback, The power generator used on the EDM was a transistor type based on an audio amp design but modified for a square wave pulse input which was provided by a “bought off the shelf” square wave frequency generator so no driver ic is required. The pulse frequency generator and the transistor type power generator are both shown at the start of the video. The voltage divider is fitted after the output current limiting resistors so that once the spark erosion process starts, due to Ohm’s law, the voltage at the electrode and in the divider will drop and this voltage drop is used to automatically control the D.C. motor controller. The motor controllers direction control works by using an input voltage which is either higher or lower than a fixed internal reference voltage, so the input voltage from the voltage divider can control the burn position of the electrode automatically. No other parts are used or are necessary although if you add a potentiometer to the voltage divider, you can manually adjust the output voltage, and set the electrode plasma burn voltage level which is handy for different spark conditions. The output current is set by switching in power resistors in parallel. My videos are not fake or click bait and I never personally ask anyone to like, subscribe or contribute financially in any way so I have nothing to gain from any of my content. I've always said that building an EDM is easy to do (there's nothing "magical" about them) and this type of “Easy-Peasy” EDM machine works simply by Ohms law and is very easy and cheap to build; also I’m surprised that no one else, now or in the past, has thought of using this way to control an EDM before?
@@edmguru9056 This sounds great...!!! I´ve read your answers to several comments, and I couldn´t figure out how it all worked, but I was really interested, And I finally can follow you... And the motor control sounds really unique !!! I´ll write again, when I understand it better...