@EdmGuru I have a couple of books about edm, not just making a machine but how the process works. One of the books has drawings of the gap voltages during different conditions. If it will help you I can scan them and post them here. The best book is available on E-Bay for around $25, much less than what I paid for it back in the day. I'll list the book name with the pictures if your interested.

 

Hi shortbus, thank you that would be helpful.

Wow I can see now from those circuit scans why people have trouble with this machine design, it’s just too over complicated. I don’t understand why there seems to be some sort of solid state relay attached to the output voltage divider via another voltage divider looking circuit? It’s no wonder the control of the Z axis always looks unstable in online videos, there’s too many unnecessary components there. I’m sure that most of that can be replaced by off the shelf circuits i.e. the square wave frequency generator to start with and that push pull transistor part for the pulse to the mosfets looks wrong to me.

Anyway isn’t it possible to use the Langlois circuit for an EDM and just replace the RC generator with a pulsed one?

Cheers.

 

@EdmGuru I have a couple of books about edm, not just making a machine but how the process works. One of the books has drawings of the gap voltages during different conditions. If it will help you I can scan them and post them here. The best book is available on E-Bay for around $25, much less than what I paid for it back in the day. I'll list the book name with the pictures if your interested.

I'm very interested and grateful!

 

Anyway isn’t it possible to use the Langlois circuit for an EDM and just replace the RC generator with a pulsed one?

I haven't looked at the Langlois book lately but I think he did a "bar napkin" sketch at the back of the book on a pulse machine he was going to make. He asked the magazine readers to respond if they wanted him to do it, but back in those days there weren't so many people doing or wanting to do edm. Most didn't even know what it was capable of.

 

Hi shortbus, thank you that would be helpful.

Wow I can see now from those circuit scans why people have trouble with this machine design, it’s just too over complicated. I don’t understand why there seems to be some sort of solid state relay attached to the output voltage divider via another voltage divider looking circuit? It’s no wonder the control of the Z axis always looks unstable in online videos, there’s too many unnecessary components there. I’m sure that most of that can be replaced by off the shelf circuits i.e. the square wave frequency generator to start with and that push pull transistor part for the pulse to the mosfets looks wrong to me.

Anyway isn’t it possible to use the Langlois circuit for an EDM and just replace the RC generator with a pulsed one?

Cheers.

It would be extremely interesting to see a diagram of simplified Ben's pulse edm. With use of square wave pulse generator.

If I'm not wrong, that's your easy-peasy version, isn't it? BTW, I'm still interested in (at least dc motor version) diagram drawing for it, hand-drawn sketch could be helpful as well. I'm ready to pay a fair price for it with discretion guaranteed

 

Ok, the book was by Elman Jameson and called "Electrical Discharge Machining". It doesn't come up on E-bay much but is on Amazon, at ~$200+. When I got my copy it was $185 plus shipping. So to save you guys some money and you can all read it I found a PDF copy, enjoy!

https://archive.org/stream/jamesone...hining Technology Association (2001)_djvu.txt

 

Wow I can see now from those circuit scans why people have trouble with this machine design, it’s just too over complicated. I don’t understand why there seems to be some sort of solid state relay attached to the output voltage divider via another voltage divider looking circuit? It’s no wonder the control of the Z axis always looks unstable in online videos, there’s too many unnecessary components there. I’m sure that most of that can be replaced by off the shelf circuits i.e. the square wave frequency generator to start with and that push pull transistor part for the pulse to the mosfets looks wrong to me.

He used to have a forum back when Yahoo hosted forums. Me and him disagreed about a lot, and like here people didn't like it when I pointed things out to him in the forum. So for a while we talked in Email person to person. It end up with him telling me if I knew so much write my own book.

The thing I disagreed with him about on the pulse design was he used I think 6 mosfets in parallel and no driver, so the first one to get turned on took the whole load, and I think he finally in one of the versions changed that. But I lost interest in his machine so I don't really know.

 

Ok, the book was by Elman Jameson and called "Electrical Discharge Machining". It doesn't come up on E-bay much but is on Amazon, at ~$200+. When I got my copy it was $185 plus shipping. So to save you guys some money and you can all read it I found a PDF copy, enjoy!

https://archive.org/stream/jamesonelmancelectricaldischargemachiningsocietyofmanufacturingengineersmachinin/Jameson, Elman C - Electrical discharge machining-Society of Manufacturing Engineers, Machining Technology Association (2001)_djvu.txt

https://ia601002.us.archive.org/25/..., Machining Technology Association (2001).pdf

 

He used to have a forum back when Yahoo hosted forums. Me and him disagreed about a lot, and like here people didn't like it when I pointed things out to him in the forum. So for a while we talked in Email person to person. It end up with him telling me if I knew so much write my own book.

The thing I disagreed with him about on the pulse design was he used I think 6 mosfets in parallel and no driver, so the first one to get turned on took the whole load, and I think he finally in one of the versions changed that. But I lost interest in his machine so I don't really know.

Hi shortbus thank you for the link and I’ve downloaded it as a pdf, hopefully there’s some good info in there.

On my main machine with a 30 Amp output I use my original transistor design of power generator which uses two sets of three power transistors connected in parallel as emitter followers. It works well with no thermal runaway but then I’m using them at only about one tenth of their individual maximum output current rating so it’s possible to do and apparently mosfets connected as source followers do a better job because of their efficiency due to their construction method.

Cheers.

https://electronics.stackexchange.com/questions/274557/parallel-mosfets

 

It would be extremely interesting to see a diagram of simplified Ben's pulse edm. With use of square wave pulse generator.

If I'm not wrong, that's your easy-peasy version, isn't it? BTW, I'm still interested in (at least dc motor version) diagram drawing for it, hand-drawn sketch could be helpful as well. I'm ready to pay a fair price for it with discretion guaranteed

Hi Bogos87, The Easy-Peasy is the DC motor version of an EDM and the Not So Easy-Peasy is the stepper motor version of an EDM.

The DC motor version is very quick and easy to build as all of the parts except for the power generator can be bought online although some will require their potentiometers replacing with panel mounted ones etc.

If I had the full schematic of Bens EDM design I could redesign it to make it work but I don’t think that Mr Fleming would be too happy about that.

As to making this design available, it’s not the money, it’s a matter of trust that’s the problem. In the past I’ve had several of my ideas taken and claimed by others as their own and believe me it’s very disappointing to say the least. If we were say co-workers in the workplace and you needed help with this I would no doubt show you how to build an EDM or if you were lucky I would even build one for you, but don’t worry I will help you along the way and who knows I may even change my mind.

Having said that I feel that it’s about time that @shortbus completed his goal of finally finishing his EDM build, as time is ticking so to speak, so I might start to draw up the schematics for the stepper motor version if he’s interested, but there’s a lot of wiring involved in that design so I might have to simplify it a bit and also it would require you to have a cnc mill to make the circuit boards on.

Cheers.

 

Having said that I feel that it’s about time that @shortbus completed his goal of finally finishing his EDM build, as time is ticking so to speak,

Tell me about the time ticking. I would love it if you could look at and refine my circuit. I built the mechanical parts back in the 1990's or so. That stuff is easy been doing it since high school, its the electronics that slowed me down. I knew how to solder and had built things from kits over the years but didn't and still don't know all that much about electronics. I know more now than when I started, but when your trying to learn starting in your 60's its a b--ch.

If your serious about this I'll post my latest try here. But if your not interested that's fine too. I have sooooo many unfinished projects I'll never get them done before I die. Just a few of them; a couple of muzzle loading flint lock rifles(made the locks from castings) a couple of guitars, a mini crawler tractor( made the drive sprockets, tracks with rubber pads, and the hydraulic steering brakes). There are things I did finish but won't bore you guys with them.

 

On my main machine with a 30 Amp output I use my original transistor design of power generator which uses two sets of three power transistors connected in parallel as emitter followers.

Hi edmguru, BJT type transistors are different than mosfets in parallel, mosfets need amperage to turn them on fast where a BJT only need voltage. That's why mosfets need some sort of driver to get them to work better, turn on faster. In Ben's design the mosfet with the least internal capacitance on the gate will turn on quickest and the others will lag behind.

 

Hi Bogos87, The Easy-Peasy is the DC motor version of an EDM and the Not So Easy-Peasy is the stepper motor version of an EDM.

The DC motor version is very quick and easy to build as all of the parts except for the power generator can be bought online although some will require their potentiometers replacing with panel mounted ones etc.

If I had the full schematic of Bens EDM design I could redesign it to make it work but I don’t think that Mr Fleming would be too happy about that.

As to making this design available, it’s not the money, it’s a matter of trust that’s the problem. In the past I’ve had several of my ideas taken and claimed by others as their own and believe me it’s very disappointing to say the least. If we were say co-workers in the workplace and you needed help with this I would no doubt show you how to build an EDM or if you were lucky I would even build one for you, but don’t worry I will help you along the way and who knows I may even change my mind.

Having said that I feel that it’s about time that @shortbus completed his goal of finally finishing his EDM build, as time is ticking so to speak, so I might start to draw up the schematics for the stepper motor version if he’s interested, but there’s a lot of wiring involved in that design so I might have to simplify it a bit and also it would require you to have a cnc mill to make the circuit boards on.

Cheers.

I wholeheartedly support copyright protection and believe that one should not easily disclose their ideas.
However, let's back to the forum topic, which is challenge of building a pulse EDM using readily available components that can be purchased on AliExpress or eBay, and/or constructing a PCB with clear and simple instructions.

 

Tell me about the time ticking. I would love it if you could look at and refine my circuit. I built the mechanical parts back in the 1990's or so. That stuff is easy been doing it since high school, its the electronics that slowed me down. I knew how to solder and had built things from kits over the years but didn't and still don't know all that much about electronics. I know more now than when I started, but when your trying to learn starting in your 60's its a b--ch.

If your serious about this I'll post my latest try here. But if your not interested that's fine too. I have sooooo many unfinished projects I'll never get them done before I die. Just a few of them; a couple of muzzle loading flint lock rifles(made the locks from castings) a couple of guitars, a mini crawler tractor( made the drive sprockets, tracks with rubber pads, and the hydraulic steering brakes). There are things I did finish but won't bore you guys with them.

Hi shortbus. I’m serious about helping you out it would be a pleasure since it’s the inspiration of good people like you online that drives me to complete the “perfect” EDM if there’s such a thing lol. I would like to have a look at your design if I may and no doubt it will be totally different to my design but fixable. If not then do you have a cnc mill to produce any circuit boards as I can send you the g-code for any new redesign of your circuit no problem as I have the software?

Cheers.

 

I wholeheartedly support copyright protection and believe that one should not easily disclose their ideas.
However, let's back to the forum topic, which is challenge of building a pulse EDM using readily available components that can be purchased on AliExpress or eBay, and/or constructing a PCB with clear and simple instructions.

Hi Bogos87. I can provide you with a list of the parts required to build the DC motor version from bought online parts and maybe a simple schematic of what connects to what and where but the power generator parts list and schematic are the problem I’m afraid.

Cheers.

 

Hi shortbus. I’m serious about helping you out it would be a pleasure since it’s the inspiration of good people like you online that drives me to complete the “perfect” EDM if there’s such a thing lol. I would like to have a look at your design if I may and no doubt it will be totally different to my design but fixable. If not then do you have a cnc mill to produce any circuit boards as I can send you the g-code for any new redesign of your circuit no problem as I have the software?

Cheers.

No CNC or access to one. My plan was to use strip type board and jumper wires for the circuit board. I have a heavy duty home etched "power board already made. I say heavy duty because it was 2oz board and hand laid out and drilled.

You said something earlier about a lot of wiring for a stepper motor, but I have a few different stepper drivers that only need a few inputs, logic wise, direction, pulse and enable. And like your machines a pulse module for the pulse.

I really, really, would appreciate any help. But like Bogos87 said we should keep his thread his thread. I'll gather up what I have schematic wise and think I even have a step by step list of what the circuit was meant to do. I'll give you a PM when I find all of it. I am willing to give you all the credit for it if we can get it to work.

 

@EdmGuru the chapters in the Jameson book that probably be of most interest to you and #5 and #6

 

No CNC or access to one. My plan was to use strip type board and jumper wires for the circuit board. I have a heavy duty home etched "power board already made. I say heavy duty because it was 2oz board and hand laid out and drilled.

You said something earlier about a lot of wiring for a stepper motor, but I have a few different stepper drivers that only need a few inputs, logic wise, direction, pulse and enable. And like your machines a pulse module for the pulse.

I really, really, would appreciate any help. But like Bogos87 said we should keep his thread his thread. I'll gather up what I have schematic wise and think I even have a step by step list of what the circuit was meant to do. I'll give you a PM when I find all of it. I am willing to give you all the credit for it if we can get it to work.

Hi shortbus. Ok it’s not a problem if you haven’t got a cnc mill I just thought that it would be quicker and easier for you to build up the circuits.

The wiring on the stepper motor version is not so much to do with the stepper driver it’s the rest of the wiring to all the other circuit boards that’s the problem. I’ll have to draw up a simplified schematic layout and you’ll see what I mean.

I agree we should keep his thread his thread but don’t worry if you have all the main parts already I’m confident that you’ll have a working EDM by Christmas! Also this new power generator build could be advantageous for Bogos87 maybe?

Cheers.

 

The wiring on the stepper motor version is not so much to do with the stepper driver it’s the rest of the wiring to all the other circuit boards that’s the problem. I’ll have to draw up a simplified schematic layout and you’ll see what I mean.

Hi, I don't quite understand that but will have to see the schematic. For both types of motors you need to differentiate between the need to travel down or up due to what the gap is telling the logic. The only real difference I can see is the stepper needing the pulse necessary to move. Once you figure out that pulse frequency you should be good to go.

One thing I've seen in almost ever DIY machine is they use too small of a lead screw pitch. With a ball screw and its larger pitch, you then can set the stepper driver so it coincides with the electrode over burn rate. Then the only problem gets to be flushing of the gap.

 

Hi, I don't quite understand that but will have to see the schematic. For both types of motors you need to differentiate between the need to travel down or up due to what the gap is telling the logic. The only real difference I can see is the stepper needing the pulse necessary to move. Once you figure out that pulse frequency you should be good to go.

One thing I've seen in almost ever DIY machine is they use too small of a lead screw pitch. With a ball screw and its larger pitch, you then can set the stepper driver so it coincides with the electrode over burn rate. Then the only problem gets to be flushing of the gap.

Hi shortbus. I think that there’s a bit of confusion here. I was referring to the number of wires required inside the control box for my stepper motor version of EDM. The wiring not only goes to the stepper motor driver and its pulse board but to all the other boards that are required also for instance the EDM control board, the head lift timer board, the square wave frequency board, the limit switches relays board and I also have the anti- arc board plus there’s all the panel mounted switches and potentiometers etc for them too. It’s quite a rats nest in there lol.

By comparison the DC motor versions control box only requires the bought online parts such as the square wave frequency unit, the motor controller unit, the head lift timer unit and a few switches and relays for good measure. It really is that simple to build, not counting the Z axis motors, power transformer and power generator etc that both versions require of course.

Cheers.