# EDM Build



## canadianhorsepower (Aug 9, 2017)

Hi all:thumbup:
this is the start from my EDM Pulse machine
This first post will explain and show pictures of why I'm using them.
The first one is a measuring tool.

It allows you to measure the proper distance between holes on you PCB and the bend your parts accordingly :thumbup:

My second one is an LCR L (inductor) C (capacitor) R (resistor) all it does it measure LCR without holding them in your finger (changing the reading) MY BEST BUDDY here's why !!!!!!!!!!
I'm going to measure a 1000uF capacitor. These are all brand new parts BUT any electrolytic CAPACITOR are self destructing . Take a new one leave it on the shelf in a moist environment 2 years it's a door knob. Picture #1check the value on the cap
Now check the value one the meter Fine
But now this is where **** breaks  loose !!!
still checking a 1000uF capacitor. and the values are :fan:
Not a chance my circuits would have work fine 
Be careful


----------



## kadora (Aug 10, 2017)

Electrolyt capacitors have capacity tolerance 30%.


----------



## canadianhorsepower (Aug 10, 2017)

kadora said:


> Electrolyt capacitors have capacity tolerance 30%.


 for your info

The percentage of allowed deviation of the measured capacitance from the rated value is called the capacitance tolerance. Electrolytic capacitors are available in different tolerance series, whose values are specified in the E series specified in IEC 60063. For abbreviated marking in tight spaces, a letter code for each tolerance is specified in IEC 60062.
rated capacitance, series E3, tolerance ±20%, letter code "M"
rated capacitance, series E6, tolerance ±20%, letter code "M"
rated capacitance, series E12, tolerance ±10%, letter code "K"

so in worst case 20% of 1000 is 200.
so 1000-200=800 minimum :wall:
one was at 672


----------



## canadianhorsepower (Aug 10, 2017)

ok here we go again.
here are the description of the next Pictures
Enjoy
#1 pcb board empty
#2 went in my shop and pick up, resistors,caps, diode, potentiometer. Lucky I had all of them
#3 using my little tool to measure the hole width I needed 
#4 use the same tool to bend my resistor
#5 this is a plated throw board, so i'm holding the resistor by one lead with alligator clip.
#6 reverse side of the board, i'll solder the lead standing up first
#7 then will straighten my lead and solder number 2
#8 the PCB board after a few hours of fun all the value of the caps can be read and resistor code are from left to right
#9 this is the assembly sheet i'm using. If you look on the left hand side there is 2 check mark. The first one when I took the parts of my shelf
and the second one when it's soldered on the board. This is the best way not to get confuse.


----------



## canadianhorsepower (Aug 10, 2017)

part 2of the pictures


----------



## Engineville (Aug 10, 2017)

Luc,

Thank you for starting this thread topic.


----------



## Herbiev (Aug 10, 2017)

Is this in kit form ?  Looks like a great project.


----------



## canadianhorsepower (Aug 10, 2017)

Yes and no
it's not a Kit form. It is so well instructed that all you want to do is go ahead and build it.
teaching robotic and manufacturing a lot of project kind of push ma against the wall and keep some parts in
stock.It is very well documented and the author will respond to any email within 24hrs


----------



## kadora (Aug 11, 2017)

Canadianhorsepower honestly I did not intend to criticise you 
I wish you were successful in this project and I am 
really interested in your progress.
Sometime in my company //when company want to change a vendor//
I have to check hundreds of condensers from new vendor and on some new pieces is possible to find huge capacity differences.
By the way is there difference in capacity reading at 120 HZ and 1 kHz frequency ?
Just curious


----------



## Blogwitch (Aug 11, 2017)

It would be nice if you could supply the addresses for the build and where to obtain things such as the circuit board.

Then people would be able to see how difficult or easy a project it would be and if they could attempt the same build.


John


----------



## canadianhorsepower (Aug 11, 2017)

Blogwitch said:


> It would be nice if you could supply the addresses for the build and where to obtain things such as the circuit board.
> John



Hi John
thanks for the reminding.
I had this info post on another thread

Hi all,
I'm am currently starting a build of a EDM machine
by Benjamin Fleming.

http://www.homebuiltedmmachines.com/



https://groups.yahoo.com/neo/groups/EDMHomeBuilders/info


----------



## canadianhorsepower (Aug 11, 2017)

Herbiev said:


> Is this in kit form ?  Looks like a great project.


 here is all the info

Hi all,
I'm am currently starting a build of a EDM machine
by Benjamin Fleming.

http://www.homebuiltedmmachines.com/


https://groups.yahoo.com/neo/groups/EDMHomeBuilders/info


----------



## canadianhorsepower (Aug 15, 2017)

OK haven't been posting alot lately
the first picture is what I have completed so far with the parts I had in stock.
Picture 2 is the order that came in today from Mouser. alot more soldering to do
after assembling the case before we go to the mechanical parts.
ENJOY


----------



## canadianhorsepower (Aug 20, 2017)

Ok the main board is all assemble 
I cut to pieces of lexan that I will mount both fans on,
as you can see there is 8 heatsink :fan: cooling is important.
one picture of parts already receive and still waiting for more
should come in this week
enjoy

for those wondering what it would look like and what it can do here is a good video

[ame]https://www.youtube.com/watch?v=6BzXqrX-HlI[/ame]


----------



## Sansspaceship (Aug 23, 2017)

Hi Luc,

Thank you for this thread, I saw your original post ... and followed your link and went and bought the same kit that evening as always have been curious about EDM but never for a second thought you could build one at home.  I will be a bit behind you as it will take me a month or so to get the gear from the USA. 

Watching with keen interest.

Cheers.
.adrian


----------



## canadianhorsepower (Aug 23, 2017)

Sansspaceship said:


> I will be a bit behind you as it will take me a month or so to get the gear from the USA.
> 
> Watching with keen interest.
> 
> ...



Hi Adrian.

after doing allot of research for good price this is what I came up with.

Mouser as quoted in the book for everything beside Transformers and analog
meters.DO NOT GO DIGITAL on the meter it's not accurate enough.

Digikey for the transformers.

Futurelec.electronic for the analog meter.

I might build  one transformer to replace the 3 of 24volts 10 amps
if I take this direction I'll post how it's done.

as for the "RAM" itself mine will be coming from Bandgood. can't make one for the price they sell one

BTW
The PCB board is a plated thru board and does not allow any mistake
removing soldered parts is almost a miracle.

good luck enjoy


----------



## Sansspaceship (Aug 24, 2017)

Thanks Luc,

Still waiting for the book and board but Ben has sent me the parts list so have put an order into mouser which for me is out of HK, so at least I should have 90% of the bits to get a good start when it arrives.  

Thanks for the lead on digikey and futurelec, will use the for the bits you mention. My maker side of the skill set is pretty good, and I can solider  but my electronics working knowledge is average ...  but it sounds like it is pretty straight forward. :hDe:

P.s thanks for the photo of the pace former, I had never seen one of those! Took a bit of tracking down but I think I have found a set in OZ. Now the components will look neat as opposed to looking like they were pushed in by a 5 yr old :thumbup:

Cheers,
.adrian


----------



## canadianhorsepower (Sep 1, 2017)

Update
ok haven't post many things cause i've been busy 
the pictures update you are having now shows the complete
control board assembly:thumbup: and after all the test shows that
all the readings are good. Because this generate quite a bit of heat and heating is expensive i decide to add an extra cooling fan for the driver,:fan:. then was afraid to get all the other components to hot I made custom stand off and incorporate a squirrel cage for cooling . All cooling channels are made of acrylic and will be grounded . the to EXTRA pictures are the etched front panel and the fully assemble front panel. 
Enjoy


----------



## Sansspaceship (Sep 2, 2017)

Starting to look good Luc, still waiting for the book, and Mouser has come up short on some components so yet to find a source for the missing items as not going to wait until Oct.  Did u do the panel design or was that info in the book ? I was going to mill mine on the cnc, but just wondered how you worked out the graduations for the reostat's?

Cheers,
.adrian


----------



## canadianhorsepower (Nov 18, 2017)

Ok I have some pics of the update.
I had to change the lexan pieces I was using 
to small . then I decide to run channel for the fan draft.
I finally receive all parts to assemble the electronic parts in the case.
I will be going in MY direction as far as circuits update goes.
The biggest problem is heat and constancy. many more temp probe will be added and fan controlling also. Don't worry all the additional information will be posted. Enjoy the picks.


----------



## kingston6 (Dec 28, 2017)

This could be helpful somehow  https://www.wellpcb.com/pcb/Flexible-PCB-Capability.html cheap PCB Manufacturer. Thank you!


----------



## MrMetric (Nov 13, 2021)

I thought I would resurrect this thread....

I've been trying to get a copy of Fleming's Pulse book on eBay, but I never can seem to get one.  So.... If anyone here is not using his anymore, and if that person would like to sell the book, I might be interested in getting it.  Please feel free to PM me.

But, this post actually has a secondary purpose.... I am obviously thinking of building the EDM, or its older variant, and I was wondering if any builder could comment on how happy he is  with the design. Has it worked well? Would he/you recommend something else?  That type of thing.

I'm just a hobbyist like everyone else, so I'm not looking for a commercial grade unit.  I did grow up around EDMs though, but haven't personally used them, so I am familiar with what they can do.


----------



## Preston Engebretson (Nov 14, 2021)

Here is one currently on Ebay...









						The EDM How-To Book by Ben Fleming 9780976759607 | eBay
					

What is EDM?. As a result, it is possible to erode or "burn" the shape of the electrode into the workpiece. If you need a square hole, (or other unique shape) in a part make a square electrode and burn it into the part.



					www.ebay.com


----------



## creast (Nov 15, 2021)

MrMetric said:


> I thought I would resurrect this thread....
> 
> I've been trying to get a copy of Fleming's Pulse book on eBay, but I never can seem to get one.  So.... If anyone here is not using his anymore, and if that person would like to sell the book, I might be interested in getting it.  Please feel free to PM me.
> 
> ...


Hi,
I have built one from his first book and it works well. I use paraffin as the dielectric.
Only issue I have found is the servo chip can sometimes fail but these are relatively cheap.
Finding EDM grade graphite can be tricky in the UK too.


----------



## awake (Nov 15, 2021)

Preston Engebretson said:


> Here is one currently on Ebay...
> 
> 
> 
> ...



I think that is the older (non-pulse) version.


----------



## creast (Nov 15, 2021)

awake said:


> I think that is the older (non-pulse) version.


Yes it's RC version. Much simpler but not as capable of super fine finish of pulsed. Have not built the pulsed as yet.


----------



## MrMetric (Nov 15, 2021)

Thanks for the responses!  Yes, that is the RC version, and I've actually got that book.  Although I may build that version eventually, I really wanted to try the pulse one.  Fortunately, one of the members here had a book from a Christmas long long ago (sounds like Star Wars), and he decided he wasn't going to pursue the EDM.  So, I'm in luck!


----------



## jkimberln (Nov 15, 2021)

Have you looked into Dan Mauch and his offerings?  I remember him from years ago.  The URL I have now comes from a google search:


			Camtronics, inc. -- CNC with Dan Mauch
		

He was doing EDM and 3d scanning.  I found EDM interesting but too messy for my garage shop.  Always wanted a wire EDM though.


----------



## jkimberln (Nov 15, 2021)

Also, the book "home made tools" has a sinker EDM listed.  Possibly this is an RC version by Dan Mauch.


----------



## jkimberln (Nov 15, 2021)

Build a Pulse EDM Machine: The Next Generation, 2011, Ben ...  a Pulse EDM Machine: The Next Generation, 2011, Ben Fleming, aFleming Publications, 2011 DOWNLOAD      - [Download PDF]    Maybe??


----------



## ajoeiam (Nov 16, 2021)

jkimberln said:


> Build a Pulse EDM Machine: The Next Generation, 2011, Ben ...  a Pulse EDM Machine: The Next Generation, 2011, Ben Fleming, aFleming Publications, 2011 DOWNLOAD      - [Download PDF]    Maybe??


nope!


----------



## stanstocker (Nov 16, 2021)

jkimberln said:


> Build a Pulse EDM Machine: The Next Generation, 2011, Ben ...  a Pulse EDM Machine: The Next Generation, 2011, Ben Fleming, aFleming Publications, 2011 DOWNLOAD      - [Download PDF]    Maybe??


Unfortunately that file is something else.  No images, random phrases, and links to all sorts of other sites.

Cheers,
Stan


----------



## Preston Engebretson (Nov 16, 2021)

jkimberln said:


> Have you looked into Dan Mauch and his offerings?  I remember him from years ago.  The URL I have now comes from a google search:
> 
> 
> Camtronics, inc. -- CNC with Dan Mauch
> ...


This Web Site is Broken...nothing works at all...

Regards,

Preston


----------



## MrMetric (Nov 16, 2021)

Wow... Dan Mauch... That is a name which is definitely familiar although I don't recall the context or "when"...  I did look at the link


stanstocker said:


> Unfortunately that file is something else.  No images, random phrases, and links to all sorts of other sites.
> 
> Cheers,
> Stan


Yeah, I was going to comment on that.  Even though I've managed to secure the book, I did decide to look at the site.  It appears very much like a scum-bag pfishing site, with a whole host of suspect links, especially bit.ly types.  NEVER trust those things!  I would be *very* cautious if you are willing to go to anything on the link provided in post #30.  (Huh... *jkimberln... *you and I are not very far apart from one another.  I am in the South Bay Area).

As for the Camtronics site.... It looks to be essentially dead. The dates referred to on the site are all from other decades, so I'm pretty sure Dan Mauch has abandoned the site; given the average age of many people in the machining hobby, there is a decent chance that he is not even around anymore too.  

B


----------



## SmithDoor (Nov 16, 2021)

The best part of EDM is using on broken taps and bolts.

Dave


----------



## MrMetric (Nov 16, 2021)

probably one of the main reasons why I want to do it... And because it is a kind of connection to what my father did.  I'm sentimental, I admit it...

FWIW, an R/C type is probably fine for doing tap removal.  If you are trying to burn a profile for injection molding in a die, I'm guessing pulsing would be better.  But I doubt that design has enough power to do a tangible amount of work.  I don't have a concrete basis for saying this, but it is my hunch.


----------



## jkimberln (Nov 16, 2021)

I mentioned Dan Mauch just to see if anyone remembered him.  Camtronics has been gone for ages but the URL was just posted as a reminder that It once existed and put out plans for a wire EDM.  ISTR Dan serializing the EDM in Ciarcia's Circuit  Celler about a generation ago.  I don't know if the old copies of CCC can be found in some archive.


----------



## MrMetric (Nov 16, 2021)

Oh! The name definitely rang a bell, that is for sure!  Although, I cannot remember the context of the conversations I had with him....  Ciarcia's Circuit Cellar... LOL, you are definitely bringing back memories there.  I haven't heard of CC in eons.


----------



## alanganes (Nov 16, 2021)

Just as an FYI, it appears that you can still purchase the pulse EDM book in digital format directly from the author's (Ben Flemming) website. This was noted earlier in the thread, but I think he still offered print versions at that point. It looks like he also still also offers "starter kits" that include bare printed circuit boards along with the book:



			Purchase Books, Starter Kits, PCB’s | Build your own HomeBuilt Electrical Discharge Machine (EDM) for machining hardened materials


----------



## stanstocker (Nov 17, 2021)

Model Engine Builder #26 has a several page article on making an electromagnetically actuated pulse mode EDM.  Very simple, think door buzzer on steroids with one end of the coil connected to the electrode, the other end to a 12 volt battery.  Other battery terminal connects to the work.  A bit safer than the old AC line and light bulb hack, not as complicated as the sexier EDM designs that might provide sinker capabilities.  I saw this being used at Cabin Fever one year, the guy showing it was poking holes that looked pretty clean.  Certainly could be used as a tap / stud burner.

Cheers,
Stan


----------



## SmithDoor (Nov 17, 2021)

stanstocker said:


> Model Engine Builder #26 has a several page article on making an electromagnetically actuated pulse mode EDM.  Very simple, think door buzzer on steroids with one end of the coil connected to the electrode, the other end to a 12 volt battery.  Other battery terminal connects to the work.  A bit safer than the old AC line and light bulb hack, not as complicated as the sexier EDM designs that might provide sinker capabilities.  I saw this being used at Cabin Fever one year, the guy showing it was poking holes that looked pretty clean.  Certainly could be used as a tap / stud burner.
> 
> Cheers,
> Stan


Can post a schematic?

Dave


----------



## L98fiero (Nov 18, 2021)

stanstocker said:


> Model Engine Builder #26 has a several page article on making an electromagnetically actuated pulse mode EDM.  Very simple, think door buzzer on steroids with one end of the coil connected to the electrode, the other end to a 12 volt battery.  Other battery terminal connects to the work.  A bit safer than the old AC line and light bulb hack, not as complicated as the sexier EDM designs that might provide sinker capabilities.  I saw this being used at Cabin Fever one year, the guy showing it was poking holes that looked pretty clean.  Certainly could be used as a tap / stud burner.
> 
> Cheers,
> Stan


Fleming's site is still up, no idea if one can order or not. Build your own HomeBuilt Electrical Discharge Machine (EDM) for machining hardened materials


----------



## stanstocker (Nov 18, 2021)

I can't post the Model Engine Builder article as 1) it's copyrighted and 2) I like Mike and Toni (publishers/editors/the whole deal of MEB magazine) and would suggest buying the PDF back issue ($6) at:









						Model Engine Builder magazine Issue #26
					

Issue #26 features build instructions for Lynn Alfinson’s Low-Cost battery-powered EDM and the conclusion of Todd Snouffer’s Pip 3 Cylinder Radial Engine drawing package (Part 3 of 3).  Also featured is the completion of Don Grimm’s Series on Magneto-Driven Igniters (Part 4 of 4)



					www.modelenginebuilder.com
				




If you look around on youtube lots of folks have made cheap tap burner type EDM devices of varying quality, safety, and capacity.

Here is a link to the video of the EDM described in Model Engine Builder being demonstrated and explained by the original builder Lynn Anfinson:



For more advanced EDM projects, I think the Robert Langois book from Village Press and Brian Fleming's two books have already been mentioned.

Hopefully this gets you the info you need, sorry not to be able to provide the article, hope you understand.
Stan


----------



## MrMetric (Nov 18, 2021)

If Fleming is still offering the items (all dates look pretty old), I have to say that I prefer 'real' books over PDF (although, it is _awfully nice _to be able to keep things together in a directory).  I have an RC book, so a physical Pulse book is much more desirable to me.

 I have a strong suspicion that only 25% of all projects (generic, not just the EDM) are ever built; heck, probably less.  So, if I am able to repurpose someone's project that they don't want, it helps them, helps me, and helps reduce landfill.  In the end, that is exactly what happened.  That said, I think I'll contact Fleming and find out where he is with his circuit board revisions.  If there are significant changes, I may opt to get one from him.


----------



## MrMetric (Nov 18, 2021)

@*stanstocker.  *That is a good video link demonstrating an eminently simple EDM design.  Thanks for posting that.  It was really quite interesting...  

As for MEB... Yeah, I agree.  Toni and Mike did a great job with the magazine.  It seems to have pretty much ceased operation now though.  Technically I still have a subscription for one more issue, but it has never been developed or sent.  Given that it is about 4 years ago, I think, that I got my last issue, I think it is probably fair to say that it will not come.  I am not entirely sure what happened to Toni/Mike.  FWIW, though, I'm not bitter about not getting the last issue.  It was a fabulous magazine that I would happily resubscribe to if it were to be resurrected.... I met Toni/Mike at the Visalia show when they first started MEB, and I signed up immediately.  I lost my set of mags in a fire and bought a replacement set from an estate.  I think I even got some additional partial set somewhere along the line too.  I should check that out as I probably should clean them out.  Anyhow, I really enjoy looking through MEB and I would highly encourage anyone interested in the articles to contact Toni/Mike.  They are great people.


----------



## stanstocker (Nov 18, 2021)

MrMetric said:


> @*stanstocker.  *That is a good video link demonstrating an eminently simple EDM design.  Thanks for posting that.  It was really quite interesting...
> 
> As for MEB... Yeah, I agree.  Toni and Mike did a great job with the magazine.  It seems to have pretty much ceased operation now though.
> <trimmed>



Glad you liked the video, it was a shock to realize it was almost 11 years ago that I talked with Lynn at Cabin Fever!  I think Mike and Toni were there too.

As for MEB, I know they have a lot going on in their lives, the most recent issue was #39.  I missed an issue or two as my email address had changed and I didn't think to let them know.  Toni sent the download links and updated my info quickly, always good folks.  I hope they are able to keep the mag going. Even digital publications seem to be going the way of shows and printed pubs as our world changes.  They also really need people who can write to create the content, there is only so much that Mike can write, draw, and photograph.  Without new and interesting content you don't have a reader base.  I know other model engineering and woodworking related mags have the same issue.  There are only so many articles about silver soldering or crankshaft machining that the world can absorb 

/WARNING - OT and change of direction pondering about the future and nature of model engineering follows!

There are far more folks doing 3D printers and routers these days, with some coming over into our weird little world as they discover needs or desires that they can't meet with additive or lighter duty cutting machines.

The huge increase in interest and enjoyment of tabletop gaming has created a resurgence in model and figure making, some of which we see drifting over into machining, often in the smaller scale range such as Sherline sized machines.  A different focus than many here have, but lots of CAD or modeling software being used to create files to print or cut.  I know more  people who are making belt buckles, knives, gaming stuff, jewelery, and special tools to support other hobbies than I know who make engines.  It's interesting, it's similar, but is it model engineering?  Does it matter?  From the articles in Model Engineering Mag in the UK apparently I'm not even a model engineering guy as I don't build steam locomotives and didn't discover that CAD might be useful just last week.

It will be interesting to see how things shape up at Cabin Fever 25, hopefully there will be some fresh faces as well as folks known a long time.  I'm pretty sure it won't be the same, it will either be a freshly invigorated event or one that is fading into the past.  I hope for invigorated.

Several groups I've been associated with for a number of years are slowly turning into the old guys piss and moan about how nobody is coming into the hobby coffee club while spending two weeks debating the benefit/risk of using grease on auto wheel studs, living in the past, and wondering why that kid who seemed pretty skilled never came back.  I'm a 63 year old kid, and I've given up or dropped to lurk mode on several groups I really used to enjoy.  Looking at youtube, there are plenty of new faces doing interesting things, perhaps we'll see some of them at Cabin Fever.

Take care,
Stan


----------



## bengt-olausson (Nov 21, 2021)

L98fiero said:


> Fleming's site is still up, no idea if one can order or not. Build your own HomeBuilt Electrical Discharge Machine (EDM) for machining hardened materials


Hi 
I orderered the digital book and recieved a day later. 
Regards Bengt


----------



## MrMetric (Nov 22, 2021)

I got my book and board from a member here on MEM. He was no longer interested in pursing the idea, I have a strong interest in it, he offered at a very reasonable price, and voila! Everyone is happy....  

The reason I'm posting now, however, is an update on the board... The one I got was a pulse 2.0.  I figured I should contact Ben Fleming before I started collecting parts and assembling a board that may be obsolete (the current version is a Pulse 2.0B). Even if I had to get a new board, I would still have been happy with my purchase as I really preferred having a physical book copy.  The 2.0 and 2.0A pictured on Fleming's website are very similar.  The biggest difference I can see is that there is a clear pad problem on one of the diodes as it encroaches into the MOSFET heatsink area.  OK, that is a layout screw-up but easily resolved.  There are also some added ground pins next to test points, etc, but those are also not that important.

Fleming was pretty quick to respond and said that there really haven't been any significant design changes between 2.0 and 2.0B; he recommended that I just go with the board I got... One thing I thought was odd when I looked at the board is that it is setup so that the MOSFET pads are mirror images.  This means that they MOSFETs have to be mounted on opposite sides of the boards.  This, it turns out, was by design, to help assist in heat dissipation.   One other thing that Fleming said that might be of interest to people here is that on the newest version of the board, he recommends only 2 of the 4 MOSFETs.  Apparently that provides adequate power.

Fleming did say that there have been significant changes to the different generations of the RC boards.  As such, you may want to obtain a new version of those should you decide you want to go down the RC route instead of pulse.  Frankly, I haven't completely decided which I want to do yet.  I have both the RC book and the pulse book, so I have to cost them out.  The big expense seems to be in transformers, but there are some surplus places around where I might be able to pick something up.... We'll see.


----------



## EDMGuru (Mar 3, 2022)

Sorry, I don’t wish to throw a spanner in the works at this stage of your builds but actually a commercial grade EDM machine is easy and cheap to build, the problem is there is a misconception that there’s some sort of manufacturer’s design secret to these machines which makes people overcomplicate their home build designs usually by using some sort of code to control the actual burn. There's no need to buy a book or anything like that, the electronics are simple and mainly use "off the shelf" parts and the resulting machine performs, in my opinion, better than any DIY build I've ever seen online. 
I've posted this comment on other forums lately and it has received mixed results but let's see how it goes on here.
It might be worth you having a look at the video that I posted on YouTube a few weeks ago in response to other people having design problems, showing a simple machine that I built a few years ago, which I think you will agree proves my point


----------



## SmithDoor (Mar 3, 2022)

It looks like a solenoid pulling up after sparks on object.  
The hard part is DC power supply a DC welder is big enough to do the job. 
Some day I will try that but been 20 years since last time I need to remove a broken tap.

Dave 



stanstocker said:


> I can't post the Model Engine Builder article as 1) it's copyrighted and 2) I like Mike and Toni (publishers/editors/the whole deal of MEB magazine) and would suggest buying the PDF back issue ($6) at:
> 
> 
> 
> ...


----------



## SmithDoor (Mar 3, 2022)

Here is one from the internet 








						EDM - Electrical Discharge Machining
					

EDM - Electrical Discharge Machining: I wanted a way to make a steel instructables character, so I decided to make my own EDM machine to help me. EDM - Electrical Discharge Machining is a way of cutting metal using electricity, Similar to a plasma cutter except under water.  The process…




					www.instructables.com
				



I have not built this one.

Dave


----------



## stanstocker (Mar 4, 2022)

EDMGuru said:


> Sorry, I don’t wish to throw a spanner in the works at this stage of your builds but actually a commercial grade EDM machine is easy and cheap to build, the problem is there is a misconception that there’s some sort of manufacturer’s design secret to these machines which makes people overcomplicate their home build designs usually by using some sort of code to control the actual burn. There's no need to buy a book or anything like that, the electronics are simple and mainly use "off the shelf" parts and the resulting machine performs, in my opinion, better than any DIY build I've ever seen online.
> I've posted this comment on other forums lately and it has received mixed results but let's see how it goes on here.
> It might be worth you having a look at the video that I posted on YouTube a few weeks ago in response to other people having design problems, showing a simple machine that I built a few years ago, which I think you will agree proves my point



I very much like the results shown in the video.  I understand the off the shelf square wave generator just fine.  I've looked at several designs over the years, from the scary line voltage through a diode and lamp/capacitor flavor to some fairly complex designs.  What you have shown in the video seems to be a very effective while still reasonable to build option.  Pretty hazy on the 100V power supply and motor driving aspects though.  From the pictures I can make at best some ballpark guesses at your general approach, but not enough to whip up the power supply/controller.  Are you considering making schematics available (free or paid), or is this sort of a prototype for the basics and the stepper based new machine?  If so, are you going to be offering a plan set, even at a minimal level, so others can build the upcoming machine?

Thanks,
Stan


----------



## L98fiero (Mar 4, 2022)

EDMGuru said:


> Sorry, I don’t wish to throw a spanner in the works at this stage of your builds but actually a commercial grade EDM machine is easy and cheap to build, the problem is there is a misconception that there’s some sort of manufacturer’s design secret to these machines which makes people overcomplicate their home build designs usually by using some sort of code to control the actual burn. There's no need to buy a book or anything like that, the electronics are simple and mainly use "off the shelf" parts and the resulting machine performs, in my opinion, better than any DIY build I've ever seen online.
> I've posted this comment on other forums lately and it has received mixed results but let's see how it goes on here.
> It might be worth you having a look at the video that I posted on YouTube a few weeks ago in response to other people having design problems, showing a simple machine that I built a few years ago, which I think you will agree proves my point



That's interesting but he doesn't provide even a simple schematic for the 'electrically challenged' like myself. Anyone up for the challenge?


----------



## EDMGuru (Mar 4, 2022)

Hi stanstoker,

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 as it is with no modifications. It’s 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, 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.

The stepper motor version machine uses my own custom design controller which is not like anything else online as it doesn’t use a comparator as such it’s more of a cascade voltage control which allows the provision to build in an anti arc circuit (basically it turns off the power generator on the very low potential arc forming pulses) it’s burn is very stable and once finished looks like it could be a real game changer for the home EDM builder.

Getting back to the dc motor version I’ve always said that you don’t need to use code or EDM design’s from a book or anything like that to build an EDM but it looks now like I should maybe put this machine design in a book as it’s simple and can have other uses.

It could be used as a small attachment for a mill or drill press and by using the dc motor to drive a threaded copper bar through a nut instead of a slide you can create internal or even by using a copper “die” external threads in hard materials.

 Another simple use I’m looking at working on doesn’t require a power generator and so long as your pattern is, or could be made, conductive is a copy mill or copy lathe attachment. What do you think?


----------



## stanstocker (Mar 4, 2022)

Thank you for adding some information.  I'll need to contemplate and digest a bit on this.  Other than some high power linear regulators in hybrid packages back in the early 1980's I've never been involved in the power electronics side of things other than repairing some amplifiers over the years, so although all the words are known to me the relationships will need some thought.

I'm assuming you are switching the power resistors with FETs driven by the square wave generator?  My guess is the small relays on the power controller are for the fluid pump and feed motor control.  Am I at least somewhere close to right, or as Pauli said so well at one physics seminar "Not even wrong!"...

I'll go back and read over Langois and Flemings stuff and try to get back up to speed, it's been quite a few years since I did electronics work for a real living.  Once I get a bit more up to speed I will probably have some questions, but I don't want to waste folks time on things that should be apparent 

I will ask one more though:  Are you running the electrode at ground or power supply level?  Your coin example showed very little if any electrode wear, and I've read in several places that running the electrode at ground and the work hot reduces electrode wear a lot.

EDM is sort of like tool and cutter grinders for me, an interesting itch I'd like to scratch although odds are there are already more projects around here than I'll ever get done before my best by date wanders around.

As for your copy lathe / mill idea, it's so far past where I am with EDM I can't even really grasp just how it all would work, but if you decide to follow up on it I'll be sure to pay attention.

Thanks again,
Stan


----------



## EDMGuru (Mar 4, 2022)

Hi stanstocker,

The square wave frequency amplifiers output is amplified by the power generator, so basically you’re just changing a square wave output of say 5 volts @ 10 mA to an exact copy of the square wave but at a voltage of 100 volts @ 10 A (or what ever the output Amps is that is set by your output high wattage resistor value) although the output amps on an EDM should be calculated at the working voltage so at half the open voltage.

The power generator in its most basic form (1 power output) can be made by using only 3 transistors and is very simple in design (the audio industry have been doing this type of thing for years).

If you are referring to the 3 small blue relays on the power generator board in the video they’re actually what is used to switch in 3 outputs which go via 3 separate high wattage resistors and it’s just a resistor in parallel calculation for the power output which in my case was 3.5 A, 7 A and 10 A.

Most of the time when using a copper electrode the polarity on a sink type EDM is kept positive, the only main exceptions are when eroding carbide (with tungsten copper) and using a graphite electrode for maximum material removal (normally a graphite electrode is kept positive but running it at negative polarity removes material 4x faster but with high electrode wear). Wire EDM machines normally run with the wire at negative polarity for faster metal removal (electrode wear isn’t an issue as it’s constantly being replaced) and they use a different type of power generator which is more like a pulsed RC type of machine.

I have compiled over 45 years of working on these machines, mainly as a business, a lot of technical information, which you won’t find anywhere online, for different electrode and work piece material at different Amp, pulse frequency and duty factor settings for spark gap sizes, metal removal rates, electrode wear, surface finish etc. Maybe this information should go in a book too?


----------



## ajoeiam (Mar 5, 2022)

EDMGuru said:


> Hi stanstocker,
> 
> The square wave frequency amplifiers output is amplified by the power generator, so basically you’re just changing a square wave output of say 5 volts @ 10 mA to an exact copy of the square wave but at a voltage of 100 volts @ 10 A (or what ever the output Amps is that is set by your output high wattage resistor value) although the output amps on an EDM should be calculated at the working voltage so at half the open voltage.
> 
> ...



If not a formal book - - - maybe an e-book written by chapter or article - - - - maybe here or a blog or some such. 

This bunch here would likely stick a special sign on any serious of posts doing what you are talking about. 
(Its a really good bunch imo - - - - I'm still quite a 'new guy' here yet though - - - grin!!!)

Technical books I find sorta frustrating. 
Example - - - - 20 years previous 2nd edition - - - still costs $460 usd for a copy. (If not more) 
Can't get it any which way - - - scarce as hen's teeth in libraries (research ones) and then too much of the information isn't really useful. 
Can't figure that last part out until you read the book thoroughly AND work through it (that all doesn't happen in a short period of time!). 

Publisher doesn't give a rip though.
Authors mostly long dead (articles written while they were in the later stages of their careers) and the area has evolved in a different direction. 

Me - - - if I've got something that is useful for others - - - I'll likely just open source it.


----------



## stanstocker (Mar 5, 2022)

I know that EDM is one of the those areas that most of the hobby folks seem to perk up and listen when it comes up.  I also know that most "That would be really great, I'd buy plans or I'd build one!" in reality never get off the ground or are overcome by events.  The world is full of partially completed Quorn / Tinker / Bonelle tool and cutter grinders I think.  I'll admit my mostly done Quorn is out in the shop waiting for me to get a few weeks to go play with it, rather than dealing with all the things that seem more pressing.

I'd love to see a schematic for your amp/power switcher.  Although as you say odds are a suitable circuit can be conjured, the fact is your circuit works well.  Many almost work, you tube is full of machines that are only a wee bit past being tap burners if that.  If you chose to invest the time though, it's unlikely to get you much more than thanks even if you were to sell a plan set for $25 or $40.  I know a few people who have published some plans, and they haven't managed to retire early on the proceeds...

So thanks for what you have shared, and if you choose to share more I'll be reading!
Stan


----------



## desbromilow (Mar 6, 2022)

Stan, FWIW I built one off the Fleming design a while ago for the express purpose of "drilling" holes in HSS sheet. If you want to see some video of it running, go to: 
It cost me about $100 to build, but I was lucky that I had some salvage transformers which were "close enough" for the build. It's a pulse type (RC) and the capacitors are ones taken from disposable film cameras which the local photo processing  lab gave me free for asking.

Since the video was taken I've built a tank from a plastic food container, with a modular aluminium frame which drops inside for clamping the workpiece in place - the big problem in the video is the work piece moving.
My electrodes are turned from carbon arc-gouge electrodes. I can use the same arc-gouge electrodes and cut any shape using files, etc.

Des in West Oz


----------



## aeroHAWK (Mar 26, 2022)

EDMGuru said:


> Hi stanstocker,
> 
> The square wave frequency amplifiers output is amplified by the power generator, so basically you’re just changing a square wave output of say 5 volts @ 10 mA to an exact copy of the square wave but at a voltage of 100 volts @ 10 A (or what ever the output Amps is that is set by your output high wattage resistor value) although the output amps on an EDM should be calculated at the working voltage so at half the open voltage.
> 
> ...


I am VERY MUCH interested in building a machine like yours. I saw your video and became intrigued. I operated an EDM nearly 30 years ago and the machine was old then. I suspect its electronics were quite basic, similar to what you have described. After studying what you have posted, I am getting an idea of your circuit. Is this close?


----------



## EDMGuru (Mar 27, 2022)

Hi aeroHAWK,

Yes that’s basically it only it’s the positive side of the 100v output that’s pulsed and the negative side goes straight to the work piece. Also your voltmeter is connected wrong; the left side of the wiring as shown in your drawing should go to the negative side and not the positive side of the 100v power source.


----------



## SmithDoor (Mar 27, 2022)

Has any one use a welder for power supply?
Mig welders start around 40 volts DC.

Dave 




EDMGuru said:


> Hi aeroHAWK,
> 
> Yes that’s basically it only it’s the positive side of the 100v output that’s pulsed and the negative side goes straight to the work piece. Also your voltmeter is connected wrong; the left side of the wiring as shown in your drawing should go to the negative side and not the positive side of the 100v power source.


----------



## aeroHAWK (Mar 27, 2022)

EDMGuru said:


> Hi aeroHAWK,
> 
> Yes that’s basically it only it’s the positive side of the 100v output that’s pulsed and the negative side goes straight to the work piece. Also your voltmeter is connected wrong; the left side of the wiring as shown in your drawing should go to the negative side and not the positive side of the 100v power source.


Thanks EDMGuru! You caught a dumb mistake for me. I just put the meter in as an afterthought and paid no attention to the polarity.

I really appreciate you providing this information. You've really taken the mystery out of it for me. It makes sense now.

Cris


----------



## EDMGuru (Mar 27, 2022)

Hi SmithDoor,
Unfortunately I believe welders use an auto transformer which is unsuitable for EDM as their output when rectified is a plus and minus voltage in relation to ground (0v) so +20v DC to -20v DC if this makes sense, although you could use one in series with an isolation transformer which should make the output voltage a more useable 0v to 40v DC.


----------



## SmithDoor (Mar 27, 2022)

Welders are not auto transformer type. They like the microwave type.

At higher amperage the voltage is between 18 and 24 volts 

Dave 



EDMGuru said:


> Hi SmithDoor,
> Unfortunately I believe welders use an auto transformer which is unsuitable for EDM as their output when rectified is a plus and minus voltage in relation to ground (0v) so +20v DC to -20v DC if this makes sense, although you could use one in series with an isolation transformer which should make the output voltage a more useable 0v to 40v DC.


----------



## aeroHAWK (Mar 27, 2022)

EDMGuru said:


> Hi aeroHAWK,
> 
> Yes that’s basically it only it’s the positive side of the 100v output that’s pulsed and the negative side goes straight to the work piece. Also your voltmeter is connected wrong; the left side of the wiring as shown in your drawing should go to the negative side and not the positive side of the 100v power source.


I updated my schematic to reflect your corrections:


----------



## EDMGuru (Mar 27, 2022)

Hi aeroHAWK,

Unfortunately your voltmeter is still connected incorrectly. It needs to be connected either somewhere between R1 and the mosfet or direct to the electrode and the other side connect to the negative side. Also don’t forget that the output pulse from your mosfet will be inverse to the input pulse so a 90% duty cycle input pulse will result in a 10% duty cycle output pulse which is no good.

You’ll need to add a pre amp stage before the mosfet to reverse this probably a small transistor will do for your design but I’m not sure as I find mosfets temperamental when ever I use them so I prefer to use transistors instead. Also check that the mosfets source and drain is connected the right way round for this circuit as I’m not sure the drawings right but I’m no expert.


----------



## aeroHAWK (Mar 27, 2022)

EDMGuru said:


> Hi aeroHAWK,
> 
> Unfortunately your voltmeter is still connected incorrectly. It needs to be connected either somewhere between R1 and the mosfet or direct to the electrode and the other side connect to the negative side. Also don’t forget that the output pulse from your mosfet will be inverse to the input pulse so a 90% duty cycle input pulse will result in a 10% duty cycle output pulse which is no good.
> 
> You’ll need to add a pre amp stage before the mosfet to reverse this probably a small transistor will do for your design but I’m not sure as I find mosfets temperamental when ever I use them so I prefer to use transistors instead. Also check that the mosfets source and drain is connected the right way round for this circuit as I’m not sure the drawings right but I’m no expert.


Hi EDMGuru,

I now understand the voltmeter connection. I was suspicious of my thought process before.

I double checked the MOSFET connections with other circuits I've built and it matches them. Also it shouldn't be inverted. When the PWM signal to the gate is high, the MOSFET conducts so it looks correct to me. Since it is an N-channel MOSFET it requires a driver to provide the proper voltage to the gate (N-Channel instead of P-Channel may  be why you commented on the connections of the source and drain). I have used power MOSFETS many times. It is common to use N-Channel MOSFETS for the high side switch of an H-bridge or Half-Bridge. I prefer MOSFETS for high power switching and I happen to have a bunch of them.

Here is a schematic for a Half-Bridge (typically used for switching one of the phases of a BLDC motor) and the MOSFET Driver. The high side MOSFET is analogous to the the way the MOSFET is used in the circuit I show.




Thank you for your expertise.

Cris


----------



## aeroHAWK (Mar 27, 2022)

EDMGuru said:


> Hi aeroHAWK,
> 
> Unfortunately your voltmeter is still connected incorrectly. It needs to be connected either somewhere between R1 and the mosfet or direct to the electrode and the other side connect to the negative side. Also don’t forget that the output pulse from your mosfet will be inverse to the input pulse so a 90% duty cycle input pulse will result in a 10% duty cycle output pulse which is no good.
> 
> You’ll need to add a pre amp stage before the mosfet to reverse this probably a small transistor will do for your design but I’m not sure as I find mosfets temperamental when ever I use them so I prefer to use transistors instead. Also check that the mosfets source and drain is connected the right way round for this circuit as I’m not sure the drawings right but I’m no expert.


Here is an updated schematic:


----------

