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G-EDM

The G-EDM is a 4in1 electrical discharge machine that supports sinker EDM, EDM engraving, EDM drilling and Wire EDM operations.

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The G-EDM is a fully automated three axis EDM CNC machine that supports different kinds of electrodes like brass tubes or brass sheets and is highly customizable. With the new wire EDM extension it is possible to cut high precision parts out of aluminum, mild steel, HSS and other metals. Besides normal operations like drilling and wire EDM it also provides an experimental EDM engraving mode that uses a normal brass rod as a floating electrode to engrave text into metal or erode pockets.

It uses 3D printed parts where it is possible and in the future it may support even laser and mill operations.

The G-EDM ( new video )

The final version of the control panel:



And more details:


EDM can create a lot of EMI noise and therefore the spark generator needs to be in a shielded enclosure. But even the electrode and the spark itself create noise.

In the first builds the negative spark wire was mounted to the rotary drill chuck within the tool head. But this converted the electrode into a antenna with enough power to shut down the communication between the ESP and the display.

This highly depends on the Amps used, the duty cycle of the pulse and the length of the electrode but I decided to just connect the electrodes as close to the work piece as possible.

For round electrodes the blank wire is wrapped around them and for sheets alligator clips are good.

It doesn't look as good as the integrated contact but it reduces the noise a lot.

The pulse generator is a pretty basic and flexible concept that is easy to replicate. A 65v switching PSU is connected to a DPM8605 step down module that will provide 0-60v and 0-5A.

The output of the DPM8605 is then connected to the pulse generator PCB which is basically just a Mosfet gate driver, some capacitors and a voltage divider for the feedback signal.

This is the pulse generator PCB ( prototype ) wired up for some basic tests.

At the moment there are two working versions of the pulseboard that drives the sparks of the G-EDM.

A tiny board that uses an opto-isolated gate driver to switch external mosfets:

And a big board with up to 6 integrated Mosfets and a discrete gate driver circuit and two shiny indicator LEDs:

And of course the heart of it all. The ESP motion controller that controls up to 4 TMC2209 stepper drivers:


  • New controlbox is almost finished

    gedm-deva day ago 0 comments

  • New control panel for less chaos

    gedm-dev4 days ago 0 comments

    New control panel to reduces the chaos.

  • New PCBs, new sensing unit

    gedm-dev03/08/2024 at 17:17 0 comments

    The new sensing unit finally evolved from a breadboard prototype to a nice and shiny PCB.

    The feedback works nice and sensitive. It is able to capture the raw water contact too. and reacts to tiny single discharges.

    I won't go into details about the parts but the board offers a fully isolated high side shunt current feedback.  A linear optocoupler is used for isolation. The ESP is now fully disconnected from the pulseboard.

    PS: Thanks to PCBway for the extra boards.

  • Repeatable results - GEDM vs 30mm steel

    gedm-dev02/18/2024 at 04:07 0 comments

    Things start to turn out very nice. Another cut on the 30mm block was successful. Some changes to the code doubled the speed of the cut.

  • 30mm steel against the GEDM - The final challenge

    gedm-dev02/17/2024 at 06:41 0 comments

    PS: Most of the other cuts on the block where testcuts. The one G would have finished but the process is too slow and I had to edit the code. Can't wait for the full cut to finish every time.

    Points so far:

    30mm Steel: 200

    GEDM: 1

    The finish is insane.

    The exit moment:

  • New water reservoir

    gedm-dev01/21/2024 at 00:55 0 comments

  • Common sense v1.0 extension

    gedm-dev11/27/2023 at 03:42 0 comments

    Currently the GEDM uses a simple voltage divider network on the spark PSU as only source of feedback. This only works with a current controlled PSU and it is not perfect.

    So it was time to get into real gap sensing or at least something that is able to sense the current that runs through the electrode.

    Wasn't easy to get some usable results but the circuit designed for sensing seems to work on the breadboard.

    It provides analog feedback and two digital feedbacks with variable setpoints.

    This is not a replacement part for anything. The current pulseboard is powerful and works acceptable well. In combination with this extension it should be possible to get very accurate control over the EDM process even with a linear PSU.

    The circuit was designed with the help from Shrawan Khatri

  • Custom single axis sinker EDM running on GRBL makes big progress

    gedm-dev10/15/2023 at 21:56 0 comments

    The first custom machine running on G-RBL starts to produce some very stable burns.

    It wasn't easy to get it running and the code had many changes that will be part of the next release. I'm impressed with this build.

    It uses a TB6600 driver ( don't use them! Don't look at them! Maybe pretend those things don't exist at all! ) the step resolution is 346 steps per mm. So it is hard to get a stable burn at all as a single step can be enough to go from the lower setpoint range to a short circuit.

    The pulse circuit is a little different from what is used in the G-EDM. It is currently a power resistor based circuit and the feedback signal doesn't measure the voltage drop on the PSU but the spark gab voltage.

    It even uses high precision cutter-mud as dielectric.

  • Next cut - Wire EDM a dragon head (images only)

    gedm-dev10/08/2023 at 21:01 0 comments

  • But what about the Powercore?

    gedm-dev10/05/2023 at 04:53 0 comments

    This log will be a little about the Powercore from rack robotics. I've heard a lot about it and people keep contacting me about it.

    After looking into it a little I came to the conclusion that it is outdated technology.

    Back in the days most EDM spark generators used some kind of power resistor to limit the current. But this concept generates a huge amount of heat and is just wasted energy.

    My first pulse generators used power resistors too until I changed to a switch mode power supply.

    It is somehow sad that they seem to not provide a lot of information about the specs of this product. The available information claim that the switching frequency is about 2khz which would be very slow if this is the max speed. On the G-EDM the lowest frequency I use is about 5khz and my personal sweet spot frequency is between 10-30khz.

    Since it is only a pulsegenerator without any motion controller yet there is not much I can say about it. There are no customer videos available. After selling a huge amount one should assume some videos to pop up that are not related to the team of the product. This may speak for itself. But I don't want to make it look bad. Without a motion controller even the best pulse generator is useless.

    But there are good news too for the powercore fans. After watching the channel from rack robotics there seems to be a great interest in ESP32 Motionboards with TMC2209 drivers in the last days. That is super cool since that is exactly what the G-EDM uses. So I know it is a good choice.


    I'm confident that they will be able to come up with the promised wire EDM build and maybe it will run exactly as good as the G-EDM. Wouldn't that be awesome?

    Stay charged

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Mike K wrote 6 days ago point

Amazing work. I am waiting for the PCB files to build and test one myself. I had made an edm machine in the past but my spark wasnt strong enough. Hopefully this board works in my machine.

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dgourlay wrote 11/22/2023 at 22:44 point

this is GREAT!  I just saw your youtube.  Excellent work!

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gedm-dev wrote 11/23/2023 at 07:41 point

Thanks. Wish it would be finished soon. But still so much to do.

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H wrote 10/06/2023 at 00:59 point

Looks amazing so far! As far as I know there haven't been any other EDM makers that were willing to share their files, so thanks (even though you're not to that point yet)!

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gedm-dev wrote 10/06/2023 at 02:19 point

The only thing unreleased are the PCBs and people may be surprised how simple they actually are. The ESP motion controller is jsut a breakout board that makes life easier. The pulseboard is a little more complex but still pretty basic. At some point they will be available.

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H wrote 10/06/2023 at 23:51 point

Oh dam I should look more into this. I don't need the motion board since I already have individual drivers + breakout boards that are easy to wire

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gedm-dev wrote 10/07/2023 at 00:34 point

The breakoutboard is very useful. It extends the SPI Mosi/MISO/CLK pins and allows to wire the display without hacking 3to1 jumper wires.

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Jimmy wrote 10/04/2023 at 08:44 point

Does your GRBL version backtrack on short?

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gedm-dev wrote 10/05/2023 at 07:26 point

Yes. The planner of grbl was replaced with one that can move back in history.

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Piotr wrote 08/10/2023 at 00:00 point

How feedback circuit looks like? I want to build similar machine and have problem in this part.

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gedm-dev wrote 08/10/2023 at 01:31 point

The feedback is just a voltage divider. that outputs between 0 and 2.8v depending on the voltage drop created. Everything else happens at software level.

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joram wrote 07/12/2023 at 08:48 point

This looks interesting. Is the esp32 code already in a sharable state?

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gedm-dev wrote 07/12/2023 at 12:49 point

Almost. I just need to confirm that the Y axis works too. Currently building the axis. Should be ready soon.

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