Hi Bogos67

So, the question is, is it possible to use ready made elements to make a sinker EDM? I think like Dominik Mefferts's design.

Yes if you use Dominik’s design of EDM but it wont do what you want it to do unfortunately as it’s a pulsed RC design which by design have high electrode wear rates also there is no provision to change the pulse frequency and current output which is necessary for the finishing stages and even then you will still need some electrical knowledge to build it. Do you have a machine frame built or in mind already? Have you thought about the dielectric system for a pulse EDM? They use an oil based dielectric which is a fire hazard so your machine will have to be sited in an out building or such (not made of wood) to be safe. It may be possible to use deionised water successfully at low Amps on a pulsed EDM but I’ve never heard of anybody doing this due to the increased voltage, pulse frequency, duty cycle and the electrical conductivity of water compared to a wire EDM which typically only work at approx 15v due to only a 20% duty cycle at the wire, so this could be a first for you if it works!

The Easy-Peasy design of EDM has probably 95% of it’s parts available “off the shelf” but you’ll need to take some voltage measurements from the speed controller etc to get the right balance for the voltage divider feedback to the speed controller which controls the Z axis during the erosion process so again some electrical knowledge and equipment (multi meter) will be required. The pulse power generator is the only part that’s not available “off the shelf” (apart from the designs online that don’t really work all that well) so you will need to build one but I can help you there. Maybe I should start selling my pulse power generator online? The first thing I would do is build a good machine frame and go from there, you’ll enjoy the journey.

Cheers.

 

I don't quit understand why your swage die needs to be split? I shot air guns too and the pellet swage dies I've seen advertised were just a flat plate with holes of different diameters. the pellet is pushed through using a pin in the hollow of the pellet.

My idea is to be a small business, so I want a durable thing. Second option is a steel. Split die is due to diabolos unique shape. Do you have an email?

 

Hi Bogos67


Yes if you use Dominik’s design of EDM but it wont do what you want it to do unfortunately as it’s a pulsed RC design which by design have high electrode wear rates also there is no provision to change the pulse frequency and current output which is necessary for the finishing stages and even then you will still need some electrical knowledge to build it. Do you have a machine frame built or in mind already? Have you thought about the dielectric system for a pulse EDM? They use an oil based dielectric which is a fire hazard so your machine will have to be sited in an out building or such (not made of wood) to be safe. It may be possible to use deionised water successfully at low Amps on a pulsed EDM but I’ve never heard of anybody doing this due to the increased voltage, pulse frequency, duty cycle and the electrical conductivity of water compared to a wire EDM which typically only work at approx 15v due to only a 20% duty cycle at the wire, so this could be a first for you if it works!

The Easy-Peasy design of EDM has probably 95% of it’s parts available “off the shelf” but you’ll need to take some voltage measurements from the speed controller etc to get the right balance for the voltage divider feedback to the speed controller which controls the Z axis during the erosion process so again some electrical knowledge and equipment (multi meter) will be required. The pulse power generator is the only part that’s not available “off the shelf” (apart from the designs online that don’t really work all that well) so you will need to build one but I can help you there. Maybe I should start selling my pulse power generator online? The first thing I would do is build a good machine frame and go from there, you’ll enjoy the journey.

Cheers.

Machine frame is not an issue for me, I'm machinist. I have some old Zeiss frame from some old aparatus, and attached z axis to it (my father built z axis for it, but I think it need some improvements)

I'm looking forward to your machine pcb, stepper motor cersion, preferable unpopulated with elements (Just parts list and I can buy/solder elements)

I will also complete my RC from Ben Fleming and see the results

 

About the Ben Fleming: I'm in the process of completing the pcb(I know to solder elements) for RC, but I'm open for pulse version of Ben. I rejected that idea because some folks mentioned that his book for pulse have old instructions and are different than his latest pcb with solved issues. Therefore I thought it's confusing and rejected that idea. Plus, it's not stepper motor version.

The last I saw he gives updated instructions with the updated PCB's.

His designs use a small gear motor, with them there is no real control so they spend a lot of time shorting out and then retracting. A stepper motor can be set to only advance a small amount and not short out the burn. Each time it shorts out it leaves a slight mark in the finish.

The RC works just fine with the correct motor and a small enough current chosen for the finish required.

 

Hi shortbus it's been a while how are you? I thought that the Langlois design of EDM was just an RC type so not suitable for Bogos87 to use due to high electrode wear.
Cheers.

I've been overall pretty good, for 75 years old, how about you?

Even a pulse machine has wear. When making injection molds of high precision for Delphi/Packard, we used a 5 electrode burn scheme, and dropped the #1 electrode out on the next cavity. Even with the Charmilles CNC type we did that. Whit the 5 electrode scheme the wear and finish was really good. Sinker or any EDM isn't a race when getting a good finish. The Langlois machine has quite a few power settings available so should with practice get good results.

 

My idea is to be a small business, so I want a durable thing. Second option is a steel. Split die is due to diabolos unique shape. Do you have an email?

Use the Forum personal messages for email. But this should be kept on forum for most things, to help others.

The intermediate neck down on diabalos can be worked around on a split die. Just make a stack up with a thin layer for the pellet waist. The stack would be doweled on each side of the two halves. Cut the waist diameter to the full depth required, and then remove that waist section, restack and then machine the rest to size. Where I worked before having EDM we did things like that all the time.

 

They use an oil based dielectric which is a fire hazard so your machine will have to be sited in an out building or such (not made of wood) to be safe. It may be possible to use deionised water successfully at low Amps on a pulsed EDM but I’ve never heard of anybody doing this due to the increased voltage, pulse frequency, duty cycle and the electrical conductivity of water compared to a wire EDM which

We started out using deionized water with the new Charmilles they bought, but due to the high amount of dross compared to a wire machine that didn't last long. They leased the deionzeing tanks and that company complained loudly, by raising the price to regenerate the tanks.

They do have oil types made for EDM but kind of expensive, but with a good filter we only replaced it around every 8 or 10 years. On the small cores for our molds we didn't even flood the tank, just put a couple of nozzles pumping the fluid on the burn.

 

@Bogos87 Have you seen the Corbin web site? http://corbins.com/pellets.htm

There is a guy on Gateway to air guns that made a single swage for .30 cal https://www.gatewaytoairguns.org/GTA/index.php?topic=173748.0 A lot more there too.

Airgunnation has a lot of stuff too. https://www.airgunnation.com/threads/swaging-pellets-diy.1271089/

 

@shortbus do you think it's possible to bypass Ben's SN754410 with stepper motor driver?

 

@shortbus somehow I'm not allowed to send personal messages, maybe because I'm new?
Anyways, I wanted to share similar look of the split die, without expanding this EDM subject.

Please take a look at the photo. It's worth noting that it's not a casting, but swaging process(that means a small piece of lead blanks inserted by hand or machine, split die closed tight and steel punch pin swaging the final shape. This material is SKD11, I believe, around 50-60 HRC, I guess. It can be a carbide insert with negative shape, too).

 

Also about the split die- surface finish is not that important- but what is extremly important is concentricity and alignment of the split.

 

@shortbus somehow I'm not allowed to send personal messages, maybe because I'm new?
Anyways, I wanted to share similar look of the split die, without expanding this EDM subject.

You should be able now to send PM's. A new member needs to have 10 postings. Unless the forum rules have changed.

That photo, or one very similar, is in a post at one of the air gun forums I gave you. They were made by a Chinese company in that thread. You say surface finish isn't important in the other post, but I beg to differ. Corbin even goes so far as to diamond lap their cavities.

 

@shortbus do you think it's possible to bypass Ben's SN754410 with stepper motor driver?

I think it is. I made up a add on board design for another guy one time to do that. Don't know if it worked or not, after I sent it to him I never heard from him again. I'll look and see if I saved it. But I'm no electronics expert so it may not have worked. If I still have it I'll PM it to you.

 

You should be able now to send PM's. A new member needs to have 10 postings. Unless the forum rules have changed.

That photo, or one very similar, is in a post at one of the air gun forums I gave you. They were made by a Chinese company in that thread. You say surface finish isn't important in the other post, but I beg to differ. Corbin even goes so far as to diamond lap their cavities.

I'm not sure about that forum, if you have a link?

 

I think it is. I made up a add on board design for another guy one time to do that. Don't know if it worked or not, after I sent it to him I never heard from him again. I'll look and see if I saved it. But I'm no electronics expert so it may not have worked. If I still have it I'll PM it to you.

If you find, it would be interesting to take a look and to try. Thanks.

 

I'm not sure about that forum, if you have a link?

The links to the airgun forums are in my post #28. Those are links to a specific post in the forums but from those you can do a search for DIY pellet swaging, that's how I found them in Google.

I won't have time today or tomorrow to look for the add on but will , have to go out of town for a couple of days.

 

The links to the airgun forums are in my post #28. Those are links to a specific post in the forums but from those you can do a search for DIY pellet swaging, that's how I found them in Google.

I won't have time today or tomorrow to look for the add on but will , have to go out of town for a couple of days.

thanks for the links, it's different pellet type, like ''slug''. The pellets I'm looking for is diabolo pellet with the shape of sandwatch. That's the reason it needs to have a split die shape.

Take your time and thank you.

 

hanks for the links, it's different pellet type, like ''slug''.

If you go deeper into those forums they have other pellet dies, I'm not going to go back again and do the research that you can do. Don't take offense at that statement, it's just that it is your project and I'm just trying to help, use the search on those forums or Google, you get many many hits.

If your not too mad at me, you may want to look at my ideas, simple schematic of what I was going to make. I haven't worked on it since because I don't know how to figure the resistor values it needs to work. It is a take on something the latest(at that time) industrial machines use, called "isopulse". It is a capacitor discharge type that self regulates the pulse frequency based on the gap its self. Isopulse is why there is less wear on the electrode and a better finish on the burn. I'll warn you ahead of time it's a long thread, but has a lot of information from others in this forum. https://forum.allaboutcircuits.com/threads/edm-electrical-discharge-machine.144655/

 

If you go deeper into those forums they have other pellet dies, I'm not going to go back again and do the research that you can do. Don't take offense at that statement, it's just that it is your project and I'm just trying to help, use the search on those forums or Google, you get many many hits.

If your not too mad at me, you may want to look at my ideas, simple schematic of what I was going to make. I haven't worked on it since because I don't know how to figure the resistor values it needs to work. It is a take on something the latest(at that time) industrial machines use, called "isopulse". It is a capacitor discharge type that self regulates the pulse frequency based on the gap its self. Isopulse is why there is less wear on the electrode and a better finish on the burn. I'll warn you ahead of time it's a long thread, but has a lot of information from others in this forum. https://forum.allaboutcircuits.com/threads/edm-electrical-discharge-machine.144655/

haha, no mad, thanks for recommendations! Split dies are not issue, my only concern is EDM. So obvious for an machinist.

 

What is EDM?
1) Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a metal fabrication process
2) Electronic Direct Mail (EDM) is a form of digital marketing strategy that businesses implement to promote products to a list of potential
3) EDM definition: electronic dance music: a range of genres of electronic music often played in nightclubs and characterized by a strong danceable beat.