Hi Nicklas the distance of the initiation is not the distance of the discharge that is: the distance of the initition is Less Than Or Equal to a value the distance of the discharge is not dependant on the distance of the intiation, and is usally much closer. in real work the tool is already at the discharge distance when the initiation voltage is turned on so the initiation still occurs, followed by the discharge the equations for the distance are beyond me because it is not simply ohms law as the discharge is a plasma and the gap is not a resistor, but a 'reactor'
and .75 amps never bothered me, that measure is of the supplied current, ( the current that would be delivered in a dead short) which is much more than delivered current ( the gap reactance again, so i have no formula, tho there are math models available on the interweb) tomp On 04/22/16 22:29, Nicklas Karlsson wrote: > .75 amps is very dangerous as soon as voltage is high enough. Low current and > it should not be dangerous even for rather high voltage. > > Preferably I want to stay at low current at least until prototype leave > desktop. > > Since dielectric breakdown strength only has volts and distance I guess volt > should be adjusted so that ionization is not started at to long distance > which would create a big crater. > > I however want to keep current low to stay safe but does the current change > how large a channel is created or will it grow large enough anyway as soon as > the real current start? > > > Regards Nicklas Karlsson > > > > > On Thu, 21 Apr 2016 22:03:32 +0800 > Thomas Powderly <tjt...@gmail.com> wrote: > >> initiation ONLY depends on voltage >> i use .75 amps and its overkill >> but it was easy to make the circuit >> the equation for dielectric breakdown strength only has volts and distance >> but >> higher voltage makes ionization easier >> typical value are 100 to 300VDC >> tho for some paarungs ( stahl bis stahl, copper to crystal ... ) upwards >> of 1000V= are used >> hth tomp >> >> On 04/21/16 20:13, Nicklas Karlsson wrote: >>> I certainly discovered the need to back off. >>> >>> As is now I use only 10mA for ionization and 10A for cuts. I want to keep >>> ionization current down for safety reason, do you know if it is harder to >>> get process running at low current? >>> >>> Regards Nicklas Karlsson >>> >>> >>> >>> On Thu, 17 Mar 2016 15:15:10 +0000 (UTC) >>> Pete_Gruendeman <gruende...@att.net> wrote: >>> >>>> Hi Nicklas: >>>> Did you set up and run the simple RC type EDM? It's a pretty simple >>>> proposition, using a filtered DC power supply, a capacitor in parallel >>>> with the gap and the gap itself. An electrolytic capacitor would work. A >>>> motor-run capacitor, of 50-100 micro Farads would work even better. >>>> Hands-on experience will answer many of you questions, especially in >>>> regard to the stability of the process. No matter how stable your process >>>> is, backing up is part of this artform. >>>> >>>> Pete >>>> -------------------------------------------- >>>> On Thu, 3/10/16, Nicklas Karlsson <nicklas.karlsso...@gmail.com> wrote: >>>> >>>> Subject: Re: hands-on EDM experience >>>> To: "Pete_Gruendeman" <gruende...@att.net> >>>> Date: Thursday, March 10, 2016, 8:49 AM >>>> >>>> > Hi Nicklas: >>>> > I wrote and sent this last >>>> night but it seems to have bounced instead of reaching >>>> you. I want you to get some hands on experience with EDM, >>>> even if it's a simple RC type EDM that you clamp onto a >>>> milling machine and flush with a turkey baster you borrow >>>> from the kitchen. Even though I had run commercial EDMs, >>>> it was eye opening to run the process manually. The whole >>>> process can be complicated but it doesn't have to be. >>>> Read below. >>>> > >>>> > Hi >>>> tomp and Nicklas: >>>> > >>>> Careful tomp as much of what you wrote is some >>>> pretty technical stuff. It might be over Nicklas' head >>>> since he is new to EDM. I barely recognize some of this >>>> but do recall that Agie offered auto-overcut compensation. >>>> I always turned that off as much of my work was something >>>> like a horizontally oriented cylinder and I typically >>>> orbited about the X-axis. >>>> > >>>> > Nicklas: Have you done >>>> anything with EDM yet?, even with a simple resistive >>>> capacitive spark eroder?, perhaps set up on a milling >>>> machine or other platform? And I don't mean CNC. I >>>> mean with control being provided by your ears and your >>>> hands. And flushing with a baster from the kitchen. Much >>>> of the discussion here will make more sense if you have even >>>> a little hands-on experience with EDM. Being a beginner is >>>> fine. I really want you to know instinctively what a >>>> stable burn sounds like, and what gap contamination looks >>>> like, sounds like and how quickly you need to do something >>>> about it when the burn starts to become unstable. These >>>> various hands-on skills will be more confusing to you when >>>> you try to learn it with the complexities of CNC added to >>>> the mix. Let's get your hands oily and a little EDM >>>> crackling sound in your ears as soon as possible. It takes >>>> very little equipment to replicate Lazarenkos' >>>> experiments and that's all I want you to do to get >>>> started. You can get started with a copper or brass >>>> electrode. Let me know how I can help you get started. >>>> > >>>> > Pete >>>> >>>> Well I am more interested in >>>> the CNC part and an EDM is what I could buy cheap. My first >>>> sparcs will be coffecup EDM with food oil, it is still a few >>>> days away since I have to spend a few days on others. >>>> >>>> >>>> Nicklas >>>> Karlsson >>> ------------------------------------------------------------------------------ >>> Find and fix application performance issues faster with Applications Manager >>> Applications Manager provides deep performance insights into multiple tiers >>> of >>> your business applications. It resolves application problems quickly and >>> reduces your MTTR. 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