Some say lower wear is caused by fast on and off edges of pulse delivered. Not just at board but at gap. Loads of high tech literature to wade thru because its is plasma not standard I=e/r electric rules. But in practice... The new fet generators with good cables and low system inductance wear less than tube and r/c gnr8rs. I have moved the final power modules to the head and ran the base DC there to get the last bit of inductance/ resistance out. Oops rambling...
Pete_Gruendeman <[email protected]> wrote: >Hi again: > My comments on people getting experience with running an EDM is Not > directed at any one person. It's just that this art form is so different > from what most people have experienced in machine shops. Go play with one > and many of these mysteries will become clearer. > >> Or is there a better material to make the electrode from? >You'll be rich when you figure that out. Find a way to 3-D print an electrode >and you'll set the world on fire. Or 3-D print the heat-treated steel mold >cavity directly! > Many writers (not me because I don't know) state that electrode wear > occurs at the initiation of the spark and that the wear is due to heat at the > electrode surface that isn't conducted away fast enough. For those who > haven't seen it, that is likely why finish electrodes/ burns have such high > wear rates. They endure so very many more sparks than a roughing burn which > has sparks of higher power but longer duration so there are far less of them. > >Question: > Does anybody know the typical frequency or pulses per second for finishing > burns? I think it's on the order of 3-5kHz but will look into it of someone > doesn't already know. 40kHz servo response is very responsive but not > necessary if the spark frequency is less than that. > >Pete Gruendeman > >-------------------------------------------- >On Wed, 3/2/16, Gene Heskett <[email protected]> wrote: > > Subject: Re: [Emc-developers] EDM gap control (Control parameters) > To: [email protected] > Date: Wednesday, March 2, 2016, 11:38 PM > > On Wednesday 02 March > 2016 23:53:36 TJoseph Powderly wrote: > > > sorry Pete > > I > disagree, any time spent in the wrong position is time spent > making > > bad discharges > > which can damage surface by overheating > > or > > spend time > throwing snowballs that fall short of hitting the target > > imo, update postion as fast as possible > > the average velocity ( a RESULT) will be > low > > but the process will be more > stabile and the surface will not be hard > > and crusty > > abd the > time will be lower > > oops power fail in > ChiangMai > > ttyl8r > > > tomp > > One thing I have > always felt needed to be asked, but don't recall seeing > > it discussed, is when doing a sinker edm to > imprint a carbon mold like > I've seen > pix of, like engraving a relieved signature, is there an > optimum current per square, either in cm2 or > in2 to design the process > to so it > functions best? > > And in > terms of wear on the shaped carbon electrode, is there a > best > current per square in terms of the > metal removed vs the carbon wasted > that > will prolong the electrode life vs metal removed? I've > seen other > processes where optimizing one > is not optimizing the other. > > Or is there a better material to make the > electrode from? > > > On > 03/02/2016 10:05 PM, Pete_Gruendeman wrote: > > > Hi Nicklas: > > > > Correct that looping once per millisecond is > definitely fast > > > > enough. On my machine, 40,000 encoder counts = > 1 inch. Spark > > > lengths, even for > finishing operations are 0.001" or longer, or 40 > > > encoder counts to go from first spark > to the electrode making > > > physical > contact and that's in 1/25th of a second. That's > not a > > > problem if the machine is > moving at 2- 4 inches per minute. At 4 > > > IPM, coming to a stop in 0.001 inches > requires an acceleration of > > > > -0.01852 feet per second squared or -0.00058 g's of > acceleration. > > > No problem. > > > > > > The > other axes would be the same in that gap voltage/current > > > measurement at 1,000 times per second > is plenty fast enough. In > > > fact, > the program I wrote upon detection of gap voltage too low > > > waits on location for 10 milliseconds > and then checks again as often > > > ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
