What die sinker to get?

[Klox]

Guys,
I'm considering getting myself a Spark Eroder (Die Sinker).
Please enlighten me on ALL aspects, for example manufacturers, conventional vs cnc vs znc, etc, etc.....
Orbital heads pro's and con's, etc, etc......
Amps, travels, etc, etc.....



Thanx a million,

Klox

[Klaus]

What type of work do you need the die sinker for and what is your budget?
The choice of machine will depend hevily on the above.

[Klox]

Klaus,
Sparking square holes of about 20x20x20mm in 316 Stainless with tolerances of 0.02mm.
Keyways in blind holes 6x6x50mm, 8x8x50mm & 12x12x50mm. Key ways in holes (also 316 Stainless or En 57).
Splined holes in couplings up to a diameter of about 2 inches and about 1.5 inches deep.

I would like a full on CNC sparker, but it's expensive. I thought on getting a ZNC machine with an orbital head (maybe?).
I don't know exactly what the pro's & con's is on an orbital head and would appreciate ANY inputs.

Then another possibilty on sparking small components for injection tooling as well.

I know it is difficult to get an all rounder package in any machine but if i can spark relatively diverse it would pay to get a spark eroder rather than sub contracting work.

I see that there is machines from Joemars (JM430+AZ75). Taiwanese machines, do you know these machines? I know that Charmilles also manufactures Spark Eroders, as well as Euro Cut, Hurco etc. Please enlighten me on any of these brands regarding spares, support etc.

Thanx,

Klox

[Klox]

Klaus,
Sorry I forgot one (or more) crucial question how does Spark Erosion rates compare to Wire Erosion rates. Also material removal rate, how do i calculate it? Some sort of rule of thumb?

Thanx,

Klox

[CAMmando]

A couple of comments …

The shop Im at now has only an old Manual Eltee Pulsitron sinker. It is a work horse and its fine for most of what we do. We just don’t do enough to justify an expensive new cnc sinker. For the keyways and such a manual machine is fine.

We have done internal involute splines in hard materials on our sinker also … BUT … burning splines to spec tolerance (checking with qualified go / no go gages) on a manual sinker without good orbiting capability is no easy task. The electrodes have to be perfect and it usually takes an iteration or two to zero in on the precise sizing of the electrode. Here we cut the electrodes on a wire EDM then test burn and cut another with more or less wire clearance and test burn again. Once the size is licked in we make a bunch of electrodes and run the job.

On a cnc, you can make the trode slightly undersize and orbit out until the spline gages properly.

Erosion Rates will vary between newer and older machines due to power supply and servo / feedback technology. Since the “electrode” in Wire EDM cutting is so narrow, speed is generally measured in mm^2 / hr or in^2/hr which is the length of cut x workpiece height. This is surface speed as opposed to “volume of material removal. Therefore comparing removal rate is sort of apples and oranges. In wire you usually cut a perimeter and drop a slug where in sinking you burn the whole slug (usually).

For a sinker you would calcuate volume of materal to be roughed, vol to be finished. Use rates based on various factors.

You can look at some of the different sinker manufacturers data to get an idea of removal rates.

The key factors are:

-workpiece material class (Steel / copper / carbide etc.)
-electrrode material (graphite / copper impregnated graphite / copper tungsten etc.)
-Surface finish (BTW - Newer generation edms are capable of surface finishes that old ones couldnt dream of.

[Klox]

Thanx for your inputs CAMmando! Yes i am planning on cutting the electrodes(copper) on my wire edm. On cutting speeds & stuff for the wire edm i'm souped up. The sparking edm is a bit of a new ball game to me as it has been 14 years since i worked on one and at that time "productivity" was just a word in the dictionary. I was also very young at the time and did not have "interest" in EDM processes......

Klox

[StampCraft]

Klox, what size are you looking for? I use a Charmilles E10 with microfinish, it has a 25 amp power supply and it's a benchtop. We ought it new 76' and its great for doing small precision die and mold details.These machines canbe picked up for around 5k to 10k depending on it condition, I too use Bobwire to cut my electrode and its a good buy. Jim Jacobs.

[Klox]

Jim,
I was thinking to get something in the line of a 50-75amp ZNC type with an orbital head. I can get new Taiwanese machines in the region of about R200 000 (about $27000). I'll rather get one a bit too big for now than a smaller one that i would "outgrow" within a couple of years.
Used Sparkers are a bit scarce in my neighbourhood, the ones availible are "FUBAR"!
Yes the Swiss machines are very good quality but a bit beyond my reach for now......
I always say when people ask me on the capabilities of BobWire, "there's a tiger in every BobCA(T)D"!

What wire eroder do you use?

Thanx for your inputs,

Klox

[StampCraft]

Klox, I use Agie wire edms. They're old, but they still hold a few tenths when needed. I have a 73' dem 15 and a 77' 15/30, I program them with Bobwire 10. Glen is currently writing a backpost file to convert my old Agie programs to a drawing file. So far he's done a fine job and is very close to solving my problem. I will probably update to Charmilles 4020si or another Agie. So, you might check out some of the used dealers like Hycon, Edm Network, Peak EDM, Mcwilliams, Machinery Values and there's alot used dealers here in the states.
Your on the right with swiss made products, I'm not familiar with the brand that you are looking at. I just know from having an Agie 45L and a Charmilles E10 that they're still running after all these years. Jim Jacobs ("BobCad/Bobwire Rocks"!!!!!)

[Klaus]

Klox,

Stampcraft is right. We use Agie wire cut and Ingersoll spark eroders here. You will be able to continue getting accurate output from these machines for their whole lifetime. And what about spare parts? We still manage to get spare parts for our 20 year old Ingersoll machine. Does your Taiwnese supplier guarantee accurate output and spare parts supply for the whole life time of the machine. It's best to think long term.
If you are not willing to go for a new machine, why not go for a reconditioned one. There are a lot of dealers and even the original manufacturers (Agie, Charmilles, Ingersoll) supply them.

[Klox]

StampCraft,
The Swiss machine prices are not outragegiously more than the Taiwanese machines.....
I'm waiting for a few quotes. I'll keep you guys posted.

Thanks again for your inputs.

Klox

[Klox]

It looks like it's going to be a close shave between a Swiss machine & a Taiwanese machine.....

Klox