Should I build a submersion tank for this Agie DEM 250?

Hello all

I recently started working on this old Agie DEM 250 doing some simple straight path cuts through carbide. Looking for some advantage, because this machine is eating time and wire.

Right now I'm cutting through these carbide blades which are just an 1/8" thick x 4.5" long x about 1.25 tall piece of carbide with a 25 degree bevel along the length of one side, which makes the cut around .300"

The blades come in all chipped out and so the cut is about .030-.050 deep into the material.

Cutting with .012" hard brass uncoated wire, and it takes 2 hours to make a pass. Babysitting it is fine, but it's eating 20mm/sec of wire.

Is there some way I can juice this up, or is this an acceptable speed for this machine?

While standing around, I hatched a genius plan to submerge the whole working area with a removable plexi enclosure that would drain out into the pan which collects the water right now.

I believe this machine has a submersion tank somewhere but I got a very cross reply when I asked about it. Maybe the old man bumped his elbows on it too many times and never wants to see it again? More likely, he broke it doing something in his constant panic state and doesn't want to think about it.

Either way, I have a great idea and would totally like to build a fish bowl for this EDM machine, if it's going to improve the speed.

Will it?

some things to consider

Hi apestate;
How are you orienting your parts in the worktank?
Unless your Agie is a tilt-head machine, your flushing will be very poor at extreme angles, which really slows down the cut.
I've found at times, counter intuitive though it is, that standing this kind of workpiece on end and cutting it as though it's 4.5" thick gives me the best outcome with the fewest problems and the best finish and precision with the least waste of wire.
Another (though not as good for flushing) option is to tilt the workpiece so the wire does not have to tilt; the idea is to keep the wire and the water flow aligned if at all possible.
The water will want to shoot down the angle of the workpiece top surface, so you have to turn it DOWN, not up if you want lots of water in the kerf in a non-turbulent state. (Turbulent water is a bad thing; it makes the wire flap around and introduces air into the kerf where you want smooth cool water.)
An alternative is to build your jig with a flat top and a slot for the wire to avoid this problem.
Submerging the work is always good if you can do it, but it won't help you enough if your water flow through the kerf is badly deficient.
Build the tank by all means...it won't be wasted work, especially if you cut stuff like tubing or honeycomb aluminum.

Regarding your rate of progress; if the machine does badly on all cuts, (even the ones that flush well) you have a machine problem; likely a maintenance problem.
Two basic areas to check are the state of the power contacts and the state of the discharge cables.
Another good place to check is the quality of your water.
If all that checks out, time to probe the electronic guts.
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

Is it possible you mean 200mm/sec?

+1 to Marcus' reply; if you're just cutting the bevel, and this is a common job, I'd say fixture the part to match the wire instead of tilting the wire to 25 degrees.

apestate,

I've got a DEM-315, which from what I understand is essentially the same machine, just with slightly greater U-V travel on the upper head. I looked into flooding the main tank, but came to the conclusion that there wasn't enough volume in the clean water tank to handle filling and emptying the worktank without adding some supplemental tanks. Definitely doable, but like others have said, it may not be of that much help in your application.
From reading your description, it sounds like you are essentially cutting off a .030-.040" strip from these carbide blades. Is this correct? If you know you will be doing lots of these, you might want to build a jig that surrounds the area of the cut, essentially turning your edge cut, into a cut out of a larger flat area. This will let you get much better contact with the flushing cups, and really crank up the pressure. This will help a lot in cutting speeds. The other thing to monkey with is your wire speed. I'm not sure if my machine is running 100%, but I've found that in quite a few cases, I get the best cutting speed with the wire running between 60-100mm/sec. Any faster and it actually slows down the cut. Seems counter-intuitive, but has been pretty consistent on my machine. (Was very nice when I discovered I could cut my wire costs in half with same or better performance.)

Yeah, I have the part oriented at 25 degrees and the EDM just runs in X through the material, taking off a slice and thus sharpening the carbide blade. The cut is 4.5" tall, but only .300 or so in X

25mm a second, actually, wire speed.

your machine seems very slow

Hi apestate:
2 hours to make a cut 0.300" long even in 4.5" thick carbide seems way too slow to me.
I've never cut carbide that thick, but my carbide cutting condition tables show an expected rate of 1.2 mm per minute in 50 mm thick carbide, and they're usually pretty good at predicting cut times.
That would make me able to cut a 2" tall blade in under 10 minutes.
Mind you, my machine is brand new (vintage July 2011) and is submerged, and I'm cutting with 0.010" wire.
So, is your machine slow when it cuts steel too?
What kinds of cut speeds can you achieve on say a 1" steel block with 0.010" wire and ideal flushing conditions?
If you can tell us that, I'm sure other Agie drivers out there can tell you if that's a decent speed or if your machine is barfing.
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

If you can, I'd say you would be better off fixturing the part so that the .3" is aligned with the wire, and the 4.5" is your cut length in X (or Y). Cutting the edge off of a block is not considered "Ideal Cutting Conditions" at any height, but the shorter the distance between your guides, the better off you'll be. It may seem counter-intuitive, getting a faster cut from the longer travel, but think about the same kind of cut at the bandsaw - you wouldn't stand a thin piece of material up on end to cut the edge off, (unless you couldn't get a fine enough pitch for the thickness of the material...) and the wedm is no different. You may have to build a little fixture, if you don't have some tooling that will easily hold the blades that way, but it would still likely be simpler than building the 'tank' that you're toying with.

Here are a couple of ways I might hold something like that:

Thanks for all the replies, everyone...

I'm just stepping into the EDM world and this is the first job I get to work on. The set-up idea is kind of a hand-me-down from the owner, but I could flip the part over 90 degrees after about an hour of setup.

Right now it's just load and go, every 2:20.00

This '81 Agie is certainly puking, you should see the hole we're trying to dig this shop out of. The old EDM is making some (was, wire just broke) money ...

I'm sure there is a world of learning about EDM before I contemplate anything like building a submersion tank... but even if I did, would we expect to see much improvement due to submersion, above and beyond fixing all the normal stuff you'd expect to be maintained?

If I recall correctly, the DEM 250 was rated at 1.5 sq inches/hr maximum cut speed when it was new. That is cutting with .010 inch wire in 2 inch thick D2 with ideal flushing conditions. Carbide was always much slower even with ideal flushing.

As I recall, the DEM 315 went up to 1.7 sq in/hr with the "adaptive control"... DEM 315 also performed slightly better in carbides.

Hey, it was state of the art in 1981!!!

Greg

You will not gain anything cutting submerged. The Dem 250 with speed set ( forced flushing nozzle on lower flush box with seperate valve and pressure gauge) cut 2.0 square in/hr. in Steel. It was much slower in Carbide. Is the machine original or Fast-tracked? Fast-track will give you forced flush from top and bottom and get you speed up into the 8-10 square in/hr range. The wire speed cannot be 200 mm/sec it maxes out at 160. It is important to know that speed vs. thickness is not directly proportional. Twice the hight will not cut 1/2 the speed and half the height will not be twice as fast. As the thikness goes up over 2in. the speeds will drop considerably. Thinner is much faster. You need to increase the flush to get more speed, submerged will keep the splashing down. you can accomplish that with some foam or plexiglass sheets. Make sure you set the part up to cut the thinnest height. You also might want to try taking six cuts only .005in deep vs. taking all .030 of in one shot. Hope this helps.

Would you please call me ( Larry ) at 801 636 8405 Thank you

Would you please call me ( Larry ) at 801 636 8405 Thank you



W

apestate said:

Hello all

I recently started working on this old Agie DEM 250 doing some simple straight path cuts through carbide. Looking for some advantage, because this machine is eating time and wire.

Right now I'm cutting through these carbide blades which are just an 1/8" thick x 4.5" long x about 1.25 tall piece of carbide with a 25 degree bevel along the length of one side, which makes the cut around .300"

The blades come in all chipped out and so the cut is about .030-.050 deep into the material.

Cutting with .012" hard brass uncoated wire, and it takes 2 hours to make a pass. Babysitting it is fine, but it's eating 20mm/sec of wire.

Is there some way I can juice this up, or is this an acceptable speed for this machine?

While standing around, I hatched a genius plan to submerge the whole working area with a removable plexi enclosure that would drain out into the pan which collects the water right now.

I believe this machine has a submersion tank somewhere but I got a very cross reply when I asked about it. Maybe the old man bumped his elbows on it too many times and never wants to see it again? More likely, he broke it doing something in his constant panic state and doesn't want to think about it.

Either way, I have a great idea and would totally like to build a fish bowl for this EDM machine, if it's going to improve the speed.

Will it?

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