sinker / ram EDM

[AshM]

HI all,

 

I'm looking into the prospect of a new sinker / ram EDM machine. I don't rate my knowledge on these machines but at the moment the stand outs are:

 

sodick?

mitsubishi?

makino?

 

no particular order there...

 

I'm looking for a quality machine which we can load up with parts and electrodes and let it run, so a toolchanger is essential. Currently we have a machine with automatic pecking, but only manual positioning and manual tool changing, so it really doesn't do much for us...

 

thoughts? suggestions?

[Oppiz]

We have a Mitsubishi VX10. We bought new almost 10 years ago. Its been a great machine. It is very versatile and easy to program. I wish we'd bought the optional toolchanger.

[AshM]

thanks for the comment. what sorts of materials do you cut with it? One of our aims is to be cutting carbide with this machine and I'm not sure if this should be a factor in our machine choice....

[Redfire427]

AGIE / Charmilles make a great line-up of sinkers. I have used them for roughly 15 years and had great accuracy and reliability.

http://www.gfac.com/gfac/products/products-details.html?tx_agieproductdb_pi_navigation%5Bmodel%5D=productgroup&tx_agieproductdb_pi_navigation%5Brecord%5D=2&cHash=32a09887da23739f976900b3841a398b

 

Carmen

[Oppiz]

thanks for the comment. what sorts of materials do you cut with it? One of our aims is to be cutting carbide with this machine and I'm not sure if this should be a factor in our machine choice....

 

I cut mainly tool steels and some carbide. We purchased our machine with the optional SP power supply. This is for fine finishing in carbide. If you take you time and use the correct flush and number of cut it burns carbide to almost a mirror finish. I'm sure the more resent machines burn even better.

[AshM]

Thanks guys,

 

I've been in touch with the local guy who distributes the AGIE machines in Aust, and I am going to go and have a look at one soon. For the Mitsubishi machines I have called and left messages with a few Mitsubishi offices to find a distributor and I am waiting to see if anyone gets back to me.

 

Like I said before I know very little about EDMing. Are you guys using Copper/tungsten or graphite for electrodes? We have only used CT becasue its clean to work with but we are getting horrible finishes in carbide. We are trying to burn a 1mm x 60° leadin / chamfer on a shaped hole in carbide but we typically only get 1 or 2 parts per electrode before we need to remachine it. We have tried all sorts of things on the machine but haven't improved this much, which is why we want to look at new machines.

[Kevangel]

I have never EDMed carbide but there is some ref. material out there.

http://global-plastic-injection-molding.com/how-to-edm-carbide.html

[disciple]

There are many techniques for different materials. it has been a few years since I have done any EDMing, but when I did it was primarily Charmilles for fine finishing and Mitsubishi for roughing/finishing. My only experience is with several grades of stainless steel, but I do know that when using copper electrodes vs. graphite electrodes, we had to change the polarity for proper finishes, electrode +/part -, and vice versa. We used several different grades of graphite as well, including copper impregnated, which I believe was called C3. The company Poco Graphite (www.poco.com) was our source when I lived in California. Don't be afraid to call suppliers for advice, they're usually happy to help. Also, 1-2 electrodes per part doesn't sound unusual to me, depending on the amount of material removed and finish required. I've made parts that required 4-6 electrodes for ultra-fine detail and surface finish.

[AshM]

Hi and thanks for the advice. It seems to me the more I learn about this the more I realise how little I know...

 

Another question, from looking around I've found the EROWA and System 3R systems. Are these the big 2 or are there others I havn't found yet? Does anyone think that there are advantages in one over the other? This seems like a major commitment to me, as much as a machine itself, because I need to tool up more than one machine for these systems to be effective....

[Kevangel]

I have a mixture of 3R and a company called sunspot. I have bought all mine at auctions online... Think new it adds up to 12K to 15K and I have around $1,500 in it. I only have 4 conventional sinkers, no CNC yet.

http://www.sunspotedm.com/

 

Just because electrode material costs more does not mean it will burn faster...buy some real expensive and some cheap stuff and run some tests..it might be a real eye opener..you can machine finer details on the denser material. Lots of ways to skin the cat.

[Redfire427]

Erowa and System 3R are the most common fixturing systems out there. More so the 3R. Another high end brand is Hirschman http://www.edm-products.com/9000.htm

 

No matter which system you use, it is VERY spendy.

 

Carmen

[Del.]

Erowa and System 3R are the most common fixturing systems out there. More so the 3R. Another high end brand is Hirschman http://www.edm-products.com/9000.htm

 

No matter which system you use, it is VERY spendy.

 

Carmen

 

 

Way overpriced but I have some of both.

[AshM]

I have never EDMed carbide but there is some ref. material out there.

http://global-plastic-injection-molding.com/how-to-edm-carbide.html

 

I have just followed this link again and noticed this recommendation for SEDMing carbide

 

"Use tungsten carbide for you electrode. You will most likely need to WEDM this, or you can machine it, but it is not so machinable."

 

WEDMing carbide is straight forward enough, but I've had no experience machining it for electrodes.... hard carbide is practically impossible, but I asked around and some people are apparently using a mold to preform carbide into a shape from a powder form under pressure, then actually machining the carbide to accurate sizes before sintering.... I guess it would be like a super abrasive cast iron.... this was news to me, but I'm struggling to find any info about this process, or if it is real. Anybody ever heard of this before?

[Kevangel]

I have just followed this link again and noticed this recommendation for SEDMing carbide

 

"Use tungsten carbide for you electrode. You will most likely need to WEDM this, or you can machine it, but it is not so machinable."

 

WEDMing carbide is straight forward enough, but I've had no experience machining it for electrodes.... hard carbide is practically impossible, but I asked around and some people are apparently using a mold to preform carbide into a shape from a powder form under pressure, then actually machining the carbide to accurate sizes before sintering.... I guess it would be like a super abrasive cast iron.... this was news to me, but I'm struggling to find any info about this process, or if it is real. Anybody ever heard of this before?

As far as I know they make a die(mold) to the shape of carbide blank they want (think carbide inserts for your lathe) and then put the powder into mold to form insert in the sintering process. You can grind carbide with a diamond wheel. I know some folks spend around 15K for a wheel. I spend around $150 for surface grind wheels with diamond impregneated. My last Charmille edm came out of a sintering powder metal shop that closed and amazing the almost mirror finish on some sample parts laying around that been sintered out of powder metal. Very cool process and tooling was beautiful..went broke..

 

http://www.todaysmachiningworld.com/how-it-works-%E2%80%93-making-tungsten-carbide-cutting-tools/

they only talk about honing,grinding or edming it.

[AshM]

The process that has been described to me is to make carbide parts and other complex components in a 'soft' state before the sintering. So with this process the carbide is pressed together, but not sintered so that it is not yet hard and still workable, then it can be machined... drilled, turned, milled or whatever...

 

I found this

 

http://www.allaboutcementedcarbide.com/03.html - where is a mention of soft machining between compaction and sintering....

 

regardless, I'm going to give up on this tangent, I'll stick to using Copper Tungsten for electrodes.... I just got facinated by the thought of using carbide to burn carbide....