Ok guys helps me out here please. Last week I order Megacut same as I have for ....years.
Today we recieve Bercocut "Special" I tell purchasing agent, not the same and I don't know if it will perform the same.

He calls saleman, saleman say "Oh they are the same thing."

I check bedra website. Um don't know about all that. Special looks like AGIE wire, 900 is for Mitz/ Jap machines. So before I make yet an even larger ass of myself, Would the good brotherhood of WireEDM enlighten me. Same or Different? I have a natural distrust for salesmen, yet even more importantly, hate to be proven to be, ah ... errr, ....wr.. wrong.

Thanks,

Dave

if i don´t mistake they are not the same, one is zinc coated and the other plain brass, the zinc coated wire is more suitable for hard metals and also for good final surfaces the other is an average wire for all purposes, in addition if i do not mistake again , the zinc coated wire should go faster than the other.

Sorry Roonie.

On this one you’re mistaken. Both of the wires Wired4life was asking about are uncoated, plain brass. My reply to him will explain.

Hi Wired,

If you were previously using MegaCut 900 and you received BercoCut 900 instead, you can go ahead and use it. The 900-suffix denotes tensile strength in N/m2 (900 N/m2 = 130,000 psi). In the case of these two wires, their chemistry, tensile strength and elongation are the same, while the BercoCut 500 and 400 have been annealed and are used for taper cutting. If you need a paraffin-free 900, try BercoCut "Grip".

OK, that should answer your Berco/Mega question, but this should only stimulate the next logical question of, "Why would anyone make two 'identical' wires?" (And label, package, stock, ship and track them all separately?) A good question but the answer is weak... it’s because of an old standard for wire diameter tolerancing.

BercoCut brass in all iterations was originally made for AGIE and was neutral toleranced at +/- 0,001 mm (.000039") because of their open & close, adjustable V-guides. The MegaCut-series was designed for Japanese machines with closed, round guide systems. The MegaCut-series wires are therefore toleranced negative at + 0,000 mm (.00000") and - 0,002 mm (.000078"), to increase the wire/guide clearance needed at the time to increase threading reliability. The tolerances above are for plain brass wires. Coated and diffusion-annealed wires are produced to slightly larger but similar + and - tolerances.

"Not getting a wire stuck" is the most commonly heard street and sales explanation for negative tolerancing. Maybe so, but over the years I have probably seen almost every machine and wire combination possible and I have never encountered or been made aware of a proven problem caused by a “Swiss” wire “getting stuck” in a “Japanese” guide (No, Greg in Utah… you can’t run .010” wire through .008” guides).

To my knowledge, Bedra (formerly Berkenhoff) is the only draw mill that produces EDM wires toleranced this way. Example: CobraCut D (for Swiss machines) and MegaCut D (for Japanese machines) are also identical and interchangeable except for the wire tolerance (and spool-type, DIN or P). If the “stuck wire” explanation holds true, then I’m curious to learn why don’t all of the other mills throughout the world who don’t do negative tolerancing, experience an inordinate amount of "stuck wires"? Anyone? Hmmm… makes ya think.

With everything today so focused on cost-cutting and efficiency, one would think they could economize a great deal by consolidating their viable wires and eliminate their duplicate wires for different OEMs. From there, deciding upon a single, common tolerance for all wires would reduce the not-small costs inherent in keeping and maintaining separate draw die inventories, route slips, labeling, packaging, inventory, tracking and handling, not to mention the extra sales, advertising and marketing costs for these “different” wires.

I don't know... it’s been over 4 years since I’ve been through a draw-hall and maybe all this has changed. Perhaps someone in the wire-making business can tell us more?

Bud

Hi Bud,

i am amazed with your knowledge about edm wires, evenhow i have quite doubts and i would like to make you some questions...
In the brochures i have it says Megacut is zinc treated, it doesn´t mean it is zinc coated?
paraffin free wires... which is the difference with another one with paraffin? are they better?

Thanks in advance for your help.

Roonie,

The "MegaCut" term relates to an entire family and line of EDM wires. The MegaCut name refers to wires designed for Japanese machines, whereas the CobraCut name refers to wires designed for Swiss machines. As Bud has noted, these two distinct wire families made by Bedra have differences in their manufactured draw tolerances and standard spool/bobbin type (P or DIN).

I will take a stab at you questions about zinc in the wire...ALL Brass and Coated wires have zinc in them, but their zinc content can vary. For example, plain brass wires typically range with a zinc content between 37% and 40%. These different zinc amounts change the wires characteristics, and in general, the higher the zinc content, the faster the machine will run...but there is a distinct cutoff. As the zinc content increases, the wire can become weaker and more prone to wire breakage.

If you are talking about MegaCut Brass wire, this wire was produced with a 37% zinc content. There are also many different types of coated wires, such as MegaCut-A, MegaCut-D, and the Topas line. These coated wires contain different levels, coatings, and phases of zinc enriched brass, and are manufactured by different methods.

As for your Paraffin question...paraffin is a type of wax that was required and needed for many older Wire EDM machines. This wax acted as a lubricant for the wire guide system and prevented wire seizure within the guides due to wire galling.

-Brian

Nice to hear from you again,
one more question, understood the difference betwenn Megacut and cobreacut (japanesse/european) but....
What is it for when the wire is zinc coated? is it just to improve external appereance? or has it got any other application like help for wire kinematic?
Is it better than cupper coating?
why the simpliest wire (just brass) is the best ,as far as i concern, when you are looking for very very good final surfaces? i s there any fast caoted wire suitable for good final surfaces?

Best regards

The zinc coating helps to flush out the slot. For a good coated wire that gives a good surface finish we use Cobracut G

Hi Roonie,

Brian did a good job of explaining the MegaCut series of zinc-coated and diffusion annealed wires. I’ll address your mention of “paraffin-free” wires.

Not to be confused with fine-wire EDMing (cutting with .1 mm (.004”) dia or less), fine-wire drawing is the process of reducing 1 mm (.039”), EDM “draw-stock” or “pre-material” down to it’s final diameter and spooling. Depending upon the wire-mill and type of wire being drawn, a .010” diameter EDM wire typically undergoes 18 to 22 reductions of the wire and several annealings.

In front of each draw die is a small, hand-sized container or “boat” that is filled with various lubricants of paraffin waxes, soap-flakes and even animal fat, although the generic term for any such lubricant seems to be paraffin. The EDM wire is drawn down through the top of the open container of paraffin and exits through a hole in the bottom before entering the draw die. After drawing, the wire is quite warm from friction and deformation and as it enters each successive boat, it melts the low-temp paraffin and wets the wire to act as a lubricant for the next reduction. This lubrication process is necessary to reduce drawing tension, extend die life and reduce linear scratches and galling on the drawn surface.

However, even after being squeegeed off under tons of pressure from the final draw die, a tiny amount of paraffin remains on the wire’s surface. This proves to be just enough and is necessary to help insure smooth final spooling at the factory and reliable unspooling in use. It also helps prevent tangential scratches on the wire during both (and explaining that paragraph is a whole ‘nuther post).

Earlier wire delivery systems used flexible belts and/or plastic, rubber, cloth, phenolic, Delryn and urethane wheels and rollers. These “soft” driving surfaces deform slightly and “wrap around” the wire as it imprints itself into the pliable surface under tension, producing more surface area and traction. The microscopic residual of paraffin on EDM wires didn’t affect these drive systems and was never an issue until new wire delivery and retrieval systems appeared using hardened steel or carbide pinch rollers for longer life and less maintenance. Some of these new systems quickly encountered wire-feed problems.

The combination of the residual paraffin on the wire and the hard, slippery surfaces and low traction of steel and carbide rollers of some systems caused wire slippage, drive and threader failures and feeding malfunctions with wires that performed successfully on earlier machines. Users were understandably unhappy with their new purchases and for a short time, blame was exchanged between the wire-mills and the OEM’s until after uniting for a solution, each made corrective actions to their products.

One involved setting up new wire cleaning or treating operations at the wire-mills and resulted in the unplanned “creation” of several “new” lines of “paraffin-free” wires (“Necessity is the mother of invention”). The other was the affected OEM’s replaced slipping drive rolls with ones with larger diameters (increasing surface area), hard urethane wheels for traction, or ceramic rollers, which are still very hard and long lasting, but experience less slippage than steel or carbide ones.

Finally, and don’t sue anybody for false advertising, but I’m not aware of any EDM wire that is actually 100% paraffin-free (clean)… just clean enough not to slip. Producing a truly 100% clean and paraffin-free wire for EDM would be unnecessary, too expensive and could very likely affect reliable spooling and unspooling.

That’s my 3¢ worth (2¢ adjusted for inflation)

Bud

Thank you bud for your complete replies