right piece first time

[mc_91]

Hi all,

Recently we bought a new wire machine - what a curse!

 

Inspite the fact that we have all the manuals of the machine never succeeded to make a piece right for the first time. As far as i know it is a process of trial and error to make it right.

It makes the boss crazy...

Does anybody knows another method of working with this type of machining?

 

thanks for any suggestions.

[Müřlıń®]

Never ran a wire edm but alot of peeps in here have.

 

What kind of problems are you having?

 

Are they Mastercam related or machine tool related?

 

Sounds like its machine tool related by your question.

 

Do you have any EDM experience?

 

Murlin

 

[ 01-14-2004, 12:39 AM: Message edited by: Murlin ]

[crazy^millman]

Well I would give thsi for advice.

 

1) make sure you have the right wire and good wire.

 

2) I would make sure that you have a good flush on the head if it is a submerable.

 

3) I would make sure that the head is true and square as checked to the Angle plate test.(use to grind my own just to make sure they were nuts)

 

4) I would make sure that you have a cotnant voltage to the machien and that you are not gettign power flucations fro mthe street if so put a tranformer before the machien that helps reglate the machine.

 

5) I would check the guides and make sure they are ok.

 

6) If you are usign a water tanks make sure you got everythign at the right Ph and everything is working ok.

 

I have not wire in 10 years so I am sure there are thing others can cover better than me but hope that helps. I use to $5000 to $10000 parts frist shot no second chance and they were right everytime. Oh yeah these parts could have run for 40 to 80 hours with a couple wire reloads with no problem either.

 

Crazy Millman

[Lars Christensen]

Hi Gilsu,

 

1) Make and model?

 

2)What are you trying to do? straight cut,taper cut, angular start up, trying to cut special types of steels.???????

 

Most manufacteres have some kind of training classes for "new" edm people, it is worth sending a person to school for a week, if no one in the shop have any edm eksperience.

 

Lars

[mayday]

Wire EDM's are the toolmakers surgical scalpel. take your closest tolerance you do in standard metal removel and increase it 10 fold IMO. I have cut to .0001 (inch) tolerance without thinking about it. 2 things to remember, you have to treat an edm job with precision in every way. dont toss a part on it with unsquare edges,ruff finishes,dirt, ect and expect the EDM to make it all better.

and finally CLEAN,CLEAN,CLEAN, if you get the hint

[chad fisher]

Gilsu

 

Relax you will get it, theres a big learning curve if you have no experience in this type of machining.

I remember a few years back we bought one and i opted to run it, no one else here had experience with one, for the most part i had to throw out my basic machining experience i had to learn this. After a couple months i was feeling quite comfortable with thie style of machining and now i wouldnt trade for anything. Like otheres have requested tell us your make of machine and control style someone here will certainly be able to help. This place is full of curtious and experienced people.

[Brent Wilkerson]

Machine, Make and Model???

 

We have an Ona Prima S250 wire EDM we cut tools all day long. We mainly cut carbide with 0.006" brass wire, Gisco Megacut. We cut mainly all 4-axis, but we do cut some steel and straight/vertical every once and awhile.

 

Like Millman said use good wire, keep the machine as clean as possible. We use an ultrasonic cleaner with Xylomate wire EDM cleaner. We rip ours apart and clean it once a week. The guides must be kept up and good water and resin. We use to use DI water but our process water switched to RO water and the water actually has a lower conductivity then the DI water did.

[Reece L Gibson]

I treat it like a mill, put cutter comp in and take finish passes like a mill.Creep up on things.

We have Charmilles Robo 310, they have some real good training.They told when the wire starts burning you troubles are over, and when you use a sinker you troubles have just begun.The thing will just about cut anything.

[Müřlıń®]

How do you guys hold such close tolerances on a wire?

I guess there is less heat generated and so the dilethric will stay cooler, and since the wire feed is continious, you don't have to worry about electrode wear and can get overburn extremely close?

 

Best I ever did on a RAM machine was around + or - .0005. But that was on small stuff.

Large burns always moved around a little due to heat and vacume.

 

 

Murlin

 

[ 01-14-2004, 11:39 PM: Message edited by: Murlin ]

[Lars Christensen]

Murlin,

 

How many electrodes did you have??

 

When you are taking tolerances on the wire within .0001, you are talking "ABOUT!!" 5 passes. 1st pass will be within .003-.001 of geometry accuratsi. So go on a sinker and burn til your part is within .003-.001 and then have 4 brand new electrodes and burn with gradili lighter power settings as you go thru your 4 (trim) electrodes. Electrodes cost alot of money to make, at last place I worked, it took me 2 years to convince them that you can not have a rule that there is 3 electrodes for every job, no matter what the job is.

 

Lars

 

[ 01-15-2004, 02:20 AM: Message edited by: Lars ]

[Müřlıń®]

quote:

---

How many electrodes did you have??

---

6 copper poco on positive polarity to hold + or -.0005.

 

Oh ya, they were ground on the surface grinder and checked with a .0001 indicator for accuracy.

 

 

Murlin

 

[ 01-15-2004, 08:51 AM: Message edited by: Murlin ]

[Lars Christensen]

Murlin,

 

So your electrodes are within .0001, and on a new machine you should have movement within .0001, and your spark should be controled within .0001, so you should be able so get within .0003.

Now on the wire, they are talking linear geometry accuratsi. so each line segments is with in .0001, and as soon you are putting that wire in a taper cut, your repeatet accurasi just went bananas.

 

 

Lars

[mc_91]

Thanks for all your answers, but i want to clarify myself.

 

Machine is an AGIECUT 350 HSS and it is two years

old in perfect condition.

Most of the time runs a specific job and occasionally other jobs that can't treated other way.

 

Because of lack of experience, to make another job i must take machine manual recommendation. The problem is that never got the desired results. There is always some deviation from the requested dimensions.

 

My last nightmare was as follows:

 

One piece only. FINISHED PART=3500$.

Material: SAE 4340, heat treated.

 

Desired tolerance: 0.015 m"m

Superior surface finish.

 

According to machine manual:

 

make three passes with offsets as follows:

d1=0.308

d2=0.208

d3=0.168

 

Needless to say that part came out with a deviation of more than 0.35 m"m!!

Boss after heart attack...

 

Any thoughts what is wrong?

 

part was programmed according to the drawing.

 

TO BRENT WILKERSON:

May i ask what is an ultrasonic cleaner, Xylomate,ro water?

 

thanks for all.

[Müřlıń®]

gilsu, you might need to take a cut, measure, take another cut, measure....ect.

 

I dont know what dia wire you were using but .3 mm sounds like around .01" wire with overburn to me.

 

Maybe the CC was on the wrong side.

 

Murlin

[Lars Christensen]

gilsu,

 

It sounds like your offsets are good for 0.3 dia wire (0.012 inch).

Like Murlin said it sounds like your cutter comp. is screwed up.

In mastercam:

Do you have cutter comp. activated in control and in machine??. so you actully are double your cutter comp.?

 

I always use cutter comp in machine, in that way my code is norminal.

 

Ultrasonic Cleaner is a nice little cleaning device there is great to clean you guides with.

Your dealer should be able to give you some priceing on one of those.

 

Lars

[Brent Wilkerson]

Xylomate is a cleaner we use. We get it from Electrodes Inc.

 

http://www.electrodes-inc.com/

 

The MSDS for Xylomate is here:

http://www.electrodes-inc.com/msds/xylomate.pdf

 

R.O. water is Reverse Osmosis water...it's how the water is processed. Similar to D.I. water.

 

The Ultrasonic cleaner we have is a small heated ultrasonic tank.

 

Check out this site

http://www.lrultrasonics.com/

 

Check out these sites also

Tuf-Glide dry-film rust inhibitor and lubricant

www.sentrysolutions.com/tuf-glide.html

 

Parts and Supplies

http://riverport-edm.com/

 

Fixtures

http://www.hirschmannusa.com/

 

Fixtures

http://www.system3r.com/

[mc_91]

Thanks all you guys

I surely learnt something from each of you.

 

Special thanks to BRENT WILKERSON,

you are a great source of information - i'll check

all of them as soon as possible.