Fanuc EDM questions

Hello everybody. I recently got hired at a shop that needed a toolmaker. Now my skill level is def not where it needs to be for this job but I told them I would do my best and try. I have never used an EDM but I am pretty good at figuring stuff out by reading manuals and looking things up on google and youtube. I can get the EDM set up and running but somedays i really struggle to get a consistent cut. I think its because I dont have the right settings like on and off time, servo voltage, water flow, wire feed etc etc. I generally run 1/2 to 1/5 the feedrate that the FAPTcut software spits out for the type of material im cutting. Is this normal? Also been having issues with the wire breaking constantly. They tell me the guy that was in the shop before that quit on them was generally able to keep the machines running 24/7 but I dont know how to do that yet.Does anyone on here use the Fanuc robo series wire EDMs? I would really love to pick some veterans brains and get some answers on a few things. Thanks in advance.

Good morning HelpImLost:
You are asking questions for which there are no short or easy answers...basically you want to get an on-line wire EDM course on your particular machine, and we don't even know yet what model of machine that is or how old and tired it is.

However, there are a few general principles which do apply and may help you.
1) Successful wire EDM depends probably more than almost any other metalworking process, on keeping the machine in good condition and if any aspect of maintenance is neglected, the machine will reward you with crappy performance that manifest as frustrating wire breaks, shitty inaccurate work, and slooow cutting.

As soon as you say you cannot use factory settings, that's the very first thing I think of, and sadly, it's a BIG topic.
There is an interdependence of factors...wire EDM is like juggling a dozen plates at a time and all things must fall within a narrow range or the plates drop and the cut stalls or the wire breaks.
A comprehensive maintenance check involves some of the following:
a) are your power contacts good? ditto for discharge cables
b) is your DI system good; fresh resin, clean water in the proper conductivity range, clean filters, proper temperature control etc etc?
c) is your spark generator generating the correct conditions?
d) is your wire drive system working properly?
e) is your motion control system working properly?
f) is your gap sensing circuitry working properly?
h) Etc etc.

2) Cutting successfully depends very much on maintaining good cutting conditions and there are several influencers there too.
The principal one is the ability of the machine to keep the kerf clean, flushing pressure matters as does the position and condition of the flush cups, and the thickness of the workpiece.
How far the flush cups are from the upper and lower surfaces of the workpiece influences how much of the HP water actually makes it into the kerf, so obviously a workpiece that's flat and parallel within close limits allows you to sneak the cups up real close to the part surface, whereas a large gap anywhere means you have to compensate by changing cutting conditions to help preserve the wire from breaking and allow the crappier flushing to still be good enough to get through the job.
Which things to change and by how much depends on the machine and on the job, so it's complicated enough to be impossible to write a general prescription for...experience is the only teacher here, so all must permit you to play and fail until you figure it out for your job and your machine.

3) When it comes to the subject of running unattended; it's all about process planning:
Things like dropped slugs, location of start holes, tabs and cut sequence are all important, so you need to get good at visualizing what the machine is going to do while you are away from it, and anticipate potential problems so you can plan around them.
This is the other hard part about wire EDM, and as before, experience is the only teacher.
Obviously it varies tremendously from job to job, so again there is no general prescription.

So you have a steep curve ahead of you, all must be patient with you as you learn this.
If I was you, the first thing I'd do is satisfy myself the machine is in good condition; a professional Fanuc tech overhaul is not a bad way to do that.
If there is something wrong, a good overhaul will pick it up and correct it...once that's done you can be confident that if it's not working it's because of your fuckup rather than something wrong with the toy.

Talk to the Boss Man and ask...make a couple of days of training part of the overhaul and you'll be a long ways ahead without so much pain.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

My Elox/Fanuc is much older than your machine and I am no expert but for whats it worth water condition is critical. If I try to run a part after the machine has not been used for awhile it will almost always break the wire. Run the filters for a few minutes and it works ok.
bob

If you are in Minnesota the Fanuc EDM dealer is T. Bryce Machine I am sure they would be happy to help you with your questions.
T. Bryce Machine 763-449-9900 or contact [email protected]

Yeah unfortunately all of the places around here will not send a tech out. Ive already told the boss that im 98% sure the reason being is that the machine hasnt been maintained in months. Filter lights came on yesterday, the electrode pins havent been checked in the 2 months ive been here, none of the day, weekly, or monthly maintenance has been done since ive started because " we are too far behind to be messing around with that" like legit im about to quit because its super frustrating to spend 2-3 hours of my day rethreading the machine for the 100th time that day. Ive never used one but ive worked in shops with them and I know that the maintenance and water conditions are a huge part and Ive been trying to tell them this but they are so concerned with getting caight up they just dont seem to want to listen. Thanks for the responses peeps

Hi again HelpImLost:
OK if this is the reality of your situation then there will be no harm in taking the initiative yourself and seeing if it gets you fired or not.

First thing to do is to find the power contacts and index them.
I've never driven a Fanuc so I don't know where they are on your machine or how to index them, but you can find them if you have the manual.
If your machine is anything like mine, it's a 15 minute job and of all the things that negatively impact performance, it's one of the big ones.

The second thing to do is to check if the DI system works.
To do that simply, find the conductivity probe and short across the terminals with a screwdriver while the machine is on.
If your conductivity gauge reads resistivity it should drop to zero and the DI pump should turn on.
If it reads conductivity, it should rise to infinity. (and the DI pump should turn on)
(Not all machines read the water condition the same way so the reading will change accordingly).

Next, assuming your Dickhead Boss actually has resin in stock, change the resin.
Your conductivity meter will tell you if it can still maintain the proper DI water conditions; the key here is to see if it changes when you cut anything.
Take a chunk of scrap anything and do a test cut to see what happens to the water conductivity when you load it with ions from the cutting process. (or just piss in the water tank, but that's kinda frowned upon!)
If the DI system turns on and runs continuously and your conductivity is still going up, your resin is shot.

BTW sweat the filters less; many machines will shut down if the filter pressure goes up too high and will force the issue for you.
Also if you overpressure them and blow them out you won't be able to keep the water even remotely clean and it'll become so obvious even Fucknuts will have to concede it's not gonna work.

Next, stick your finger in the worktank a few times during your next longish cut.
If the water is getting warmer your chiller is fucked.

Next do whatever you have to do to keep from getting so many wire breaks.
At the control, there will be settings you can modify on the fly.

When I have a bitchy job to get through the first thing I do is turn down the nominal feed rate. (note that on a wire EDM, the actual feedrate is governed by the feedback loop of the gap voltage; the sensing circuits will override the nominal feedrate in response to that voltage to keep the gap the correct width for sparking and flushing)
Turning down the nominal feedrate makes the gap easier for the machine to maintain.

Next I turn down the ON time and on my machine the "auxiliary ON time".
Next I turn down the wire tension a bit, I turn up the wire speed a bit and I open the servo gap which changes the threshold voltage at which a spark will be triggered and thereby will trigger a spark across a bigger gap, improving the flushing, but FUCKING UP YOUR SIZE CONTROL so watch it if you have to hit a precision target.

Between all these adjustments you can often get the machine to behave acceptably with regard to wire breaks but at the cost of size control and cut speed.
Once you jigger the settings, all bets are off on what you'll get so if in doubt, leave a bit extra on the roughing pass, expect to have to take more skims and expect to have to measure your developing part and sneak up on the size.

So this whole fuckaround violates a basic thing about wire EDM, and that is, if all settings are kept nominal and the machine is in good condition, you can expect consistency within a fraction of a tenth, but as soon as you dump the nominal settings to make it go, you throw all that out the window.

It's always cheaper to keep the machine in good condition; it cuts better, it holds size better, and you can spend the time you'd waste re-threading actually doing what the machine is supposed to be doing.

But if the Boss Man is too stupid to understand that....well it's HIS money going in the toilet after all...so Fuckim, do your shit the best you can and start looking for a better gig.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

If you are in Minnesota like your location says, T. Bryce will send tech's out, they are out every day.

T. Bryce Machine 763-449-9900 or contact [email protected]

Well then my boss is lieing to me. Ive asked for them to get a tech in to help me learn how to maintain the machine properly. We finally got new filters in today. The water went from murky brown like the waters of the Mississippi to clear. Amazingly once those got put in I was able to set up and run a 1 inch block of 440 stainless at the settings put out by the programming software without any wire breaks. Lo and behold. Whoda thunk it.

They may not be lying to you; it's possible that their relationship with the local Fanuc supplier is strained. Try getting them on the phone - get a quote and present it to your boss - if nothing else, maybe you can open up a conversation with the tech, and they can steer you in the right direction without a service call. No machine builder likes to have unhappy users out on message boards...

On the other hand, if they refuse to even speak to you, because your employer hasn't paid them for previous service, then you know who you're working for.


Dan

Hi HelpImLost:
You wrote:
"The water went from murky brown like the waters of the Mississippi to clear. Amazingly once those got put in I was able to set up and run a 1 inch block of 440 stainless at the settings put out by the programming software without any wire breaks. Lo and behold. Whoda thunk it."

Yep, the filters were so clogged they were overpressured and blown at some point in the past so they didn't filter doodly squat anymore
Glad to hear such a simple fix improved it so much for you.

Now, sadly you have no clean tank side...it's full of shit crap and corruption too.
Ideally you'd strip down the whole DI system, scrub out both the clean tank and the dirty tank and then put her all back together again.
A filthy nasty job that will take you a good day or so to do thoroughly and it will make the DI system have to work much less hard to keep the dielectric constant of the water where it should be
Also a truly clean "clean tank" will help preserve the pump seals and the HP pump especially is EXPENSIVE to rebuild or replace.

Your Boss Man will likely pitch a fit if you take the DI system apart like that...but now that you know it's a shit hole in there, you can just change out the DI resin more often and spend his money.
So clean the conductivity probe thoroughly (takes 15 minutes or so) and then replace the DI resin.
Change it out as soon as you can't hold conductivity constant as I remarked on before, and it'll be as good as if the clean tank were actually clean...it'll just cost NumbNuts a bit more profit.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

The "Minnesota Nice" dealer will help you, especially if you get wire, filters, DI tanks from them.

Contact them - T. Bryce Machine 763-449-9900 or contact [email protected]

A call to Matt is free!

I have what i think is an interesting question, but I could be wrong. I have a 2021 Fanuc Robocut C600 and it has the core stitch function (which I have no use for). I don't like the core stitch as the areas that get stitched are inconsistently cut compared to the rest of the cut, and if I have to take a file to my cutout then why use an EDM anyways.
Now to the question. Does anyone know if it's possible to use the cutting conditions from Core Stitch to deposit brass onto an entire previously cut surface? I'm thinking for some scenarios where maybe a cut has gone too deep that brass could be built up on the previously cut surface, and if required then a re-skim to bring it back into tolerance. Some of the things I cut are just holders for various items, and having a few thousands of an inch of brass isn't an issue.

In my experience in doing my own accidental core stitching by not moving power contacts enough or bad cables, the brass will only build up on the top of the part. I'm guessing there's no way to have it go down the length of a whole surface.