Wire Breaking on the start of finish pass-looking for suggestions

Hi everyone I was wondering what the best way to go here. I am Mitsubishi MD Pro 3 wiring 4 axis profile with a max 23 dg angle in a 2 inch thick piece of hardened steel. I am using the angle master flush cups and diamond guides. I am also using soft Mega T wire too. I am using the power master feature and I have the angle set properly in the interface.

Here's what's happening. The first rough cut goes great then I have it programmed to go back to the thread point where it dwells,changes the power,starts the wire and then goes to the machining cycle. About about 5 seconds into the program when the machine is imparting the first angle before the machine even makes contact the machine stops (please note the roller wheels jerks a little)! So I try a dry run out in the open off the piece to try to figure what the heck is happening then boom it duplicates the same thing. I feed hold the machine and sure enough the wire is broke down by the bottom flush cup. So I went to hard brass wire and ran the same program to make sure it wasn't the program and it ran no problem at all. Oh I forgot to mention I am using .010 wire.

Here's my questions:1) Is running the power master feature not recommended? Are there setting I am missing in this feature? 2)Should I run with Power master and if so any recomendations on settings?3)I know it has to be a wire tension problem or possible a wire speed problem?

Thanks!

It's been a long time since I worked on a Mitsubishi so not sure about the power master stuff, but a general rule of thumb for me to definitely turn the tension down when you start getting into steeper angles like that. I'd say reduce it be 30% or so.

Generally the skim pass will have a higher tension in the technology, so that might be why it's not breaking on the rough cut.

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Thanks for the tip. I am still experimenting to see if I can work around this.

wdevine has it right. Too much wire tension. The extra drag when pulling the wire over the diamond guide radii will cause the machine to pull the wire into.

Not sure about Mitsubishi, but all the Charmilles tec files are for straight cutting.

High taper angle cutting puts even more tension on the wire because of the way it drags through the guides.

Once you go past 10 degrees it's not unusual to have to adjust the tension down, but that's usually just on the rough pass ime.

Switch back to the soft wire, adjust your tension down and your off-time up.

Also,

You are cutting a 23 degree taper, that's a lot.

You're losing a lot of direct flushing if your heads aren't right "on" the part.

If you have any sharp corners, your taper angle in the corner is going to be way more than 23 degrees.

Make sure you aren't dragging on the nozzles.

Power Master only applies to rough cuts. Your problem is almost certainly due to wire tension. My MV book says 7-8 for above 20 degrees for .010" wire. I also see that the jet nozzle needs to be removed above 20 degrees....not sure about your machine though...

I've got a large selection of old flush cups I've crashed or whatever and then sanded down soI have a big ole hole for steep tapers.

I also have a set of 45 degree guides for our Chmer machines.

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NC CODER

contact the machine stops (please note the roller wheels jerks a little)!

this...

it is pinching the wire a tad and it stalls for a split second and cannot go thru guides when this happens its instantly burns the wire and cuts it....there is a setting that can control the amount and speed at which the rollers close onto the wire....adjust that...that is where the problem occurs....to check me.....when it happens unscrew bottom cap and guide and pull wire thru opposite way...you will then see tiny crushed area on wire

Thanks I will check that out