Wire machine feed question

[Bill Cronkhite]

Does anyone have any opinions on whether to run G94 constant feed rate or voltage servo. I'm not having much luck with G94, and a part I need to quote to the boss is going to take a while running voltage servo. Just need some opinions.

Thanks.

[Brad St.]

My opinion is your going to have a lot more variables to consider than just those. What kind of conditions are you facing:

 

variable thickness

material

flushing

wire type / diameter

oh there's more =)

 

If you could change any of those to optimzie and run a constant feedrate is it worth the change or is it a one of a kind job that you could leave unattended and eat the cost of the wire not necessarily the operator time/handling expense?

 

We only use fixed feedrates here for a very specific cases otherwise the servo gain will actually give us more when it can than if we left it at a static rate. That of course is on our Makino's SP43's.

[Del.]

Seems like it would depend on how many corners you would have also and whether or not you needed skims. Making it a constant feed may make your skims much slower if it is not removing enough material on rough pass. As for me I am a voltage watcher.

[Bill Cronkhite]

Sorry, thanks for the responses. Got involved in a major form steel for the mill and had to put this aside for a while. Problem is my time quotes are getting so long the bosses are starting to want to send everything out for wire work.

 

Regarding questions:

 

material, soft A-2 4 inches thick flat top and bottom

wire, Sumitoma .012 dia programmed at .0145 for over burn

Single pass no skim cuts

machine series Q Elox w/Fanuc controll. (OLD still has paper tape reader and I can't get the RS232 to work so it may not even be there)

 

settings:

type 0

voltage 8

on time 7

off time 28

V. servo 24-26

tension 400

wire feed 4

water flow 4

 

water condition excellent. 2 month old filters and 3 month old resin tank. Also have access to di water for top offs.

 

Possibly the power supply is getting weak as I have noticed that after 12-14 hours of run, I start getting large voltage drops which leads to shorts and backing up. And times get huge.

 

Thanks for any help. Programmed wire 2 and 4 axis for over 28 years, but only running and setup + programming for about 6.

[Del.]

Bill, Not familiar with that particular machine or power settings but off the top of my head I would make sure that my upper and lower power feed contacts have been cleaned and moved to a new surface for the wire to run against. I move mine every 40 hours of burning. I would also check all of my cables for bad places and make sure all connections are tight and clean.

[Bill Cronkhite]

Del,

 

Thank you, I never thought of moving the contact surfaces (so obviously I havent moved them since we got the machine.) I'll try that. It makes sense with what I'm seeing. Just gotta get the times down. Thanks again.

[John@WMM]

Like Del said index those upper and lower power feed contacts and you should get better performance. On my Fanuc Robocut I get around .030-.040 a minute on soft A-2 thats 4 inches thick...