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Power contact life

RJT

Titanium
Joined
Aug 24, 2006
Location
greensboro,northcarolina
Our last set of contacts for our Mits FA20 are averaging only 20 hours of run time before we start breaking wire due to the deep groove in the contact. Pretty sure we used to get 50 -60+ hours before rotating. Supposedly the same contact we have been using for years. What kind of run time is "average"? We happen to be running a production job,same program we have used multiple times, so that's not a variable. Same wire, same speed, same tension. Wondering if this is a wire issue or a contact issue? Haven't changed wire vendor or contact vendor. Machine get very regular maintenance, brass housings are in great shape.
 

SeymourDumore

Diamond
Joined
Aug 2, 2005
Location
CT
Pretty interesting timing ....
Mine started doing the same thing ( Makino ) on the lower head.
Normally bandsaw cuts of the very same production runs - average 50-60 hours/index.

All of a sudden the last 4 indexes were necessary after 30 hours.
What I did notice is that the grooves were quite a bit wider than normal, and looked like they were not "abraided", rather eroded.

The last time I saw similar wear was in the upper head and it was due to insufficient contact cooling ( lubing if you will ).
Turns out that the orefice for contact cooling was partially plugged by debris.

I'm about to dive into mine, hoping that there is a way for seeing only the contact cooling volume on the lower head.
The upper was pretty easy, the lower is prolly going to be a PITA.

I know we have different different machines, but the same rules still apply when it comes to these kind of issues.
 

RJT

Titanium
Joined
Aug 24, 2006
Location
greensboro,northcarolina
Talked to my contact supplier, he asked if we soaked the contacts for hours or days in toilet bowl cleaner,said it could deplete binder in carbide. We clean the with it , but don't soak them for more than a few minutes, and it's diluted with water. I'm getting a new set of contacts and running a comparison, he said if we see a big difference , he would credit the suspect contacts. We'll see. It may take a few weeks as I don't have much wire work lined up at the moment.
 

wdevine

Aluminum
Joined
May 17, 2010
Location
Massachusetts
My last job we used to import ones from China for really cheap. 90% of the time they worked perfect, but then occasionally you'd get batches that wore out really fast, with really wide slots. We saved so much money it was worth the trouble.

So yes it could very well be a bad batch of contacts.
 

Pro-Wire Tech

Plastic
Joined
Feb 15, 2022
Hello the power feeder carbide average about 60 to 80hr machining time. It all depends if you’re rough cutting most of the time or skim cutting. It also depends how thick your part is because you will determine the EPACK setting sometimes the EPACK are more aggressive depending what you’re cutting and how thick. I’ve also seen some people keep an eye on the top of the power feeder and go about halfway into the radius. If you’re cutting the same thing over and over it will help if you go to the maintenance machining timers and zero it out when your in a fresh spot. This way you will know how far it will go before it starts breaking and set a timer on the Power Feeder timers. This way the machine will shoot out a warning before the timer is up and you’ll know to move the power feeder.
 

RJT

Titanium
Joined
Aug 24, 2006
Location
greensboro,northcarolina
Replacement contacts are acting the same way (about 20 hrs use before we need to rotate). It's been suggested that my power cables may need replacing, even though they are clean, they are getting stiff, I'm told they should be very flexible. How difficult is it to change them? Something we should attempt, or will we need a mits tech?
 








 
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