TPA Question Arrow 1000

[Arrow eeyore]

Hello! It looks like I need to pay some attention to my y axis tpa switch, 1996 Arrow 1000. Are these switches serviceable or should they just be replaced? will be tearing in to it in the morning.
If Replacement is required, source/vendors for these switches?
Thanks in advance for any help!
Bill

[advt001]

It really should not be a problem.if you are lucky the part number will still be in place.

[TarHeelTom]

What does "tpa" stand for?

Tom

[Arrow eeyore]

Not sure what TPA stands for, but I think it is a two stage switch serving as a travel limit type of switch and a over travel safety switch, During the Alignment process, the table goes over and bumps these switches. I have had a few intermittent problems where the machine did not align then over traveled and shut down, popping up alarms!
thanks! Bill

[mallardfizz]

TPA = Target Point Align
there are two switches for each axis usually ( depends what schematics and software the machine has ) one for tpa and one for overtravel. if an axis starts to travel wrong way when aligning and can only be stopped by the emergency stop it's a sure sign that the align switch is stuck down.
regards
mallardfizz

[CHAD LAWSON]

your local square d distributor can get these you just have to let him know how many meters of cable you need. Also do your self a favor and pay close attention to exactly where the switch is mounted and get it back as close as possible. The worse part of all this is fishing the cable through the tray under the table. If time does not allow we often spray them down with a good lubricant pb blaster works well and work them back in forth will buy some time while waiting for switch. But our shop is out in the middle of no where so always have to wait atleast a day for parts.

[TarHeelTom]

Any electrical parts supply house keeps lots of cable lubricant in stock. You might be able to get a quart from them, or bum a cup full from your local electrician. Electricians who work on jobs involving cable in conduit buy the lube in 5 gallon buckets. It's usually applied by hand.

Tom

[CHAD LAWSON]

guess i did not clarify well enough the lubricant is to free up your exsisting roller switch. The coolant grime builds up on them causing them to stick. sometimes you can break them free and get several months out of them. Do not use pulling lube for this. Also make sure you clean the chip build up out from under table everytime you have way cover off as this will prevent lots of problems.

[TarHeelTom]

Chad,

Yep. I totally misunderstood your meaning. I thought you were talking about lubing the new cable to pull it in.

By the way, you may have already seen this post, but...

Several years ago someone (don't remember exactly who it was) conducted a very controlled experiment on the effectiveness of various penetrating oils. They put together a particular bolt and nut combination and "aged" them in a controlled way. Then let each nut-bolt soak in a penetrating oil for 24 hrs, then measured the torque needed to achieve breakaway. Lowest torque wins.

By a good measure, the most effective fluid used was a mixture of power steering fluid (or ATF) and acetone. Another exception to the "you get what you pay for" rule was Marvel Mystery oil. It scored just about neck and neck with one of the much more expensive penetrating oils.

Tom