Arrow 500 Air hog!!!

[reflexx]

Please help!

I've had a Cincinnatti Arrow 500 (1997) for a few years and it's always been a huge air user. I have an 80 gallon compressor, with another 30 gallon tank next to the machine, and it cycles every 4 minutes!!!

It seems excessive for a machine that only uses air for spindle oil mist and tool change. The factory cannot give me a clear answer and I've checked the oiler system. I'm afraid to turn down the air supply to the spindle (they're a bit EXPENSIVE if I fry it).

Any suggestions? Other users?

thanks,

REFLEXX

[reflexx]

ANYONE???

Problem still exists. Fellow Arrow CNC users, what do you think?

[Geof]

Your compressor could be cycling frequently because it is too small for the machine consumption. You have a total of 110 gallons of tank capacity but the important thing is the cfm output of the compressor. If the compressor cfm output is correctly matched to the machine consumption another reason it can cycle very often is because the cut out and cut in pressures are too close. For a piston compressor it is not unusual for the two pressures to be different by up to 20 psi; cut out at 115 psi and cut in at 95 psi if the machine regulates the pressure down to about 85 psi. The further apart the two pressures are the less often the compressor cycles and the longer it runs in a cycle.

[reflexx]

Thanks, Geof!

I thought about that, but this machine clearly uses a very large amount of air in the spindle "misting" system.

I feel air blowing past the spindle like an air gun set on half open. I realize that it is to keep the coolant and contamination out, but it seems a lot more than necessary. It's the only use of air in the machine besides the tool magazine, and that certainly doens't cycle that often.

I'm just hoping to find someone that has the same machine to confirm.

Is there a gauge that measures CFM that I can put in-line.

[Geof]

Originally Posted by reflexx Is there a gauge that measures CFM that I can put in-line.

I googled and yes sure there is and they all look like many $$$$$.

If you can feel the air blowing I suggest trying to find what psi the spindle misting is supposed to operate at. I don't have the same make of machine but I know my systems run on 18 psi and it is not possible to feel any air escaping.

[Verfur]

reflex the blow down through the spidle should only happen at tool change. If seting idle with no tool in spindle there should be no air leak exept for the positive pressure for the spindle bearings/lube and I do actualy arrow 750, and 1250 machines.

The only machine I have with coolant through spindle is the 1250 (not a mist) flood coolant.

I suspect you have a valve stuck.

Can you feel the air come out of the inside the spindle with no tool in the spindle??

John

[reflexx]

Verfur,

I do not have blow down thru spindle (to clean the taper). There's no air coming thru the center of the spindle. I feel air coming between the part of the spindle that rotates and the stationary metal at the bottom of the head.

Imagine you wanted to spin the spindle by hand (no tool in the spindle), where you grasp it to spin it is where I feel air blowing on my thumb and pointer finger. Does that description make sense? do you feel the same on yours?

I'm certain that it is the spindle bearing misting/lube and postitive air pressure system, but it seems to be overkill.

[Verfur]

I do not feel any air comming out of the spindle bearing area, I can how ever hear it slight hiss and a pulsed his when you spin the spindle I will look and see what the press. is set at in the morning and post the readings. if memory is right there are two regulators on the back one main and then one for the spindle.

John

[Verfur]

Ok,

Here is the setting I am running on my machines main press. at 80psi and second reg set at 20psi and spindle lube set to 2bar (VIP2) is the type of lube control on my 750.

2bar = Aprox. 29 psi

hope this helps
John

[reflexx]

John,

What's the brand name of the mist/lube system on the back of your machine? Mine says "DROPSA" a box with a yellow/orange cafe with LEDs.

There's a pressure gauge to the right of it (black face) reads 4 BAR and there's one directly above it (small, white face) only goes off when he luber cycles.

The machine is set at 80psi. Is this what you have also???

thanks again,

gene s.

[Verfur]

reflexx,

DROPSA is the brand and it is a VIP2 its a little blue box with two LCD displays.

As far as the gauges go there is a little whit face gauge above the Box and I belive you are right it only moves when the lube cycles.

I belive the reson mine has the extra regulators is because it has the glass scales on X and Y.

hum 4Bar = 58. psi

again my machines sound about as loud as a crummy air hose quick connect SSSSSSSS. you have to have you head in the machine to even hear it above the spindle cooling fan.

What RPM spindle do you have?

The one on the VMC 750 has a 8000rpm cat 40 spindle. and the 1250c has a 10,000 rpm cat 40 spindle.

John

[sarms]

My Arrow does the same thing. I just put up with it. It air supply is a 200 gallon twin piston. Under opperation the compressor runs every 12 minutes. I'm a 90 psi.