1994 model VF-2 tool and gear change problems.

When shifting the transmission from low to high gear and when changing tools, the machine lacks sufficient air pressure to carry out the operation. The transmission grinds gears and the tool change often fails to orient the spindle because the shot pin won't push in to catch it. A HAAS technician put a new solenoid valve on the machine, but it didn't solve the problem, so he put our old one back on.

I followed advice that I found on this site and cleared the transmission gear shifter and its small air hole of trash. This solved the problem for a few weeks at which point, I'm guessing the shifter is clogged again. Would it be reasonable for me to assume that a new solenoid valve is in fact what I need in combination with cleaning the shifter again? I'm quite sure that the HAAS technician didn't even bother with the shifter before trying the new solenoid.

Thanks for any advice.

If cleaning the shifter worked before, I would try it again before you replace a solenoid valve that may or may not be bad.

If it is dirty again, you may want to investigate why you have so much garbage in your air system.

Thanks for the reply. Our air lines aren't great, but we also have a '98 HAAS VF-4, '98 Fadal 5020A, and an '88 Mazak H-400 on the lines with no pneumatic problems at all. The problem with the VF-2 arose immediately after HAAS rebuilt the machine, putting a new head and transmission on it. HAAS gave us the run around for three months until the warranty ran out, and then the technician locked up the gears in the transmission by shifting them by hand and walked out saying, "Well, it's your machine now. You guys can try to fix it if you want."

We freed up the gears and the machine runs fine as long as it remains in one gear (I keep it below 1200 RPM in low gear) and doesn't have to change tools too much. I open the drain valve on the air tank regularly, and no water or trash ever blows out. So, being fairly inexperienced, I don't know if the problem is trash in the lines, a bad solenoid valve, or something that HAAS may have screwed up when they rebuilt and "upgraded" the machine.

traceflair said:

Thanks for the reply. Our air lines aren't great, but we also have a '98 HAAS VF-4, '98 Fadal 5020A, and an '88 Mazak H-400 on the lines with no pneumatic problems at all. The problem with the VF-2 arose immediately after HAAS rebuilt the machine, putting a new head and transmission on it. HAAS gave us the run around for three months until the warranty ran out, and then the technician locked up the gears in the transmission by shifting them by hand and walked out saying, "Well, it's your machine now. You guys can try to fix it if you want."

We freed up the gears and the machine runs fine as long as it remains in one gear (I keep it below 1200 RPM in low gear) and doesn't have to change tools too much. I open the drain valve on the air tank regularly, and no water or trash ever blows out. So, being fairly inexperienced, I don't know if the problem is trash in the lines, a bad solenoid valve, or something that HAAS may have screwed up when they rebuilt and "upgraded" the machine.

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Well this statement is vastly different than the first one.

Typically with gear shift problems, it is usually one of the following:
Bad/Dirty solenoid
Obstructed air line
Sticking shift mechanism
Bad or sticking High/Low switches

Did this just go out of the 90 day warranty or has that been long ago? If it just came out of the 90 day warranty and you have been bringing this up to your HFO as you described, then call them back in and demand that they fix the problem. Call Haas Oxnard if you have to and tell them the same.

What is the issue with the tool changer?

It has been a number of months now since the end of the warranty. Sadly I don't have the authority to interact with HAAS, and management just kind of said back then, "Oh well. See if you can fix it." The shifting mechanism seems to work fine, and the machine ran like a dream for about three weeks after clearing the air hole and replacing the O rings. This is what's leading me to believe that the problem is in the solenoid.

The tool changer orients the spindle with a shot pin mechanism rather than an encoder, and the shot pin seems to run from the same solenoid valve as the gear shifter. When a tool change is called, the spindle often tries over and over to orient, but the shot pin won't move in enough to catch the spindle -- causing the machine to throw a Spindle Orientation Alarm. We have the orientation speed reduced in the parameters to aid the shot pin.

All the air lines appear clear, and we ran a few drops of pneumatic tool oil into air lines on the advice of a HAAS technician. I believe I'm going to again clean the shifter and replace the O rings and then replace the solenoid valve that operates both the shifter and the spindle shot pin.