Petros cnc machine tool's blog

Ran across an interesting site that I thought I would share to help look up machine alarms. It looks relatively new and not all links are currently working. But has most of the fanuc alarms and alarm messages present on the site. Its a great way to look up a machine alarm without having to pick up the manual.   CNC alarms .com

What if the RS232 port is bad or not working on your Fanuc control?

Recieved this from a Member of Machinetoolhelp.com for if you have a bad RS232 Port on a main board or some fanuc controls. Since most fanucs have two ports you can just swap the plug to the other port that is not being used and have a fully functional RS232 port. Then use a different channel for setting your RS232 settings. Wish I would have known this years ago or thought of it.

A Fanuc Powermate F alarm 090 224 occurred on a customers machine at power up. Had tried to walk him through resetting the powermate home position several times but the original procedure would not work. The 090 and 224 alarm indicates a lost home position. However batteries were ok and they were replaced as a precaution. The problem was that it was impossible to reset the home position and it would not take. Fanuc Powermate drives often are stubborn from my experience when setting there home positions.

301 B axis communication error came up on a fanuc controlled machine that had scales for the B- axis or rotation of table. After troubleshooting everything and getting down to that it had to be the scale. Ordered a new scale and tried it. Unfortunitly the same alarm occured. After looking into the parameters I was able to tell that someone had turned off the scale at one time because all the paramters had told me so except for one. Parameter 1815 bit 1, bit4, and bit 5 were all 1's.

All to often I get phone support calls for soft overtravel alarms on fanuc controls. The soft overtravel limit alarms typically occur after a power outage, hitting an overtravel, or crashing a machine. Many times it is an Alarm 500 nth Axis stroke limit + or 501 nth Axis stroke limit  on the newer fanuc controls 16/18/21.

Definition of a softovertravel or soft over travel limit alarm.

Today had an alarm on a Hitachi VN40II " can't cycle start Auto operation "

I was working an Emag CNC machine the other day. The customer was having problems when they were boring into the part. The spindle would bog down during the cut. When viewing the Spindle actual RPM compared to the commanded spindle speed the actual would decrease to about 1200 from 3000rpm. To try to determine the problem I had a few things I checked first. The tool ins

Had a good problem that I chased my tail on the other week.  When the program was running occasionally the machine would alarm out with "tool not clamped". The machine was a Mori Seiki MH1000. I checked the typical prox switch on the back of the unclamp cylinder to make sure it was back which is the only clamp confirmation signal for this machine. I was able to see that it was not back all the way one time during the process. I tried taking a pry bar and to pull the cylinder back and it moved about a 1/8 inch.

Hitachi Generic alarm generated.

The alarm that was being generated had no description at all. On this particular Hitachi machine tool you must look at the diagnostic addresses on the Fanuc side which will tell you the alarmed bit. On this machine I had an alarm that could only be generated from a breaker trip circuit according to the electrical prints. However when the alarm occurred the breaker did not trip. I looked at what was in this breakers circuit and found that it was for multiple things. Air cooler exchange fans, cabinet fans, machine light and several other things.

When machining a part using Circular interpolation machine problems can be found.  CNC programming for circular interpolation often uses G02, and G03 for example. Sometimes you can find in the holes that are circular interpolated the parts have slight divots in the quadrants for a particular axis as I found on a recent job. What I found in this scenario was that the ballscrew nut had lost  its preload and had excessive backlash. This type of backlash can not be taken out by a parameter to remove the dimple/divot.

This is a brief description of OKK HM4 spindle replacement. This OKK HM4 spindle is a simple inline cartridge style design.The spindle was fairly easy to replace and would be a great job for a newbie to take on. Below is a brief summary of how to begin this task.

Had a job that I went into today that the customer complained about Z axis varying by 1/16 to 1/8 after a lightening strike. They were running castings and taking mill cuts across the top. This depth seemed to be changing. My immediate thoughts were an encoder problem since that's typicql if the encoder does not read all the pulses.

Had a customer request making a Hitachi HG400 machine safer and have the spindle stop when the side door opens. I have noticed many Hitachi machines set up this way and had looked into how to make this safer. What I found was a simple easy change that could be made. I traced through the ladder and found  Par 11-0 could be changed to automatically stop the spindle. This had to be changed on the Micon side through the small CRT screen on the side of the electrical cabinet. If there is no switch at all on your machine it may also be added.