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Soft overtravel limit alarms when Zero returning alarms - 500 & 501(soft over travel)

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.

Next tool code positions tool but does not change tool. Help!

We have a Mori Seiki GV-503 5AX with a Meldas M66 control. I want to position the magazine for the next tool. When I write the code shown below, the tool positions at the pot correctly but the tool in the spindle does not change at the next M6. The tool thats in the spindle goes to the tool change position but does not change and continues the program.


Hitachi alarm- " can't cycle start Auto operation

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

Spindle speed bogs down while cutting

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

Tool clamp signal going off during cycle on Mori seiki MH1000

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.

Alarm on Hitachi can be tripped by breaker only, but breaker was not tripped.


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.

Добро пожаловать в русскозычный блог специалистов по ЧПУ.

This blog is welcomed for all specialists involved in design, building, retrofiting and servicing CNC controls and drives in russian Federation. 

Блог специалистов по системам ЧПУ. Добро пожаловать разработчикам систем ЧПУ, приводов, всем, кто занимается модернизацией, ремонтом и техническим обслуживанием.

Предпочтительный язык русский, английский и немецкий также не возбранются, хотя и не поощряются. Пожалуйста, отвечайте на языке того лица, которому отвечаете. 

Circular interpolation milling has divots in axis quadrants or reversal using G02 and G03 commands

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.

Axis drop preventer for all types of CNC machines (at the time of power failure)

Having tool brakage or job damage during POWER FAILURE?

ANSWER: Axis drop preventer.

We manufacture AXIS DROP PREVENTER FOR ALL TYPES OF CNC MACHINES which will prevent the vertical axis from dropping during power failure minimizing the loss and increase in production
The accuracy of our unit is <20 microns
Contact: 097414 97292

OKK HM4 spindle replacement

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.

Z axis not repeating on a vertical machining center

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.

Hitachi door to stop spindle from turning when opened-safety issues

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.

Ways to learn and find people with your interests and hobbies

I know this topic is sort of unrelated. But what I have found may interest you in a lot of repects. This weekend I attended something called a barcamp. What it was was a community of web developers and people that enjoy what they do and get together for some brainstorming. The weekend event that I attended was great, completly free and was sponsored by adobe. They supplied food and beverages  for the entire weekend. The people speaking and giving the seminars were not paid a dime and enjoyed doing it for they learned from everyone as well.

Mitsubishi M64 control Corrupt user program memory symptoms

Symptoms of program memory needing to be formated which occured on Mitsubishi M64 control. This happened on Mori seiki GV-503 CNC machine with a meldas 64. Customer said a DOS screen appeared on Bootup once or twice with “ diagnostic code 005 Enter. As well as analyzing data.

Zimmerman CNC machine with lubrication alarm

Had a problem the other day with a Zimmerman bridge type CNC machine tool. The machine utilized a grease lubrication system for it's linear guides and ballscrews. The Zimmerman had a lubrication alarm that came on after about 15 seconds after the alarm is cleared.

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