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tilikoom

Head/head machine constantly crashed

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We have a head/head 5 axis that gets constantly crashed due to reckless programmers and operators. It has been crashed over 20 times in the last year. The person in charge is remote and is not a machinist, and doesn't understand the situation. The guys who crash the machine know how to do a poor-man's re-alignment on the B and C axes, and they're damn good at it. The machine never gets properly re-aligned by a qualified technician. For example if the B axis is knocked out X degrees, they enter that amount in Fanuc's parameters and the machine runs as if it were aligned.

How many cheat-alignments can we get away with before the parts in the head are damaged? Is it normal to cheat the alignment so many times? I haven't worked with too many head/head machines. The truth is these guys are damn good at cheating the alignment, and the untrained eye would never notice it.

Just doesn't seem right. We all have an occasional crash, but if this were my company they would be fired for sure. The B and C axes should align without having to manipulate the parameters.

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I have to ask….are you using Vericut to prove out your programs? 

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14 hours ago, tilikoom said:

How many cheat-alignments can we get away with before the parts in the head are damaged?

The correct question is "How many crashes before damage?".  The answer is "one".  Every crash will damage the machine further, and it will never be as good as it was before, even if realigned.

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After the first crash the entire process should be changed to ensure the likely hood of another crash was nil. Learning by accidents on CNC equipment will costs serious $$$$.

Better to pay up front and get a correct post, verification software and competent programmers/ operators.

 

 

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Thank you all. I do acknowledge this was largely a rant driven by frustration. This machine has been crashed more times in a year than the total number of crashes I've witnessed throughout my entire career. The floor lead is totally complicit - he just cheats the alignment every time he has a crash and nobody ever knows. He swears the machine is fine.

But I beg to differ - it can't be truly aligned to the machine axes after that many crashes. He uses an alignment hack where he determines the amount of run-out in the B and C axes, and enters that amount in the parameters. I believe they are Fanuc parameters 1240, some in the 19600 and 19700 ranges.

In this post I should have asked the following questions:

1) What are the appropriate methods of testing, re-aligning, and repairing, a 5-axis gantry machine head that has been crashed an excessive number of times (acknowledging it will never be perfect)?

2) To my understanding the above re-alignment procedure is for fine tuning - NOT for correcting crashes. Is there anyone familiar with this procedure? Am I wrong in this claim?

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On 9/11/2021 at 9:29 PM, tilikoom said:

Thank you all. I do acknowledge this was largely a rant driven by frustration.

Head head machines are particularly vulnerable ..... have you got a test program to test your "adjustments".

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You will be doing adjustments in the machine parameters and then the machine will start to become non repeatable is what will happen.  It will start to wander away and then at some point it will have an alarm.

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offsite programming with no accountability.

the owner of that machine is going to learn the cost of that the hard way.

Root cause needs to be fixed first.

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The causes of these crashes need to be addressed

At some point the machine will have enough mechanical damage that the guys will not be able to fake 

it back into spec with parameter tweaks.

You will discover the problem when a part that looked like it ran OK fails inspection.

 

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4 hours ago, gcode said:

The causes of these crashes need to be addressed

At some point the machine will have enough mechanical damage that the guys will not be able to fake 

it back into spec with parameter tweaks.

You will discover the problem when a part that looked like it ran OK fails inspection.

100% THIS ^^^^^^^^^

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