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Automatic retract before drill burns up

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10 replies to this topic

#1
powerfulp

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Hi all,

Is there any way to write a macro that would make a drill automatically retract to the r-plane and stop with a message if it reaches a certain HP? I'm trying to save drills from burning up.

The macros would be Custom Macro B language, as we have fanucs, mitusbishi and mazak controls. I met a programmer awhile ago who said he wrote something for his machines like this, I never looked into it until now. How do you even get the information needed to write something like this?

Any help would be appreciated...

- Paul

#2
AshM

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This is not an answer to your question. If you are frequently killing your drills you may just be over doing it with your feeds and speeds, what materials are you drilling?

If you are drilling lots of holes and using the drills to the end of their life all the time you might be able to set a running time para in the tooltable of the machines which should stop cycles with a warning at tool changes. Heidenhain controls work that way.... If you are doing heaps of holes in a single setup put a full retract every 50th hole with a tool call to force the running time parra to update if you need to.

This is a bad guess, but do do what you want, some controllers have a probing g code that monitors an input whilst in rapid to start points to prevent destroying the probe. Perhaps this can be used to monitor a different input. Or perhaps you could aim to temporarily lower the spindle torque alarm setting prior to drilling. I would suggest talking to the machine tool agent for the info.

#3
powerfulp

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There are a few jobs we run across with terrible material, where the tool life monitoring just isn't sufficient. I would like to run as close to "normal" as possible on the parts where the material is good (probably 75%+ of parts), so that's why I would like some sort of spindle load monitoring thingy, which only a couple of my machine have (the older KT Gemini D control has HP limits)...

#4
AshM

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alternatively, you could add a tool break check between holes (or maybe every 5-10 or something)...

Even if you had a load monitoring thingy that worked the drill would be stuffed when it triggered wouldn't it? Otherwise you would need to set the trigger value too low and you might have it go off for heaps of false possitives....?

What is the material? What are you running into?

I've done some jobs in cast steel, where I encountered hard pockets and inclusions in the castings as I went. My only way around many of them in the end was to keep changing tips and tools to get through the bad bits all the time, many of which I destroyed in the process. Every one of the broken tools got delivered to my boss as a reminder to scream and shout at the mob who did the castings and to look for someone else next time...

sometimes when your in it up to your top lip, you need to know when to use a snorkel....

#5
specv

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As far as i know the machine would have to have load monitoring built in to it. A macro can only trigger or be triggered by lines of code. So you can only check values before and after a cycle not during.
so you might be able to find out what the spindle load was on the previous hole, or something to that effect.

#6
GoetzInd

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What size drill? Load monitoring on our machines can usually stop down to a 3/16 drill before it becomes "one" with the part.

Mike

#7
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It's not going to be simple. You can't check during a cycle, you would have to break up the motion and check load between each motion increment. I can tell you this though, if it where as easy as using/writing some Custom MACRO B code, companies like Caron Engineering and ATAM Systems would not be in business.

Besides, depending on the tool diameter, you may actually need hardware to sense load.

#8
Joe788

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On the Mazaks it should be easy. Just put the max spindle load in the tool data page. It'll stop if you go above it.

#9
Chris Rizzo

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companies like Caron Engineering


Just the other day an Okuma AE was telling me about Caron and TMAC. Rumor about motoring a .0625 drill.

#10
powerfulp

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This was written in a different forum about the same thing...

There are no Standard System Variables supplied by Fanuc to alloy Polling for Spindle or Axis load. Some MTBs supply additional System variables, but their supply is infrequent. Nakamura is one maker that I've seen supply System Variables for Axis Load.

What you want to do is possible by calling a Macro Program via an Interrupt Signal (UINT). When a tool abnormality is detected, processing to handle the abnormality is started by an external signal. To achieve this, you would have to add some hardware to monitor the load on the machining system. Axis load would be my choice, not Spindle load. If your machine has a Z axis load metre, it would be possible to tap into that circuit to trigger the Interrupt Signal.

An interruption type Custom Macro Function can be applied partway through a block. When the interrupt signal (UINT) is input, any movement or dwell being performed is stopped immediately and the interrupt program is executed.

#11
High Performance

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This was written in a different forum about the same thing...

There are no Standard System Variables supplied by Fanuc to alloy Polling for Spindle or Axis load. Some MTBs supply additional System variables, but their supply is infrequent. Nakamura is one maker that I've seen supply System Variables for Axis Load.

What you want to do is possible by calling a Macro Program via an Interrupt Signal (UINT). When a tool abnormality is detected, processing to handle the abnormality is started by an external signal. To achieve this, you would have to add some hardware to monitor the load on the machining system. Axis load would be my choice, not Spindle load. If your machine has a Z axis load metre, it would be possible to tap into that circuit to trigger the Interrupt Signal.

An interruption type Custom Macro Function can be applied partway through a block. When the interrupt signal (UINT) is input, any movement or dwell being performed is stopped immediately and the interrupt program is executed.


Cant comment on the macro side as I have never attempted to do what you are doing. I could look into it, but some of those values can be difficult to find (control manufacturers dont share all of the variables too nicely, if they even exist in some cases). But powerfulp's comment seems to be more useful than the way I would have approached it, so I wont comment on that lol.

As mentioned tho, Mazaks have several ways of dealing with it. You have horsepower and thrust force on your tool data, that should limit the speed and feed if the load climbs too much. Theres auto pecking (which feeds until it hits a max load, then starts to peck (but thats designed for HSS drills), and finally theres an overload detection option which is activated with a series of Mcodes. Ive used this before to help customers with "less than attentive" nightshift operators.
Basically the machine will either stop feeding and give an alarm, or it will stop feed and spindle and give an alarm when a set load is exceeded for a set amount of time.