default precision

Hello guys i wish to discuss a subject related to cnc moving accuracy.

Idea is : if a part must be crafted with a wide tolerance, than why should the machine move at it's best ? Why not modify cnc precision to suit the desired part ? Final result is delivering the part faster So set the machine to fit a certain cutting accuracy

So far, only on mills (osp 300 m), i can say that :
... rapid movements can be drastically reduced, by changing the " in position window (IPW) " parameter , located into "system parameters" window, or accesed by VINP* variable (* X Y Z); putting this to 0 makes the machine move way faster; also, is recomended to disable HiG, so to avoid shorter acceleration/decelaration paliers that delivers "bumpy" behaviour
... manuals present this IPW as a parameter to speed up default cycles .... i can attach the pages, if someone wishes to; a lot of help into this techniques come from guys on similar okuma forums ...

So i can speed up the mill movements during positioning, and inside cicles now i wish to do the same, during cutting ... i think that i must start play with the HighCutPro

So far i only read about it, without testing it on the machine; so, please, is it posible to deliver faster a part with general tolerance = 0.1, if HiCutPRo is on ? on speed machining, and with tolerance = 0.08 for example ?

My question was just an example; i do not know what HiCutPro does exactly, and i wish to modify cnc precision during cutting, to fit the part ... maybe someone can help with his experience, so to reduce trials duration kindly !

Maybe if you moved to a warmer climate, your machines would move faster. Just sayin'.

if machine oscillates in position even .001" that can damage cutting tools. for example a short length drill drilling a hole would not like moving sideways back and forth .001 or .002 while drilling.
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often it has little to do with tolerances

DMF_TomB said:

if machine oscillates in position even .001" that can damage cutting tools. for example a short length drill drilling a hole would not like moving sideways back and forth .001 or .002 while drilling. Often it has little to do with tolerances

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whatever is done, sideways during drilling will not happen because of code, but because of mechanics

if machine oscilates durring drilling for whatever reason, 0.001 is more than ok ... a 3D drill nose oscilates during cutting more than 0.005, if not at least 0.01

during driling, syncro between Z and S should be left as it is : only thing to do is changing acuracy for hole position, and peeking tolerance; for example, don't drill at X±0.003 Y±0.003, but at X±0.05 Y±0.05, so faster positioning

so don't interfere during cutting, but only during positioning

a rough milling operation may be done with decreased accuracy, so the machine won't move at it's best on a rough toolpath how to do such a thing ? is why i post this thread

The point DMF was making is that your machine tolerance doesn't just affect your part tolerance. It affects tool life. Even if your required part tolerances are low, it's unacceptable to allow a tolerance of 0.01" during cuts. With a tolerance like that your chipload can swing up and down by 0.02" at any moment which is a guaranteed way to break tools.

0.001" difference on a final part dimension may not matter, but 0.001" worth of runout or "wiggling" is a big deal. Try that with a 0.5mm drill. It isn't going to last long!

In addition to all that, I'm just not seeing the point. The machine can move as fast as it moves, the controller doesn't care whether your positional accuracy requirement is 0.0005" or 0.01". It'll move just as fast to get there either way. In a cut you can only move as fast as your machine and the cutter allows. You can't go faster just by being "less accurate." That's both moving the cutter way faster than it should be going through the workpiece, AND holding poor position. You're going to break 100 tools a day and have horrible looking parts.

SVFeingold said:

The point... parts.

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Hello i was thinking from a while about this, and i thought to go ask in the forum, and get some ideas; so i am only testing now

here are some reasons :

1) on mills, i started reading about HiCutPro, because i was curios about it; still, i have no real idea what HiCutPRo does, because i never used it, but there was a text in the manual, that i have attached, saying that a balance between "accuracy" and "speed" can be achieved

* HiCutPro is available also for lathes ...

2) on lathe it may be used M61 ( attached image ), that has it's main purpose to reduce cutting time ; however, " chipload swing " appears

so, there is something, and i did not wanna go there on my own ... so, i guess " chipload swing " is ok, if "swing" is not so big

why when i wish to view the images that i upload in a post, they appear smaller comparing to what i have upload ? ... there is info inside them, and scaling down makes them harder to read

are there size restrictions ? kindly !

A rather dim light bulb just came on at half voltage . . . I think the concept is like 'exact stop' option, where the control makes sure the movement has reached its exact programed position before it executes the next block. This does indeed slow down the execution of a program.

One of the things I really like about CNC machining is that the machine does exactly what I told it to do (right or not!), and does it exactly the same the next time, and the next time and . . .

Hello James

Red James said:

I think the concept is like 'exact stop' option

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[ mill ]

once " in position width (IPW)" is minimized, " exact stop" occurs; if machine is at x1, and must move to x2, and during movement, real position is at x3 (x3 close to x2), if IPW>|x2-x3| than next block is executed

a lower IPW delivers sharper corners ; IPW can be set 0.001 .. 1 ; i think [IPW=0.001] = [G09] or [G61]

G09 delivers IPW=minimized only once
G61 delivers modal G09, until G64 comes in ; G64 is power on default

so, by G64, at least for positioning (G00), mills move by default with IPW="value from system parameters page", to speed up G00, just declare IPW=0 i got this trick from an Okuma veteran

during cutting, IPW may be declared anywhere between 0.001 .. 1, depending on part precision

check this code :

now i am testing a drill code ...

[ lathe ]

G64 is also power on default, but it behaves diferently than on mills ;
... mill G64 : IPW="value from system parameters page"
... lathe G65 : IPW="value from user parameter page", called droop

so lathes move by default with IPW disabled, while mills don't

IPW is activated by default on mills, and by G65 on lathes

even more, on lathes, there is the "rapid droop" option, that will allow using an increased IPW when a G0 movement meets ( G0 / G1 / no travel )

considering only IPW, lathes are more versatile; from trials i can say this :
... IPW=0 on mills deliver faster movements
... G65 & rapid droop on lathes deliver slower movements, because by default they power on with IPW=0

IPW trigers local behaviour .... once i finish with this, i will investigate general behaviours, thus, the " following error " ...

please, does anybody uses G09/G61 or G60 ? if so, please, can you share the reason why ?

i think for G09&G61 for ultra precision parts .... but why G60 ? when is this required ? kindly !

deadlykitten said:

please, does anybody uses G09/G61 or G60 ? if so, please, can you share the reason why ?

i think for G09&G61 for ultra precision parts .... but why G60 ? when is this required ? kindly !

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Dude, you have 27 smiley emotes. Enough with that shit, this isn't the 3rd grade.

Mtndew said:

Dude, you have 27 smiley emotes. Enough with that shit, this isn't the 3rd grade.

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maybe there should be a limit for emoticons in forums, and also a limit for smiles in real life

did you become a mature person in 4th grade?

deadlykitten said:

maybe there should be a limit for emoticons in forums, and also a limit for smiles in real life

did you become a mature person in 4th grade?

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I'll let you know when I get there.

By the way , where in Antarctica are you? It is a big continent.