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Author Topic: Mill or Turn?  (Read 4403 times)

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Offline RICH

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Re: Mill or Turn?
« Reply #140 on: May 18, 2019, 05:51:15 PM »
The tool table can perfectly reflect the tool offsets.
Just understand that everything associated with and when using / moving the tools controlled point can influence the final cut dimension.

As Hood stated wear and offset adjustments can be used, but, for the most part, I leave the original populated values for the tools alone unless the tool wears or breaks. My tool table has a few tools with names call TEMPx and the x represents some modified version of the original tool #. Logical or meaningfull names that reflect the tool
is helpfull. ie; Threading tool , then copy rename it to LRTO ( Left Right Turning Outside) and with a adjusted offset.Do what ever makes sense to you.

I added an X and Z adjustment DRO's and a button so I can adjust the current / any tool in the tool table. It realy comes in handy for drills, reamers, and other tools used on my lathe and when touching them off.

Using the tool  to probe the work or a setter is a thumbs up over the cut and measure method. Just my thoughts and to each their on how they want to work.

RICH
« Last Edit: May 18, 2019, 05:52:53 PM by RICH »

Offline RICH

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Re: Mill or Turn?
« Reply #141 on: May 18, 2019, 06:58:16 PM »
Can't see why yet??

TOOL OFFSET ADJUSTMENT
1. Tool accurately machined the stock to dimension.
     - no adjustment all ok
2. Tool when used caused the stock to be over dimension.
    - The tool offset needs to changed such that the tool moves in more / removes more
       material. So the tool offset needs to be increased.
3. Tool when used caused the stock to be "under" dimension.
    - The tool offset needs to changed such that the tool moves in less / removes less
       material. So the tool offset needs to be decreased.

Think the above is right! ::)

FWIW,
Machine coordinates are displayed in radii. The tool table offsets are in radii for the X axis.
KISS!

Be carefull when making manual adjustments to tools and consider radius or diameter mode.

I confuse easily.............. ;)
RICH

Offline Davek0974

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Re: Mill or Turn?
« Reply #142 on: May 19, 2019, 02:26:15 AM »
Thanks Rich, got that.

Two things,

1 - This was one cut after the other - cut, measure, move, cut , measure and the second cut was off. I will re-test this today hopefully.

2 - Does anyone know precisely what the tool DRO's/buttons actually do - 175/176 & 324/326 respectively???

Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Mill or Turn?
« Reply #143 on: May 19, 2019, 05:27:08 AM »
Todays tests…

Tool was set by taking a random cut then measuring and entering dia into “touch X” DRO.

Next i requested a cut depth and noted the results, left is requested, right is result, error in brackets…

21.00mm = 20.69mm (0.31)
20.00mm = 19.62mm (0.38)
19.75mm = 19.47mm (0.28)
19.50mm = 19.23mm (0.27)

So the error is fairly consistent - 0.30mm would cure it, and it points towards the tool being set wrong by 0.30mm??? But how can it be wrong if i did a cut-measure setup??

Baffling me and clearly not right yet.

I tried another tool and got this…

21.00mm = 20.92mm (0.08)
20.50mm = 20.44mm (0.06)

These are more accurate but was setup in exactly the same way.
its a different insert shape tool.


Any ideas????
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline TPS

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Re: Mill or Turn?
« Reply #144 on: May 19, 2019, 06:21:06 AM »
just an idea, is your tool cutting realy in the Center of the spindle?
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline Hood

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Re: Mill or Turn?
« Reply #145 on: May 19, 2019, 06:52:19 AM »
Put a clock in the tool holder and command moves and see if the moves are accurate, going by your measurements I would say they will be but still worth checking. If in dia mode the clock will move half of the commanded movement.

As TPS has said centre height and orientation of the tool is critical for accuracy but it will only see small variances over small changes in dia so not likely your issue here.

Was your initial cut the same depth as your others?

Rigidity of your setup may affect things and thus setting up may require two passes to get right and doing the pass at normal DOC for a finishing pass is usually best on a set up with less than optimal rigidity

One thing to also consider with carbide inserts, it is often not a good idea to take a depth of cut less than the nose radius of the tool although it will depend on the inserts geometry as to how much it will affect things in doing so.

Offline Davek0974

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Re: Mill or Turn?
« Reply #146 on: May 19, 2019, 07:45:10 AM »
just an idea, is your tool cutting realy in the Center of the spindle?

Yes, it faced-off with just the tiniest pip in the centre.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Mill or Turn?
« Reply #147 on: May 19, 2019, 07:48:34 AM »
Put a clock in the tool holder and command moves and see if the moves are accurate, going by your measurements I would say they will be but still worth checking. If in dia mode the clock will move half of the commanded movement.

As TPS has said centre height and orientation of the tool is critical for accuracy but it will only see small variances over small changes in dia so not likely your issue here.

Was your initial cut the same depth as your others?

Rigidity of your setup may affect things and thus setting up may require two passes to get right and doing the pass at normal DOC for a finishing pass is usually best on a set up with less than optimal rigidity

One thing to also consider with carbide inserts, it is often not a good idea to take a depth of cut less than the nose radius of the tool although it will depend on the inserts geometry as to how much it will affect things in doing so.



The depth of cut was variable, just pulling numbers out the air.

I have some more tooling on way, they use my favoured CCMT tips, the ones i'm messing with are more sacrificial and use triangle tips that i never really liked. I'll do some more tests when they arrive.

I'll also throw a DTI on there as soon as i get a gap this week, but i'm fairly confident it will be ok.

I did put a DTI on the quill when taking a cut to check for push-back etc but there was none, i also put some force on the quill by hand and again there was minimal movement so the quill looks pretty stable.
« Last Edit: May 19, 2019, 07:50:05 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline RICH

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Re: Mill or Turn?
« Reply #148 on: May 19, 2019, 10:04:05 AM »
2 - Does anyone know precisely what the tool DRO's/buttons actually do - 175/176 & 324/326 respectively???

Precisely in general terms..............................
DRO 175 requires an input from the user. Button 324 uses the inputed value of  DRO 175 and when pressed,
executes the following code:
x=GetOEMDro ( 175 )
call Set Tool (x)

For a description of  Set Tool X see page 81 in the Mach3 Macro Programmers Reference Manual.
Now have a look at GetOEMDRO on page 24 and also look at SetOEMDRO on page 73.

Similar for 176 DRO / 326 Button which relates to the Z.

You actualy have three positional DRO's in Lathe, namely Machine Coordinates, Program Coordinates,
Part Coordinates MC / PC/ PartC respectfully. Additionaly there is  Radius and Diameter Mode.
That said, depends, can't say  "precisely".

RICH

Offline Davek0974

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Re: Mill or Turn?
« Reply #149 on: May 19, 2019, 04:24:14 PM »
That's odd because OEMDRO 175 and button 324 also affect/update the tool table as well, that is not documented though it seems?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives