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Author Topic: Problems threading on the lathe  (Read 330097 times)

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Offline RICH

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Re: Problems threading on the lathe
« Reply #500 on: October 09, 2009, 11:35:24 AM »
ART,
Made a 78 slot disc for timing, unfortunately, my optio is bad and need to order another one.
So no advanced timing test.

The plug in that i used for the advanced timing test was the one posted on page 24 / reply #238 of this
thread. Can you confirm that is the one to use?
There are only about 15 or so test's that have been posted in this thread!   ???
RICH

Offline ART

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Re: Problems threading on the lathe
« Reply #501 on: October 09, 2009, 02:02:39 PM »
Rich:

  Yup, thats the one. If you set the index and timing to the index pin, youll still be able to use it with only an index pulse..no wheel required.

Art

Offline RICH

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Re: Problems threading on the lathe
« Reply #502 on: October 09, 2009, 07:44:39 PM »
ART,
I tried the advanced timing. It only shows that there is one slot and provides no slot or timing rpm data.
I looked at the diagnostics and it shows there is timing.
The index is port 1 pin 15
The timing is port 1 pin 10 ( pin15 and pin 10  are using the same signal )
If i remove the wire from pin 10 then the diagnostics will show 0 slots.
SO that one didn't work!

-------------------

"If you set the index and timing to the index pin, youll still be able to use it with only an index pulse..no wheel required."Ok, that plugin was posted on page 26 reply 253.
The index and timing is port 1 pin 15. Same as the other one no rpm data.

 ???  ???  ???  ???
RICH


Offline ART

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Re: Problems threading on the lathe
« Reply #503 on: October 09, 2009, 08:06:47 PM »
Sorry about that Rich.

Ill check why and reissue the plugin after I test it on my lathe for RPM operation. I probably need to make a small
change to allow for single pulse intput..

Art

Offline RICH

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Re: Problems threading on the lathe
« Reply #504 on: October 09, 2009, 08:12:15 PM »
No problem.   ;)
RICH

Offline ART

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Re: Problems threading on the lathe
« Reply #505 on: October 10, 2009, 11:16:13 AM »
Hi Rich:

  Just to be sure we're on the same plugin , I publish it here.

My results show the RPM is much more stable under the advanced threader plugin. It shows a normal RPM of 393-395RPM fluctuating constantly,
the advanced threading shows 393.50 to 393.6 RPM and very steady. This fluctuation could accoutn for a highe rpitch error at low RPM, and lower error at high
RPM due to the fluctuation being a smaller % of the total RPM, and your testing seems to point directly at that possability. If this can be confirmed, I will simply
change the single point threading to measure the RPM based on time, not # of interrupts.

  Here is a photo of my advance3d threading run, both Timing and Index inputs are enabled and both are set to pin 15 ( my index signal).

 I ran a test thread in the air and all runs fine, so I suspect you can thread quite well even with one slot per rev which is what will display under such a setup.

 Im of the opinion that it isnt necessary to have a slotted wheel, though it may make things more accurate as instead of being one rotaiton behind, the corrector
will be one slot behind.

Let me know how it goes..

Thx
Art
 

Offline RICH

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Re: Problems threading on the lathe
« Reply #506 on: October 10, 2009, 02:59:20 PM »
ART,
I love it when a plug in works first time tried!
This is using Mach version .028
Here are screen shots at 115 and 402 rpm.

Even though the lathe screen DRO flickers by 1 rpm in both 115 and 402, the advanced diagnostics is showing the slot based rpm to be greater by percentages which relate to the threading  tests that were done ( ref my reply #488) .

So for 115 rpm .9 rpm  such that .9/115=.0078  ( .8% change in lead )
During the 115 threading dry run the rpm for threading to the thread based rpm only changed by only  .01.

 So for 402 rpm 1.27 rpm such that   1.27/402=.0032  (.3% change in lead which very close to the .0035 lead error) and somewhat confirming the testing.

Maybe you have found were the rat was feeding and it's about to get a dose of poison!  ;D

Question / confirm? 
If i do actual thread testing, then I'll need to have the Advanced Threading checked / Enabled and it will modfy the threading cycle appropriately?

RICH

Offline ART

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Re: Problems threading on the lathe
« Reply #507 on: October 10, 2009, 09:13:18 PM »
Hi Rich:
 

   Yes, in theory the multislot works just as the single slot does in terms of correction, but though it will thread it isnt heavily tested.
Id be interested in the results, but dont be too disappointed if some other problem develops, I think your testing has shown what
the culprit is, the RPM varys too much when based on # of interrupts, but when based on the gigaclock counters, its much more
accurate and true, so in theory all I need to do is change the normal threading to gigaclock based counters and we should be able to prove a
perfectly working system can thread just fine, though thjose with varying systems may still see some aberations..

Let me know how it goes..

Art

Offline RICH

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Re: Problems threading on the lathe
« Reply #508 on: October 10, 2009, 10:27:13 PM »
ART,
I'll do some testing tomorrow and mid-next week we'll see if we can measure the actual motor variations.
Attached is a file which kind of puts things into perspective. The threading has come a long way thanks to your efforts.
You may want to take a look at the "Rich Chart" on lead error. I think we are close and can get there.

RICH

Offline RICH

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Re: Problems threading on the lathe
« Reply #509 on: October 11, 2009, 11:45:51 AM »
ART,
Only one test done using advanced threading. Picture attached.
Something went wrong after the 6 th pass. The first 6 were a single scribe but the lead decreased .006" in an inch.
Like you said, expect the unexpected and keep the hand on the ESTOP!
RICH

MODIFIED: OOPS, the .0007" dim should be .007" in the picture.
« Last Edit: October 11, 2009, 11:49:15 AM by RICH »