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Author Topic: Turning wizard says 0.75" but part ends up 0.5" diameter  (Read 1594 times)

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Turning wizard says 0.75" but part ends up 0.5" diameter
« on: August 11, 2017, 01:29:40 PM »
Hi, here are the steps I am talking to use turning wizard. I start with a 1" dia piece and want to turn to 0.75" dia but it turns to 0.5" dia

Diameter Mode
Home machine
Touch off piece and place at edge
Place 1" in x and click part zero
Place 0" in zed and click part zero
Go to turning wizard
Place 1" in start x
Place 0.75" in end x
Place 0" in start zed
Place -0.25" in end zed
0.010" rough cut
0.005" finish cut
0.1 clearance
Post code
Go to auto, cycle then cycle start
Cuts to zed -0.25"
however x is cut to 0.504" instead of 0.75"
What is normal backlash? Could this be affecting it.
When I touch off and set on edge and move just off face and then  G1 X0 tool goes to other edge not center of piece at 0.
Why? I though zero on lathe is center of object being turned.

Help, What am I doing wrong?

Thanks
Dave

Offline RICH

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Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #1 on: August 12, 2017, 09:17:26 AM »
Dave,

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Help, What am I doing wrong?

Frankly, you don't understand a lot of the  basics relative to lathe, no big deal you just need to know before you go. READ AND UNDERSTAND what is in the Lathe Manual.
I'll post some info to get you started, but first let me clear up some questions.

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What is normal backlash?

There is not such thing as "normal". You have what you have for a system so know what what it is  and either fix it or live with it. Backlash does work, but a software solution is not the ideal fix, it's just a matter of degree of backlash.

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what number(s) is placed in the backlash compensation screen and how do I determine them?
Look in Members Doc or do a search as ther is plenty of info posted on what to do. The amount is the unit value  required to remove non-movement of the axis.

BACKLASH SETTING 50-50-50 RULE
http://www.machsupport.com/forum/index.php/topic,29149.msg204717.html#msg204717

How to check backlash
http://www.machsupport.com/forum/index.php/topic,12513.msg81002.html#msg81002
 
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Could this be affecting it.
Final part dimensions, yes, but not what is happening as you describe.

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Are there any manuals describing the Wizards?
No.  You need to just play with them. Suggest you just have no work offsets active and set Machine Cooordinates to 0,0 and home is same as MC 0,0. Then use the wizard in diameter and radius mode and post. Keep the amount of cuts down as it makes understanding the code easier and see the results via dry running.


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Is Part Zeroing for parting off the workpiece
You first reference the machine and then define the work piece location relative to home.
Need to undestand how to setup a job.

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Why? I though zero on lathe is center of object being turned.
X axis location never changes and Z will vary. Movement of X can be different depending on front or rear lathe and where it was referenced. See attached file.
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When zeroing a part in the lathe do you place cursor on Progdata so LED is on
DRO's indicate axis position depending on Coordinate system being viewed.
See attached for a understanding.

RICH
« Last Edit: August 12, 2017, 09:55:48 AM by RICH »
Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #2 on: August 12, 2017, 07:34:16 PM »
Thanks Rich for the detailed response Very well done. What did I do wrong in my description?

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Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #3 on: August 13, 2017, 06:21:06 AM »
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What did I do wrong in my description?

Not sure what you mean.

RICH
« Last Edit: August 13, 2017, 06:24:07 AM by RICH »
Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #4 on: August 14, 2017, 08:16:10 AM »
Rich,
When I home machine and then move tool tip to edge of work piece which is 1 inch in diameter and touch off x and z and zero both.
Then I place 1.000 in x and 0.000 in z in diameter mode. When I enter G0 x0 shouldn't the tip of the tool go to center of material x=0?
It is going to other end of material. Is this correct?

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Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #5 on: August 14, 2017, 10:48:44 AM »
I think  that you are creating a Work Offset.
Study the manual and the info I posted.

RICH
Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #6 on: August 14, 2017, 11:37:39 AM »
I am sorry for troubling you, I have studied the manuals.
I may have a mental block but I just want to confirm the
following.

So my last question is after homing the machine and touching off
when I enter the diameter of the
work piece into the DRO does that change the x=0 from the
center of the work piece to the opposite end of the work piece diameter
from where I touched off the tool?

From what I have read x=0 stays at the center line of the lathe.

And for what it is worth I thought this was a support forum.

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Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #7 on: August 14, 2017, 03:34:41 PM »
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I am sorry for troubling you, I have studied the manuals.

You are not troubling me.

Please post your xml file you are using for the lathe.

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And for what it is worth I thought this was a support forum.

It is and that kind of comment will not get you very far with me. >:(
 

RICH
Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #8 on: August 14, 2017, 04:41:58 PM »
Rich, I am sorry for the remark I am frustrated. Shouldn't take that out on you.
Please see attached xml.

Thanks
Dave

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Re: Turning wizard says 0.75" but part ends up 0.5" diameter
« Reply #9 on: August 14, 2017, 07:20:43 PM »
I'll reply sometime tomorrow. Busy got to go.

RICH