Messages

5581

General Mach Discussion / Re: G76 Threading Wizard ?

« on: October 16, 2009, 08:31:09 AM »

Phil,
THREADING DEFAULTS:
Section 5.4.7.2 page 5-9 in the Using Mach 3Turn manual says that a default value will be used if a value in a G76  canned cycle is omitted by the post processor.
RICH

5582

General Mach Discussion / Re: Problems threading on the lathe

« on: October 15, 2009, 09:27:28 PM »

ART and Hood,
I realy don't know.  Can certainly use Hoods as "standard" and like you said it's been around a long time, has proven good results are possible.
I have only been at the threading for say a 1 1/2 years. What stupid thing ( the rat where it is ) is the problem?
I am sure we will laugh about it someday, but in the mean time "search and destroy"!  


RICH

5583

General Mach Discussion / Re: Problems threading on the lathe

« on: October 15, 2009, 09:07:02 PM »

ART,
Here is a velocity report.
RICH

5584

General Mach Discussion / Re: Problems threading on the lathe

« on: October 15, 2009, 08:42:40 PM »

 Here is a typical code and the inputs to wizard. The only change would be rpm if lower or higher.
RICH

5585

General Mach Discussion / Re: Problems threading on the lathe

« on: October 15, 2009, 08:22:03 PM »

Hood,
It is interesting, and you need to remember that this is three computers, before with the Dell and the Sherline i never got good threading past say 1" with the SS, then you have a borrowed computer and my new one. Now i just got a replacement opto so i can do index and timing now if i want. But the tests we just did with a friends equipment kind of rules the pulse out. His instrument can actualy pick up the difference in a timing belt timing riding up in the timing pulleys or not seating properly, but, that is "very small" contributor  to rpm or feedrate varience  to the "lathe system". He can also identify the effect it has on an encoder. You can actualy measure the effect of say not using an idler on the belt. We didn't do all that but he knows his "stuiff" and has folled with his owne setup.
There are four of us here that all see the same effect of the threading, granted, i'm somewhat different in the sense that i am trying to put data against it.

You would certainly see and can measure the effect on a long thread of 200mm / 4" . If  a single point tool is used
the pitch diameter would decrease, the nut would become loose, and you would see the difference in outside diameter also / tapering in.

If you use a tool / chaser insert the lead will be more constant per grouping of threads, but, the lead would also decrease overall. Likewise on the outside diamter, if your using one of those inserts which shaves the thread OD as it cuts the v , you would not visualy see it as compared to a single pointed tool.

There is a big difference as i think you are using servos and encoders with your lathe. I am not putting my pulse into the SS board, but rather into the PP. Not sure what you have there in terms of a PLC and what it's doing.
So the "lathe systems" are quite different.

The code is generated by the threading wizard.
I like to have the M1076 .MIS generate the code as G32 since i can relate to a pass number what i see visualy as threading progresses. Very small passes .0001" cuts and a lot of them ( 40  ) as i figure if something is going to get screwy over time it will happen over that manny passes and most folks won't do that manny in practice. The depth then is limited to .004" which saves time. The angle is set to 30 degrees so it radial cutting / no z offsets occuring. That reduces the trigger/acceleration/feedrate to the equivilant of a commanded  move to point as you did.
G01  Z-1.0 F1.0  equivilant to G32 Z-1.0 F1.0 ( it just adds the triggering ) but in terms of distance actauly moved there should be none fom a common start point. It's also a good comparitive test to do if your going to try picking up a thread.The rpm used is always the same  ( ie; DRO says 402 i use 402, if you use something higher like 404, if that was a high seen in the diagnostics, i still use the DRO as didn't see any change in the resulting scribe lines. That's the logic i have used.

RICH

5586

General Mach Discussion / Re: Problems threading on the lathe

« on: October 15, 2009, 06:43:35 PM »

Art,
They feedrates were were all the same for every pass associated with a thread run. 40 passes with a listing of 4
or five per pass all the same.
RICH

5587

General Mach Discussion / Re: G76 Threading Wizard ?

« on: October 15, 2009, 05:53:05 PM »

FWIW,
How about using the wizard and generate the same code. Only difference change the M0176.mis file such that it will generate code for  G76 and then for a G32.
RICH

5588

General Mach Discussion / Re: Problems threading on the lathe

« on: October 15, 2009, 05:47:18 PM »

Hood,
Got the SS installed today and decided to run a few threading tests out of curiousity.

These were done using  MACH Ver.027 with the SS and also shown below are prior test using using the PP with ver .027.

.1P / 40 PASSES / .0001" PER PASS

PORT    RPM       DECREASE / INCH
-------    ---------   --------------------------
PP         115         .008"
SS         115         .006"   COMMENT#1
PP         402         .0035"
SS         402         .0032"

COMMENT #1 - There were multiple cuts due to varing lead ( almost as if you were doing an alternate flank cut thread ) but enventualy going back to the center of the scribe. They occured at pass 16, 22, 30, 37, 38.
The SS @ 402 rpm test had similar effect.

Frankly, just based on what has been done recently, i would say the PP  threading has improved over the SS based on scribing tests. I would have to explore it some more though. 

ART,
I did about 20 dry runs and the rat never took the baite, so nothing to say about error reporting. I did everything i could image to screw up the timing, nothing!. The error report did pick up that i disconnected the pulse plug though and resumed the threading. 
RICH

5589

LazyCam (Beta) / Re: Post Code

« on: October 15, 2009, 06:58:37 AM »

skipper,
LC will default the saving to where Mach is installed in the folder MACH3\GCode. That directory is created when Mach is installed. It will send the code to Mach3Mill if you have it open. SO you just minimize LC and then restore Mach3MIll
and your ready to go. In the manual section 6.2.2 you can change the directroy for saving the file by clicking the "Browse" button.
I need to put something into the manual to cover this in a little more detail.
Thanks,
RICH

5590

General Mach Discussion / Re: Problems threading on the lathe

« on: October 14, 2009, 09:48:06 PM »

ART,
I'll try it it tomorrow. My luck, the rat will stay in it's hole and not come out!
RICH