Messages

3971

General Mach Discussion / Re: can threading be done in mach without an index pulse?.

« on: December 23, 2010, 09:06:37 PM »

natefoerg,

my index pulse generator is cooked

Buy a new index pusle generator, CNC4PC has one which is not very expensive or make one up from parts. I use a Halls effect sensor to get the index pulse.
Save yourself a lot of a trouble.

thread without an index pulse just "relying" on the spindle to keep in correct position

anything is possible, but, the answer on my end is NO / won't work since there is a lot more going on than you think

stepper motor on the spindle for indexing

no problem

stepper motor on the spindle for  threading

servo ok, but stepper is not good ...... even bad

How can I get mach to believe that the rpm is 30 without an index pulse?

You need an index pulse in order for the threading cycle ( G32 or G76 ) to work and without it you will get an error and the program will stop .
How can Mach ever know what true rpm your running at if you never telll Mach via an input? Hope the question makes sense.

use A as the spindle and as an indexer (rotation in degrees)
Use two different configurations for the lathe one as linear ( step per unit ) and one for indexing ( angular / degrees ).

Suggest reading section 2 in Threading on The Lathe which can be found in Members Docs.
A stepper is bad for driving the spindle because as it's rpm goes up it will loose torque, the speed will not be linear as you increase it.
The speed is limited thus you wont get the spindle rpm's your after for turning work.

RICH

3972

Tangent Corner / Re: Custom tool grinding

« on: December 23, 2010, 06:58:02 PM »

One more thought, check out a good sharpening service as they can  probably grind them using an end mill sharpener.
RICH

3973

Tangent Corner / Re: Custom tool grinding

« on: December 23, 2010, 06:52:22 PM »

RC,
I have a bunch of pilot drills and they are all marked "SEMCO" so you may want to try that company and see what they make.
Maybe search under "aircraft drills".
Grinding them yourself would be a PITA and may take more time than you think and they won't be consistant. It would seem that somebody out there would make what
your after.
RICH

3974

General Mach Discussion / Re: Making a tapered thread. Please help

« on: December 23, 2010, 09:19:06 AM »

Thanks Russ, Graham, and Hood for some info on this,

The Simple Threading Wizard will  do tappered threads. There are are a few things that the user needs to be aware of when using it.
I'll post a little write up on it in the future.

what does the taper value represent?

Degrees ( in degrees and in decimal form / ie; 45.218 ).........the generated code will represent an angle = to 1/2 your inputed angle....I need to see what happens if using diameter or radius mode)
So for now be carefull....

piece of scrap that had a taper on it and i wanted to follow that taper

You will need to precisely locate the cutter point X & Z location based on the wizards generated code.
I would strongly suggest you try scribbing the cutting along the taper ( and very accurately measure the tapper you are going to follow), better yet, do a scribing test for a straight thread.
If test is good for a straight thread, move on, if not, don't waste your time trying to do a tappered or multi start thread as your lathes system is not capable.

BTW, if you really want to have fun playing around and testing out your lathe, cut a tapered thread using alternate flank cutting and a single sharp pointed tool. If that works do the same
for a four  start tapered thread. If that works you win the prize!


RICH

3975

General Mach Discussion / Re: Making a tapered thread. Please help

« on: December 22, 2010, 07:02:43 PM »

I am having no success on playing with the wizard to cut a tappered thread........it will cut a taper though!
There were some postings that said it would not do a tappered thread some time ago.
DAH.......nothing is ever simple and not in the hacking mood.

How's your recollection on this, Hood?

RICH

3976

General Mach Discussion / Re: Making a tapered thread. Please help

« on: December 22, 2010, 05:15:27 PM »

No need to feel silly , it's a good question never asked to my knowledge.
G76 cycle provides for a taper in one of it's parameters, but, if you post the code as G32 from the wizard , the generated code shows the beginning and end X moves so you can find which units are correct when using the wizard.
I don't know if the units are a ratio of diameters ...taper per foot...degrees ( decimal ).......whatever ........so need to check.
The manuals don't define input value and not sure it follows what is in Smid's description.
A quick look at the turn options dosen't provide a default for a taper ( i mention this because it could be a disaster for obvious reasons ) so need to confirm.
That said, I will take a look, post here,  and add the info to the Threading on the Lathe write up.

RICH

BTW: M1076.MIS is the macro for threading.

3977

Finished Plugins for Download / Re: Huanyang VFD controller plugin

« on: December 21, 2010, 10:41:07 PM »

Mark and Dave,
Thanks for restraint in your replies.
RICH

3978

LazyCam (Beta) / Re: drill sel holes does and drill radius holes not working

« on: December 21, 2010, 04:38:45 PM »

Know nothing about Skecthup Pro 7 so i'll consider you the expert on that one. Glad you got it working.
RICH

3979

Newfangled Solutions Mach3 Wizards / Re: I need help with Shapes Wizard

« on: December 20, 2010, 07:42:49 PM »

Fred,
Post some pics as i have never really used it. Others may see instantly what is wrong.
RICH

3980

General Mach Discussion / Re: losing steps

« on: December 20, 2010, 07:31:00 PM »

Dave,
Are you using backlash compensation?
Exact stop or CV mode? Maybe just post the  XML file.
What version of Mach are you using?

I am just attaching a pic of the hinge for others to see that your contouring the hinge and there are a lot of moves ( some of them .005 to .010" ).
With a lot of moves the chance to skip steps goes up and there is a fair amount of change in direction. ( One file has 20000 lines of code compared to 1000 in the other )

I would have thought that since the drive is meant to stop on some range of  / or an error your axis would have stopped moving ( i think that's what i read above......) so that would have given you
some idea on where in the code it happened and provide a way of maybe trying to hone in on the problem.

The problem, the way i see it is it can be the drive control loop or the machine is creating the problem. There are a number of things that you could do, such as:
- Air cut only with all  axes, with the just the X axis, with just the Y axis
- Bypass that controller board if possible. If the stepper is going to skip it will skip with or without some loop
- Place a pause in the code every so often so you can see if the error is cumulative ie; say every 100 lines in the 1000 line code ( G4  P5 gives you 5 seconds to check position )
- Swap the drives and do similar to the first suggestion
- Just write a little subroutine that repeats some of the moves thus is easier to monitor for postion or try to create a repeatable axis fault

Sometimes it's easy and sometimes it's not...........
How do I know ?........... Well i have a similar problem with my mill when running some 3D contouring. I know it's is not the Gcode, nor the drives, nor Mach, don't think it's a setting
 and believe it's machine related. It is a PITA. Since the machine never skipped in years. I have some thoughts on mine, but am not going to muddy this thread up with my problem as i am interested in solving yours.

BTW, Now you don't need to feel like your alone!
RICH