Messages

2571

General Mach Discussion / Re: Noise - Aluminium foil screen? - Faraday Cage?

« on: July 01, 2012, 09:12:13 AM »

Nigel,
Shielding may keep noise / an offending magnetic field in or out. Sort of like a tube which keeps water inside or outside water from coming inside the tube. Shielding can be different %'s, wire meshes or braiding are have a basis for use. Maybe save yourself some agrivation and just replace the wiring with shielded cable. You will find 100% will have both a foil wrap and also
a braide. The ground provides an easy path for the noise or  interference to travel and should be an independant ground system.

RICH


 

2572

SmoothStepper USB / Re: Trouble with smooth stepper

« on: July 01, 2012, 08:55:42 AM »

santos,
I am having difficulty due the translations so bear with me.

You need to have the index working properly to do threading. When working properly the displayed RPM  is accurate. There can be some change in the rpm and Mach will adjust the threading cycles based on the rpm.
If the rpm drops too much, say 50%, the threading cycle "may" recover. If the actual threading stops then probably the thread is ruined. Have a read of the Threading on The Lathe write up in Members Docs (page 4) .  

From your replies you say using a  proximetry sensor, 2hp motor,  and trying to do a 5mm pitch x 500 length thread at 229 rpm. So will comment on the above:
- proximetry sensor- don't care what you use as long as the displayed rpm is correct AND can provide an accurate  consistant index pulse  for the feedrate you are using during threading. If you use the threading wizard to generate the code it will provide the feedrate and required accel based on RPM and pitch.
 
-500 length - like Hood said, he has no problem cutting long threads. You should scribe test and see what you can do. Have a look at the Threading wirte up on what to do. Also eliminates motor slow down as a factor when testing.

- 5mm pitch  & 2hp motor - pitch is the distance between same points along the thread parallel to the axis.
So 5mm ( approx .197" imperial) between points. How much hp you need to cut that kind of thread will depend on type of thread and depth of cut and how it is being cut. So 2hp may or may not be adequate.
-------------------------------

threading stop for one second in first depth of cut and continue withine second same cycle because of that our threading pitch shift in second depth of cut of cycle.

Are you meaning ......during the actual cutting of the thread the spindle rpm drops a lot / almost comes to a halt.
If that is the case, then Mach "may" try to fix the thread. Any "fixing" would be applied to the next threading cycle. Chances are, the thread will not be correct. You may want to consider doing the thread using alterante
flank infeed method ( see page 44) in the wirte up on how to set.

RICH

2573

General Mach Discussion / Re: Z axis problem, HELP!

« on: June 29, 2012, 06:01:57 PM »

One thing puizzles me is that you were the only one to respond

Ussca,let not your heart be troubled. Certainly nothing personal as it matters not if you are big or small time on this forum.
Sometimes we just like to leave it to Hood to reply as it gives his fingers somethng to do. 

RICH

2574

General Mach Discussion / Re: z axis moving up

« on: June 29, 2012, 05:39:42 PM »

Happy you got it working right.
Have fun,
RICH

2575

FAQs / Re: Cannot Toggle to MPG in (hit_tab) joggingscreen

« on: June 28, 2012, 08:43:11 PM »

Hmm.........never used mine in some calibrated mode. They are configured for "feel" ie turn slowly  axis creeps .... turn fast the axis moves quickly.
Try it that way you may like it.
RICH
 

2576

General Mach Discussion / Re: Shift in my X Y and Z axis

« on: June 28, 2012, 08:35:50 PM »

Are you doing 3d work?
RICH

2577

General Mach Discussion / Re: How to import 3D files for 3dworks

« on: June 28, 2012, 08:27:09 PM »

Does lazy cam interpret a dxf file to 3D works for gcodes?

No

You can use Autocad to create a 3d file from a 2d file by defining / manipulating the profiles and then save the file in a 3d format for use by CAM programs to convert it to code. Lazycam will not do that for you.
Cambam can provide 3d code if given a 3d file,but, it's code generation is not as elaborate as CAM programs meant to that task.

RICH

2578

VB and the development of wizards / Re: CNC CamGrinder (;-)

« on: June 27, 2012, 07:03:22 AM »

Have only seen one or two in all the model engineering shows i have gone to. They were modified Sherline lathes to accomplish
the cam grinding and were  not CNC.
RICH

2579

VB and the development of wizards / Re: CNC Grinder Wizard /Screenset

« on: June 27, 2012, 06:55:20 AM »

Looking good and your spot on about the cross over....good work.
Will you be able to set the crossover or will it just be some % of the step over?
I know that my grinder has a lot of backlash in the X and Y  ......thinking that maybe BC  could be used and would
satisfy doing a surface. In general, similar considerations as a mill conversion would apply when  converting a manual surface grinder
to CNC.

RICH

2580

VB and the development of wizards / Re: CNC Grinder Wizard /Screenset

« on: June 26, 2012, 06:14:53 AM »

Have a small manual bench top grinder that is used infrequently and made by Sandford.
Can see accounting for wheel wear as a challenge which relates to bringing something to tolerance.
BTW, anyone can grind a surface parallel and flat,but to a tolerance ...that is a quest.

Seems you'll need some kind of Z DRO reset based on both wheel diameter ( maybe depends on how things are done) and Z height after dressing and also after so manny passes.
May be worthwhile having a work sequence defined before doing the remainder of the screen design.

Rough manual sequence below:
1.Dress wheel
2.Touch off wheel to surface high point
3.Amount of material to be removed is known
4.Do a number of passes
5.Check surface flatness and dimension.
6.Now have new amount of material to be removed (maybe call the above a rough grind)
7.Continue grinding, maybe redress wheel and if so need to touch off again (call this a fine grind)
8. Now go for surface finish and final dimension, so the passes increase and Z feed is less.

Note that in the above the wheel was never measured and is more or less "a go as you know" sequence.
There was only one or two postings on grinding posted in the last few years that I can recall.

FWIW,
RICH



RICH