Messages

91

General Mach Discussion / Re: Help with 4th axis

« on: August 06, 2010, 12:46:40 PM »

Thanks for your response. Why can't you set Z0 as the surface of the bar? I am so used to the surface of my work piece being Z0 I have a hard time with it being the center of rotation. That means that if you are using a 1" round bar you would start with the cutter in the Z +.5 position?

Hi Astro,

You can set the suface of the bar a Z0. It depends on whet you are trying to achieve.
For surface engraving (which I have not done) it may be best to set Z0 as the top surface of the bar.
If you are machining a component in 3D then Z0 set at the centre of rotation works for me.

The important thing is to know where the origin is in your CAM and set the tool in the real work to match.
I'm sure some CNC Wraper guys will be along to help soon

ATB
Derek

92

General Mach Discussion / Re: Help with 4th axis

« on: August 06, 2010, 08:07:26 AM »

Hi Astro,

I do not use CNC wrapper but I set the cutter to the same real work position as the origin used in the CAM
For me, I set Z0 the centre of rotation of the A axis origin and end of the bar as by X. (Y is centre line of the bar.)

If Im just using the A axis as an indexer, then I set Z0 to the top face of my trunnion (which is 25mm above the rotary table axis)

ATB
Derek.

93

General Mach Discussion / Re: Announcement: MachStdMill screen set - release target

« on: July 07, 2010, 03:49:10 PM »

Starting to drooll in anticipation......

94

General Mach Discussion / Re: My 4th Axis

« on: July 04, 2010, 06:20:34 AM »

Hi Hood,

The worm is on an eccentric, and is easilly adjustable (its the bronze coloured ring to the left).
Worm also has a thrust race that is preloaded and the eccentric has a clamp collar to remove just about all the end float.

I  just tested the back-lash, with a DTI touching the jaw of the chuck (max radius) and indexing via mach, backlash of 0.035º or if I try and wrench the table round by hand, there is about 0.04mm of play, but it's more the spongyness of the drive train than "real" backlash.

So that looks good sitting on the bench, wonder what it works out in the real work when cutting some metal !!! time to find out :-)

Greg, I like the look of DeskProto, when I have a moment I'll install the 30 day trial.
ATB
Derek

Looks good

What kind of backlash do these Vertex tables have?
Hood

95

General Mach Discussion / Re: My 4th Axis

« on: July 03, 2010, 01:10:47 PM »

a short vieo, indexing air

http://yfrog.com/0xmvi7112z

96

General Mach Discussion / My 4th Axis

« on: July 03, 2010, 12:27:17 PM »

Hi All,

AT LAST ! my need for rotary is fulfilled  

The table uses a 5Nm stepper onto a 2:1 pully driving the worm.
I 'just' need to sort out the CAM and start some serious chomping.
Initially I will use the 4th Axis as a progamable trunion indexer - plan is to use a length of 50mm square mild steel to jig up 5 parts per side which will save a whole load of tool changes on the parts I make.
I'll upload a video to the Tube in a while.
The long term aim is to set it up to do some 'proper 4 axis work' but for now just glad its all working !!!

Mach is great !

Derek

97

General Mach Discussion / Re: Hurco mill want to run vipers with Mach 3

« on: June 27, 2010, 04:36:13 AM »

Hi Jackal,

Here is a link on the CNC zone to my Colchester lathe upgrade using Viper 200s.
http://www.cnczone.com/forums/showthread.php?t=82579&page=3
It explains the tuning a little.

If you know what the PID parameters 'do' in a servo loop then you'll do the tuning quickly.
If not then it will take a bit longer - its easy, if not just a bit of a guestimation exercise,

ATB
Derek

98

General Mach Discussion / Re: Closed loop system, encoder connected to mach3

« on: June 26, 2010, 06:31:14 AM »

I think the Granite drives can be configured to use stepper motors with encoder "assist"

ATB
Derek

Hi Ian

Thanks for the reply...

I understand how the servo closed loop systems work... And also know that  a good stepper system doesnt loose steps..
What I wanted to know whas in the event that it would happen, or that one of the steppers would stall for an instant  for what reason at all... that mach could  correct this by moving to the right position according to the feedback of the encoders..

SO if I understand correctly.. I CAN connect encoders to the shafts..  of each axis and connect it to mach... mach will show the coordinates in the DRO but in the event of a slight stall or loss of a step   mach does not correct it and continues from the "wrong"spot.. Or the other way around... that mach just puts out a pulse stream at a certain frequency untill the encoder says he reached the spot  and then stops..

Thats to bad.. hahah Just wanted to know if it whas possible  to have a cheap stepper system with the benifits of an encoder just like a servo system... and mach would have a realtime knowledge of where the axis are and correct any faults..

Thanks

Robin

99

General Mach Discussion / Re: Announcement: MachStdMill screen set - release target

« on: June 22, 2010, 12:29:34 PM »

I like the new screens, they look professional and plenty of bling  .

Use of technology by persons above a certain age should be made illegal as it compromises the functionality for the rest of us slightly younger (under the ilegal age to use tech) and makes it a much more difficult task for the programmers   

I'd like to see the tool path next to the code as when using a wide screen projector, its like watching a game of tennis.

Great job, I can't wait to use the new set.

ATB
Derek

100

General Mach Discussion / Re: Polygon Turning

« on: June 14, 2010, 02:56:14 AM »

seriously considering doing this though just need to find the time

You said it! no going back now ;-) - it would be fantastic to see Mach doing this.

Last page was interesting too - "thread whirling! !!!!! what the heck is that !!!!!!!

ATB
Derek.