Messages

911

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 27, 2010, 01:46:41 AM »

Hi Bob,

The posts I listed are by people who say they actually are making parts by milling whole day long to tight tolerances. These are NOT speculations. If you know how to do it right with a boring head and it works for you then no reason to not use it, especially if your machine is not a very expensive VMC.

I think this discussion is not far from becoming a scientific discussion  so I think we have to agree to disagree on it.

Thanks,
Dan

912

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 26, 2010, 03:30:28 PM »

Hi Bob,

Read the thread (a nice forum BTW, thanks for the reference), and that's exactly what I was saying. See replies number 6, 17, 21, 22 and 25. You can get 0.01mm tolerance and even better by interpolation on a good VMC.

I am aware about fitting tolerances recommended for precision bearings - have fitted a few and designed a few fittings And I am still saying that getting better than 0.01mm is much of trial and error and by clever programming can be achieved by interpolation milling as well.

And just to give an idea about the "theoretical" tolerances we are discussing, a 10 degrees Celsius temperature difference would change the size of of a 30mm bore in aluminium by 0.006mm and twice that in steel - 0.012mm!!

Dan

913

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 26, 2010, 11:00:48 AM »

Hi Bob,

Don't know... I wouldn't use a boring head if I had a good VMC with ground ball screws. My mill has rolled screws and a bit backlash but with clever programming I can orbit a circle within 0.015mm!

A bore accurate to 0.01mm is good enough to nicely fit a bearing inside, so don't think I get your point about depending on the VMC's accuracy...

Are you saying you can get better than 0.01mm using a boring head...? I (and probably most CNC workshops out there) don't have the tools and can't even measure that accurate

Dan

914

Flash Screens / Re: How should I manage tool change?

« on: April 26, 2010, 01:21:43 AM »

If it's intended for any user, then may be leave the same 'behaviour' as with the standard Mach screen set...?

Dan

915

Show"N"Tell ( What you have made with your CNC machine.) / Re: My first finished project on my new lathe

« on: April 26, 2010, 01:15:29 AM »

Nice yo-yo. Looks like it is a single piece...?? Could you explain then please how you made the ID bore with the conic rod in the middle? Custom ground tools?

Thanks for showing.

Dan

916

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 26, 2010, 12:53:35 AM »

Never saw a good VMC using a boring head They can orbit a circle as good as within 0.01mm (and very often much better than that) by interpolation and get a better surface finish than they would with a boring head and plus it's much faster than using a boring head.

Dan

917

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 25, 2010, 01:57:38 PM »

Aside from lead screws' increased friction there is also the slides friction and here conventional slides have advantage over linear ball slides.

One thing we usually forget about backlash compensation, and thus underestimate its benefit in producing more accurate parts, by saying "the cutting forces will drag the table in unpredicted directions" is the fact that backlash compensation really matters on the finishing cuts which in their turn produce very small cutting forces which usually wouldn't be able to overcome the friction force of a conventional slide. Not true for every machine and case, but I believe that considering the above, most of the hobby users can benefit backlash compensation, especially when planning well the machining operation.

Also, backlash compensation helps programming a lathe more straight forward and easy, not thinking about the backlash on each move.

Daniel

918

Show"N"Tell ( Your Machines) / Re: Success! Mini Machining Center under Mach3 control - Video link

« on: April 22, 2010, 06:01:07 AM »

Hey Hood! Congratulations for hitting the 10,000 posts mark

We appreciate your contribution!

Daniel

919

SmoothStepper USB / Re: Whats the current developement state of the SS?

« on: April 22, 2010, 02:25:01 AM »

Hi Gerry,

It is a simple board that Steve has designed to accomplish in hardware the same effect of using the SwapAxis() command in Mach3. Two pairs of Step/Dir signals are in and two pairs are out. A triggering signal from Mach3 swaps the output signals between the two pairs.

Daniel

920

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: April 20, 2010, 03:28:54 PM »

Very nice job, Tweakie! Finally got to see it working

Now need to see how it cuts some hard stuff which I assume it was primarily made for.

Daniel