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Messages - simpson36

1121
General Mach Discussion / Re: Limitations of PC Parrallel Port
« on: June 18, 2009, 10:49:05 AM »
I don't know of any disadvantage to using the lowest pulse rate that gets you the speed you want, but setting it arbitrarily high is counterproductive as you gain nothing, but narrow the gap between 'it works' and 'it doesn't work'.

On the other hand, setting the acceleration arbitrarily low can cause a host of problems, depending on what you are cutting. This forum has a very large percentage of hobby users who cut soft materials at very low rates. If you are in that category, then you are probably OK with very low accelerations.

For short moves, a slow acceleration Will not allow the motors to reach full speed and the net effect would be an overall slower travel, but also a very inconsistent travel as longer moves would be faster and one would imagine this makes the CV operation far less effective.

The big problem is going to come in if you are cutting 300 series stainless or most tool steels and/or you are using carbide inserts. You want to maintain a certain chip load per tooth especially with inserts as if you stop cutting and ride up over the material, it gets extremely hard extremely fast and now you have a hard-as-hell 'crust' for the next tooth to cut through . . . which it may or may not be able to do.

It does not seem logical to persons new to cutting metal, but tiny chip loads (which you will get during slow accell and decell) can cause an incredible amount of heat build up in the tool and the part. The re son is that the if the chips are the right size and are cut at the right speed, the lion's share of the heat will go overboard in the chip itself, instead of sticking around to make our tool bit turn pretty colors  :(

Personally, I would run the acceleration a little below where the motors cannot tolerate. The faster the acceleration, the more consistent your feed rate will be on average. Mo' better to tool life and finish.


1122
General Mach Discussion / Re: Limitations of PC Parrallel Port
« on: June 18, 2009, 06:55:07 AM »
Note that just because a computer can pass the driver test at a given speed does not mean it can operate Mach at that speed.

If you right click in the bar on the bottom of your windows screen, you get a window where you can choose task manager . . which has a performance tab . .  which tells you the CPU load. When  it maxes out, you have problems.

1123
For those who asked, I will also be posting the swap axis macro and mayby some others.

After seeing Ray L.'s beautiful macros, I'm just too embarrassed to publish my sloppy code until I get it spruced up a bit . . . :-[

Hi simpson36,
  When you post your "improved" code, would you also include the original that worked for you before "cleanup"?   
It would be interesting to see what works without being "elegant".    Don't be embarrassed....  I'd just view the process as a "development".     ;)

Great details in the photos.  Nice setup!
Thanks,
Bloy

Here are the two basic macros with minimal comments added:

'M940.m1s 06/01/09 ©2009 www.theCUBEstudio.com
'Macro to make 4th axis become spindle
'use M950 to swap back and re-home


resetaxisswap()

SwapAxis(6,3)

End








'M950.m1s 06/01/09 ©2009 www.theCUBEstudio.com

'Macro to swap 4th axis back to A and re-home
'use after M940 to restore 4th axis to A axis

'Waits until axis stops moving before reset
'Moves axis 20 degrees if home switch is active
'Re-homes A axis
'Resets machine A to zero


While ismoving()
sleep 100
Wend


resetaxisswap()


'CHECK IF A AXIS HOME SWITCH IS TRIGGERED


If getLED(39) Then   

   here = GetABSPosition(3)
   
   here1 = here + 20
   
   Message ("Axis home switch triggered - moving off to " & here1)
   
   
   code "G0 A" & here1
   
   While ismoving()
   sleep 100
   Wend
 
End If



'RE_HOME A AXIS
   
DoOemButton(1025) 
   
While ismoving()
sleep 100
Wend
   

'RESET A AXIS TO MACH ZERO

SetMachZero(3)

End

http://thecubestudio.com/Mach3/macros/Mach3Mill/M940.m1s
http://thecubestudio.com/Mach3/macros/Mach3Mill/M950.m1s

1124
Vmax, I recall you mentioning that before. I have installed needle roller thrust bearings on each end, those are neccessary for operating as a spindle and they actually peeked out past the surface in one spot . You can see the oil leaking out at that spot in one of the photos. If not for cutting the ends for the thrust washers, I could do as you suggest.

A new servo drive (Viper) and a little more voltage should get the 4th axis to a max of 2,500 RPM with a 2:1 ratio. Sustaining that speed for hours on end would cause trouble with the setup you are suggesting. At a minimum, it would consume a lot of power and I don't have so much I can give it away to a plain bearing or to a non bearing thrust. Used as an indexer or at low speeds, I agree with your assessment.

A full ball bearing head with sealed bearings is the way to go for a reliable zero play spindle on a budget, methinks. I'm going to 'ghetto' it a little with just some quality SKF 'Precision Plus' bearings and not angular thrust or high precision. No point with the current machine that flexes all over the place anyway . . .  :-\

Hood, how do I post something specifically to a Mach3 group on Youtube? I have Mach3 as a keyword, but that's all I know to do. Not a big 'tuber. Still dinking around trying to get the best HD quality too.

1125
Here is it . . . will be avail in HD after YouTube is finished processing, but is viewable now.

http://www.youtube.com/watch?v=NzY-OqckqpI

Special thanks to Hood for the re-homing info.  Also Vmax, RayL, Machinemaster, and others . . .  

BTW, lots of light cuts this go round. I will have a lot more power once I get the Viper drive (delayed waiting on parts  :()  With the 1800 line encoder, the Gecko faults with a normal cut.



1126
General Mach Discussion / Re: Soft Limit Warning
« on: June 15, 2009, 08:11:01 AM »
FWIW, I have noticed this behavior when I have offsets in the code. I does not seem to happen if I use the offset table, only if I offset 'on-the-fly' within the code. That's my recollection anyway.

It seems like perhaps Mach collects the physical extents as it generates the path, but then applies those to the current position at the beginning of the program without regard for subsequent offsets within the body of the code . .  just a guess . . .

1127
General Mach Discussion / Re: problem cutting acrs
« on: June 15, 2009, 08:01:44 AM »
That's aluminum. You can clearly tell by looking at the molecular configuration.  ;D

True, but you overlooked that the molecules are clearly British, so the material is Aluminium.  :D

Right well . . carry on . . .

1128
General Mach Discussion / Re: problem cutting acrs
« on: June 15, 2009, 07:56:28 AM »
Something to try is oversize balls for your ballscrews.

I have the little Thomsons with 1/8" balls and was able to get .001" overize balls. Took out all of the play.

Longevity of this solution will of course vary by how many hours and how much stress (some folds call it stress, I call it abuse), you put on it.

1129
For those who asked, I will also be posting the swap axis macro and mayby some others.

After seeing Ray L.'s beautiful macros, I'm just too embarrassed to publish my sloppy code until I get it spruced up a bit . . . :-[

1130
Hi, Simpson36
Very Nice job you've done, Show us more if you get time.
Chip

OK, I'll be making another video soon. Very cool as you can clearly see the swap-axis and re-homing functions as it makes the part in the previous post. For now, here is the final drive mechanism. This will be moved over to the new head once I have that built:


Poor thing after many hours of abuse:

This is still one of the last temporary 'get-er-done' quickie that needs a final design: