Hello Guest it is January 17, 2022, 02:28:37 AM

Author Topic: Success! Mini Machining Center under Mach3 control - Video link  (Read 331556 times)

0 Members and 1 Guest are viewing this topic.

Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #280 on: January 25, 2015, 09:17:28 AM »
Truly inspirational work.  I am itching to build one now as well!

A couple of questions if I may.

How is the 'universal' mount (shown on page 24) fixed to the spindle?

How is preload of the bearings done now you have done away with the threaded section on the spindle?

Thanks,

Dave.

Offline simpson36

*
  •  1,369 1,369
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #281 on: January 26, 2015, 05:20:16 AM »
There are two models of the InTurn™. The new ULTRA has a one piece Forged Chrome Moly Steel (4140) spindle with a D1-6/A6 mount.

The MEGA shown in this thread has a two piece spindle with a D1-4/A4 spindle.

D1 and A are standards with D1 being CamLoc and A being bolt on.

On the MEGA, spindle is two piece with the flange being a heavy press fit, heated to 550F and pressed on with a 20 ton press at that temp. It is exceedingly unlikely that you could dislodge such a press fit with the several times the 2HP available for the MEGA.

In addition to the press fit, the hardened steel cams for the CamLoc system extend thru the flange and into the spindle itself so the absolute maximum the flange could ever move is the .001" - .002"  clearance in the Cam holes in the flange. The very first prototype MEGA was abused by my own hand for a few years before being sold when replaced by the new ULTRA. A few crashes bent the chuck's backing plate, but the spindle nor D1 flange was ever effected. A bent backing plate is easily skimmed to re-true it. Eventually, I made a thick cast iron backing plate which never bent even in severe crashes.

Early on, I spoke with the engineers at SKF about preloading the ball bearings. Deep Groove balls (as opposed to AC) are not specifically designed to be preloaed, but they have a lateral load spec and as long as that is not exceeded, there is no problem with preloading. Because the spindle is hollow, it has a very large OD which results in a huge bearing that will never see the loads it is capable of in this application, so there is plenty of excess load capability, even for drilling 1" dia hole into steel.

The preload is light and intended only to remove lateral play inherent in the bearings. The amount of preload is far less than what the bearings experience in operations like drilling into the center of a workpiece.

The preload is retained by the steel locking collar on the back of the spindle. The force exerted by backing out a stuck drill bit, heavy cuts on the back side of a workpiece, or using the wrong parameters for TPI on a large tap will exert significantly more force on the retaining collar that just holding the light preload.

The maximum predictable force on the locking collar is easily contained by the friction of the collar against the spindle, which is provided by a fine thread clamping screw. For the forces presented by the MEGA, a threaded connection is not needed, nor was there ever a treaded connection on this piece.

Perhaps you are confusing the MEGA with the new ULTRA. The ULTRA build videos clearly show the threaded retaining collar, but that is required by the optional tapered roller bearings, which are adjusted by clearance and not force applied. The 'micrometer' type of accuracy provided by the 20TPI locking collar is needed to provide this fine adjustment. The collar is still clamped in place using a large fine thread bolt.

In both machines, the locking collar doubles at the main pulley mount so there is also torque applied to the joint. Both applications work out fine on paper with 3x the horsepower ratings of the respective machines. There are lots of MEGAs out there and to my knowledge, only one has dislocated the locking collar. Most likely I did not set the collar tight enough from the get-go, but the user was able to re-establish the pre load and lock the collar down.

There are only a few of the new ULTRAs and only one had the tapered roller option, so it is a bit early to declare victory on that scheme.


 




 

Offline simpson36

*
  •  1,369 1,369
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #282 on: January 26, 2015, 05:46:57 AM »
I would have thought that a stepper can actually spin pretty fast if programmed correctly though perhaps im wrong there.

*Please anyone feel free to correct me if im wrong here*

I believe, that if you are running Mach at 35,000 mhz kernel speed, that implies that it can make 35,000 pulses per second, meaning 35,000 steps per second, which at a full step would be 175 rotations per second which is 10,500 RPM. Now, the caveat is, that is a 1:1 ratio which obviously wont work, and 10,000 is probably beyond the rated RPM for a stepper. If you throw an 8:1 ration on there, you're looking at 1312 RPM (at the 4th axis) with the stepper running 10,500 RPM. Also, as Simpson mentioned, the faster a stepper turns, the more torque/holding power it loses. So basically, you'd be at the point where it would be pointless not to do a Servo if you are planning to do high speed operations.

That all being said, I still went with a stepper because of cost, ease of setup, and I didnt need to do lathe work on my mill. Its all about what your intended use is for the machine.

Sorry, I missed this port on my last visit.

You invited: *Please anyone feel free to correct me if im wrong here*

Any while you are not wrong at all, there is a feature of most servo drives that you did not mention which (in many cases) negates the step frequency issue that you correctly identified.

There are a variety of names for the feature; 'step multiplier', 'pulse ratio', 'electronic gearing' and so on, but the function is the same: to alter the frequency or number of steps needed to rotate the motor.  The limits and fineness of this adjustment varies greatly from perhaps a few pre-set choices in hobby drives, to being able to separately specify the numerator and denominator of the ration in industrial drives. Some drives it is as easy a specifying how many pulses per revolution of the motor as a single input number.

In the case of MACH running on the PP, typically the drive would have much higher frequency capability than MACH and the ratios for industrial drives can be very high indeed. "High-resolution encoder of 4194304 pulses/rev" taken from the Mitsubishi J4 series manual.

Without a very serious multiplication of the steps available from MACH, this motor would only be useful for moving something the speed of a farm tractor.  :D

 

Offline BR549

*
  •  6,952 6,952
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #283 on: January 26, 2015, 11:18:16 AM »
HIYA Steve, (OT) do yo have a picture of your 4th doing a radial type drill opertaion? I am working to finish a new WIZARD for 4th axis drilling and am in need of a good picture to go on the page.

A static picture (setup) would be fine if it just showed a round object in the chuck and a drill in the spindle just above the object. I will trade you a copy of the wizard for the picture (;-) I have a new TURN version for drilling as well for lathes to do offset face drilling. Do you have a picture of that as well?

(;-) TP

Offline simpson36

*
  •  1,369 1,369
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #284 on: January 26, 2015, 03:28:56 PM »
HIYA Steve, (OT) do yo have a picture of your 4th doing a radial type drill opertaion? I am working to finish a new WIZARD for 4th axis drilling and am in need of a good picture to go on the page.

A static picture (setup) would be fine if it just showed a round object in the chuck and a drill in the spindle just above the object. I will trade you a copy of the wizard for the picture (;-) I have a new TURN version for drilling as well for lathes to do offset face drilling. Do you have a picture of that as well?

(;-) TP

There are videos posted on both of these operations, but I should also have some quality pix around here, so let me dig a bit and I'll get you fixed up.

Offline simpson36

*
  •  1,369 1,369
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #285 on: January 26, 2015, 05:41:35 PM »
Terry,

I found a few very hi res photos of radial setups. As soon a sI get them edited and copyright notice on them, I will upload them to my ftp and put a link here for download (big files).

No pix of the horizontal, just video, but I have the original HD footage and can lift a decent photo. Here is the vid. Give me the number off the timeline of the images that you want and I'll pull a couple of pix off of it for you

https://www.youtube.com/watch?v=Dd_M6Li_OrA

Offline BR549

*
  •  6,952 6,952
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #287 on: January 27, 2015, 11:43:30 AM »
Thanks Steve , here is what I am working on. IT can be a Wizard OR a page on the screenset

(;-) TP

Offline simpson36

*
  •  1,369 1,369
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #288 on: January 27, 2015, 01:35:40 PM »
Wow, Thet thar's one fancy Wizard!

Couple 'features' to consider adding:

*Hard tapping (a.k.a. Rigid tapping)

*Universal threading for the 4th axis (internal and external)

Also, it would be extremely convenient if you can add the lock/unlock macros via the wizard. If not, then provide instructions and links to editors that make this step very easy.

* CNCcookbook made special additions to their G-code editor to 'intelligently' add macros only where needed  . .  one would imagine by analyzing the context, but that's just speculation on my part.

*Notepad++ (this is free) has the ability to inject control characters into the 'replace' string so you can replace on line of Gcode with more than one line.

ex:

Find "G0A"

Replace with "M4010\nG4P.25\nG0A"   in the entire file.

Anywhere there is N*********G0A*********

there will be

N*********M4010     (unlock macro)
G4P.25
G0A*********

Finding the spot fore the lock macro is trickier . . . needing that 'intelligence'.


One approach of many. Just a thought . . .  ;)








 

Offline BR549

*
  •  6,952 6,952
    • View Profile
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #289 on: January 27, 2015, 07:49:18 PM »
The G84 button is on the list to do. You can already do it with a Bolt circle just input the 84.

I can do a button to insert the LOCK or UNLOCK into the saved gcode OR LIVE. AND make an auto insert function as well.

With this Wizard you have the option to run it LIVE or Save Gcode file (;-)

AND there will be a button to delete the last line of Gcode so you can erase the last line as many times as you wish to delete a function. It saves having to open the Editor and delete code.

I will LOOK at the threading but I am seriously out of room now (;-). I could expand it to 2 pages.

(;-) TP
« Last Edit: January 27, 2015, 07:51:02 PM by BR549 »