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Messages - simpson36

221

Crusty OLD Machinist (;-) ???? I resemble that remark a great deal (;-).

(:-)TP


In addition to your machining experience, which is extensive, you also are a wizard at G-code, so I can think of no person better equipped to create a truly 'universal' threading program.

I prefer scripts to G-code because of access to better math, but I sent you a couple of my internal threading G-code programs as well as a G-code fragment specifically for calculating multiple passes in a specific way for specific materials. Hopefully there my be a morsel in there that will be helpful.

Now I am chomping at the bit to see what you come up with and test the whole system ( and I think system is the right word). Perhaps I can entice you somehow into expanding the system to take advantage of the InTurn™ Turning capability in prepping the part prior to the drilling/tapping operations.


Now, one more fish for your pan; provide the coordinated motion to bore and thread holes that are not in the center of the part. Example: simple flange with 4 tapped holes on a single BC. With NO horizontal spindle, this can be accomplished using a stationary cutting tool by coordinating AYZ motions to create an 'orbiting' motion in the part that will allow drilling/boring/tapping off center.

'Should not be that Hard' . .  is a phrase that I heard somewhere . . .  :)



222
Should not be that hard :D (famous last words).

That's what I thought . . . . may I suggest that you not test with aluminum, but with DOM tube. Picture perfect threads on aluminum are all too easy. Clean internal threads on DOM tubing will earn you a case of beer.

Also remember that real threads are not pointy. They loose (((P/2)/TAN(30))/8) in height by spec. Given that bit of threading trivia, an uber convenient addition to any internal threading wizard would be a calculator that provides the correct actual ID for a given thread.

Then, when you are finished with the threading code, you can add the boring code ahead of it for 'on-stop-shopping'.

And as any good 'Crusty Old Machinist' knows, taper the back of the bore and lift the last thread to prevent creating stress risers in the part.  ;)

223
OK i made some room and have 10 extra function buttons available.

IF you can explain what axiss you use to do the internal external threads I will give it a go. Should not be that hard :D (famous last words).

The tool can be held in the Z or Y axis. Threads can be cut from the top or bottom (Z axis) or front or back (Y axis).  Just what you wanted to hear . . LOL!

It sounds like unnecessary redundancy, but consider that cutting internal threads is best from a lubrication standpoint to have the cutter at the bottom where the oil collects, however, with a large diameter part, it can be difficult to reach the bottom with a cutting tool before the mill head contacts the top of the part with the tool bar on the 'far' side of the head. This arrangement is needed for long parts and puts the mill head above the part and the shorter tool overhang to cut the top of the hole becomes the determining factor for the setup.

Fortunately X remains X, so it is primarily a matter of exchanging Z for Y and positive for negative moves.


A picture that shows a distant view that shows ALL of the machine would help.

(;-) TP

As it happens, at this very moment I have an Ultra Spindle mounted for final turning and drilling the CamLoc flange, so I can get a lot of fresh photos showing exactly the setups you want.

 8)

224
4th axis single point 'universal' threading:

This is the 800lb Gorilla, especially if you are trying to meet a spec. for thread fit. I have experimented and tried so many methods it's just ridiculous and while I have several successful 'universal' threading G-codes and Macros, including some that will cut any arbitrary tapered thread, the 'perfect' solution continues to evade.

I have tried the 'old school' 29 degree step down learned from crusty old machinists many, many moons ago. This works great for aluminum, but 'not so much' for stainless. Then 'quadrant' type cuts where the thread form is broken down into interconnected 'blocks' in the manner of an FEA mesh. 'Farming' or 'plowing' where successive vertical or horizontal rows are removed followed by a configurable number of 'spring passes'.

The two main positioning methods I have used are actual ID/OD or a 'surface start' at Z zero (or Y zero depending on where the tool is). I will provide, privately, some of the carcasses of these animals for you to dissect if you think it may be useful and of course, I am happy to discuss different methods, theories, or ideas on the best approach, but I do not have 'the' answer to this one.  :-[

It would be great to get some fresh ideas on how to skin this cat. A theory to work on. I can cut threads, no doubt, but I don't have that grin . . . you know what I mean.




 

225
4th axis tapping:

ANY time I can TAP or DIE CUT threads, I take that rout . . . did I mention ANY.

Tapping to a center hole and/or driving a chucked workpiece into a die holder is stupidly simple so I tend to just write the code 'on the fly' into the MDI, but I think it would make a nice addition to a wizard.

The calc is quite simple and the whole operation is one line of Gcode  . .  well, two if you count backing out.

That brings us to single point threading,  . . . the holy grail . . . . which I will comment on separately.

226
Tapping preferences:

Based on comments thus far, it seems this wizard is MACH4 only? I was not aware MACH3 supported G84

That being said, my mill spindle is servo powered, so I use a custom macro for rigid tapping. The macro is a bit complex. It first gathers and saves certain settings, performs a software 'swapaxis' to 'C' axis, performs the tap action at a set speed and dwell and retract. Settings are then restored on exit to what they were on entry.

To 'jump' over obstacles, there is a retract parameter. The macro first compares the current Z with the retract and if they are exactly the same, it assumes the tap is at retract Z and does a rapid to zero before executing the tap action. With this macro all tapping begins at Z zero being the end of the tap at the top of the hole. This can be accomplished with a G52 if it is embedded in a larger G-code program. I tend to use it 'manually' most of the time.

With the exception of the retract mentioned above, all motion is incremental. This allows any arbitrary and precise tapping depth while maintaining the same starting azimuth. Which in turn allows more than one pass for deep threads in stringy or hard materials.  

Having G84 available changes the landscape and I would agree that FPR would be preferable. I would only use G84 if M19 was also working and could be executed prior to the G84 for reasons cited above.

227
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 . . .  ;)








 

229
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

230
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.