[BrianSP]

Thanks Dcoupar,

I am going to print out your example with each line quadruple spaced and work through it.

I have a smaller diameter single-point carbide thread cutter since I haven't decided which insert cutter to buy yet. I would think by the time I have converted your program to work with my cutter I will have a pretty solid idea of how the theory works. I will let you now how I get on.

Stand by for cleaning up lots of ally chips !!!

Thanks again.

[BrianSP]

Thanks Al,
I am heading out to my shop to do the backup right now before I play with Dcoupar's program.

[John_B]

Thanks Al,
I am heading out to my shop to do the backup right now before I play with Dcoupar's program.

Brian,

Check your inbox, PM sent.

Also, you may want to consider using an entry and exit arc when threadmilling. The example that dcoupar posted is a good one, but for longer cutting tool life it will help to add an arc instead of a straight line to your lead in. I always arc in using as large an approach as possible nowadays, and have increased tool life something like 4-fold (I machine alot of large pipe threads in cast stainless steel).

Rgds,
John B

[BrianSP]

Hi Guys,
Had a good day on Saturday. I got the parameters backed up and I converted Dcoupars program to run on my machine and cut air, now I have to modify the program for my single-point threading tool and cut some real threads.

I spoke to the mill's previous owner. Apparently my machine came from the prototype dept. of an electronics company. They bought the mill then, when they learned how useful CNC was, upgraded to a machine with a tool-changer and an extra axis and put my mill in a corner for odd jobs. He told me that some options were turned on but he did not really know which ones. He only used the helical but never thought to mention that to me and I did not know enough to ask.

This leads to my next problem/question. The tool offset page in the control unit does not look like the page in the Fanuc manual. Instead of referring to tool "offsets" the pages call this tool "geometry". Each offset position has a letter "G" in front of it as in "G 001", this is not shown in the manual. Additionally, when I use a standard Fanuc tool call as in Dcoupar's example "T03 M06" I receive an "Alarm 151" which translates to " TOOL GROUP NUMBER NOT FOUND". I have tried entering the tool call in various ways but it does not help. There is very little help on the internet for this alarm, any ideas? I suspect one of the options is activated but I have no documentation on this.

I think that M06 is not a valid code for my machine since it has a manual tool change but removing this code does not solve the problem.

John,
Thanks. When I have the basic program working I will add the arc.

[Al_The_Man]

If you care to send me your 900 par. I can tell you what options you have.
If so I can send an email add by PM.
Al.

[Gncc50]

I don't know much about the Fanuc control but maybe the problem is in you Cad/Cam program.

Your Quote

"I'm new at this but my original need was to reduce the amount of code generated by my CAM program for thread milling. Someone was kind enough to write a sample thread mill example for me and the threading part of the program took 3/4 of the code yet most of the actual work was contained in the first quarter. Since the helical interpolation would be built into the CNC I am imagining that the amount of code required to thread mill would be much reduced. Would this be correct?"

Your program might be posting out in small lines instead of arcs. In OneCNC, you can turn the option on and off in the program post settings. Does your program support helical arcs? If so, is it turned on? See the second attachment, the box is checked to support arcs.

See attachments, it is the exact same operation one with arcs checked, one without.

Whole bunch more code without the helical arcs box checked.

This may not be your problem, just thought I would mention it.

Pete

[BrianSP]

Gncc50
That is exactly what happened but my example made even more code. The support person from Dolphin, really nice and really helpful, thought that I would have to use software helical generation so the code he sent as an example was very much like your "worst" case.

My first project is like your 3D view except that my thread is internal.

Thanks, Brian

[Gncc50]

What did he mean by that? Was he suggesting you get another stand alone program to do thread milling?? If so there are some out there.


or ................ Give OneCNC a call


It sounds like your problem may be your software not the machine.

Pete

[BrianSP]

Gncc50,

As I have mentioned I am new at CNC and, at the time, I did not know that my mill had the helical option so he wrote code with Dolphin that simulated helical operation in software. This produces a large volume of code as you pointed out. Dolphin can perform software helical but it produces a lot of code. I suppose all programs work the same way. By the way, I like that toolpath graphic.

Fortunately, my problem seems to be solved.

[Gncc50]

...

[BrianSP]

Gncc50

Here is a sample of the code:

N2345G01X0.279
N2355X0.2788Y0.0099Z-0.4135
N2365X0.2784Y0.0198Z-0.4132
N2375X0.2776Y0.0296Z-0.4128
N2385X0.2765Y0.0394Z-0.4124
N2395X0.2751Y0.0492Z-0.412

Since it starts with G01, yep - it is a series of straight lines. The helical option on the mill has saved me because I intend do a lot of helical milling and threadmilling.

Thanks for your input, Brian

[Gncc50]

"The helical option on the mill has saved me because I intend do a lot of helical milling and thread milling."



I don't think the helical option on your mill will help you at all as long as the code you are putting into your machine is like the example in your post.

In other words if you tell you machine to cut lines, it will cut lines if you tell the machine to cut arcs, it will cut arcs.

With the output you are getting from your program your machine doesn't see an arc or a helix. It only sees lines, very small lines, but they are just lines. Your control control won't convert lines to arcs even if you have the helical option.

I hesitated replying because I am certainly no expert. I hope one of the more knowledgeable guys will chime in here and verify what I have been saying, or tell me I'm wrong.

I think your problem will be solved when you output your code with arcs instead of lines.

Pete

[Al_The_Man]

Brian, Do you have the Fanuc programming manual for the 0M?
The programming format is usually GO2/G03 X..Y..Z..J..K..F.. for arc centre or R for radius type.
Only 2 axis specified for the interpolated axis depending on the plane selected.
If you need the manual, let me know also I would suggest CNC Programming Handbook by Peter Smid, he uses Fanuc as an example.
Al.

[BrianSP]

Thanks Al,

Dcoupars example showed the way to do this so I think I am OK.

I tried to find a good book on CNC programming recently. I even went to the famous Powell's Books in Portland which is nationally famous. They had a measly 24 inches of shelf-space for books on modern machining and none on CNC programming. This shows how little regard the population has for such a vital business. I will check on the book you recommend from on-line stores.

Brian

[dcoupar]

It appears your Dolphin CAD/CAM can be configured to post helixes for thread milling rather than line segments. Don't know if you've seen this or not.

http://www.dolphincadcamusa.com/cad-...Thread Milling

[BrianSP]

Dcoupar,

Not yet. I am still working with basic arcs.

Got to teach myself g-code basics, Dolphin, machine use, fix all the problems - Oh, by the way I need it done by next Friday cos' Dcoupar says we all have to take Friday off :cheers:

[Gncc50]

"It appears your Dolphin CAD/CAM can be configured to post helixes for thread milling rather than line segments."

Now....... ........ your problem is solved.

Thanks, dcoupar



Pete

[Al_The_Man]

I tried to find a good book on CNC programming recently. I will check on the book you recommend from on-line stores.

Brian

Another really excellent book is Computer Numerical Control Programming, by Michael Sava & Joseph Puszai, hopefully still in print.
Al.

[gbowne1]

Yeah, I have that book Al. I just started buidling my CNC textbook library.

Always take Friday off.

Try Amazon.com, Barnes & Noble Booksellers and of course, eBay.

Greg

[sinha_nsit]

In case you are also interested in learning macro programming, you may look at
[ame="http://www.amazon.com/Programming-using-Fanuc-Custom-Macro/dp/0071713328/ref=sr_1_3?s=books&ie=UTF8&qid=1278746639&sr=1-3#_"]Amazon.com: CNC Programming using Fanuc Custom Macro B (9780071713320): S.K Sinha: Books[/ame]