Mill as lathe programing?

[gundog]

I would like to try and turn some 1" 6061 in my mill spindle as a lathe I have 2 diameters I need to turn (a spool type shape) on the end of the shaft. I can't get my mind around how to make the toolpaths. Basically the shaft is 1" and there are 2 slip fit surfaces that are the same diameter I will use .750" as an example in between those 2 surfaces is a clearance area that is turned to .625". The clearance area is the part that stumps me the other surface I could make with a drilling path but I have been trying to figure out how to do the clearance diameter path. My cad does not have a simple solution and neither does my controller at least I have not been able to figure one out.

I would like to face off the end then turn to the .750" dimension and finish by doing the clearance path down to .625" between the two surfaces that will be .750".

My Cad will output to a Fanuc 6 code that I need for the mill but I am not sure how to generate this path.

I can post a picture if this is unclear.

Thanks Mike

[macona]

If you use cam to create lathe path g-code it should run fine.

[gundog]

If you use cam to create lathe path g-code it should run fine.

My Cad/Cam program does not do lathe work it is a program designed for router tables Aspire by Vetric. It is a great program for my router table and will do most things I need for the mill but this is one thing it won't do. My controller will also not do this. So I either need to have someone else make the cut files or buy a new program do you know any reasonable ones?

Mike

[Dan Dubeau]

I've done it before. I just programmed in the xz plane. I use edgecam at work, and it has a "slot" cycle, whereas it creates code base on the geometry you draw. Draw the geometry in the zx plane and run a slot cycle on it, and it will move the machine the exact way you want it. Takes a bit of figureing out what to draw to get the machine to cut what you want. But that's the basics of it.

worked great when I figured it out, and got it working. Just have to think a bit different about what you want to cut and how you need to move the machine to do it.

[Stepside]

Is the part spinning or is the cutter spinning?

If the part is spinning then it will be a series of X and Z moves. This will take a bit of playing around with cutter shape and probably you will need 2 cutters to get the corners cut out.

If the cutter is spinning you could use something like a keyseat cutter. This would be a series of X and Z cuts as well as some I and J code.

It is all hand writeable.

[gundog]

I am going to spin the part in the quill and use a tool like this clamped in the vise. http://www.youtube.com/watch?v=-CezQkZwHMA

I just have to figure out the code.

Mike

[macona]

It really should not be too hard to program by hand.

You might look at Lazyturn. It is being written by Art, the guy who wrote Mach3. I don't know if there has been any recent work on it but you might look into it. There is just not a lot of interest in cnc turning for the home guys.

[PixMan]

I think you can make this work, but the program will need lots of tweaking to get chip control. Understand that the material in the video is 1045 steel, and the groove-turn inserts used are designed for steels. In aluminum the chips are going to get all wrapped up around the work and scratch it all up.

Aluminum is such a completely different beast. The 6061-T6 (wrought, not cold-finished T651 variant) is about the worst for breaking chips. Your machining life would take a turn for the better if you could find and use 2024-T4 or (better yet) 2011 "Microchip" aluminum.

[Jaakko Fagerlund]

I'm not too familiar with G-code, but here is my idea. 1" bar attached to the spindle and a DNMG bit attached to the vice with the cutting edge at X0 Y0 and cutter shank in X-axis direction with the cutting bit pointing right and Z+0 at the end of the workpiece.

I'm assuming 1" length for the whole spool, groovestarting 0.25" from the end and being 0.25" long. 6000 RPM (WAG) and a big feedrate.

S6000
G40
; Outside diameter
G0 X0.4375 Y0 Z1
G1 Z-0.996 F100
G0 X0.55
G0 Z1
G0 X0.375
G1 Z-1 F100
G1 X0.55 F100

; Groove
G0 Z-0.25
G1 X0.3125 F100
G1 Z-0.5 F100
G0 X0.55
M30

I'm too too fond of G-code and trying to think in inches makes my head hurt, not to speak of "turning" stuff with a radius and not diameter readings.

[gundog]

I am not sure this machine takes true G-code it has to be in the form of a Fanuc 6 language. Here is a sample of some that was written using my Cad/Cam program Aspire and saved using the Fanuc 6 post processor that I was told to use.

%
:1248
N20G91G28X0Y0Z0
N30G40G17G80G49
N40T1M6
N50G90G54
N60G43Z1.0000H1
N70G0X0.0000Y0.0000S4000M3
N80G0X0.7500Y0.7850Z0.2000
N90G1Z-0.4175F30.0
N100G1X0.7550Y0.7900F100.0
N110X0.7500Y0.7950
N120X0.7450Y0.7900
N130X0.7500Y0.7850
N140Y0.7350
N150X0.7580Y0.7356
N160X0.7662Y0.7374
N170X0.7743Y0.7406
N180X0.7820Y0.7452
N190X0.7889Y0.7511
N200X0.7948Y0.7580
N210X0.7994Y0.7657
N220X0.8026Y0.7738
N230X0.8044Y0.7820
N240X0.8050Y0.7900
N250X0.8045Y0.7972
N260X0.8030Y0.8047
N270X0.8004Y0.8121
N280X0.7966Y0.8192
N290X0.7917Y0.8259
N300X0.7859Y0.8317
N310X0.7792Y0.8366
N320X0.7721Y0.8404
N330X0.7647Y0.8430
N340X0.7572Y0.8445

This is not the whole code it is just part it was too long to post it all. I am also not sure this code works I am going to try it today. This is a series of bored holes to accept the other end of the shaft we are talking about.

Here are a couple pictures of what I am trying to accomplish and the shaft is cold finished 6061 T-6.

Mike

http://img.photobucket.com/albums/v292/millnut/PA130002.jpg

http://img.photobucket.com/albums/v292/millnut/PA130005.jpg

These are the mounting shafts for the fillet/rigging tables I make for sport fishing boats the shafts mount in fishing rod holder mounts. There is a hex and a hole that need to be drilled but I understand that part. For the hex I will hold the parts in my indexer chuck mounted vertically. I have made these shafts on my lathe but they are pretty slow going and I want the accuracy of the CNC and speed. By the way my spindle max RPM is 4200. Here are a couple pictures of the tables these shafts hold.

http://img.photobucket.com/albums/v292/millnut/PA130003.jpg

http://img.photobucket.com/albums/v292/millnut/PA130004.jpg

I am a hobby machinist and self taught so I only learn enough to make the parts I need. When I retire I will take classes to learn this stuff better but working rotating shifts nights and days I can't take classes now. Thanks for any and all help if someone is interested in seeing this through with me I would be willing to pay for your time. I am just trying to figure this out one way or another. The tables are made on my CNC router table and are my own designs. My router table is a 8'x4' Shopbot PRS standard the mill is a new to me Trak DPM 3 with an AGE 3 controller. I am not an expert with the router table but I have learned my way around it pretty good I hope to do the same with this mill.

Thanks Mike

[macona]

Thats pretty generic G-code. The only place it will probably make a difference is with canned cycles.

[gundog]

My code did not work I am back to square one and trying to figure out the control or downloading the cam. I tried programing the controller for some simple boring toolpath but it is giving me a Z axis error something about exceeding a limit I will read the manual some more and try and figure out what I am doing wrong.

Mike

[Paul Alciatore]

I know nothing of your machine, your CAD/CAM, or your controller, but I would start with one simple operations and get that right. Then add one more at a time. Perhaps start with facing the bottom (as it is mounted in the spindle) and then turning a simple cylindrical diameter. You might try to "park" the cutter at the anticipated start position of the next cut on each step to confirm that move. Those two operations should give you a lot of knowledge for trying to make a groove in the diameter, etc., etc., etc. Add one or two movements per trial until you are confident as to how it all works together.

[Steve Seebold]

You should be able to do it fine if you use radius instead of diameter programming.

[gundog]

I have decided to abandon the turning in the spindle after talking to a more experienced than myself guy over on the CNC zone and talking to the machinery dealer that sold me the machine. They tell me I am looking at this wrong and I tend to agree. The plan now is to hold the shaft vertical and mill around it. This will work better because I can do 2 more operations to finish this end of the shaft all in one position. I am going to work on this in the next couple days I will post a picture of the results. I did a test cut to see if the surface finish would be acceptable using this method and my results where a close to mirror finish I am pleased so now I just need to program this part and get a suitable cutter.

I have not solved my post processor issue yet but I think they are working on a solution. SWI the maker of the controller has emailed Vetric the maker of my Cad-Cam software and it looks like Vetric with the help of SWI are going to modify a post processor that will work for me. This is good news for me I just have to wait until they get it done. In the mean time I am learning to program the machine at the controller. The machinery dealer dropped by my shop and gave me a short tutorial that has really helped.

Thanks for the help I will keep you posted with my results.

Mike

[FOG]

I don't know what machine your using but back in the 80s I owned a CNC shop. Two of my lathes were Wasino Gangsters. I made a third from my Bridgeport Series 1 Boss 5 cnc mill.

By simply fitting a tool block that held a number of end cutting tools on the table and useing a fixture in the spindle to hold the work. Te programing was Bridgeports version of G codes entered through a Telex. 110 baud. I think my phone has more power these days.

FOG