HEXING ON LATHE

[Master Whidbey]

 

I'm trying to hex useing live tooling on a HAAS SL-20 lathe have no post for mastercam yet, so I'm useing a G77 can cycle from the machine. Can't seem to get tool marks out of the hex. Can any one either help with MC or the G77 cycle.

Stock size is 2"

hex is .679-.690

Material is 4130 46rc

G00 T101

S10 M03

M133 P800

G00 X2.

Z-.5

G77 J.395 L6 R.1875

Z1.

M135

M05

G28

[Philcott]

Hi Art,

 

I will guess you are bringing a tool in parallel to the "z" axis and then walking around the circumference to cut the hex.

 

I have to also guess on the kind of tool marks you are getting. (try to post a bit more detail in the future to reduce the amount of guessing) If the mark you get is a line in the middle of the flat it is mostly caused by machine backlash. The hex is cut by the tool moving in the "x" minus direction to the middle of the flat then changing direction to feed back out to the corner of the hex. If this is your problem make sure you do a rough and then finish cut and also try to adjust your backlash for the "x" axis.

 

hope this helps,

 

Phil

[Master Whidbey]

Yes, your guessing is correct.

 

tooling is coming in parallel to the z axis.

 

the tool marks look like chatter on all sides of the hex,

[PE @ IHS]

It sounds more like a feed/speed and setup issue. Use the largest diameter and shortest tool possible, make sure you climb-mill, and play with feeds and speeds.

[Philcott]

Art,

 

Chatter can certainly be a problem milling a hex in 4130 due to the amount of surface contact. Go back to the basics. Reduce tool overhang, stub up the part as much as possible, make sure all bolts are snug, use one tool to rough and another to finish the hex.

 

Another process I have had success with is to finish with a cutter mounted perpendicular to the hex, call up the individual flats and machine in the "z" minus direction. The limitation of this is that you can't machine up to a shoulder due to the radial sweep of the cutters diameter.

 

Phil

[Allan Brown]

Master Whidbey asked me to share these pics:

 

 

 

[McRae]

Peter and Group,

 

Using an old Mori SL25M with the live tool, I found that keeping the pressure on the tool by using climbmilling assisted in Chatter Reduction. The drive conection on the machine was sloppy and would rattle around excessivly. Secondly, use the polar interpolation feature if available and roll around the corners to keep the tool in cut. This should help.

 

The other suggestions about reduction in tool lenght and the rest are all extremely valid.

[Nominal]

$0.02 WORTH....

 

Is this a linearization issue? Is it trying to create a straight side using one linear slide X and the rotation of the spindle to produce the flat sides? Maybe there is a linearization tolerance that can be changed with a parameter since this is all being done by the control.

[Reece L Gibson]

Use the Y if you have it.

[Philcott]

Art,

 

Looking at the part brings another question to mind. Are you milling the hex before turning the taper and thread dia? If not, you should as you will have more support for the hex.

 

Is it just me or is the part in the photo some strange new ultra-secret aluminized 4130 material?? .

 

Phil

 

PS as others have said, climb mill and rolling around the corners are both very good ideas. Also slow down RPM

[McRae]

Think Polar - Not a linearization issue - Interpolate a straight line using the rotary axis and the X axis - No Y Required. The polar interpolation option allows you to program in x-y coordinates and then the machine will figure out where and when to turn the c-axis in sync with moving the x-axis slide.

[chris m]

quote:

---

Is it just me or is the part in the photo some strange new ultra-secret aluminized 4130 material??

---

You read my mind on that!

 

+1 for sure on milling those flats when the part is thick, that spindly (is that a word?) little threaded end isn't gonna do anything for rigidity.

 

C

[Philcott]

Chris,

 

It kind of reminds me of Scotty's transparent aluminum in the Star Trek movie(voyage home??). Guess it could be called ferrous aluminum.

 

Phil

[Go Navy]

As you all can see by the material that we are working with America has spared no cost on materials that serve our forces here and abroad. Only with this kind of dedication to quality are our forces able to protect freedom worldwide.

 

 

Yes, the picture is aluminum it is only a test piece for set up.

 

I appreciate all the input it did help, it was just as simple as going back to the basics and adding a rough cycle.

[CNCme]

Good day

 

Is this a bar feed job??

 

If it was you could use a double bar feed...

 

1: feed...short, do the hex

 

2: feed out again and do the taper /thread

and then cutoff

 

Unless you are chucking

 

Tony G

Unemployed Programmer

N.E Massachusetts - Southern New Hampshire

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