Programming a Slitting Saw

[behindpropeller]

I need some advice on programming a slitting saw. The saw I will be using is a 4" saw, HSS material, 36 teeth, 3/32" thk. I need to cut some 6061 aluminum, approx .75" x 1.25".



What are some good practices for this operation?

Thanks

Tim

[Geof]

Am I allowed to suggest that you should not be slitting you should be making the part from two pieces? Slitting is very slow, you will need one entire machine operation just for the slitting and it will leave very sharp edges and push a burr into the bolt hole which will have to be cleaned up.

I guess I didn't wait to see if I was allowed to suggest all that.

Now I will try to make amends for being cheeky.

Use the smallest slitting saw possible, the larger it is the slower it has to run and the worse it is from an available torque point of view so you need to feed slower, or stall your spindle like I have done.

Don't plunge straight in, this also needs a slow feed and it is possible that the chips will clog the teeth because the cut path is long.

Use lotsa coolant.


We make several parts that need slits and one is about 1.7" wide and over 1" deep using a 5" by 3/32" saw. I found the best approach was to nibble at it using a G03 semicircle that is incremented forward. Here is the code you can have a look at using Graphics.

%
O00000
N7000 T7 M06
N7001 G43 H07
N7002 M03 S800
N7003 G00 X0. Y5.7 Z1.
N7004 G00 Z-0.445 M08
N7005 G01 Y5.5 F40.
N7006 G90 G01 Z-0.445 M97 P7100 L3
N7007 G00 Y5.8
N7008 Z1.
N7009 M99
N7010 (----)
N7100 G90 G03 I0. J-0.36 F5.
N7101 G01 Z-0.355
N7102 G03 I0. J-0.36 F5.
N7103 G91 G01 Y-0.345 F40.
N7104 G90 M99
N7105 (---)
%

[Donkey Hotey]

I'll add: I think I'd conventional-cut rather than climb-cut with the slitting saw. With a large diameter and flexy arbor, the saw might have a tendency to dig in on a climb cut.

[behindpropeller]

2 pieces?

Next time!

I appreciate the advice on the 2 pieces....for now I have the stock to use, so I will do some slow slitting. You can make suggestions anytime......

Ill throw this in graphics on the cam editor and see what happens and probably have some more questions.

My thought was to slit it and then re-drill the bolt holes and then tap them.

Thanks

Tim

[behindpropeller]

Originally Posted by Donkey Hotey I'll add: I think I'd conventional-cut rather than climb-cut with the slitting saw. With a large diameter and flexy arbor, the saw might have a tendency to dig in on a climb cut.

Would you mind expanding on the difference between "conventional" vs. climb. I think you are talking about the diection of the saw moving in relation to the rotation but I just want to be clear.

Tim

[Geof]

Originally Posted by Donkey Hotey I'll add: I think I'd conventional-cut rather than climb-cut with the slitting saw. With a large diameter and flexy arbor, the saw might have a tendency to dig in on a climb cut.

My experience is the opposite, chip clogging seemed to occur more readily using conventional.

The flexy arbor comment is pertinent however, you are not allowed to have a flexy arbor and the diamter of the arbor and flange should be as large as possible. we made out own arbor and machined it in the mill to get it running true.

[Donkey Hotey]

Originally Posted by behindpropeller Would you mind expanding on the difference between "conventional" vs. climb. I think you are talking about the diection of the saw moving in relation to the rotation but I just want to be clear.

Yes, exactly. With climb cutting, the saw wants to grab into the work and climb out of the slot. With conventional cutting, the saw starts out rubbing and eventually works its way into a cut. I think it's less aggressive and will wear the saw faster, but it's safer.

I'm a wimp when it comes to this stuff so I'd probably do multiple passes and a bunch of other cautious steps. Go with whatever Geof suggests; he's been there.

[Geof]

Originally Posted by Donkey Hotey ...I'm a wimp when it comes to this stuff so I'd probably do multiple passes and a bunch of other cautious steps...

Nothing wrong with being wimpish.

After you have seized up a 5" slitting saw in a cut and sprayed shrapnel around inside the machine you adopt wimpishness. You also have a good reason for proving programs with the door to the machine closed.

[widetrack]

Okay, the point about climbing is a valid one if you dont have any back lashe in the ball screws, if you do then you will pull the mat into the saw and break it, or stall. I dont know how much hp you have, but the width of the saw says "slow". but dont try to cut all the way through. when the part comes loose it will catch in the saw, so leave about .010 and then break it off after. I use slitting saws often here, and mostly on BeCu.

[behindpropeller]

This will be on a TM-2 so I am guessing conventional cutting is probably the way to go.

Tim

[Geof]

Originally Posted by widetrack Okay, the point about climbing is a valid one if you dont have any back lashe in the ball screws, ...

Haas machines don't have backlash.

The program I posted is run on a Haas MiniMill which in terms of spindle and ballscrews is no different to a TM machine; I think you are fussing way to much about the cutter climbing into the material.

[widetrack]

Yea, I know haas, I got 2 VF 0's with 20 hp, 1 OM2, 1 sl30 with l/t, and 1 tl1. the slitting saws I run are as small as .010 thick and 2" dia in the BeCu. the ones for parting off are .03 and 3" dia. all climb cut. the only prob i get is with om2. the spindle will stall and the saw is instantly gone. but these are carbide, so i run pretty fast on the rpm as long as i dont mind the slot width going over some. the feed on the om at 4k rpm is about .0005 per tooth.