[Larry Myers]

Hi All

I am looking for a little advise concerning the use of M19, spindle orientation, on my VMC. I have a Sharp 2412 with a Fanuc Oi-Mate controller.

Here’s what I want to do: I have a 1” X 1” X 1” pocket in a piece of aluminum. The corners have a 0.0625 radius. I want to clean up the corners with a broaching tool that I had made for me. I realize that there are different schools of thought in terms of broaching with a milling machine. For now, I would like to put those thoughts aside.

The broaching tool has a 0.5” X 0.5” square end (bottom cutting surface) that has a concave bottom for cutting and chip removal. It has a tapered shank 1.5” (upwards) to a 1” shank that will fit into a tool holder.

I want to move the tool to line up the corner of the tool with the corner of the pocket. This is assuming that that the tool is properly positioned in the tool holder. I want to drop the tool down in Z just to shave off the about 0.002” off of a wall and then retract it to a safe distance above the pocket, and then move it again to shave off the adjacent wall. Then onto another corner.

Here is a simple program. 0,0 is in the center of the square. You will see that for this example, I am not concerned about exact X and Y coordinates. I am more interested in the format of what I am attempting.

%
O02500 (CORNER BROACHING)
N1 G20
N2 G00 G17 G40 G49 G80 G90
N3 T1 M06 (broaching tool)
N4 G00 G90 G54 X-0.25 Y0.25 M08
N5 G43 H1 Z0.1
N6 G01 Z-1.0 F20
N7 Z0.1F100
N8 M09
N9 M30
%

For the life of me, I can not find any information on how or where to put M19. I want to lock the spindle in one position. There is no spindle lock on my machine. I know that if I press the SPINDLE ORIENTATION button on the machine, it will rotate the spindle back and forth and then lock it in place. The only way that I can find to unlock it is to hit the reset button. But then I really do not know what I am doing!

Any advise will sure be welcome. Many thanks in advance!!!!!

Larry Myers
http://www.colfaxtactical.com


I also posted this in the Sharp machine forum here in CNCzone. But it is usually pretty quite there.

[sinha_nsit]

Without spindle lock, your method may not work.

M19 is given before tool change.

[psychomill]

If the spindle has a brake (not necessarily a "lock") then you should be able to command it at any given time after tool change. If you have an ATC and it's a flange taper machine (like CAT, BT, HSK (some forms), etc), it should "lock". Code it here:

%
O02500 (CORNER BROACHING)
N1 G20
N2 G00 G17 G40 G49 G80 G90
N3 T1 M06 (broaching tool)
N4 G00 G90 G54 X-0.25 Y0.25 M08
M19
N5 G43 H1 Z0.1
N6 G01 Z-1.0 F20
N7 Z0.1F100
N8 M09
N9 M30
%

You can check it by hand to make sure it "locked". Just be careful because "lock" and "brake" are two different things. Generally, "lock" is a different M code but most verticals don't have this. Need to be sure you don't overcome the brake when broaching. Might need to add a bit of dwell if your machine starts moving before orient is complete.

As for releasing it, some MTBs write in the ladder to release the brake when commanded a M5. Some release if you command a M3S0. For sure if you command a M3 with a low speed (like S30) then the orient will release. But if all you're doing here is broaching with this tool, then you don't need to release it. Just tool change to the next tool and move on.

note: Another option some spindles have is the ability to orient to a specific angle. Generally something like "M19S900" for example would orient the spindle at 90°. Codes can change a bit depending on the builder. Not all machines have this. There's another way to do this through parameters which you can write over then change back in a program but that's a bit more sketchy if not careful.

[Larry Myers]

Thanks Psycomill

I'll try it

Larry

[sinha_nsit]

Can we have more info about the difference between lock and brake?
In layman's language, how can the spindle be locked without a brake?
What is the mechanism?

[Superman]

My understanding of LOCK and BRAKE

Lock is where the position is held stationary by a motor, the motor would pulse +ive and -ive to keep it close to the set position. Likening it to keeping the car in gear on a slope and using the accelerator (just) to stop rolling forward or backward.

Brake is where the rotation is restricted by a physical clamp, like using the handbrake on a car. It must be released before motion is resumed.

Rotary axes on a machine are usually held in position by a "lock", but if higher cutting forces are experienced, which could make the axis move, an M-code can be applied to activate a physical "brake"

[psychomill]

Superman explains one type of distinction..... This can also be reversed.....

Machine builders describe "lock" and "brake" and even "clamped" slightly different from another builder. The point is to understand what is being described for each word with each machine and/or builder.

For the most part, it is as Superman describes. Brakes are also used when feeding on a rotary axis. Some 5X and Mill/Turn machines have this (sometimes referred to Mid-Brake). On those machines, they'll often have another setting for locking which may be called "Clamp".

On other machines, the builder may refer to a locked condition, but the reality is that is an electrical brake (motor pulse).

Bottom line, understand the equipment you're using.

[jamesu229]

I do not know if it will apply to your machine or not, but our new fadals have the fanuc oi and the lock code is 189, 19 is only orientation.

[dcoupar]

Larry,

Your machine uses M19 Spindle Orientation ON and M20 Spindle Orientation OFF.

There is no clamp or lock on your spindle, only orientation.

[sinha_nsit]

So, after commanding M19 (only), is it possible to change the spindle orientation manually by applying
1. virtually no torque, or
2. some torque, or
3. large torque?

[dcoupar]

So, after commanding M19 (only), is it possible to change the spindle orientation manually by applying
1. virtually no torque, or
2. some torque, or
3. large torque?

I believe that while oriented with M19 applying too much torque will cause an alarm (over current or some such thing).

[sinha_nsit]

This means that M19 is only for alignment purpose where one wants to have a particular orientation for the tool in the spindle. A separate mechanical brake (actuated by some M-code) is necessary if the spindle is required to remain locked in this position even in case of large torque. If so, an application like broaching may not be possible without a brake.

[Superman]

Not necessaryily so,
Basic orientation (M19) is usually held in place by the spindle motor, applying torque can force the spindle to rotate slightly, but it would fight to return back to the registered position. Higher end M/C's like mill/turn can rotate and clamp the spindle at various angles depending on the head angle.
I can purchase holders that can mount 3 different turning tools that can be used on this M/C

You could broach, but the tool would have to be set up in respect of this orientated position.
ie to broach in all 4 corners of a pocket, when this pocket is at 30° to the X-axis, you would set a square broaching tool at this 30° and you could then do all 4 corners when the spindle is orientated, if programmed correctly.

Caution!!!!
Broaching does put stresses back up the spindle axis, so think about your expensive machine and the precision bearings that would be absorbing this pressure. High precision bearing replacement ( especially those with ceramic bearings ) is expensive ($40K+). Because the spindle is not rotating, the bearings can shatter or leave indentations in the outer races, leading to premature failure and an empty wallet.

Let the boss decide if this avenue of broaching should continue, it's his money

[sinha_nsit]

Certainly, the bearing is not designed for large axial loads, that too suddenly applied. Moreover, in the absence of a mechanical brake, there is likely to be some angular vibration under the application of cutting forces. He will have to use very small lateral depth of cut which would increase machining time.

Alignment of the tool with respect to the workpiece is another issue.

The basic question is, why a design requires zero radius corners. If possible, the design should be modified. Unconventional machining is always expensive.

[psychomill]

The thing to look for on this is the fact of whether or not you have a mechanical clamp available.

With the M19 command, spindles can orient to a variety of angles and some down to 2 decimal places. However, most of them (to be honest, I can't think of one) cannot apply the mechanical brake (or stop) at just any angle. They are generally only capable of locking at specific increments such as 30° for example (depends on the builder).

Therefore, extra caution must be taken when machining at an angle that cannot be mechanically clamped.

[gabedrummin]

Finish the part in the cnc execpt for the corners transfer the part to a manual machine and broach from there. I use to broach on a Bridgeport . Very carefully . Dont risk breaking the VMC for a 30 minute job on a manual machine...Some guys get too spolied when running cnc;s and forget how to crank handles....

[boudj]

Dear M. Myers,

I have vertical Mori-Seiki NV-5000 and horizontal milling SH-400.

I have a brass part with a small keyway. I have 4000 – 5000 parts per year to make on CNC Mori-Seiki SH-400 (horizontal milling) or vertical NV-5000. (see attachment drawing).

I would try to broache the keyways on my milling because now, i use another supplier for make the keyway.

The broaching on milling give you a good results or a bad results. I would try to broache the keyways on my milling because now, i use another supplier for make the keyway. $$$

I check with 2 suppliers of tooling: FP Officina Meccanica S.R.L. and Eltool and theses 2 company are categorics: just use the M19 code and locking the spindle have not necessary.

Thanks

SB