Doosan Lynx 2600SY Terrible Spindle Accel/Decel

[gregormarwick]

Sounds like the synchronization process is just slow and cumbersome, probably Doosan's integration of it.

On a sub-spindle or dual-spindle Mazak, we could clamp the sub-spindle on the part, then just let it "free ride", if synch is not needed. Main spindle has plenty of power to drive part and sub together.

Can Fanuc/Doosan do this? Might be a cheezy workaround to the long, long synch and un-synch cycles....

The tool pausing to cut until the programmed SFM is reached should be a parameter...??

ToolCat

Of course you can do that on a Fanuc, but if you are cutting off without driving the sub as well, what happens to the part off insert as it breaks through to centre? And the synchronisation doesn't take long, just a fraction of a second.

OP's problem is probably related to spindle tuning or probably specific acceleration rate parameters during sync.

 

[mmurray70]

Does it really matter if it starts cutting before full speed? Its programmed ipr anyway? Shouldnt be chipping inserts. Chip load is same.

I have spindle ramp slowed on my old mazak and it does same thing, but feed is proportional to actual rpm and its no big deal.

 

[mmurray70]

Of course you can do that on a Fanuc, but if you are cutting off without driving the sub as well, what happens to the part off insert as it breaks through to centre? And the synchronisation doesn't take long, just a fraction of a second.

OP's problem is probably related to spindle tuning or probably specific acceleration rate parameters during sync.

Im sure theres tons of inertia in the sub spindle to finish machining that little bump on part off! Actually getting it to stop would probably be a much bigger problem if its truly coasting along without any control from drive.

 

[Vancbiker]

OP - there is a (Fanuc) parameter to change so the tool will only engage when commanded revs are met

Since we don't know what control the OP has, he'll have to find it on their own. It will be in the spindle control parameter section and the mnemonic will be SAR. Set that to 1 and the machine should wait until the spindle has passed 80% of commanded speed before starting to move an axis.

 

[Mtndew]

Does it really matter if it starts cutting before full speed?

It most definitely matters in some situations. Large cuts especially. Horsepower,torque not being there when it starts the cut could stall the spindle or alarm out. etc...

 

[mmurray70]

It most definitely matters in some situations. Large cuts especially. Horsepower,torque not being there when it starts the cut could stall the spindle or alarm out. etc...

It should still be taking the same chip though right if its programmed ipr? Most machine tools have 100% torque available at zero rpm.

I mean come on guys, I cant see doosan just overlooking this problem. I bet they said while its still accelerating its better to be cutting at a slower rate then just waiting and doing nothing. Be interesting to cut a finish pass and see if the feed per rev stays constant on start

 

[Speedie]

You wouldnt think in the modern age it would take so long to sync spindles.

 

[ViktorS]

I can almost guarantee there is a parameter for how careful it will behave when running in sync.
The spindles have so much power and inertia that smaller parts will get shredded to pieces if running full tilt without the load meter even noticing. If the mfg did not use conservative numbers we would have threads about that instead.

On mazak there is a parameter for torque limiting when running in sync and if I alter that the spindles will go how I choose. Look through your documentation.

 

[aj]

I mean, they are going to be pretty GD close regardless, then connect the two with a piece of material and they are pretty well locked until you part through right?[/QUOTE

We have 5 twin spindles here. I program them all to part down to around 0.100 then shut sync off. It stops one spindle and effectively rings the parts apart and I don't have to part to X0.000 and risk chipping my part off insert.

 

[aj]

Bought our first Doosan as we needed a mill turn. The problem is that when the spindles are synched and turning together, it takes 7 seconds to spin up to max RPM or to spin back down.

Anyone else have a Doosan with dual spindles who has run into the same issue?

Thanks,

We have 6 Nakamura twins. Whenever the spindles are synced for part-off spindle acceleration is considerably slower than when they are running independently. It's nowhere near 7 seconds though. It might be worth an email to Fanuc. Seems I remember a tech at one of the Fanuc repair houses told me accel/decel was programmable.

 

[DouglasJRizzo]

FYI - To speed things along, I program something like this in the classes, and still do.

G28 U0(HOME X)
G28 W0(HOME Z)
G0 G40 G54 G99 T0909(PART OFF)
G97 S1500 M213 P11(PHASE SYNC MAIN SPDL COMMAND)
X2.25 Z-2.625 M8 (PART OFF POSIT)
M31(MAIN SPDL INTERLOCK BYPASS)
M131(SUB SPDL INTERLOCK BYPASS)
M169(SUB CHUCK OPEN)
G0 B.25(POSIT SUB)
G1 G98 B-1. F20.(B AXIS PART OFF POSIT)
M168(SUB CHUCK CLAMP)
G96 S800 M213 P11 (CSS PHASE SYNC MAIN SPDL COMMAND)
G1 G99 X0 F.002(PART OFF)
G4U1.(DWELL)
G0X2.5 M9
G28 U0(HOME X)
G53 G28 B0(HOME SUB)
G28 G54 W0(HOME Z)
M206 (PHASE UNSYNC)
M5 P11 (MAIN SPDL STOP)
G97 S1500 M3 P13(SUB SPDL FWD)
G0 G40 G55 G99 T1111(SUB OD TURN)
X4. Z-2. M8

MACHINE PART ON SUB...

 

[colton_m]

There is a keep relay to wait for spindle to get to speed before cutting. It will be in your Blue Book.

Paul

Hi Paul,

I just wanted to follow up on this one, maybe someone else will find it useful.

I found what you are describing in the book: K02 bit#3 (KSAR).

Curiously this was already set to "1/ON" In our machine. I tried setting it to zero and that made everything much worse (I can completely finish a 8" long facing pass before the spindle us up to the commanded speed). Do you know if there is a way to force the machine to check that the spindle is at 100% of the commanded speed before proceeding with the cut? It seems like after it reaches 65-70% of the commanded speed it is allowed to proceed even with this function enabled.

Thanks,
Colton

 

[colton_m]

Since we don't know what control the OP has, he'll have to find it on their own. It will be in the spindle control parameter section and the mnemonic will be SAR. Set that to 1 and the machine should wait until the spindle has passed 80% of commanded speed before starting to move an axis.

I tested this out K02 bit#3 (KSAR) (on our mill), it seems to be more like 65-70% of commanded speed prior to the axis moving.
Any ideas on forcing it to check for 100% of commanded speed?

Thanks!

 

[Vancbiker]

I tested this out K02 bit#3 (KSAR) (on our mill), it seems to be more like 65-70% of commanded speed prior to the axis moving.
Any ideas on forcing it to check for 100% of commanded speed?

Thanks!

The K parameter is a machine builder parameter. The SAR parameter is a Fanuc parameter and is not the same as KSAR. Not sure if the builder parameter takes precedence over the Fanuc one in this case. That would likely depend on how the builder’s ladder program was written.