Roland -180° turn blocked !

[technician]

This has happened a few times nothing serious until now.

The clamp is getting stucked from pieces falling down from the Zi disc.

The problem is that the software only take notice that something is wrong when theres a big change in current from the spindle itself and not for the clamp. So there can be a BIG problem (se pics)

Why the machine doesn't stop when the clamp can't turn is big problem.
I guess that this could easily be corrected in the software (V-panel?)

It would not have been a problem if the depth of the collecting tray was deeper.

This is a serious problem and I guess I'm not the only one.(maybe)

Glenn I know of course that you have nothing to do with the european market but you are the only person that I know that has the connection can you please ask if this could be fixed to prevent more problems like this?

Wtf!


The pice that made me cry....

 

[zero_zero]

The mill is just a tool...its only as good as you're using it.... gotta make sure that no pieces will fall off...the control is not conversational. ..the software ( CAM or v-Panel ) doesn't know what's going on...unless an error is reported back from the mill...but then is too late...

 

[technician]

The mill is just a tool...its only as good as you're using it.... gotta make sure that no pieces will fall off...the control is not conversational. ..the software ( CAM or v-Panel ) doesn't know what's going on...unless an error is reported back from the mill...but then is too late...

Yes but if the machine stops when the clamp is stucked the spindle does not collide with the clamp.

 

[shane williams]

This happened to me when I was milling PMMA. For some reason the bottom tray kept sliding out, and when it would try to flip, it would get wedged up against the bottom tray. So now I take out the tray.

 

[Sam-CAP]

I had this happen to me twice in the same day in an Origin mill. Good times...

 

[Marcusthegladiator CDT]

Check and double check your nesting. If pieces are falling out and breaking burs/zirconia framework. Its a user error.

 

[zero_zero]

Yes but if the machine stops when the clamp is stucked the spindle does not collide with the clamp.

The clamp shouldn't get stuck... double check your nesting and run a simulation if unsure. Shouldn't be any pieces left unsupported there.... An industrial mill would cut the clamp in two if such error occures...

 

[shane williams]

The clamp shouldn't get stuck... double check your nesting and run a simulation if unsure. Shouldn't be any pieces left unsupported there.... An industrial mill would cut the clamp in two if such error occures...

If a piece from the disk falls into the tray at the right spot, it will wedge itself so the clamp will not turn.
Just make sure when you nest a job, and I'm not sure if you're using SUM3D or not, but make sure that you have connectors going from the crown or bridge to the small areas between crowns that will fall through if left unsupported.

 

[Marcusthegladiator CDT]

Can we see a screen cap of the nesting that produced the program that was running when this happened?

 

[technician]

Can we see a screen cap of the nesting that produced the program that was running when this happened?

Yes I know its my fault because I rotated one crown to change the connector points and I didn't realize that I then by doing so cut off an old support piece.
What I mean is: if the software can sense when theres a big difference in the current going to the spindle and stop the program it should also be able to do the same with the motor for the clamping system
so the two won't collide.

 

[Marcusthegladiator CDT]

Yes I know its my fault because I rotated one crown to change the connector points and I didn't realize that I then by doing so cut off an old support piece.
What I mean is: if the software can sense when theres a big difference in the current going to the spindle and stop the program it should also be able to do the same with the motor for the clamping system
so the two won't collide.

Not sure why your tool and your housing would collide. That's a program code/strategy issue, I would run a simulation and see if you can find where its happening.. A broken piece of the blank isn't going to throw your tool into a rapid movement straight toward the housing. What software are you using.

 

[zero_zero]

It cannot sense any stall on the rotary axes...has a reduction gear, no position encoders ( only a home switch ) and I'm pretty sure that the drive circuit is not designed that way...the spindle on the other hand is driven by a servo motor...so it has feedback. ..

 

[Sevan P]

I have been through that! Sucks the big one. Zero_Zero nailed it. The one down fall of the DWX-50.

 

[technician]

Not sure why your tool and your housing would collide. That's a program code/strategy issue, I would run a simulation and see if you can find where its happening.. A broken piece of the blank isn't going to throw your tool into a rapid movement straight toward the housing. What software are you using.

As you can see on the picture the broken piece got stuck under the clamp stopping it from turn around, but as you said why this could happen maybe is a miss in the programing.

 

[Glenn Kennedy]

Sevan,

Sorry for the delay, I was at the Eastern States Show over the weekend. While I was gone it looks like you guys covered this topic well so the only thing I will add is a promise to report this to the product management team to make them aware of it.

As mentioned above the short term solution is nesting to avoid falling chunks. Long term, lets see what can be done to improve the design so falling chunks are less of an issue.

-Glenn

PS: Sevan, are you going to be at DLOAC this weekend? I hope to see you there!

 

[BobCDT]

This happened to me when I was milling PMMA. For some reason the bottom tray kept sliding out, and when it would try to flip, it would get wedged up against the bottom tray. So now I take out the tray.

When the mill goes into five axis the tray tends to slide out. Once out it will stop the disk holder from turning 180. We put a small pice of masking tape on the tray to hold it in place during milling. Problem solved.

 

[Sevan P]

Sevan,

Long term, lets see what can be done to improve the design so falling chunks are less of an issue.

-Glenn

PS: Sevan, are you going to be at DLOAC this weekend? I hope to see you there!

Make the lower catch tray deeper, if possible. that way if a broken piece of ZR falls it will clear the rotating axis.

P.S. Yes i am. I will stop by and say Hi.

 

[EGE]

Sevan, I think that the right software should not allow that chunck of material fall...you mention about the problem linked with the rotation of the workpiece being blocked by the material at the bottom of the tray...and we try to find solutions to change the design of the machine or to use masking tape, or that you dont know how to use a mill...another would ask you to sit next to the machine with a thin stick and more fallen parts out of the tray... this is a joke ! Lets come back to the initial problem : why are parts falling inside the tray ?

 

[Sevan P]

Sevan, I think that the right software should not allow that chunck of material fall...you mention about the problem linked with the rotation of the workpiece being blocked by the material at the bottom of the tray...and we try to find solutions to change the design of the machine or to use masking tape, or that you dont know how to use a mill...another would ask you to sit next to the machine with a thin stick and more fallen parts out of the tray... this is a joke ! Lets come back to the initial problem : why are parts falling inside the tray ?

What Software? The CAM software? Are you kidding me? The CAM software will never know or be able to know if an axis of the machine is jammed in any way! It simple writes the path for the machine to translate to the stepping motors. The issue is with in the machine and the way it is setup to monitor where the axis are at what time and if they have reached their safety point before other parts of the mill move. Ain't NO software gonna solve this issue. It is a simple user error on nesting that caused this to happen. But still you think the Roland DWX-50 is a smart enough mill to know that the A/B axis is not fully rotated to a safe point? NO! That's is not how the DWX-50 was built. I know HOW to USE a MILL and CAM software my dear friend. There are many hardware and design issues with the Roland the NEED to be fixed. Suction & drivetrain are just a few on the list.

The part could of fallen into the mill from when the user tried to tighten the disk into the mill, and if he was using the old screw down top, it simply could of stressed the disk and caused a fracture in the already milled ares and the vibration of the mill did the rest and dropped the piece into the catch tray.

 

[technician]

It cannot sense any stall on the rotary axes...has a reduction gear, no position encoders ( only a home switch ) and I'm pretty sure that the drive circuit is not designed that way...the spindle on the other hand is driven by a servo motor...so it has feedback. ..

If this is the motor type you are talking about maybe it can be done:
Stepper motors enable precise positioning without needing sensors to measure motor position. Each pulse to a stepper motor turns its shaft one step which for many steppers is 3.6 degrees. One hundered pulses will turn a 3.6 degree stepper exactly one revolution.

If the software calculate the pulses to control the position of the clamp then why not use it to avoid collision or just stop the machine?