Machine ramping while using indexer

[Justin G]

So I just got my new 6" indexer connected to my machine, after speaking with shopbot support to find the correct unit values (mine was not programmed leaving shopbot Hq) I have it working. I am currently cutting a quick test file/ piece of wood.

I started with a 2.75" X 2.75" rectangle length of wood and chucked it up inside the jaws, and also found the center point with the crossed lines.

I programmed the pocket cut file using aspire 8, and have it cutting a raster path, parallel to the X axis, which is how my indexer is set up. everything is zeroed, centered, yatta yatta.

What I am curious about is the ramping of my X axis. As the machine is going back and forth, the X move speed was not input from my programming, and neither was any ramping. I have my move speed set as default 5 ips. my program called for 2ips with a .05 DOC which is pretty small, but as this is my first time doing ANY rotary work since high school i'm babying it for now. depth of cut and the program as a whole appear to be good to go, but the machine is banging back and forth on every raster as it stops and reverses directions. I Lowered the move speed manually mid-partfile to the appropriate value, but still no ramping is present....

Any Ideas guys? thank you

[Brady Watson]

Yes. Reset your VR using the Reset option at the bottom of the VR fill-in sheet.

If you want to do some further work, read the VR/Ramping and Tuning article (http://www.shopbotblog.com/2008/03/a-ramping-the-vr-command-and-how-to-tune-your-tool-for-maximum-performance/).

You'll need to set your B-axis jog speeds using the VS command. There you can set B move speeds as well. X&Z speeds will be handled via your SBP.

Keep your B jog speeds below 180 (that's 180 deg per second! - or 9"+ per second if you unroll a 6" part!!!) - try cutting around 30-60 deg/sec depending on material. Go with what sounds right...and don't forget that the outer surface distance = pi X diameter.

You generally want to run slower speeds on the indexer because the material is between centers & really not held all that well if just using centers for grip. You also want to consider inertia especially on larger diameter blanks where the effects of hysteresis will cause the blank to lag behind or continue moving when started or stopped (at least a little bit - and this can act like a pendulum). It is important to really get a good grip on that puppy.

-B

[Justin G]

Yes. Reset your VR using the Reset option at the bottom of the VR fill-in sheet.

If you want to do some further work, read the VR/Ramping and Tuning article (http://www.shopbotblog.com/2008/03/a-ramping-the-vr-command-and-how-to-tune-your-tool-for-maximum-performance/).

You'll need to set your B-axis jog speeds using the VS command. There you can set B move speeds as well. X&Z speeds will be handled via your SBP.

Keep your B jog speeds below 180 (that's 180 deg per second! - or 9"+ per second if you unroll a 6" part!!!) - try cutting around 30-60 deg/sec depending on material. Go with what sounds right...and don't forget that the outer surface distance = pi X diameter.

You generally want to run slower speeds on the indexer because the material is between centers & really not held all that well if just using centers for grip. You also want to consider inertia especially on larger diameter blanks where the effects of hysteresis will cause the blank to lag behind or continue moving when started or stopped (at least a little bit - and this can act like a pendulum). It is important to really get a good grip on that puppy.

-B

Thanks Brady. I wrote about a page long response before my token expired and I lost my post... This one will be shorter.

I reset the ramping values. That of course reset ALL of my ramping settings but luckily I had them saved and was able to re apply my settings for the first 3 axis.
That is great info on the speeds for the indexer, I really had no frame of reference other than the normal 3 axis work so I was starting off with pretty conservative cuts. Inertia of indexer makes sense as well. check.
The math for finding distance on a circumference, although obvious for most people, was unknown to me. Never was much of a math guy. Huge light bulb there.

So back to my ramping stuff. I'm pretty sure it all comes down to my post processor. ramping continues to work just fine for other cuts. but as soon as I employ the indexer wrapped Postp the machine moves around like ****.

I am going to look into how to edit the postp to include ramping and spindle speeds. I am hoping its something I can type in the header or other easy ish type programming.

Thanks again for your help. I DID read your ramping article a long time ago and based all of my 3d cuts off of it.

[Brady Watson]

Justin - No problem.

It IS strange that the tool would be 'banging' at the ends of an X raster (correct?) when using the rotary post. If there were some coordinated movement, such as a barley twist, where both the X and B were moving in unison, I would point to the VS command to get X and B in lockstep with known good speeds.

What happens if you run the same file (in the air) and set your slow corner speed to either 30 or 35? Does this soften it up?

-B

[Justin G]

You are correct in that it is banging at the ends of the x raster. I have not had a chance to test out the slow corner speed settings but once I do, will report back.

[Justin G]

So it has been quite some time but I am almost back up and running again. I tested the slow corner slows idea and it did soften things up. I had to lower it significantly, I went all the way to 20 for a rounding gadget toolpathe using multiple strategies as tests. All banged back and forth at the ends of the X raster until I lowered the SCS as mentioned. So I can only assume I have some other whacked out ramp setting. I run my machine pretty snappy usually so I'll have to do some more investigating.

On an unrelated note. I reset my config file and lost my unit values that shopbot gave me a while back. Now they cannot figure what they should be and i have no confidence in the accuracy of the 4th axis rotation. Also of course I did not save the file before loading a different one. Whoops.

[Brady Watson]

What are you running for a gearbox (ratio) and motor? If it is the 12" one, IIRC it is something like a 15:1 planetary Neugart or something + an AS911 motor?

Post up the gearbox plate specs and motor label specs.

-B

[Justin G]

It is the 10:1 motor bought from shopbot directly for a 6" indexer. 26653

[Brady Watson]

On the driver itself, are all the little switches to the LEFT?

What is the multiplier for the B axis in VR?

In VD is the B axis set to degrees or linear/inches?

-B

[Justin G]

On the driver, all the small white switches are to the left. M26654ove and jog speed for B axis are both 10.16.

Under VD, b axis rotary, A axis is linear 0.

[Brady Watson]

What is the multiplier for the B axis at the bottom of the VR fill-in sheet? Scroll to bottom of sheet...

-B

[Justin G]

Brady I may be missing something but I do not see a multiplier. 26655

[Brady Watson]

Sorry I meant VU, not VR.

-B

[Justin G]

Multiple for B is 5, same for all axis.