additional cam bug @seth.madore

[johnptc314159]

 https://a360.co/307gsVd   if you run a round insert grooving tool on insert center the turned part looks like a ball which was constricted around the equator.  the insert center was correctly set in the lathe.......  the sim looks good ??

it seems any of my uses of round inserts  leads to trouble. also when you select round insert in tool editor ( grooving tool)the is no diameter call out so i assume it is the width.\

@seth.madore 

[johnptc314159]

very helpful.  i am going to run the attached file based on yours.

i got rid of the facing by turning below the center line select in radius tab while editing the finish profile.

let you know asap the results

[Anonymous]

If you use center of round insert in Fusion as programmed tip, touch tip of the tool in X and Z axis.

Next, go to geometry offset and shift X axis value in negative direction by twice the value of radius for OD tool and one times radius value in Z negative direction.

As shown in pic below, programmed point will then be retracted from part geometry by radius value in Z axis and tool diameter in X axis, while tip of the tool is on desired path with part geometry.

There is no difference in end result but looking at tip tangent vs center point, tip tangent is more logical way to do things, you touch tool and you are done, programmed path just reflects different guiding point during cut.

If accuracy of the sphere is of any concern, always use I and K for arc definition in G code.

 

[Anonymous]

Small facing move I added is to reduce stock amount at the center of part. There is virtually no surface speed at X0 so when you drive finish pass starting at X0, tool is actually driven ino .005 stock left by roughing with no rotation of stock, resulting in chipping tool tip on anything other than plastic or aluminum.

There is rotation at given speed of course, it's just that at axact X0 point there is none, and reducing stock amount helps preserve tool tip.

You cannot start cut below center line because rotation is opposite to cutting edge and it will knock the cutting edge off of insert on contact.

[johnptc314159]

so far getting rid of the tool holder was GREAT !!  it made a very nice part in aluminum....probably why i got away with cutting below the axis. I will switch to your scheme on the final SS parts 🙂 now i have working  code !!!

@ seth.madore  is the tool holder as explained above a bug ??  it seems thats what i have been fighting 😞

let me now and we can close the thread 🙂

[Anonymous]

I noticed the size of your tool was some odd number and I changed it to .25 diameter in inch just for illustration purpose.

Be sure to check / correct actual insert dimensions you intend to use before moving on.

[johnptc314159]

thanks.........  its nominal 6mm but measured 5.88 mm  then converted to inches 🙂

appreciate the heads up.    john

[johnptc314159]

@seth.madore 

i havent heard from you in a while.....do you think the tool holder is in  fact the bug ??

john

[Anonymous]

I originally replied to your thread because Seth asked me to, he was too busy to reach all requests at the time.

So let me add this thought to your inquiry, for round insert to be able to work from 0 to 180 degrees on lathe, it would have to be configured in grooving tool holder where width of shank at certain length has to be narrower than diameter of round insert.

That would classify holder as related to grooving tool and as such it would be rejected in turning operation as 'Wrong tool".

Although it is possible to use grooving tool as turning tool in other software, this is not possible in Fusion for some odd reason.

So, not only that not being able to use grooving tool as turning tool is a bug, not being able to define holder along with round insert is also a bug, no question about it in my mind.

Although grooving tools are designed to primarily plunge into the stock, many tools on the market can be safely used for minor turning, driving tool sideways wherever possible.

With round insert being restrained by set screw in the center, you wanna be careful about direction you drive your tool in.

Driving tool from front to back will pressure tool ino its seat, friction of insert bottom and side wall with holder, along with tork of a set screw will resist tendency to result in spinning of insert under load of a cut.

Drive same tool in back to front direction and it won't be long before pressure of a cut will loosen up the set screw and allow insert to spin in its seat, fraction of a second later you will have two or more fragments of that insert.

[seth.madore]

Thanks Vic for jumping in.

What he says is correct; I'm getting swamped from a dozen different directions and my shop just landed a job that requires all of my focus. I think next week is going to see me quite absent from these pages....

[Anonymous]

Last day of my mini vacation, Monday is back to work and my new project, likely far less time on forum for a while.

[johnptc314159]

thanks a million for your help, i was hoping to get seth to put it in his bug list to be fixed 🙂

stay well

[seth.madore · Accepted solution]

It's on my list, and I do apologize. I run a shop full time in addition to my invovlement with Autodesk. I've been getting slammed lately with some hot jobs and participation has (understandably) dropped.