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May 21, 2018, 19:50:59 pm

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 on: Yesterday at 18:02:21 
Started by jgmick - Last post by jgmick
Background:  Asked for some assistance in cutting a 3D profile.  Bubba stepped up and gave me back a .cb file that solved it.  Thank you sir for your help.

I fooled around with the file a bit trying to understand it better, decided to generate an ,NC file and just go cut some parts to see what I got.  I made a couple of minor changes (I think they are minor).  Changed "constant velocity" to "exact stop" (better accuracy but slower, good trade in my book).

What I got was a disaster.  I went back into the .cb file and did some measurements.  The file appears correct.  CamBam did NOT reproduce the part the same way.

If you look at the attached file and switch to viewing the part in the XZ plane you will see a circle that I just added to the drawing.  It has a radius of 0.375" and is tangent to the edge of the part pocket that I am trying to cut.  It is very obvious that the internal fillet in the part has the same radius.

The finished part has a MUCH smaller radius.  I didn't measure it exactly (no radius gauges) but it is about 0.150"

I had seen comments on the poor quality of the solid model and watched it as the roughing MOP was running.  I can clearly see facets in the part.  I had added a 2nd "waterline finish" MOP to the original file given me by Bubba since the one he supplied was set for "waterline roughing".   All I changed was from "waterline roughing" to "waterline finishing" in the 2nd MOP.  My thinking was that it would clean up the facets somewhat.  The tool path it produced in that MOP looked encouraging so I thought I was on the "right track" in doing that.  The finishing MOP did NOT actually do much to clear out those facets. (maybe a small cleanup.) So much for that theory.

I cut a 2nd part (raw stock is cheap, run time is about 55 minutes) but omitted (stopped short) of allowing the 2nd MOP to run.   Got the same undersized radius.  The problem is in both MOPs.

I went back and looked more closely at the tool paths generated while viewing them in the XZ plane.  I can pretty much see now that the end of the tool is following a smaller radius then the part profile.  Can't measure in that view to get exact numbers but it does appear that the tool path dives in more sharply than the part curve.  Didn't occur to me to look at that earlier. (Not sure I would have picked up on it anyway before the fact.  History is a wonderful teacher.)

At this point I am about off the end of the diving board with no life jacket.  I am enclosing the .cb file that I used for this.  If I made an error somewhere please advise.

What went wrong?

 on: Yesterday at 15:16:55 
Started by WireCut - Last post by pixelmaker
my first question is why do you make a 3D model at all when you mill it in 2.5D?
A simple 2D drawing is enough to mill something in 2.5D.
If a polygon object is drawn around with lines, the edges of the polygons remain. . The polygon has the correct dimension at the points points, but at each point of the edges and surfaces it is below the desired dimension.
A polygon object can of course be processed and deformed, but this is not possible for dimensionally stable objects.
When natural shapes are modeled it is no problem, you model from a cube or a sphere.


 on: Yesterday at 14:20:34 
Started by WireCut - Last post by Bob La Londe
I have not found STL files to be easily editable.  Sometimes I can convert modestly simple ones to solid models in ViaCAD.  If you have Olsen's toolbox you can sometimes convert slightly more complex ones, but 95-99% of the STL files I work with have too many facets and conversions tool just bog down and fail. 

Ultimately I save every project in its native format before exporting the STL to begin with. 

 on: Yesterday at 13:37:37 
Started by WireCut - Last post by lloydsp
Perhaps this is a silly question, but how did you create the .stl in the first place?


 on: Yesterday at 13:18:11 
Started by WireCut - Last post by WireCut
I need to modify the STL file, changing somethings.

I think that the best things to do is to transform the STL file in a bi-dimentional DXF file, and then import it in CamBam and then make the needed modifications.

Googling for hours I do not found a solution.

There are any procedure, tricks or suggestion?


 on: May 19, 2018, 21:35:37 pm 
Started by Bubba - Last post by EddyCurrent
specially to Eddy who took the time and effort to create precise a easily to understand schematic along with detailed instructions.

Thanks, I used to get a lot of practice writing instructions, mainly to avoid call-outs through night when the electricians got stuck.

 on: May 19, 2018, 20:46:16 pm 
Started by Bubba - Last post by lloydsp
Hooray, Bubba!


 on: May 19, 2018, 20:35:31 pm 
Started by Bubba - Last post by Bubba

Thanks to all who offered help, specially to Eddy who took the time and effort to create precise a easily to understand schematic along with detailed instructions. Following this, connected the wires, flipped the switch and.. voila  Cheesy Grin

Surprisingly don't have to wait long at all to change rotation of the chuck. Post link to video soon, I hope.. Wink Cheesy Grin

Thanks again.

Here is video I have promised..

 on: May 19, 2018, 20:28:19 pm 
Started by Bubba - Last post by Bubba
Hey, it happens to me as well, no a problem.. Grin

 on: May 19, 2018, 20:26:44 pm 
Started by Bubba - Last post by Bubba
2nd minor item:

If you have run machines with 3 phase motors then you (like everyone else that uses them) has gotten used to a feature that if you want to stop the motor in a hurry then you just bump the switch into reverse for a short time and that really slows the motor down quickly. 

That trick will NOT work on this motor.  Try it and it will just keep running in the same direction.  FWD/REV ONLY means something on these kinds of motors if they are starting up from a stopped condition, not if they are already running.

Yes, I'm well aware of it with true 3 phase motors that run straight out on 3 phases mains or rotary phase converters.
My bridgeport is running on static phase converter and it behaves the same way as this lathe will when reversing power to early.

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