Machine Casting using STL

[Reko]

Hi,

 

I have read everything possible on this site about setting up a part to surface/restmill using an STL file so that I'm only machining the casting and not cutting air. I still need help getting this thing to work.

 

So far, I created a separate solid that is water tight and I converted it to an STL file.

 

Then, I used the STLHEAL c-hook and it seemed to work fine.

 

Then, I set the stl file as my stock in "stock set up." It looks good.

 

When I try to machine the surfaces using the surface/restmill option, I get the following two errors:

 

http://i610.photobucket.com/albums/tt185/MCReko/n1.png

 

http://i610.photobucket.com/albums/tt185/MCReko/n2.png

 

The part looks like this:

 

http://i610.photobucket.com/albums/tt185/MCReko/n3.png

 

Any suggestions would be greatly appreciated. I have a new job and I work with almost all castings so this knowledge is essential for me to acquire.

 

Thanks :>)

_________________________________

MasterCam X4 Mill Level 3/Solids

Dell Precision T3400

Intel Core Duo CPU 2.33 GHz

2.33GHz,2.00 GB RAM

Windows XP Pro SP3

NVIDIA Quadro FX 570

[Superman]

The resolution that you created the STL is tooooo fine, there are toooo many facets for mastercam to calculate offsets to.

 

For a verify STL I've used 0.002" or less but for stock on a toolpath op I've gone as high as 0.02" or more( even 0.05"). Just allow an extra 0.04" plunging distance to avoid the tool smacking the stock on descends.

( Toolpath calculations will be much quicker too )

[MotorCityMinion]

I'm missing something here as well. Why not machine the solid? Then use the solid in verify as well.

[Superman]

If you get models of the stock casting and the finished part, why create toolpaths in areas where no material exists ?

 

Seems a waste of time and effort

[gary adams]

There may be an issue with your resolution, but be sure when you save your stl (I usually use data in the mastercam folder), that you select this file in your rest mill operation. There is an area where you either use previous tools or ops or link to an stl file you must select this file.This function does work and is reliable.

Gary

[KMartin]

What is a good stock resoloution.

[Reko]

Superman,

 

Not sure what you mean by resolution. I'm creating a solid and then creating an STL from that. It doesn't ask for anything. When I set the "restmill parameters" I use the default stock resolution which is ".25" so this is much higher than the .05 you suggested. Still no luck.

 

Gary,

 

That is where I select STL file and this is also where the stock resolution is set. Still no luck.

 

Motor City,

 

I'm open to suggestions if you have a better way to do this. From everything I've read, the STL file seems like the way to go, but I'd like to hear how you do it. I'm not sure what you mean by "Why not machine the solid? Then use the solid in verify as well." What would verify have to do with machining the part?

 

Thanks again for all of your responses :>)

[Superman]

quote:

---

Not sure what you mean by resolution. I'm creating a solid and then creating an STL from that. It doesn't ask for anything.

---

When you "Save Some" and select the solid you are going to use as the stock STL CADfile in the restmill op, select the filetype--> STL, open the save options and alter the STL resolution there before accepting to save ( check the STL file size before and after, it'll be dramatically smaller )

 

quote:

---

When I set the "restmill parameters" I use the default stock resolution which is ".25" so this is much higher than the .05 you suggested. Still no luck.

---

This doesn't affect the resolution of the STL CADfile you have saved, play with this after getting it to eliminate aircuts ,to adjust for adding extra cuts in corners, I think it tightens cornering accuracy

[cunder]

This may sound like an odd work around but it works for Me. I set the stock view to TOP. Load a solid in Mastercam. I use one "manual entry" operation and verify to the solid. This does have any real toolpath but it allow Me to save a SLT right from verify. I then use that verify for the rest material file.

[gary adams]

Check that your proceedure works on a simple part linked to an stl for stock?

Do toolpaths run on your part model other than the restmill function?

Your part looks like there are open faces, I see you have solids so have your part as a solid and select solid faces to run your paths on.

Gary

[MotorCityMinion]

Reko, lets assume the casting has .125 stock to machine off the surfaces in various locations. You have a solid of the "as cast" material, and a finished solid or wire frame that you can get finished geometry from which to machine. In verify, you can select the raw casting solid as your stock and watch the material come off as you go. If need be, you can save the results of the verify as a STL for later usage. I usually assign colors to the different tools, rough, finish, whatever, and watch the stock come off that way.

 

Not quite sure what your after here. Are you trying to machine all the surfaces on the entire casting? With .125 stock or less, you can probably get away with using the finishing toolpaths with stock to leave on the finished solid, finishing non critical areas, but verify using the as cast solid. Then come back and rest mill the critical areas. Usually, I'll program the roughing op so that I can just dupe it, change a few things and use it to finish with.

 

(The scallop tool path is excellent for semi-finishing or roughing with medium to fine cuts, grouping different types of surfaces together in one op. Kinda sucks for finishing though.)

 

As far as machining using the STL to toolpath from, I've no experience with it and have never been able to get it to work.

 

OT, where abouts are you located?

[Reko]

It WORKS!!! Thank you everyone for all of your input. I was really pulling my hair out but I think I have it now.

 

I was missing WHERE to set the stock resolution for the STL. Superman, your explanation was the key. You said, "open the save options and alter the STL resolution there before accepting to save."

 

I never realized that was even there. I set it to .050" and that solved it. I felt like a little kid in a candy store when there weren't any errors and the file started processing!

 

Thank You, Thank You, Thank You! Everyone!

 

Gary,

Yes. Everything else works but on a casting, there doesn't seem to be a viable option to rough the surfaces. Surface/Contour works down the sides until the cutter gets toward the bottom and the stock is too heavy. I work with castings that have about 1" material left on the surfs.

 

cunder,

Are you saying that you use that "verify" for the STL creation? If so, please read my answer to MotorCityMinion. :>)

 

MotorCityMinion,

I think I see what you are saying. You just create the STL from verify after running a roughing operation. I haven't tried that all the way through yet. I keep stopping the process because it takes too long. See, my problem is my files are HUGE. This file is over 600Mb as the largest diameter of the part is over 125 inches (over 10 ft.). I read that you weren't supposed to use turbo in verify when saving an STL so that seems to take way too long to wait for verify to run. Unless you have any suggestions for speeding it up, I mean.

 

BTW, I'm in the Tri-City area in Mid-Michigan. You?

[Superman]

The boss will expect bigger and better things from now on. Sorry forgot faster as well.

[MotorCityMinion]

Downriver, just south of Detroit. Glad you got it to work.

 

Large files indeed. Even in turbo mode, that can take some time. Your saved STL's will be Garganuan as well. Yes, turbo and saved STL's = funky.