HST - Roughing

[Ployd]

Hey guys, I’m working on a large mold. The fiberglass is about 0.4” high and I need to machine it down to zero. My step down is about 0.05”. Right now I have to make about 8 surface high speed raster toolpaths steping each one down . I know that I can post them all together and let the machine run.

 

But I was wondering if there is a roughing program that will start 0.4 above the surface and step down 0.05 until it reaches zero. I’ve been playing with the high speed roughing programs but haven’t had any success.

 

I think of it like a casting that needs to be machined. We aren’t starting from a block of material. It already has the basic shape but the material can’t be cut in one pass.

 

I appreciate you help.

 

 

[Guest]

Bill,

 

It sounds like a HS Area Clearance should be able to get what you're looking to do. Unless I am missing something.

[Ployd]

Thanks John,

 

I've got my stock to leave as 0.4 and the stepdown set to 0.05 and it just does one pass at 0.4. Then if I change it stock to leave at zero and 0.05 stepdown I only get one pass at zero.

 

no stepdown

 

I need a way for it to know the material is actually higher than the dive surface at zero.

[3R!< W3NG3R]

Did you try pocket? This does 90% of my roughing.

[Matt Berube at Ferron Mold]

I think if you create a model that equals the starting stock, save it as a .stl file, then create a SURFACE ROUGH RESTMILL toolpath with the rest-material defined as a "CAD FILE" (the .stl you made earlier) you should get exactly what you need.

 

If you don't have solids to create the model you could probably create a dummy toolpath with .400 stock to leave then verify it and save the verify stock as a .stl and then use that .stl for your "cad file".

 

It's been a while since I did any of this but I am 99% sure it is possible to do the way I am describing...

[Ployd]

Eric,

 

The pocket toolpath doesn't do what I need, thanks though.

 

Matt,

 

I see what your saying I will have to play around with it. I wonder if I can copy the surfaces onto another level, offset in z +0.4 and use those surfaces as my starting stock. Or save as another file.

 

Seems like I should be able to create a program that follows the shape of my part (so there isn't a lot of wasted time). And I could say these are my drive surfaces start at +0.4 above surface and end at zero with a 0.05 stepdown. Seems simple enough. Am I missing something?

 

Seems like it would be a HST core roughing program.

[Redfire427]

Write a raster toolpath that leaves .4 stock on the part. Now do a remachining toolpath that references the first toolpath and there you have it. The other option as described above using an stl file works great as well. Either way will get you where you are looking to go.

[Zoober]

+1 on Matt's rest machining. I do it a lot. STL is your friend!

[Ployd]

Prosin,

 

I'm not sure I understand what the remachining toolpath is. I did a raster at 0.4 and then created another raster at zero that references the previous under the rest material tab. I got an error that it couldn't create the toolpath.

 

Robert and Matt,

 

I need to go back and read some more threads about the .stl files. Not sure I have a grip on it yet.

[edmBosto]

quote:

---

I'm not sure I understand what the remachining toolpath is

---

A smaller cutter is used and will mill where the larger would not.

[Redfire427]

Ployd,

 

I tried to do a print screen and paste it here for you to see but I am not skilled at doing this. First, use a 1 inch ball end mill and create a high speed raster toolpath leaving .4 for your stock to leave. This toolpath is merely for calculation purposes for your second toolpath. The first toolpath, if you were to use it, would give you approximatley what you already have as stock. Now create a new high speed rest roughing toolpath with lets say a 1/2 inch ball endmill. In parameters, rest material, choose: one other operation, then select the first toolpath from the list on the right. Choose your stock to leave ( maybe .01 ? ) stepdown, stepover, etc. and Mastercam will only cut the remaining material. The resulting toolpath uses pocketing and contouring techniques in order to cut only the remaining stock.

[Ployd]

Thanks Prosin,

 

I'm still getting an error "unable to determine a valid machining zone - no toolpath created."

 

I'm sure it's something simple I'm missing. I'll keep playing around with it.

 

Bill

[Thee Rickster ™]

quote:

---

I'm still getting an error "unable to determine a valid machining zone - no toolpath created."

---

Ployd

 

When i get this I have two choices

 

Its like the path is corrupt or some thing and

I shut down MC and Restart and 'Sometimes' that

fixes the problem

 

OR

 

I make a new path, the same as the one that

gives me that error and that always fixes it

Then delete the PITA one.

 

HTH

[Ployd]

Prosin,

 

I was going to tell you that if you want to insert an image or screen print in the thread you have to get the image on a server. A lot of people here use photo bucket . Or you can place them on your server.

 

Under the full reply form you can insert an image by clicking on the image button. Then paste or type the path from the photo's web address into the http display that pops up. That should get you going. For instance the link to the screen shot I placed in this thread is as follows http://www.5axistooling.com/images/mold1.jpg

 

 

HTH