[Jason3]

Hi All,

I'm hoping someone might be able to tell me where I'm going wrong here. I'm trying to create tool paths for this part. It needs roughing and finishing on two sides and a simple bore on a third face.

I followed along with MadCAM 4 axis milling video, the one making tool paths to cut a head since it's very close to the process I want. Here's what I did:

1. Open part. It has a stock model (red) and the part, first pic.

2. Madcam Options => Axis setup => 4 axis

3. Select Cutter (4mm flat end)

4. Select stock model

5. Set Cplane World Bottom (I want to start from the bottom as this leave more stock to support the part for cutting the top)

6. Set clipping planes top Z bottom = 0

7. Create 3D Roughing toolpath. It looks OK except it has gone outside the stock model (Pic. 3 below)

8. Set Cplane world top

9. Create 3D roughing toolpath. This time it ignores the clipping planes. In the video the clipping planes appear to reset appropriately when the Cplane is set? Not sure what's going on here. Anyway, I set the clipping planes lower limit to Z=0 again. Then I create tool path and find it's reset the clipping planes to encompass the entire part again. So I reset them to lower limit Z=0 yet again, and try again. This time it doesn't overflow the stock model and respects the clipping planes, this is how I wanted the bottom tool path to look as well (highlighted in 4th pic.

Can anyone suggest why I'm getting a different size tool path when cutting the top vs. the bottom? Also any explanation that could help me understand what is going on with the clipping planes in this operation?

Is a stock model required for indexed 4th axis work, or can I use the box size setting instead?

I've tried doing the steps in a different order and every other combination I can think of and so far cannot get it to work. If I could resolve it while I still have some hair left, that would be great

Many thanks,

Jason

[Dan B]

Any chance of posting that model so I can take a look?

Thanks,

Dan

p.s. Sorry about not responding sooner, but it was a holiday here in Canada yesterday.

[Jason3]

Hi Dan,

The model's not mine so I can't post it here but will PM you a link. Many thanks!

Jason

[Dan B]

Hi Jason,

I took a look, followed my usual order of operations, and it worked for me. I would say it's all in the order that you are performing your steps.

Here is my order:

1) Activate the part
2) In the options, pick the 4-axis machine
3) Pick your tool
4) Set your Cplane to define your direction (I used 3 point placement)
5) Select the 5-axis indexed mode icon
6) Select your stock model
7) Set your clipping plane
8) Create the path

Now to do the other side, follow this order after completing the first side:

1) Set your Cplane to define your direction (I used 3 point placement again)
2) Select the 5-axis indexed mode icon again
3) I selected the stock model again (not sure if I really need to but I did to be safe)
4) Set the clipping plane again
5) Create the path

The path looks good, and so does the simulation.

2012-05-23_0542 - DanBayn's library

Try it and let me know how it goes.

Dan

[Jason3]

Hi Dan,

Yours looks great! Mine is unfortunately still not working I wonder whether the problem could be my Rhino installation, or my computer with it's integrated graphics? I'm running Rhino 4, Sr9 and MadCAM 4.3, Nov. 23 '11 update.

Do you know why the toolpath goes outside the stock model? I want to restrict it so that the cutter does not travel past the ends, as that's where I'm holding the part. I tried it without setting a stock model at all, but of course that doesn't allow for the cutter to profile the part where it meets the boundary of the cutting envelope. Once I select the 4 axis machine it will not let me specify a custom cutting envelope.

Is a stock model always required for 4 and 5 axis work?

Another oddity is that when setting the clipping planes, it disregards my settings and replaces them with the original setting the first time. If I do it again, it works as expected.

I'll keep trying, but I'm nearly out of ideas! Thank you for your help, if you have any other suggestions they'd be gratefully received.

Regards,

Jason

[svenakela]

Haven't read the thread really (been crazy busy lately). Dan is really good at multi axis operations, I'm sure he knows what's going on.

The graphics card affects the simulator performance only.
Did you configure Rhino as stated in the MadCAM help file? I don't think that's the case but check it anyway.

[svenakela]

Oh BTW!

You don't have to use CPlanes at all, you can prepare the model with standard 3D functions and still have it running in a 4th axis setup. I rarely use another Cplane than the World Top.
Prepare the model (Select model, stock model, Clipping planes, regions etc).
Make the 3D toolpaths as if the machine was a 3-axis machine.
Select the model AND the toolpath, rotate 180 degrees in the machine 4th axis direction (move Clipping planes, regions etc if needed).
Make the 3D toolpath for the new upper side.

Now, post process both toolpaths at the same time. It will be an indexed process where both toolpaths will be executed on the model with a rotation of the part automatically.

/S
Now,

[Jason3]

That's great, thank you! Very useful to know I can just rotate model and tool path - am I right in thinking I can rotate to any angle the same way, for instance to do a bore on the back after cutting top and bottom?

I didn't check the MadCAM settings, actually. I've generally been quite slack with that as my templates aren't set up right and whatever settings I use are lost for the next part so I usually just make sure the max distance edge to surface is set small. When I reinstall Rhino I'll try and address that so I don't have to keep setting it every time.

Many thanks to you and Dan for your time! I'll report back and let you know how I get on

Regards,

Jason

[svenakela]

That's great, thank you! Very useful to know I can just rotate model and tool path - am I right in thinking I can rotate to any angle the same way, for instance to do a bore on the back after cutting top and bottom?
...

Yes, you can do it exactly like that.

[svenakela]

Had some spare time so I did an example.
Indexed 4-axis - YouTube

[Jason3]

Hey, thank you very much - I appreciate you taking the trouble and that's very helpful!

It's possible that you've illustrated the reason I've been having so much trouble. I re-selected the stock model after I rotated it, but I wasn't re-selecting the part itself for Madcam. I'll go and give it another try now. I'll report back...

Many thanks,

Jason