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John Coloccia
03-14-2013, 12:44 PM
I have a spoilboard bit from Amana that I'd like to use for surfacing my table and also for facing parts and things like that. It can't be plunged. It has to ramp something like 1/4" over 20" (not sure if that number is exactly right, but the important part is there's a ramp and no plunge). Is there a simple way to do this in MadCAM? I'm sure this is a dumb question, but I'm still pretty new to the CAM world, so bear with me :)

svenakela
03-14-2013, 04:03 PM
All 3D-methods have Radius lead and Ramp approach options. You can even do a facing operation with the 2D features, like Facing. Pocketing actually works better for you. they both have a Ramp approach but the Facing command has a radius in that automatically sets the angle of attack. All other commands you simply set the angle for the Ramp approach yourself.

John Coloccia
03-14-2013, 04:17 PM
All 3D-methods have Radius lead and Ramp approach options. You can even do a facing operation with the 2D features, like Facing. Pocketing actually works better for you. they both have a Ramp approach but the Facing command has a radius in that automatically sets the angle of attack. All other commands you simply set the angle for the Ramp approach yourself.

I've been trying all of this. Nothing seems to work. In 5.0, Radius seems to have no effect (there's no ramp setting), and when I put in the appropriate value for ramp in pocketing, it simply plunges. I think the ramp takes it beyond the extents of the box I made, but I would have expected it to do a helical ramp, or something like that...not plunge.

So I figured it's a bug in MadCAM 5 or I'm doing something wrong. I dropped to 4.3 and I can't even select the simple box I made for my model. It's literally just a rectangle that I extruded and capped, but I get "You have to select solids or surfaces....". When I try to add the box with "Select Surface" button, it does nothing. It's the same exact model...same file. I'm just opening it in 32 Rhino 5.0 for MC4.3, and 64 bit Rhino for MC5.0.


It's randomly working and failing. Here's the exact sequence I did:

Open Rhino5 32bit. Make a box. Selected the box and added it in MadCAM 4.3. Great. Deleted the box. Selected the same box and tried to add it again. FAIL. Sometimes, I just make a new file, create a simple box and it refuses to add it.

svenakela
03-14-2013, 04:56 PM
Hang on here, you can't use MadCAM 4.x in Rhino 5 can you? It shouldn't work, they are different creatures.

Just did a test (Rhino 5, MC 5), it seems that the 2D Facing command Radius setting has no effect at the moment. It also seems that the angle of the Ramp approach set in Pocketing takes effect in the Facing dialog as well. You could try that too, make a Pocketing with 10 degrees Ramp first and the Facing will probably have the same ramp

Anyway, if you want to do the facing with the 2D commands you need to use a curve which is at least the model boundary + cutter radius to cover the entire work piece. If I were you I would use the 3D command Planar Finishing instead. You have so much better control over the toolpath and it covers the entire surface. Either use the Contouring option with Start from outside checked or a Parallel to X/Y path.

John Coloccia
03-14-2013, 05:03 PM
Hang on here, you can't use MadCAM 4.x in Rhino 5 can you? It shouldn't work, they are different creatures.

Just did a test (Rhino 5, MC 5), it seems that the 2D Facing command Radius setting has no effect at the moment. It also seems that the angle of the Ramp approach set in Pocketing takes effect in the Facing dialog as well. You could try that too, make a Pocketing with 10 degrees Ramp first and the Facing will probably have the same ramp

Anyway, if you want to do the facing with the 2D commands you need to use a curve which is at least the model boundary + cutter radius to cover the entire work piece. If I were you I would use use the 3D command Planar Finishing instead. You have so much better control over the toolpath. Either use the Contouring option with Start from outside checked or a Parallel to X/Y path.

When I bought it, the guys at McNeil said it would work, and it seems to work just fine until now. In fact, I didn't even have the 5 beta until a couple of weeks ago or so. I don't know what I'm doing wrong. Maybe some file got corrupted somewhere?

Thank you for the suggestion. I will try planar finishing. Am I right that if the ramp angle takes the cutter outside of the boundary that it should do a helical plunge? It's not a big deal. I can work around stuff like this, but I'm curious what the intended behavior is.

Thanks again for help. I'm wondering if a Rhino or Windows update somewhere screwed things up on my system? I've now shut off automatic updates, but maybe too late. Either that or maybe I got some very bad information and 4.3 will not ever work properly in Rhino 5. I don't have Rhino 4, so that would be very scary. I'd be moving forward in my production with nothing but CAM beta. Yikes!

svenakela
03-14-2013, 05:17 PM
Don't worry, I've been using version 5 long time now for all work. :)

The workbox (the green wire frame) is not a hard boundary, that's a common false assumption. The cutter will happily swipe at least the radius width outside the box if you don't setup a boundary (like a vertical surface) or select the model with surrounding obstacles and then add a region curve and/or Clipping planes.

The 2D commands on the other side, will be enclosed inside the curve selected for the operation. But then you might end up with uncut corners depending on the curve shape. If the Ramp angle is low enough it will be a kind of helical.

John Coloccia
03-14-2013, 05:24 PM
Maybe that's a 5.0 bug, then? I don't get a helical ramp on the pocketing with a low ramp angle. When it gets to a certain point, I just get a plunge.

svenakela
03-14-2013, 05:59 PM
Maybe that's a 5.0 bug, then? I don't get a helical ramp on the pocketing with a low ramp angle. When it gets to a certain point, I just get a plunge.

I certainly get a ramp. Do you have the latest beta installed?
What seems to be a bug is the non working radius lead in the facing command.

John Coloccia
03-14-2013, 11:10 PM
I get a ramp, but when the value starts getting low, I get a plunge instead. I'm just not sure if that's a bug or if there's some limit on how low I can go. The latest 5.0 beta I have is from the end of February.

It would also be great to know if 4.3 is supposed to work with 5.0 32 bit. Maybe I should just stop trying to do that. I was under the impression that was the most stable configuration to use, but maybe not.

John Coloccia
03-14-2013, 11:21 PM
So I'm doing more testing, and for pocketing, a ramp angle down to 1.1 works, but nothing below that works. If I put in 1.1, I get a nice "helical" ramp (not really helical, but it ramps down in a spiral). For 1 degree, it will plunge. My particular bit requires .7 degrees. I suspect that 1.1 will be fine in practice, but I see no reason that I shouldn't be able to go to 1 and below if required.

Dan B
03-19-2013, 05:36 AM
I recall a similar bug in the early days of 4.2 or 4.3. If you made the ramp angle too small it plunged. Looks like that may have re-appeared.

Dan

John Coloccia
03-19-2013, 07:53 AM
I think there's a lower limit of 1 degree. Actually, it seems to not work at 1 degree, but 1.1 does, so Joakim has a > somewhere where there should be a >=. LOL. Thinking about it, that's just too much...it's almost twice the ramp that I actually need. That's too bad because I really would have liked to use this bit in my normal workflow. I'll send Joakim an e-mail one of these days. Maybe he'll lower the limit. It seems arbitrary but maybe it's set to 1 for a reason and that's that. :)

edit: The ultimate solution for me is just to use a regular router bit for the facing my hardwood parts as part of the workflow. It's really not a big deal. I happen to have some large bits here so life is good. The finish is better too. The surfacing bit tends to splinter and tear wood fibers sometimes, so in the end it's a poor solution for me anyway.