After reading most of the threads on this forum back to 2012, watching many of the MadCAM video tutorials, searching for solutions online, and studying the MadCAM help files, I’m struggling to setup a 4th axis with rotation limits (XYZA).
My set up is unique as the 4th axis has a bracket clamp to support the part (see attached image). Its ideal as it allows for machining concave regions on the bottom of the part without having to reorient it or use a 5 axis machine (which is not in the foreseeable future).
The disadvantage of the clamp design is possible tool crashes. My initial approach was to try limit the rotation angle of the 4th axis, an option in the Machine Setup. The clamp is positioned at 180 degrees (down, 6 o’clock, BDC) in the home position and requires about 40 degrees for tool clearance (+/-20º) at TDC. So if I could limit the tool paths to +/-160º, the clamp bracket won’t crash into the tool. Limiting the 4th axis angle in tool set up did not work in MadCAM 4.3 and does not appear to work in 5.0 trial version. I also tried setting up a 5 axis machine with the 5th axis locked (0º,0º) and the 4th axis angle limits set in both 4.3 and 5.0 with no luck.
Regardless of versions or settings, the generate tool paths in full 360º, resulting in tool crashes with the bracket clamp for both indexed and continuous 4th axis operations.
The attached tool path file is the best I can come up with after a several days of generating hundreds of tool path combinations (PM for tool path file as I can't seem to attach a Rhino file). Each part is custom and only machined once. The workflow I’ve come up with is less than desirable for one-off parts as each part/stock material is not always centered on the A axis. This requires tweaking every clipping plane (top and bottom) and boundary curves. The end result will work, except it probably takes five times longer than if the A axis rotation was limited and I could set up one finishing continuing finish pass instead on 5 indexed passes. I like to maximize set up efficiency itself of using the time consuming workflow I currently have.
FWIW, I’m using MadCAM trial version (5.0.2015.417) with the trial version of Rhino. I have Rhino 4 with MadCAM 4.3, but ran into the same 4th & 5th axis angle limitations (not functioning), so I thought I would try the trial versions of MadCAM and Rhino to verify it will work before upgrading two software packages for a singular application.
So this results in several questions:
1. Is the machine set up axis angle limitation designed to limited the rotation of the rotation axis as I envision it?
2. If it is, is it not functioning because it is a limitation of the trial version of MadCAM 5?
3. If not, any idea why I’m not able to set it up (I do save any settings changes)?
4. Are there other ways to limit the rotational travel of the 4th axis to prevent a tool crash with the clamp (eg, create a custom Drive Surface to prevent tool paths colliding with the bracket clamps)?
5. I’ve loaded .stl files of the bracket clamp into the machine setup. However, they do not appear in the simulations. This would greatly help visualize potential tool crashes. Is this a limitation of the 5.0 trial software?
6. Does anyone have tips for a better workflow than I’ve manage to scrape together?
7. In the Help file the clipping planes appear to be visible, likely so you can drag and drop them to raise and lower. However, the clipping planes don’t appear in any of the viewport windows. Is this typical?
8. Regardless of whether the stock material layer is visible (or not) and the simulator settings, the simulator does not show the removal of stock material, only the part is shown (see attached image). This makes it difficult to set Clipping Planes, etc. for subsequent finish passes. Is this a limitation of the trial version?
One observation that may help others with setting up a 4th axis: When setting up the Boundary Curves, I found them to only effective if drawn in the X plane (front/back viewport). I found this out by accident after several hours of trying to configure BCs in the Z plane. The Region curves are effective if drawn in the Z plane. This seems odd as both are effective in the same plane (Z), yet are drawn in different planes. Perhaps it is only the version of the software I have.
I’ve reached out to the MadCAM support, but as I haven’t received a response, I guessing JM is enjoying summer sailing. So if any seasoned MadCAM users have answers and/or would be willing to review the attached file(s) and suggest ways to improve the current workflow, your help would be most appreciated. Also, I realize what I am trying to accomplish may be outside the design intentions of the MadCAM software, and some the preceding limitations may be due to the trial version of the software.
Thank-you,
LO