HST Instructional Question

[Rickg5106]

Hi All,

Very new to Mastercam X8 and I am taking a class at a local Community Collage to learn the software.  The instructor basically turned us loose with the book and asked us to complete the 8 detailed exercises, submitting the results.  No lecture, raise your hand if you need help, go forth and be fruitful.

I have a CAD background so the geometry creation was pretty easy, the Toolpaths I am understanding and I hope to round out that knowledge here.  

One question I do have is about HST related geometry.  My instructor doesn't like us to translate geometry.  He says that although the book has us do it, he wants it all in a flat plane.  In doing one of my exercises with a hexagon "island"  in the middle of a machined pocket that is lower than stock height but higher than the floor of the pocket, he commented that he didn't like that I had dropped the top face of the island down to it's proper Z height.  He said that I should bring that up to stock height where "it belongs".  I complied although I knew that this move would confuse my Dynamic Milling toolpath.  Sure enough, the tool path blew up and wiped out my island.  

Am I missing something in the tool path definitions that would allow all the geometry to be on the same plane but set an avoidance chain that somehow cuts the top off the island at the proper height but also maintains the geometry so I don't P off my instructor?

Thanks for your time,

Rick

[Jayson Kramer]

I hate to say it but this instructor really does not seem to know what he is doing. He should be showing you how it should be done if he wants you to not follow the book. I don't use the books for teaching I hate doing that.

Can you share the file with me to see what is going on. Also don't translate the geo but use Dynamic WCS to setup how you want to cut it..

 

What school is this?

[Rocketmachinist]

What school?

[Colin Gilchrist]

No offense to your instructor, but he sounds like an idiot.

 

Geometry should be located "where it is" whenever possible. Sure, you can draw out geometry on a flat plane, and enter the Z depth where you want it to cut, but only the most limited programmers would ever program that way.

 

As an NC Programmer, I very rarely have to draw out an entire part from scratch. Most often, I receive a solid model of the part, and use that solid to program my tool paths. The geometry I am then cutting is already at the proper depth.

 

Almost all programmers start out using "Absolute" for their programming method, where they are entering the depths manually. This isn't what a "good" or advanced NC Programmer does. A "power user" will always program using "Incremental" as their "depth" method. Using the "incremental" option does not output "G91". It tells Mastercam that the "depth of the geometry" is to be referenced for the coordinate output. So you you put in "0.0" Incremental, it means "use the actual depth of the geometry". If you put in "0.03" Incremental, it means "stay 0.03 above my geometry".

 

Another advantage of using Incremental depths, is that you can change the location of your Origin (G54 location) in your program, and the depths will update automatically, just by regenerating your program.

 

You should always put the depth of your chain where you want your cuts to be.

 

For 2D HST Toolpaths, I would have a chain "up in Z", at the height of my Stock block. Then, I'd have another chain at the correct depth for the profile/pocket I want to cut, and additional chains for Islands at their respective depth. Then I would chain each contour at the correct depth, and be done...