new guy needs help with a large part

[HRTFAB]

hi guys, so I have this part that I need to machine that is relatively large and it exceeds my mills x travel which is 16 inches. Its going to be roughly 20 inches long 3 inches deep and 3 inches wide, ill attach the f3d file so you can see the model and cam I have for it . Just wondering on how you guys would tackle this, I was thinking about splitting the model and creating toolpaths for the left half and then for the right half and keeping the origin centered the whole time then creating cam for the left and the right and offset the wcs to adjust for available travel if that makes sense. the material for this job is out of uhmw, but due to its size each part costs over $100 in material, so I make try this with a piece of wood first.. let me know what you think...

Daniel

[LibertyMachine]

How much travel do you have in the "Y" axis? If you have around 14", you could kitty-corner the part like this:

Barring that, yeah, you'd have to make two setups. You don't need to physically split the part in Fusion (although that is viable). You can use sketches to drive your toolpath rather than splitting your part. See attached file for more info. Basically, draw a box that you want to contain the toolpath to and select that as your boundary (you need to use a 3D Adaptive for this to work)

Couple thoughts/comments: Are you permitted to put a couple tooling holes in the part? Reason: You need to remove all the material on one side. You will have nothing to locate on when it's time to move the part. You need to make sure there is an accurate way of establishing the orientation of the part, as well as the location.

If holes are not permitted, I'd avoid removing ALL the material on one side, perhaps apply tabs instead so it's still somewhat stable. This ties into my last thought: That part is likely going to bend a fair amount, and it's an unknown what direction it will go in. Be cautious and don't shoot for finish sized right off the bat

How are you going to clamp it and machine all around the part? You can't have 10" of part unsupported by clamps, it's going to have so much flex that it will likely be impossible to attain a good finish and/or results.

What is your machine, btw?

[Anonymous]

Another option is to build a fixture plate that has known locating holes in it and slide the plate, you will have to do some containment work in your tool path though. I like to use pins and holes -.0005 smaller than keyways and slide in through in the keyway. Downside is you have to make a fixture plate to hold the part. You can also use pins and blocks with your keyway similarly, but this has more opportunities for error.

[HRTFAB]

thanks for the idea I hadn't thought of that, unfortunately my table is a 10 in the x and 16 in the y  so kitty cornering it wont fit, but good idea. I'm not actually worried about part deflection, the part is fairly large and should have decent strength. UHMW is a easy material to machine and the blocks I have give me an additional 1 inch of material  to hang on to, I would do an adaptive 2d to remove the bulk and leave .05 on the contour to finish.  I think I will have to machine the corners down so I can get some clamps and then clamp the for corners directly to the table. As far as drilling fixturing holes in the part, I could do that, I know the customer and what he needs and that shouldn't be a problem, I may have to to face the extra one inch once I flip the part. thanks for the ideas

Daniel

[HRTFAB]

As far as the machine goes , its an old Bridgeport series 2 interact with a gecko mach 3 retrofit, unfortunately the 24 ATC was removed before I got the machine, but the machine works well and holds very good tolerances.