[KUWill]

Hey guys, I was looking for some help on what the quickest way to cut this bracket is. I was machining two of these out of roughly 4.5 x 2 x 1.2 block just being held in by tabs but the cycle time was just too much at 4 hours. Does anyone have any advice in the quickest way to machine this? The machine is a Haas TM-3 with max speed of 4K RPM and 200 IPM. I thought about trying HSM techniques on it, or milling one half and then flipping it and machining the other half but the simulation times didn't seem to compare well to machining two of them tabbed in a block.

Anyone got any ideas?

[txcncman]

Mill the entire bottom profile first. Then flip and do the side. Then flip and do the top. 4 hours? This should be about 15-20 minutes on the bottom with probably 4 tools. Maybe 20 minutes on one side with 2 tools. Maybe up to an hour on the top with up to 4 tools. I don't see much surfacing on this part. This is mostly a 2-1/2D part. Total machining time about 1 hour 45 minutes. 3 set ups.

[wizard]

Is a weldment possible?

It often surprises me how things I would do with weldments end up machining projects in these forums. I suppose application might have something to do with it but sometimes I suspect it is a case of using the tools you have.

[txcncman]

Should not be surprising. Almost all aircraft parts are machined from solid/billet material. I won't go into the engineering reasons why. In addition, to make a weldment and then precision machine it still requires a machine. Most of these guys do not have the welding rig, but they have the machine. So, solution is just machine it from solid.

[fizzissist]

You're gonna use 1 1/2 x 2 1/2 mat'l....one at a time.

Start by finish machining the base and features in the bottom. Flip it right side up and mill to completion the rest of the features except the two cross holes.

Your 3rd operation will be re-orienting the part to drill the cross holes. You're done. You could conceivably clamp on the base on the 3rd op and do the holes and the 2 angles for a cleaner surface finish

Assuming this is alum? Run time I'd expect to be at under 2 hours.

I think txcncman and I are on the same page. (my page is the one with the grease on it from the bag of curly fries I set on it during lunch)

[KUWill]

Should not be surprising. Almost all aircraft parts are machined from solid/billet material. I won't go into the engineering reasons why. In addition, to make a weldment and then precision machine it still requires a machine. Most of these guys do not have the welding rig, but they have the machine. So, solution is just machine it from solid.

@txc: Heh, you're understanding of engineering is impressive. I suppose I should expect it though from people who have been in the business of making our PITA creations.

@wizard: Racecar parts that allow adjustment of things. Billet will minimize surface area, allow us to have extras in case anything is FUBAR'd, reduces weight, and helps with serviceability. May not be the best solution, but it's the one our team came up with.

@fizz/txc: So what method of workholding do I use? I use to just clamp the whole depth in a vice and attempt to not hit the jaws while the cutters worked inside the edges of the billet. I also did it in 1 setup (no cross drilled hole) with a lot of 3D cutting which gave me a cycle time of 4 hours for two brackets. (2 hour cycle time, technically?) Am I going to save a reasonable amount of time by doing multiple setups with different zeros? If I flip it on its side how can I hold it and still get to the bottom of the part without milling the jaws?

Sorry for all the questions, I'm just very inexperienced and have given it a few whacks, but I feel like this can be done much faster.

[txcncman]

Clamp in your vise, sitting on parallels. If I get a chance, I will make some sketches for you. If I had a solid model (STP) of your part, I could even make a demonstration in MasterCam.