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Making 2 Complete (Multi Op) Parts on One Fixture

Max Weber

Aluminum
Joined
Jun 15, 2017
I'm looking to make 2 parts. One part is 4 operations and the second is 3 operations. The goal is to have one of each part completed with every cycle. Has anyone done something like this with a fixture plate on a 3 axis mill? Here's a photo of a rough mock up of what I'm trying to do... If this is possible (Fusion 360) what's the best approach? Thanks
setup.jpg
 
This is absolutely possible in Fusion 360. Model your blank/in-process stock geometry for each operation and use "from solid" to specify the stock. Each operation should be a separate setup and you can select all the other stock geometry as fixtures for better collision avoidance & detection. Use NC Programs to export your programs. This will allow you to select multiple operations and will even optionally reorder toolpaths to minimize tool changes (be confident of your clearance heights if you do this though, since it will be harder to simulate).
 
I've done stuff like this in Fusion both for flat setups and 4/5 axis setups. In some cases (Brother C00 control that doesn't do TCPC or true 5 axis) I needed to do multiple WCS (per side) or program to the center of rotation and be really picky about the fixture setup (used test cuts to dial in the offset to center of rotation) but on 3-axis setups I will just put locating geometry on the fixture and then use that single WCS for everything. If something is really finicky I'll use the in process probing to dial it in.

The NC Programs feature is really powerful when you start digging into it.

As mutiny said, WATCH YOUR RETRACT PLANES! You can semi-automate this by including the fixture in the setup definition and then using the model top as your retract reference (which will now set the retract to the maximum Z of the entire setup). Just check it all in simulation anyways.
 
Not just possible, but quite common.

A few ways to skin this cat.

Single Offset: You have one datum on the fixture and drive everything off of that. That is a pretty complicated fixture though, and I am guessing it isn't going to get made to 0.0002" all around, so I would build it, measure where everything winds up, and tweak the CAD model to shift everything around - sort of like an As Built CAD model instead of the original CAD model. Once you do that however, it will stay very stable provided your fixture doesn't wear out and move a whole bunch. If you are single person shop where the CAD/CAM is on a laptop next to the machine and you can make tweaks all day? This is the best path.

Multiple Direct Offsets: Each station in the fixture gets an offset that is directly tied to the location. For example, G54 is the top left corner of the raw stock on Part 1/Op1, G55 is touched off from some machined datums on the part built previously, etc etc. You wind up with a lot of offsets to set up, but what you have with this is complete control over each part directly at the machine. This is for larger scale environments where operators need to manage production and can't be futzing with the CAD/CAM setup easily; they can tweak parts and do dial-in at the machine control, just by fudging the offsets around. Setup is a bear, but a little automated probing can ease the pain substantially (manually probe the first offset, and have a program that uses this first location to automatically touch off all the others).

Multiple Offset Copies: Use a very solid physical datum on the fixture as the primary offset, and copy it for each workstation. You would do the same upfront work as the Single Offset and drive all CAM operations off of it, but each station would call its own copy that can be individually tweaked as needed. If a part has an offset issue, operators can go to that station's offset and make some fudge adjustments by a couple of thousands to get it dialed back in.

Multiple Offset Copies is my preferred method, and works extremely well on 4th axis applications where everything is programmed off Center of Rotation. It does require slightly more experienced operators in multi-axis environments as you can often be working with translated work planes that can produce some real head-scratcher puzzles to figure out which direction to tweak things. In a 3 axis setup, most of the work happens after you build your fixture and dial in the CAD model, but in a 4th axis setup where you might have a funky fixture or some other weirdness it can be difficult to figure out why a part is perfect at A0, but is 0.005" off at A90, when a dial-test indicator is telling you everything is exactly where it should be.
 
Yes this is very doable, as others has said, multiple ways to offset. But I can't stress enough, USE ONE OFFSET, just make your fixture well. Trying to dial in 8 different offsets on something like this can get tricky quick. Plus you want to be able to set it up easily, or else what's the point?

Keep it as simple as possible, I see you're using mitee bites, but it looks like your mitee bites are holding blocks that are holding parts? Am I seeing that wrong?
 








 
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