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new to 5 axis question

bruiserba

Plastic
Joined
Oct 23, 2011
Location
NC USA
we just got a umc 750 haas and I am using esprit 20xx to program it. my question is when I am programming do I have the operators to touch off z from top of part or is there some where other 5 axis programmers get z from . I keep x and y in the center most of the time but z I get confused on. thanks for your kindness and your help.
 
You can set X, Y and Z anywhere you want as long as it matches where you place your WCS in your CAM system.
I keep seeing stuff when researching that ppl make 1 offset with xyz using cor and putting in g59 and never using probe had me thinking I was doing something wrong. thanks for taking the time to help .
 
I keep seeing stuff when researching that ppl make 1 offset with xyz using cor and putting in g59 and never using probe had me thinking I was doing something wrong. thanks for taking the time to help .
That is one way to do it and the old way. But then, you are programming the machine and not the part. Very different and old way to do it. This was before TCP and TWP/DWO, many moons ago.
 
my question is when I am programming do I have the operators to touch off z from top of part
First things first: operators operate. They press the green button. Operators don't touch off work offsets or do anything else of the sort. This is up to you or a setup person in between. The programmer is responsible for making sure the program is correct and produces the first part.

Is this simultaneous 5-axis or 3+2 positioning? Based on all the things posted here about Haas UMCs, you might need to run some test cuts and then indicate off the surfaces in various orientations to see how far things are off before proceeding.

Here's the current party on the subject. Best to wear all your pads and the bullet proof vest before you say Haas:


And this is why:

 
That is one way to do it and the old way. But then, you are programming the machine and not the part. Very different and old way to do it. This was before TCP and TWP/DWO, many moons ago.
Been in some modern shops that still do it this way. Not the best way to do it anymore but I guess it still works for some people.
 
Why's that a bad or old way, using center of rotation?

There's benefits to using both methods, set WCS to COR, or to the part/stock/etc.

Starting out and new to 5-axis? Probably easier to get your feet wet setting to the part, though.
 
I probe the top of the part as Z zero, but I also compare it to a known value so that the machine won't run if the wrong blank is loaded. The known value is saved in G55 while the probed offset is saved in G54.
 
Why's that a bad or old way, using center of rotation?

There's benefits to using both methods, set WCS to COR, or to the part/stock/etc.

Starting out and new to 5-axis? Probably easier to get your feet wet setting to the part, though.

In 2024, on a modern 5 axis machine, there is precisely zero reason not to be using Dynamic Work Offsets...

Doubly so for someone who is just getting their feet wet.
 
I think this depends on the job. In my case many components are already turned before my first 5 axis milling setup, and that turning interfaces with a fixture within the machine, which is the "Z" value. The stock itself can vary in length but the part needs to be correct relative to the contact face of the fixture so no offsets are ever changed. Instead a first op that has macros is run that takes a variable set by the probe and performs a roughing operation based on how much or how little stock is beyond the surface at which the program will normally operate afterward. The component is dialed to be on CL with the rotary axis of rotation before as well. This insures the part is correct each time in all dimensions, with the first setup being very accurately aligned with the second setup.

If this is a first setup or a part that is varying in it's location within your work holding and you dynamically keep changing the offsets based on the stock, you may wind up touching your fixture like Orange Vise just pointed out, unless you have some programming in place to alarm if the value is out of range.

Kinematics are great but if you can reduce your reliance on them the chances the part will be correct the first time are higher, there are so many variables it is always nice to reduce them as much as you can. I like to use the surfaces of the vice/fixture as 0 so I never machine into them no matter what stock is placed in the machine, this is pretty important when "onion skinning" a part that is being held with a vacuum fixture (Plastic in the 5 axis router). Once again, it depends on the application.
 
Why's that a bad or old way, using center of rotation?

There's benefits to using both methods, set WCS to COR, or to the part/stock/etc.

Starting out and new to 5-axis? Probably easier to get your feet wet setting to the part, though.
with machines that have TCP/dynamic work offsets, theres ZERO reason to set WCS at COR. what i do personally, is i have sub plates on all machines that precisely and repeatably locate all the workholding i use, and typically the WCS is at the center top of the sub plate, i never have to change it unless i need to pick up a part for rework.
 
Programming to the centers of rotation eliminates the need for any types of dynamic offsets or tcpc to even be called at all. Most of the times I’ve seen it used are when there wasn’t an off the shelf post processor (or knowledge available to make one) to get the real multi axis features working correctly. A machine like a UMC which pretty much has a proven pipeline from any cam software to making parts should always use the multi axis features, set the wcs wherever. Zero reason to do otherwise.
 
Been in some modern shops that still do it this way. Not the best way to do it anymore but I guess it still works for some people.
The only reason people still do it this way is mostly based in the fact that they have numerous, if not hundreds, of proven programs that require running from the COR. They don't want, and really don't need, to reprogram all of those parts if the old method still works for them. The main problem is setup time and dialing in the finished part all the while trying to avoid scrapping them. High dollar parts run the risk of being scrapped. Also, some people just refuse to try something new.
 
Here's a decent writeup on the subject of machine centric programming and part centric programming.
 

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Programming to the centers of rotation eliminates the need for any types of dynamic offsets or tcpc to even be called at all. Most of the times I’ve seen it used are when there wasn’t an off the shelf post processor (or knowledge available to make one) to get the real multi axis features working correctly. A machine like a UMC which pretty much has a proven pipeline from any cam software to making parts should always use the multi axis features, set the wcs wherever. Zero reason to do otherwise.
it doesnt eliminate anything.
you're still gonna have drift from heat expansion throughout the day, so TCP/DWO is essential if you want any resemblance of accuracy. if you have those, programming from COR gives you zero benefit. literally the ONLY reason to do so is if a machine/control doesnt have DWO/TCP.
 
Also related to this is the fact that without TCP or TWP you are forced to use Inverse Time feeds. At that time, being really the only solution, it "worked" but not perfectly. With the advent of TCP and TWP you can now program in real IPM or MMPM. A really good explanation is attached.
 

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In 2024, on a modern 5 axis machine, there is precisely zero reason not to be using Dynamic Work Offsets...

Doubly so for someone who is just getting their feet wet.



Ah, okay perhaps I wasn't clear in my point.

My point is using COR as an offset is highly beneficial. Not programming from COR and using inverse time or dpm.


You can absolutely use DWO&TCP and center of rotation together. That's how I have my fastems cell setup. Offset set to COR.

Only one offset is used to run any part setup in the system. Offset gets buggered? Easy enough to fix when it matches the COR parameters. In fact, I have my pallet change program reset it.

Programming from a common offset is extremely beneficial and saves quite a lot of time. Whether the offset is set to center of rotation, or in the case of my machines with trinity system, top of the vero module, or something else... a common offset is a great way to go.


But DWO set to the top of the part? If your parts are complex enough where you use and rely on simulation, that's just a recipe for headache later.


If the programmer and setup/operator are not the same person and you're relying on simulation, what is the point of setting WCS to the part/stock/other? If the setup does not match the model and simulation, there's no point? If the setup does match the model and simulation, you already know where everything is...

I use both. For a simple/quick part and I'm not sure what fixture/vise/pallet is available to use, I might just program WCS to the part, then use a different offset at the machine. Something I'll run more than one of, or need to use simulation to check things? Common offset (COR in my case)
 








 
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