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Different machining time for same NC Code.. reasons?

lcmRES

Plastic
Joined
Aug 11, 2017
Hi all,

I've carried the experimental tests (using the same NC code and set up) in two different machines (Haas TM1P & Haas VF3) and the machining time was completely different, nearly 2x slower on the TM1P.

The basic specifications of the machines are:
TM1P: 7.5HP and belt drive spindle
VF3: 30HP and inline direct drive

Would you know more reasons on why such difference in the machining time? Any insight is valuable..


Thanks in advance
 
Would you know more reasons on why such difference in the machining time?
Had a friend with a late model something-or-other and an elderly ExCell-O 104 with Gettys drives (DC). Put the job from the newer machine onto the ancient old-technology ExCell-O, parts went about 30% faster :)

Them Gettys drives, if sized correctly, can shit-n-git. Lots of acceleration, even with slower top speed, ended up cutting cycle time.
 
TM1P (short for tooling mill) doesn't have nearly the RPMs available as the VF3. Depending on how your program is written with a slower RPM comes a slower federate. If memory serves me the rapids aren't near as fast either as Booze Daily said. Tool changes. I believe the VF stages a tool to be ready for the change and the tooling mill doesn't, after putting the tool away it turns the carrousel to load the next one. Quite a bit slower
 
Tool change time, rapids, spindle and axial acceleration and deceleration. There's other settings and parameters that can have adverse affect as well.
 
Tool change time, rapids, spindle and axial acceleration and deceleration. There's other settings and parameters that can have adverse affect as well.

This is it exactly. Even with identical code, the TM series is going to be much slower than the VF series, even on a program with no toolchanges. The VF series have much higher torque servos and can Accelerate and Decelerate much faster. The same goes for the spindle. Because of the higher horsepower with nearly equal rotating mass, the VF can bring the spindle up to rpm and stop the spindle much faster.

There is an interesting youtube video of a VF2, VF2SS and a DM2 running the same code, same feeds and speeds.
 
Especially when you can get rid of 3/4 of the roughing cuts
with the Excello.....
Since it looks like there's at least one other ExCellO fan here, gotta share ...

Went to a show some time around 1980. The baby ExCellO was brand new, that was one of the machines I really wanted to see. Typical show of the time, the Anilam guys were waltzing around in their wizards costumes, the US Machine Tool guys had the bikini babes laid out on the tables, and over on the edge (I forget who the distributor was but it's an old name) was the ExCellO. But the thing was brand new, they didn't have a spare, Grove Valve had pre-paid and needed to run parts, so here was this little ExCellO, surrounded by flash and bling booths, with a greasy-ass guy in overalls loading cast iron valve bodies into it and running production. It was running Trim-Sol and making a mess :)

Same show had a RAM 630 wailing away on steel. Sounded like someone with a B.A.R. going crazy inside the enclosure. You could put your hand on it and not even feel any vibrations.

@ ewsley - American machine tools were good. Not all of them, but the good ones were spectacular. The Japs are kinda-sorta-maybe catching up now, decades later. If only the electronics had been reliable ... :(
 
Tool change time was more or less similar, even a bit faster on the slower machine. The rapids hold the same reference value on both..
 
TM1P (short for tooling mill) doesn't have nearly the RPMs available as the VF3. Depending on how your program is written with a slower RPM comes a slower federate. If memory serves me the rapids aren't near as fast either as Booze Daily said. Tool changes. I believe the VF stages a tool to be ready for the change and the tooling mill doesn't, after putting the tool away it turns the carrousel to load the next one. Quite a bit slower

The RPM set in the code was based on the TM1P max. The observed tool-to-tool average time was quite similar for both machines (surprisingly slightly faster on the TM1P).

That's the machining power profiles of both cutting processes in which you can see the tool changes:
Picture1.jpg
 
Tool change time, rapids, spindle and axial acceleration and deceleration. There's other settings and parameters that can have adverse affect as well.

This these are the keywords 'spindle and axial acceleration and deceleration'.. the differences on the transient state of each machine.
 
if i may : tick-tock timer is not tests :)

Hi, I should've told more about the experiments before, my apologies. I'm monitoring the power consumption of the cutting process on each machine. However, my measuring frequency wasn't large enough to catch the transient states in details, but can ensure tool change isn't the issue. I've attached the power profiles I got for each machine and the power distribution for machine VF3 so you may see better about the process. Thnx, Lorena
Picture3.jpg
 

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Thank you. Would you know more about the mechanical time constant of those machines' servomotors?
 
I've attached the power profiles I got for each machine and the power distribution for machine VF3 so you may see better about the process

pls share a better quality of those images, and pls share from where you got them :)

i suggest WeTransfer

just send the files to your own e-mail, and paste the link here :)
 
I've carried the experimental tests (using the same NC code and set up) in two different machines (Haas TM1P & Haas VF3) and the machining time was completely different, nearly 2x slower on the TM1P.

The basic specifications of the machines are:
TM1P: 7.5HP and belt drive spindle
VF3: 30HP and inline direct drive

hello again :) as long as cncs are not identical, also machining durations will not be equal

please consider that identical cncs may be tuned differently, so to deliver different durations on same code :)

why do you bother with such differences ? whats the goal ?

I'm monitoring the power consumption of the cutting process on each machine

even if it seems relevant, actually you should not reffer to that diagram, but to specific code paragraphs

for example, to compare rapids, simply run a program with many rapid movements :)

to compare spindle, simply run a program that will acc and decc the spindle :)

same for feed, etc ...

but in the end, whats the goal ? you will have the time differences, and after ?

Thank you. Would you know more about the mechanical time constant of those machines' servomotors?

if you wanna push things, try to tune your cnc ... unfortunately, i can not help you with tuning specifics for haas :)

few dare tuning servos, etc, and most are comfortable with the way the cnc works :)

if it works, dont touch it ...

i dont know what you are after : understanding the basics, or pushing the cnc ?
 
could it be different parameters for say a drillig cycle?

I have a mycenter with yasnac control and an okuma with osp...
when drilling with g83 the cycle times are completly different using the same program
but if i switch the g83 to g73 in the okuma the times are right in line with eachother
 








 
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