Move and Touch Speeds

[jon_dav_uk]

We recently had a new CMM installed and the engineer has recommended setting up the software to run the move / touch / scanning speeds etc in absolute mode as opposed to as a percentage. We have four other machines which are all set-up and running as percentage.

Whats everyones thoughts on this, i.e. advantages / disadvantages and also if I was to switch all machines to absolute (I dont want to fix something that isnt broken), where would I get the recommended speeds / accelaration values etc for each individual machine.

I would guess these would be stored in the controller and I would need to access them using hyper terminal but this is just a guess

Thanks in advance

Jon

[#2#]

Can you change this? I always assumed it was "hard wired" and dependent on your controller.

Not the speeds but whether touch and move are a percentage of max. or touch is a percentage of move.

Maybe I'm reading this wrong.

[Jan d.]

It really does not matter AS LONG AS your maximum speed, as programmed in the controller, does not change. Service people are known to mess with this number though. Sometimes they believe that they can get more accuracy out of a machine by lowering (and even sometimes increasing) the max speed. If you run percentages, after that service call, suddenly all your speeds have changed. Nasty business.

You probably have a service tech that either did this in the past, or knows of buddy's that have done this. He is therefore honest with you: if you program speed absolute, you will never have to deal with this problem.

I once had a machine and it started to exhibit unacceptable mechanical vibration levels (ie, false triggers). The first service tech spend a few hours and said he fixed it, and it appeared that way. The only thing he had done was bring the max speed from 500mm/sec to 300mm/sec. So now all my percentage programs were toast.

Because of this issue, I have made it a habit of ALWAYS programming the touch and scanning speeds absolute. That way you know how fast you go when it really counts/measures. Move speed I always leave at 100%.



Jan.

[MrComment]

Good tip Jan.

[jon_dav_uk]

Cheers Jan that helps me out. Looks like it will be beneficial to set up the other 4 machines to run in absolute or I foresee a few problems when switching programs between the older machines and new machine.

I will not be changing the max speed as set by the controller but would like to know what it is and how I would find this out. The reason for this being that the four machines I have running currently as a percentage are running at move speed 80% and touch speed 1.5%. If I set these to absolute and do not know the speed in the controller, I obviously cannot workout what this equates to in mm/sec.

Jon