Tweaking a Fadal

[krustykrab]

I have 2 Fadals. One 60 by 30 with box ways, and one 40 by 20 with linear ways(boxZ). Both still have the original cnc88hs control, with hs "jokingly" referring to high speed.

These machines were considered high speed in their day, but not now, by any stretch.

If anyone has any input on how to tweak these machines to get the fastest and most accurate cutting feedrate out of them with whatever M and G codes are available, please let me know.

I have been pretty much using them at feedrates of about 70-80ipm for finishing using M91 and no G8 or G9 programmed in. (However, I believe G8 is a default at startup anyway). I just don't like the banging resulting from the use of M92, and my service rep says it's better without it due to the stress to the bearing mounts.

[cadman]

Use M94 or M94.1, especially for 3D work. When cutting aluminum, Ren, plastic or foam I'm usually in the 125-275 ipm range. I don't change my gain settings, just leave then at normal unless you want all that banging and shorter machine life.

You should also check your backlash. I adjust mine every 3 months. This does affect accuracy.

[krustykrab]

Thanks,

What would be a normal gain setting?

[cadman]

M91 is normal. This is the factory setting. You can increase the each gain setting by adding a P word. A P word of 125 will increase the gain by 25%, 150 will increase 50%, etc... .I don't know if a P word setting of 90 decreases it by 10%. I've never used this so I can't tell you how well it works, but you never know unless you experiment.

Good luck

[Scott_bob]

Haven't you ever wondered why Fadal has not improved their control in so many years?
And now, they have released their new 104D control with so few improvements that customers demanded other options, why is that?
Does all that "banging" that happens on your Fadal controlled CNC machine hinder accurate motion, delivering poor quality parts and wearing out machine components?

Most guys who will read the above will say I must be talking about banging (your word) caused by chatter or dynamics that can be overcome by finding the right RPM and feedrate. I'll bet they don't have a Fadal control. G8, G9, M91, M94 All codes poorly designed by Fadal to improve a very poor CNC control. Those of us who have Fadals, end up trying everything, to get better results both in part quality and better tool life...

You just cannot succeed at this game. This game is rigged against you and you will only see hints of hope. I'm not suggesting a conspiracy out of Fadal, I'm convinced they just don't know any better...

I happen to like most of mechanics of the machine (VMC box ways, high RPMs, liquid cooled spindle and ball screws, affordable cost)... It just has the worst CNC control.

That can be remedied.

[krustykrab]

Thanks for responding so quickly. :frown:

I've already pretty much given up on the whole tweaking the Fadal.

With the garbage drives and crappy controller, it's pretty apparent that they make their money on service and parts.

We just purchased a YCI vmc machine with all funuc drives and spindle, and fanuc controller. The difference is like night and day.

Finishing at 150-175 ipm currently without any upgrades in tooling, compared to 70-80ipm......if I'm lucky on the Fadals.

We only look forward to replacing the aged Fadals with real cnc machines.

[nervis1]

Whats your quote there "tis a poor workman who blames his tools", geeze I need boots in here because the irony is getting so deep.

[Scott_bob]

I just knew if we could get krusty talking about his Fadal, specially after getting the YCI, that signature of his would shout for a change!

Come on krusty, you CAN blame your Fadal...
I have had the distinct pleasure of working with some very fine tool makers in my days.
And I must admitt that when I hear a white collar guy (not you krusty) saying something stupid like 'tis a poor workman who blames his tools', it makes me crazy.
Nothing personal krusty... But can you change your signature?

I have worked so hard lately to upgrade the really crappy CNC machines that the toolmakers have to work with and I get the "Our toolmakers are magicians in steel" shpeal. You know, when someone who has no idea what it takes, equipment and skillwise to hold +/-.0005 tolerances, says "A good toolmaker can make anything with old, worn machines, they don't need new machines, they're so good"...

I just want say, "try it yourself to hold tight tolerances on an old worn out machine"! Then, tell me your opinion...

Just some thoughts,

[krustykrab]

I am not sure how to repond to feedback regarding my signature line, if I really need to at all. It's nothing more than a satirical Irish quote.

As far as maintaining tight tolerances on older machines, I've being doing it for many years. Yes, you can make-do with the tools that you do have, be it the cnc machines themselves or the tooling. However it is quite a bit easier and much quicker to do it with better technology.......HENCE BETTER TECHNOLOGY.

To make it quite clear, my initial thread involved only reducing the banging of the machine.......NOT a quest to better do my job. The banging that I hear is simply a result of poor drive controllers that cause the drives to rapidly change direction without any inclination to accelerate or decelerate prior to these directional changes. This only damages the thrust bearings and, in time, the ball screws.

Thanks folks for your informative replies....save the rest for those with a lot of spare time.

[carbidecraters]

Dont change your signature...its how alot of tool makers and fine machinist feel. Times arent really changing much even though you will hear "big cuts are old school" ...thats a line from someone who isnt very experienced, big cuts and small defining cuts have almost always been around..

[Scott_bob]

I am not sure how to repond to feedback regarding my signature line, if I really need to at all. It's nothing more than a satirical Irish quote.

You're right, no need... Satir and and irony is not for everyone. Sometimes I take it too seriously.

The banging that I hear is simply a result of poor drive controllers that cause the drives to rapidly change direction without any inclination to accelerate or decelerate prior to these directional changes. This only damages the thrust bearings and, in time, the ball screws.

Just remember the "banging" is also showing up in your machined part, and taking a toll on the cutter as well, all adding up to lower feeds to compensate for poor control by your CNC machine.

Just some thoughts,