Spindle Encoder or resolver?

Hey guys,

I'm in the middle of a retrofit on a brother TC225. I have ordered a replacement spindle motor for the machine as a package with drive cables ect.

I originally requested the motor with absolute encoder for rigid taping syncing and orientation. But just got an email that they are recommending a resolver due to the high speeds (10,000 RPM)

Is a resolver sufficent for syncing for rigid tapping?

I'm not very familiar with the resolvers so any input is appreciated.

the spindel for tapping is not to be run at 10k RPM
is it the right spindle you ordered
it shoudent be greeter then 5k

depending on your control board it is a standard encoder

I'm not really sure what your saying. It is unlikely that I would ever try to tap over 5000 RPM I agree.

The spindle motor is 10,000 RPM and will opperate at those speeds when it's milling drilling ect.

I just need to know if a reaolver can work effectively to sync the spindle motor and z axis for rigid tapping using a 7i76e

Are you sure that you can do rigid tapping, do you have enough Nm on low speed? Or do you intend to do thread milling?

Mike,

Rigid tapping should not be an issue it's a 5.5kw spindle with 23nm up to about 3k RPM

The question is will a resolver be accurate enough and interface able with Mesa/lcnc to sync z and spindle for rigid taping?

For what it's worth we have a 8k rpm machine here and it has a 4096ppr encoder on it from the factory and it does rigid tapping all day long. Can't comment on the resolver but I wouldn't think that an encoder would have a problem with an extra 2k rpm.

Ask pcw or study doc of your Mesa manual. They can count quite high, I have something of 2mhz in my greyed cells container.

It might be that the drive has resolver input from motor and outputs encoder signal to the control. Just like my TC211

my tc225 under Linux has rigid tapping working.

the motor is only 6000rpm. the encoder is 1024 line (4096 count) incremental. I do not remember now what speeds I tested, I forgot to film it, but I think I went all the way up to 6000rpm and aside from bad z motor tuning, it worked. it looked crazy doing it

this is plain rigid tapping, not sync tapping, which is important. the z is just tracking the spindle encoder, and the spindle is not being used as a c axis like in some peoples setups.

my servo loop had been 1khz -4khz during testing.

the original control ran tapping at 3000rpm - I think this was for torque reasons, as the motor is 3000rpm "base speed' and torque drops off to 6000rpm (like any standard axis servo does). as for the torque, I ran an M12 tap in aluminium for my tests (on the stock control, never cut under Linux). supposedly this is happy tapping M16 in steel and aluminium. its a tapping centre after all! because the spindle motor is a fan cooled axis servo the basic name plate can be deceiving. you've got (in my case) 3.2kw continuous at 3000rpm, 4.1kw for 30 minutes, and up to 10kw for bursts of a few second - which is what tapping is.

if the motor you ordered is not an AC servo, the scenario should be exactly the same, but you will not get anything close to the performance of the original in tapping. They probably tell you to use a resolver because their abs encoder isn't rated for high speeds. I would just go incremental. you don't need an abs encoder though. the brother never had one in the first place.