Torque / Speed curves for different Spindle Types

[Chaz]

Depends on how he's doing it I suppose. What's acceptable to him might not be for you.!! . . . I definatley wouldn't replace the main spindle with a 2.2Kw spindle has it will spoil the machine but would possible use it to drive the main spindle with a ratio to increase torque and lower 2.2kw spindle speed to match Main spindle bearings.?

If you want to try this I can lend you a 2.2Kw spindle and VFD. Thou it would be a lot work to find out it's not much good.!!

I was thinking to gear it 10:18. I suppose I could find a different belt / pulley setup. This is the smallest I can find (easily) to go (10) using the stock setup.

This lowers the speed to almost half and should therefore provide almost double the torque. Its a pity that the removed Servo motors are a bit small, else they would be ideal, specifically with closed loop control. They also do 8K RPM, worth a look at all?

[JAZZCNC]

Its a pity that the removed Servo motors are a bit small, else they would be ideal, specifically with closed loop control. They also do 8K RPM, worth a look at all?

Yes worth a look because it's linear torque so there rating will be higher than the 2.2Kw at lower speeds because the torque on these falls away quickly when speed is lowered unless using a more expensive Vector drive and this isn't always possible depending on the VFD make.?

Servo will offer more torque across the speed range.! . . . . You can get some largish and Cheap Servo drives from ali-express so may be worth a look and it will make a proper job of it.!

[Chaz]

Yes worth a look because it's linear torque so there rating will be higher than the 2.2Kw at lower speeds because the torque on these falls away quickly when speed is lowered unless using a more expensive Vector drive and this isn't always possible depending on the VFD make.?

Servo will offer more torque across the speed range.! . . . . You can get some largish and Cheap Servo drives from ali-express so may be worth a look and it will make a proper job of it.!

They are 800W motors I think but still have resolvers. Actually, I think with the drives Ive removed, I may be able to get one running. Worth a try I think. It would be interesting to run with a dual setup - two of these motors running in sync could work too if you could fit them and get the control to work.

[andy_con]

i also have a denford triac with the standard sem servo motor, owned the machine for 3 years. ive never once managed to stall the spindle.

i do 1mm deep cuts in ally with a 20mm end mill no problem, i also do 2mm deep cuts with an 8mm end mill no problem. the motor has plenty of torque.

but i do agree it is pretty slow on the rpm front and i have also been looking at other options for new motors. although i can take 2mm of ally off at once with a good finish, due to the low rpm feed rate is pretty slow at about 250mm/m.

the current sem servo motor in the traic is £1200 new and brand new replacement with more speed is going to cost even more. the thing to bare in mind when looking at the high speed chinese spindles is the atc and bt35 tool holders are only rate to about 8-10k rpm.

[Chaz]

i also have a denford triac with the standard sem servo motor, owned the machine for 3 years. ive never once managed to stall the spindle.

i do 1mm deep cuts in ally with a 20mm end mill no problem, i also do 2mm deep cuts with an 8mm end mill no problem. the motor has plenty of torque.

but i do agree it is pretty slow on the rpm front and i have also been looking at other options for new motors. although i can take 2mm of ally off at once with a good finish, due to the low rpm feed rate is pretty slow at about 250mm/m.

the current sem servo motor in the traic is £1200 new and brand new replacement with more speed is going to cost even more. the thing to bare in mind when looking at the high speed chinese spindles is the atc and bt35 tool holders are only rate to about 8-10k rpm.

Thanks. Maybe my feeds are a bit too agressive but wow 20mm, thats a lot.

It looks like my controller has died. Ill probably just get a newer version of the controller and then look at the high speed spindle options later. My brushes still look OK, perhaps a bit worn, looking to find some replacement ones to be sure.

Is your machine the same as mine? BT30 or 35? Mine is BT30. A good rpm speed is around 8K I think. So take the 24K Chinese spindle and gear it down by a factor of 3. I think that will give a good balance for speed / torque.

[andy_con]

yeah i regulary use a 20mm end mill just to get lots of meterial away at once then switch to a smaller cutter for final finish. i had a massive problem with my sem motor, smoke the lot. the rpm keep jumping up and down by like 500rpm when running. ive installed sinplde feedback into mach.

so i recently sent the motor away for repair, cost me £500 but it has been working very good since the repair. the brushes on mine looked fine but there was clealy another issue.

mine is bt35

8k with some decent torque would be ace. things like this pop up on ebay regulary, but its trying to find out the exact spec of the motor thats the difficult part -

http://www.ebay.co.uk/itm/Parker-Aut...#ht_881wt_1395

ive also been working on a 10 station atc for my triac, it currently only has a 6 station

Thanks. Maybe my feeds are a bit too agressive but wow 20mm, thats a lot.

It looks like my controller has died. Ill probably just get a newer version of the controller and then look at the high speed spindle options later. My brushes still look OK, perhaps a bit worn, looking to find some replacement ones to be sure.

Is your machine the same as mine? BT30 or 35? Mine is BT30. A good rpm speed is around 8K I think. So take the 24K Chinese spindle and gear it down by a factor of 3. I think that will give a good balance for speed / torque.

[Chaz]

yeah i regulary use a 20mm end mill just to get lots of meterial away at once then switch to a smaller cutter for final finish. i had a massive problem with my sem motor, smoke the lot. the rpm keep jumping up and down by like 500rpm when running. ive installed sinplde feedback into mach.

so i recently sent the motor away for repair, cost me £500 but it has been working very good since the repair. the brushes on mine looked fine but there was clealy another issue.

mine is bt35

8k with some decent torque would be ace. things like this pop up on ebay regulary, but its trying to find out the exact spec of the motor thats the difficult part -

http://www.ebay.co.uk/itm/Parker-Aut...#ht_881wt_1395

ive also been working on a 10 station atc for my triac, it currently only has a 6 station

Mmmm, found my own thread with google. So, my motor is giving problems. Would you by any chance have any spare brushes? Who did your repair for the motor?