[LSM]

Well the biggest short coming I have with the 1100 is lack of spindle speed.
So I was wondering if any one has modified their 1100 to get more speed out of it ?
A 1100 with the 10000 rpm speed of a 770 would be a very capable machine.
Do they use the same bearings in the spindle ?
Could you just crank up the vfd to get more speed?
Somehow I don't think I'm the first person to have these questions

[gjvander]

I have been looking at this for a while.

The spindles are not the same, and I am pretty sure neither are the bearings. My personal opinion is that the bearings in the 1100 are capable of 10,000 RPM, but I think the limiting issue is balance. Tormach sells the 770 spindle as an assembly (with pulley), and it balanced as an assembly. So if you could balance the 1100 spindle with the pulley, I think you would be OK.

The v-belt is probably not acceptable - need to go to belt similar to 770. Not a big deal, but more changes.

Motor would need to be changed to 3450 RPM motor, and then careful consideration on hp requirement (i.e. 3 hp vs 1.5 hp?). VFD could stay the same. Motor would need to balanced too.

The 5000 RPM is well matched with the 100 IPM feed rate for aluminum, so you would also need to think about faster feed rates to take advantage of the faster motor.

My ideal machine is 10,000 RPM, 200 IPM feed, 400 IPM rapids. But the stock 1100 is a very good package, and I am certainly not complaining, just always wanting more...

Cheers,

Geo

[Al_The_Man]

Motor would need to be changed to 3450 RPM motor, and then careful consideration on hp requirement (i.e. 3 hp vs 1.5 hp?).


Geo

Would a 2 pole motor get you ahead? a 4 pole motor can usually be ran at 120hz (~3600rpm), I would not recommend running a standard 2 pole induction motor at 120Hz.
If vector rated motor, maybe.
Also a 2 pole motor is not so efficient at low rpm as a 4 pole, so you may lose in that area?
Al.

[gjvander]

Al,

You obviously know a lot more about electrical motors than I do.

I was thinking the 770 uses a 3450 RPM motor with approximately the same pulley ratio as the 1100, but maybe someone with a 770 can let us know what they think the approximate ratio is for the high setting. I am not sure what the limitations are of the 1715 RPM motor. I work on rotating parts for a living, so I get a little nervous when you double and quadruple the spin speed of a machine.

For sure the low speed was going to be problematic. That is why the big machines are 20 hp - to cover the 200 RPM range. I keep my 1100 on high and rarely run below 2500 rpm since I only cut aluminum.

Regards,

Geo

[philbur]

Trouble is personal opinions don't count, not unless you're a senior technical engineer for a major machine tool spindle manufacturer, even then you would need to provide some credible documentation that supported your opinion.

Phil

My personal opinion is that the bearings in the 1100 are capable of 10,000 RPM.

[gjvander]

Controlled title holder (read senior technical engineer) at biggest jet engine manufacturer in the world. Specialize in bearings, seals and power gearboxes. Perhaps not a tool spindle manufacturer, but my understanding is spindle manufacturers buy off the shelf bearings, and in aerospace we design our own bearings. The bearing manufacturers makes them to our prints, so I have a fair understanding of what makes bearings work (both oil and grease packed).

The fact is you would not even know what to ask for in terms of 'credible documentation'. L1, L10, B1, lambda, DN, SV, contact stress, curvature ratio? Nor would you know the allowables for any of these parameters.

But please keep contributing to this forum - your posts are always of great help.

Geo

[philbur]

Controlled title holder (read senior technical engineer) at biggest jet engine manufacturer in the world. Specialize in bearings, seals and power gearboxes. Perhaps not a tool spindle manufacturer, but my understanding is spindle manufacturers buy off the shelf bearings, and in aerospace we design our own bearings. The bearing manufacturers makes them to our prints, so I have a fair understanding of what makes bearings work (both oil and grease packed).

The fact is you would not even know what to ask for in terms of 'credible documentation'. L1, L10, B1, lambda, DN, SV, contact stress, curvature ratio? Nor would you know the allowables for any of these parameters.

:bs:

Bearing manufacturers recommendations would have sufficed, but hey I'm game, go ahead, give us the L1, L10, B1, lambda, DN, SV, contact stress, curvature ratio and the allowables for these parameters for the Tormach spindle bearings. Oh and don't forget the maxium rpm for a given preload/bearing life. Throwing in lots of irrelevant terminology in order to impress invariably has the opposite effect.

Phil

But please keep contributing to this forum - your posts are always of great help.

Wee gee thanks for your approval, I don't know where I would be without it.

[gjvander]

I would be happy to give numbers if I thought you were genuinely interested.

I did run the numbers on the 1100 bearings, and they are not challenged at all at 5000 RPM. 10,000 RPM would be more challenging, but you would give up some life which can made up with high quality grease.

Bearing manufacturers recommendations are just that, recommendations.

I had you on my ignore list, but thought you were contributing to the thread, so I unblocked you. Big mistake, but easy to fix.

Please keep posting, I am sure more and more people are adding you to their special list.

[philbur]

I thought I was contributing by challenging you to support a technical proposal expressed as a personal opinion. In your engineering world do you accept personal opinions at face value from persons unknown to you. That doesn't seem like a very professional approach and surely not one condoned by the largest jet engine manufacturer in the world.

Phil

I would be happy to give numbers if I thought you were genuinely interested.

I did run the numbers on the 1100 bearings, and they are not challenged at all at 5000 RPM. 10,000 RPM would be more challenging, but you would give up some life which can made up with high quality grease.

Bearing manufacturers recommendations are just that, recommendations.

I had you on my ignore list, but thought you were contributing to the thread, so I unblocked you. Big mistake, but easy to fix.

Please keep posting, I am sure more and more people are adding you to their special list.

[philbur]

I am genuinely interested in the numbers. What was the preload you used and what was the predicted bearing life at 10,000 rpm. What high quality grease did you use in the calculation of bearing life. Also what was the predicted bearing life with the OEM grease for the same conditions.

Phil

I would be happy to give numbers if I thought you were genuinely interested.

I did run the numbers on the 1100 bearings, and they are not challenged at all at 5000 RPM. 10,000 RPM would be more challenging, but you would give up some life which can made up with high quality grease.

[WOTDesigns]

I keep hoping to see a price on the re-release of the spindle speeder. Someone a while back mentioned they were testing one for tormach and sure could use one! Spindle RPM is my limiting factor on production time since my parts are roughed with 1/4" and second op is 1/8". 5-6 days of roughing and 10-15 days (if days were only 8 hours) of second ops. Speeder would save me probably 10-20 hours per run.

I have thought about getting a 770 but the 10,000 rpm and small envelope means I can only fit 16 parts for second op instead of 24.... But it does give me a nice second machine to use the rest of the time too.

[SCzEngrgGroup]

I would be happy to give numbers if I thought you were genuinely interested.

I did run the numbers on the 1100 bearings, and they are not challenged at all at 5000 RPM. 10,000 RPM would be more challenging, but you would give up some life which can made up with high quality grease.

Bearing manufacturers recommendations are just that, recommendations.

I had you on my ignore list, but thought you were contributing to the thread, so I unblocked you. Big mistake, but easy to fix.

Please keep posting, I am sure more and more people are adding you to their special list.

Perhaps you could address another issue that comes up frequently, and causes a great deal of hand-wringing on this and other fora (fori?), w.r.t. spindle bearings and power drawbars - Would you consider a static load on the order of 3000 pounds (to compress Belleville springs to release a TTS tool) to be a problem at all for the stock spindle bearings? I don't believe it should be any problem at all, but "you're the expert". :-)

As far as spindle speed goes, I would expect running 10K RPM on the stock bearings would, very worst case, result in somewhat reduced bearing life, assuming they are properly pre-loaded (and this would need to be checked before running that fast). Personally, even if it meant replacing the bearings once a year, I wouldn't consider that a major issue, as the bearings are neither expensive, nor terribly difficult to replace. I've run the dead-stock spindle on my Chinese BP-clone knee mill well over 8K RPM for years, without any problems whatsoever. They don't even get more than slightly warm after many hours of running.

Regards,
Ray L.

[jid2]

Read some of the RF45 threads. Lots of us running 8000 rpm on $40 worth of AC bearings and Kluber grease with 2:1 pulleys and 1750rpm 2 hp motors. This provides more useable power than a Tormach. I take cuts with a 1/2" tool at 7200 between 6 and 8 MRR.

[SCzEngrgGroup]

... between 6 and 8 MRR.

I don't think so, unless you're talking about plastics. 8 cu. in./min in 6061 would be about a 3HP cut...

Regards,
Ray L.

[gjvander]

Perhaps you could address another issue that comes up frequently, and causes a great deal of hand-wringing on this and other fora (fori?), w.r.t. spindle bearings and power drawbars - Would you consider a static load on the order of 3000 pounds (to compress Belleville springs to release a TTS tool) to be a problem at all for the stock spindle bearings? I don't believe it should be any problem at all, but "you're the expert". :-)

I would not recommend reacting through the bearings. The contact stresses could be high enough to cause permanent damage to the race (my hand calcs show it is borderline). Each rolling element is subjected to more than just the axial load divided by number of rolling elements - the contact angle amplifies the load. If you don't damage the races from pure load, you will provide enough to cause surface distress over time from any contamination (aluminum oxide is pretty common). Contamination is especially problematic on Tormach design since the spindle is not sealed very good. So the bearing will be more likely to spall.

Regards,

Geo

[Gerry Sweetland]

Well the biggest short coming I have with the 1100 is lack of spindle speed.
So I was wondering if any one has modified their 1100 to get more speed out of it ?
A 1100 with the 10000 rpm speed of a 770 would be a very capable machine.
Do they use the same bearings in the spindle ?
Could you just crank up the vfd to get more speed?
Somehow I don't think I'm the first person to have these questions

Got a newsletter from Tormach today in my email.
They have a new speeder for the PCNC mills.
Here's a link...
31350 - Tormach Speeder Series 2

Gerry

[WOTDesigns]

I keep hoping to see a price on the re-release of the spindle speeder. Someone a while back mentioned they were testing one for tormach and sure could use one! Spindle RPM is my limiting factor on production time since my parts are roughed with 1/4" and second op is 1/8". 5-6 days of roughing and 10-15 days (if days were only 8 hours) of second ops. Speeder would save me probably 10-20 hours per run.

I have thought about getting a 770 but the 10,000 rpm and small envelope means I can only fit 16 parts for second op instead of 24.... But it does give me a nice second machine to use the rest of the time too.

Got a newsletter from Tormach today in my email.
They have a new speeder for the PCNC mills.
Here's a link...
31350 - Tormach Speeder Series 2

Gerry

Guess I should have said I keep hoping for a large bag of unmarked bills on my porch when I wake up. Damn.

I will be ordering one when I get ready for my next run in a few weeks. Guess I cant really use it on the main fixtures as they require quick tool changes, but for the 1/8" EM running all day without change that sure will shave some time off.

[rlockwood]

I don't think so, unless you're talking about plastics. 8 cu. in./min in 6061 would be about a 3HP cut...

Regards,
Ray L.

It's certainly pushing the limits, but..

SFM=1050, IPT=0.00715, RPM=8025, FEED=114.78
DOC=0.4, WOC=0.15 = 30% = 66deg
MRR:6.9in^3/min
HP:2.1
Torque:16.17in-lb
Breaking Torque:118.57in-lb
Cutting Force:64.70lb
Tool Deflection:0.0000in
Max Tool Deflection:0.0010in
Effective Dia:0.5000in
Chip Thickness:0.00715in


Though, hopefully the motor was made on a good day.

[jid2]

Sorry, that post was after a long day in the sun and recalling stuff from memory. I meant between 4 and 6 MRR. And yes, up around 6 MRR is really pushing the limit. My main point is that my setup can remove at the higher rates at full RPM and not just in the 3000 RPM range.

[zephyr9900]

Though, hopefully the motor was made on a good day.

The spindle motor shows up in post http://www.cnczone.com/forums/bencht...ml#post1045686 on jid2's thread (the whole thing is worth a read or three) and it is a nice-looking Marathon MicroMAX from Automation Direct with a TECO VFD.

jid2 jumped in with both feet and did a masterful upgrade to his RF45. (As a PC1100 owner since 2006) I'm wondering where the equivalent PCNC builds are? He more than doubled his spindle speed without resorting to Space Shuttle turbopump bearings. Just a faster motor and reasonable step-up pulley set and good lube in decent bearings.

Or is the fact that we have a duplex bearing at the bottom of the spindle killing an equvalent effort?

Randy