Part Dimensional Expectations With Taig Mill?

[mikeysp]

Hello. I am trying to get a number on the worst case part tolerances to expect on a Taig Ballscrew Milling Machine?

Lets say a 2" diameter part cutting a cylindrical shape in 6061 Aluminum. How close +/- to round would you be willing to assert you can repeatably perform day in and day out?

I am not asking how to cut a cylinder, I am trying to determine the Taig's capabilities. I just thought that a path such as a circle would stretch the machine's capabilities thus tell me what to "expect" from the machine. I say this as I don't want to get the advice to ad a rotary table, I want to know the machines real world capabilities and expectations, assuming it is set up properly.

I have searched over two hours to find this data, but to no avail. Perhaps I just don't know the right question to use in my searching.

Thank you for your help. -Mike

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[awerby]

Are you asking this because you are having problems holding tolerances with your ball screw equipped Taig, or because you're thinking of buying a Taig mill? There are lots of factors that will affect accuracy, like tool deflection, cut quality, temperature variation, and any looseness in the adjustable parts of a machine. A ball screw equipped Taig mill should be able to hold +/- .001" reliably, but all these things factor in,

[mikeysp]

Thank you VERY much for the reply. I really did search, but since the ballscrew version is only a couple year old, I could not tell if the numbers I came across were for the ballscrew or the older leadscrew version.

I am considering a purchase of one.

I am working on the predication that I fulfill my obligations as an operator, so I will have it set up properly for accuracy and learn/use the feed rates and tooling that give the best results.

I just don't want a guy saying he gets .0001 on his Taig when it was a roll of the dice day on his machine or only a depth accuracy on the Z. I want a realistic expectation of regular performance as long as I keep my end of the bargain.

.001 is a helpful piece of info. I had seen on a vendor's site the .001"... but the page had the words "ballscrew" and "leadscrew", so I was not sure if the tolerance was antiquated.

I am aware the machine is more appropriate for softer metals such as my primary of 6061 AL especially with the RPM's on the TAIG; however, during this hunt for data, I came across the 500 and 750W industrial sewing machine stepper motors for variable speed that some men have used on the TAIG. Does this ability to run lower spindle speeds, mean mild and stainless can be done also at this same .001" Is the machine stout enough for regular operations such as this with the understanding of heat control and petty feed rates, or would such operations lead to a very premature death of the machine.

-Mike

[Bob La Londe]

The stock spindle is a multi pulley belt drive. Top speed is 10000rpm, but there are much slower speeds. The motor is only 1/3HP if I recall, but you can have either high rpm and low torque or low rpm and high torque. Within its power range it will cut just about anything. Some work hardening alloys may be problematic just because it doesn't have enough power to take a big enough chip, but most can be cut if you plan around what you have.

[mikeysp]

Thank you Bob!

That makes sense. I did see a thread of a man who changed his motor and pulley section. The motor is about 1HP stepper sewing motor I think, and a R8 Mill Headstock for the Taig for using the Tormach tooling.

I am not sure what benefit that gives him, but it may be more power for bigger bites, and a pulley section that can handle higher RPM's for certain cutting operations? It also mentioned for use with an ATC, although I haven't seen any ATC for sale for the TAIG.

I really appreciate you gentlemen chiming in to help a stranger. -Mike

[Bob La Londe]

Thank you Bob!

That makes sense. I did see a thread of a man who changed his motor and pulley section. The motor is about 1HP stepper sewing motor I think, and a R8 Mill Headstock for the Taig for using the Tormach tooling.

I am not sure what benefit that gives him, but it may be more power for bigger bites, and a pulley section that can handle higher RPM's for certain cutting operations? It also mentioned for use with an ATC, although I haven't seen any ATC for sale for the TAIG.

I really appreciate you gentlemen chiming in to help a stranger. -Mike

I'd think an R8 spindle would be awfully heavy. Also too much power might cause tram issues with the tiltable column. Its a great LIGHT DUTY mill.

I do high speed aluminum milling and put a .8kw 24k spindle on mine. There are ATC high speed spindles.

Google Taig Owners Club. Its a low activity forum but atleast one member has built their own ATC.

I have an older v-lead mill. It would hold .0005 or it would go fast, but not both at the same time. I don't currently use it, but I'm playing with pulling it down and playing with it again.

[mikeysp]

Found the club. thank you. I have looked at a few of the threads on ATC and well keep searching through there.

[mikeysp]

What is the difference in running a lower RPM setup such as the OEM motor or even a Brushless servo motor and say a 24000 RPM spindle?


What would be the pros/cons of these styles?


I did see a thread on cnczone of a guy from Isreal who programmed his highspeed Spindle's VFD to output the full 10 AMPS even when it ran as slow as 200RPM. This apparrently gave him the torque that is usually lost at low RPM. It only worked with water cooled spindles because of the serious heat at that low RPM and high Amperage. He had a descent sized radiator. So he had the torque from 200-24000 RPM as far as I could understand.


Here are the Automatic Tool Changer (ATC) options I have found so far:


Mechatron
They make the Mechatron STC 65 and 80 ATC adapters 65mm and 80mm spindles up to 2.2KW. So, this is a apparently well built German adapter and you can add a cheap chinese spindle and operate. 2.2KW seems like way too much power for a Taig, but I don't know. Does higher RPM, mean lower torque and make it ok? What would be the safe max KW for a highspeed spindle?


CNCCAT
also has a spindle adapter, but did not investigate it too far as I want to decide which type offer what benefits.


With these adapters it seems you can use a cheap chinese spindle and this ATC adapter and change out spindles when they go bad and reuse the ATC adapter.


GlockCNC R8 Headstock
I have exchanged a few emails with GlockCNC and read some of their data. I asked them if they have a video of their R8 on a Taig and they said they would be putting one out soon.


The GlockCNC R8 headstock and headstock mount/adapter plate with their brushless 750 watt brushless motor is only 2lbs heavier than the OEM headstock and motor.


For $550 you get the headstock and a taig adapter. At this price point it comes with ABEC-5 deep groove bearings, the top speed would be around 8,000RPM and a TIR of .0005"


Options:
ABEC-7 super precision deep groove bearings $197 will shave off a few ten thousands in the TIR.
ABEC-7 sealed angular contact bearings $357
ABEC-9 sealed angular contact bearings $997


The 750 Watt motor is about $600


Here is an interesting comment from one email: Overall expect better finish and accuracy for several reasons. The big reason is energy handling. You'll have a headstock and headstock mount that's much more robust. With more "meat" in the headstock casing and spindle combined with much larger bearings, you have better vibration handling during cuts. Also, the OEM dovetail method of mounting the headstock isn't the best idea. The R8 headstock uses a solid billet aluminum chunk for the mounting plate. If your budget allows, going with ABEC-7 will get you even better accuracy. (As a bonus, the headstock adapter plate accepts a AXA quick change lathe tool post...so you can use your mill as a lathe!)


I just sent a follow up email asking about the RPM limits with the better bearings.


Any comments are appreciated.


-Mike

[Ican]

Hello. I am trying to get a number on the worst case part tolerances to expect on a Taig Ballscrew Milling Machine?

Lets say a 2" diameter part cutting a cylindrical shape in 6061 Aluminum. How close +/- to round would you be willing to assert you can repeatably perform day in and day out?

I am not asking how to cut a cylinder, I am trying to determine the Taig's capabilities. I just thought that a path such as a circle would stretch the machine's capabilities thus tell me what to "expect" from the machine. I say this as I don't want to get the advice to ad a rotary table, I want to know the machines real world capabilities and expectations, assuming it is set up properly.

I have searched over two hours to find this data, but to no avail. Perhaps I just don't know the right question to use in my searching.

Thank you for your help. -Mike

The Taig machines can hold extremely clost tolerances. That being said, the folks I see having problems are the ones that seem to think you can't machine unless you are stuffing a 3/8" end mill 1/2" into the stock and wanting to run at a linear speed of 40 IPM. Yep. You'll have a problem. Here... See what looks like lines in the background of that ring.... those are 0.3 mm high fonts ADADADAD just as close as I could get them. That is off of a stock Taig mill without ball screws. ....Alot of your accuracy will depend on your programming...no matter the machine. Hope this helps.

[wjh308]

Without adjusting any gibs, nor doing any ballscrew compensation, my Taig ballscrew mill made a part to within .03 mm, or about .001 in all dimensions. Very pleased.

[mikeysp]

Thank you for the feedback gents.