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I just bought a mazak!

proturn

Stainless
Joined
Jan 20, 2010
Location
zimmerman, mn.usa
Well, I made the plung. I just sold a fanuc controlled lathe and bought a 1997 Mazak QT20HP. The owner said that it has a hydraulic leak around the quill on the tailstock though. Have any of you replaced that seal before? Is it easy? Other than that, he assured me that it was in good running order. The turret index motor and coupler shaft are brand new, along with the through turret coolant seal. I bought this lathe without inspecting it personally. I know I'll get some crap from some of you for doing that but I'm a gambling man! Is there anything else that I should look at or that is a constant mantanance issue?

Thanks much
Proturn
 
Nice. Well done. You're going to love that machine, I'm betting. Once you get the minor stuff ironed out, as long as you PMCS it, it will last forever when taken care of. Good luck!
 
Congrats on the Mazak purchase. Easy as pie to run. You will love it--just be patient as you learn how to 'talk' to it. Ask questions before getting frustrated with it.

The Mazak is NOT a FANUC (thank God) and doesn't need you to tell it how to make each and every single little move for every tool--just tell it to make the damn part. :cool:

Kinda surprised you did not buy a live tool lathe as mentioned in previous thread. :confused:
 
Congrats on the Mazak purchase. Easy as pie to run. You will love it--just be patient as you learn how to 'talk' to it. Ask questions before getting frustrated with it.

The Mazak is NOT a FANUC (thank God) and doesn't need you to tell it how to make each and every single little move for every tool--just tell it to make the damn part. :cool:

Kinda surprised you did not buy a live tool lathe as mentioned in previous thread. :confused:

Before I started my own shop i ran a QT20 so Im well versed in Mazatrol and one of the biggest reasons I bought this one. I'm getting a lot more 10-25 part orders and with the Fanuc they were taking too long with all the edits. By the time I had it tweeked the job was done. 2 hour jobs were taking 6! I've really been missing having conversational lathe controls. I think I got a smoking deal and that is another reason I didnt get a mill-turn. I'm thinking that I'll keep the VM10 and just get another 4th Axis. I know I'd kick myself for selling it anyways. I'll sell the Hurco if I get my price and if I dont.......Oh well! It's hard to sell something thats paid for.
 
Just a heads up. In your way lube system there are a couple die cast manifolds with brass "valves". Replace ALL of these little brass valves with NEW ones. They control the flow of waylube. They get clogged, or just wear out and quit working without throwing up any "way lube alarms". All of my mazaks are of that same vintage and I've changed the valves in all of them. I had one machine getting loud at the ballscrew because it didn't get any lube for probably a year! (so it needed a new X axis screw) A LOT cheaper to change these little buggers. They last for years... Just a tip for ya. Good luck!
 
1997 Mazak QT20HP. The owner said that it has a hydraulic leak around the quill on the tailstock though. Have any of you replaced that seal before?

Congrats on your purchase of a Mazak! Like said, you will love the machine...especially for short run job shop work, Mazaks SMOKE any g-code machine.

The QT20HP is the big bore model of the QT20, which is the updated version of the venerable QT15, of which I have two.

Your max rpm's on the 20HP are 3600 (versus 5000 on the QT20), but with a 10" chuck, 3600 rpm's is plenty enough! Your 20HP should have a 10" chuck, as the spindle nose is A2-8, versus A2-6 on the standard QT20. Now if you want an 8" chuck, you can buy an A2-8 to A2-6 adapter plate.

I have never replaced the tailstock quill seals, but Mazak's have a pretty good parts manual, with cut-away views of all the assemblies. You should be able to use the cut-aways to help decipher how it all comes apart, and what parts you will need to fix it. With any luck it may just be a hose fitting connecting to the tailstock.

A mod I have done to all my hydraulically-indexed Mazaks is install a hydraulic flow control valve in the rotate-motor circuit. Thus I can control the speed of the rotate-motor, slowing it down some, to make it much easier on the motor and all the gears, and thus make them last a lot longer! Flow control valves only regulate flow, not pressure, so you will still clamp the turret with full pressure.

Good luck!

And yes, it didn't happen without pics....

The Catman
 
If you have to put the hydraulic seal in buy the damn pliers before you piss yourself off and wreck a seal... I have done so many of those damn seals and the day I bought the pliers, damn that was a good day.
 
Congrats on your purchase of a Mazak! Like said, you will love the machine...especially for short run job shop work, Mazaks SMOKE any g-code machine.

The QT20HP is the big bore model of the QT20, which is the updated version of the venerable QT15, of which I have two.

Your max rpm's on the 20HP are 3600 (versus 5000 on the QT20), but with a 10" chuck, 3600 rpm's is plenty enough! Your 20HP should have a 10" chuck, as the spindle nose is A2-8, versus A2-6 on the standard QT20. Now if you want an 8" chuck, you can buy an A2-8 to A2-6 adapter plate.

I have never replaced the tailstock quill seals, but Mazak's have a pretty good parts manual, with cut-away views of all the assemblies. You should be able to use the cut-aways to help decipher how it all comes apart, and what parts you will need to fix it. With any luck it may just be a hose fitting connecting to the tailstock.

A mod I have done to all my hydraulically-indexed Mazaks is install a hydraulic flow control valve in the rotate-motor circuit. Thus I can control the speed of the rotate-motor, slowing it down some, to make it much easier on the motor and all the gears, and thus make them last a lot longer! Flow control valves only regulate flow, not pressure, so you will still clamp the turret with full pressure.

Good luck!

And yes, it didn't happen without pics....

The Catman

Thanks for all the good info. I wanted the 10" chuck because my okuma is also a 10" machine and I can share jaws between the two of them. The 10" just seems to be a very versatile size. This machine also came with a 3j collet nose and some trusty cook spindle liners. I realized very quickly after looking at a few machines that I would really miss the huge work envolope that my Yami has. I looked at the Okuma Cadets and QT20's but both had only 2" bar capacity. I know the extra .75" in the QT20HP will come in handy. From everything I've read the HP has a 4k spindle though. I guess I'll find out soon enough. Here are the Specs that were advertised:

Chuck Size

Collet Chuck



Max. Swing over bed / Cross Slide

17.32" / 10"



X Axis Travel

7.125"



Z Axis Travel

20.125"



Max. Machining Length

19.69"



Maximum Machining Diameter

10.62"



Spindle Speed

40 - 4000 RPM



Spindle Bore / Bar Capacity

3.15" / 2.76"



Spindle Motor

20 HP



Spindle Nose

JIS A2 - 8"



Rapid Traverse X, Z

1200 IPM/1300 IPM



Turret Indexing-chip to chip

1.4 seconds



Turret Type

8 Position Turret



Machine Dimensions LxWxH

105"x68.5"x73.1"



Machine Weight

9,600 lbs
 
9600# and 1200"/minute?


A) Not much to be gained in a small lathe from rapids over 800 IMO, other than heart attach and more expensive crash.

B) Better anchore that sucker down if you doo!



----------------

Think Snow Eh!
Ox
 
9600# and 1200"/minute?


A) Not much to be gained in a small lathe from rapids over 800 IMO, other than heart attach and more expensive crash.

B) Better anchore that sucker down if you doo!



----------------

Think Snow Eh!
Ox


Glad I am not the only one that feels that way!
 
Yep, allready planned on it. The company that I bought it from had it bolted down. I figured i'd better do it too. The old girl liked to be tied down ;)
 
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Max swing and max machining diameter are published numbers. My old 10N has the same 17.32" max swing rating, but I can clear 19". It also advertizes max machining diameter at 8" or so, but again, those numbers are conservative to say the least.

The 8" Howa chuck I have is much more versatile compared to a regular Kitagawa of same size. The main advantage I like about the Howa is the T-slots are the same width as a 10" Kitagawa, but the slots are also a little deeper. This gives me a substantially bigger T-nut size when I am making custom T-nuts to bolt up 10", 12" and even 15" jaws with common 60° x 1.5mm serrations. The 15" jaws need extra holes drilled to mount to the 8" chuck, but they work fine for light parts. See my avatar. :D
 
Yes, the QT20 and QT20HP have 1200 ipm (x) and 1300 ipm (z) rapids. Blazing fast! I would recommend parameter changes to "slow" both axis' down to about 1000 ipm. You will never know the difference in cycle time. And your servo drives, servos, and ball screws will thank you with a long and profitable life!

Another popular mod is to slow the accel/decel rate on your spindle drive. An easy parameter change, and like the rapids reduction, you will never see a difference in cycle time. Your spindle drive will last a lot longer. Just ask wippin'....

Ox, these venerable Mazak cnc lathes are flatbed style with linear guides...thus helping to enable the blazing rapids, especially in X.

Yes, the QT20HP has 4000 rpm max. The previous version of this machine was the QT18, which only had 3600 rpm max. (The wildly popular QT15 became the QT20.)
 
Yes, the QT20 and QT20HP have 1200 ipm (x) and 1300 ipm (z) rapids. Blazing fast! I would recommend parameter changes to "slow" both axis' down to about 1000 ipm. You will never know the difference in cycle time. And your servo drives, servos, and ball screws will thank you with a long and profitable life!

Another popular mod is to slow the accel/decel rate on your spindle drive. An easy parameter change, and like the rapids reduction, you will never see a difference in cycle time. Your spindle drive will last a lot longer. Just ask wippin'....

Ox, these venerable Mazak cnc lathes are flatbed style with linear guides...thus helping to enable the blazing rapids, especially in X.

Yes, the QT20HP has 4000 rpm max. The previous version of this machine was the QT18, which only had 3600 rpm max. (The wildly popular QT15 became the QT20.)

Ditto! :)

One other thing to watch is to clamp the MAX spindle RPM in the program to a reasonable speed. There is very little cycle time to be gained by programming 3,000 RPM MAX when facing off large parts where the programmed SFM for a given tool is 500 SFM or less. The spindle just winds up right before it hits center, then has to slow right back down. I changed one job from 2,000 RPM MAX to 800 RPM and cycle time went up by 10 seconds for an 8 minute cycle time. Not worth beating up the machine for a 10 pc order.

The opposite is true when running small dia aluminum jobs. Set the MAX RPM where you want to run the entire job and edit the SFM on the tools to 5,000 SFM to keep the spindle pegged at MAX RPM throughout the job. Mazatrol will always run at constant SFM (G96). Using this method overrides the control essentially putting it in G97. Less stress on the spindle drive as it hits full speed and does not need to change RPM until part is finished. Use this only when tools are all going in same chuck direction (M03 for example).

I keep my rapids turned down to 70% on my old 10N as the old DC brush servos are not very smooth compared to the AC servos. The machine rapids at 470IPM, but feels real jerky at 100% rapid. The machine feels much smoother at 70% and this also helps the old girl live a little longer as well. Cycle time is not really an issue for me as it takes 6 seconds to do a tool change on my chain turret for the furthest tool. I do mainly prototype stuff so a little extra cycle time is nothing compared to how fast I can setup and program one part. Having 16 tools in the machine touched off and ready to go greatly offsets any added machine run time for my prototype and short run jobs I do.
 
Phil,

I have a 1985 QT10N with standard 8-station turret. Man, she is a workhorse! Anyway, I can give you the two parameters to change, the ones to slow your X and Z rapids to whatever rate you want. That way, you can just run the machine with the rapid overrides always on 100%.

I will look them up tomorrow and post them.

Greg
 
Phil,

I have a 1985 QT10N with standard 8-station turret. Man, she is a workhorse! Anyway, I can give you the two parameters to change, the ones to slow your X and Z rapids to whatever rate you want. That way, you can just run the machine with the rapid overrides always on 100%.

I will look them up tomorrow and post them.

Greg

Thanks Greg. I probably have them here if I would just remember to look them up. :dunce:
 
Phil,

On a T2 control, the rapid parameters are easy to find: the parameter page with "X Z C" columns across the top. Below these, the "RF" line is for rapid feed. The values are in metric. You have to power down/up for these machine parameters to become effective.

Greg
 








 
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