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New Mazak SQT250 MS

will_0000

Aluminum
Joined
Dec 16, 2012
Location
Great Britain
A week ago we had this arrive, a 2001 Mazak 250 MS. A nice machine that has mainly run plastics for it's life. Having spent the last week cleaning and stripping it down to inspect what needs going the list isn't to bad.

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Rear guard leaf on the Z carriage
Lower ball screw guards for B axis
Parts catcher bucket
Sward conveyor lid (original was jammed with swarf and buckled)
Re align sub spindle to main spindle

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This afternoon was spent truing up the sub spindle, it was over 0.75mm out of alignment. After about 2 hours we had under 5 microns taper and spot on forward and back, however it is 150 microns high. I know there are two shim plates between the spindle and B axis carriage but I can't believe that these need grinding. What else could cause the sub spindle to be high? I have check the levels again and the bed does't appear to have any twist in it.

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How do you make active a numbered tool such as 1B. Tool position 1 has my roughing tools in for the main and sub spindle. When in Jog Mode the position screen shows my tool 1 data but I want to see the data regarding my sub spindle roughing tool 1B when I am jogging up to the spindle
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As to your last question, go into MDI. Input-T0100.2, then cycle start. But be careful, if the turret is not on position 1, it will index to it, so make sure it wont hit anything when it indexes. If you want tool 1C, then input T0100.3 Etcetera. All the way to Z. There are one or two letters you cant use, but I cant remember which ones they are.
Every SQT we have ever purchased, the sub spindle has been high from the factory. They do it on purpose . Don't know exactly why.
 
Thanks, that solved my tool selection. I can't understand why you would want a sub to be high.

Having got fed up with the sub spindle I unbolted the whole lot and pulled it off. What a whole lot of mess underneath, rust, gunk and sludge.

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The sub spindle on these machine float forward and back and is adjusted by a set of push me, pull me's but is pushed rearwards in the Z axis by a gib to seat against two machined surfaces on the sub spindle carriage.
I cleaned and stoned all the parts and settled everything back together.

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It was just a matter of chucking up the datum bar between the two spindles to get roughly centered and then using a clock to do the final adjustments, after taking a test cut I have a taper of 5 micros over 150mm. The spindle is still high so I am going to cut two new shim plates and grind them to the right size as I am going to be turning shafts between spindles.

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How does the sub spindle powered? Does it have its own integral motor? I have a QT15 and it seems like everything I am doing with it needs a second op. Sure would be nice to have a sub spindle.
 
Have you indicated both main and sub on top of your work pc? that should tell you if you need to crank the middle leveling screws to raise main inline with sub.
Is your machine bolted down to floor?
 
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The teeth on the turret bungs have been machined the whole way wound the shaft, it doesn't matter which orientation the bung is inserted then. They should be the same as a 96 SQT.

The sub-spindle sits on the standard tailstock carriage and is driven with a ballscrew that sits between the two boxways the carriage rides on with the servo motor mounted in the main casting under the Z axis ways, the two are connected with a pulley and belt (I think it is a pulley as I haven't inspected it yet, could be a chain?).

This is how I went about leveling the machine, tell me if you think it is wrong.
The machine has 7 leveling feet on the main casting as shown. 3,4 and 6 were engaged on to their pads with the rest left retracted. The machine was rough leveled off the Z Axis ways. The remaining feet were torqued down except 1 and 2.

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The turret was brought to the middle of it's travel and a level was placed on the turret both ways with blue-tac to show a true plane. The turret was then moved along its negative and positive Z travel to determine any twist or crowning of the casting.There was a bit of droop under foot 7 so that was raised and tiny amount was seen in front of the chuck, feet 1 and 2 were then torqued down and this lifted the back of the spindle a fraction and took the crowning out.

The turret face and tool holders were then indicated to check squareness.

A datum bar was placed in the main spindle and a 0.2mm test cut was taken over 150mm this showed a 4 micron taper. (This should show that the main head stock is parallel and straight to the Z axis). A test bar was then placed in the sub-spindle in it's home position and the same test cut taken over 150mm. This produced a 5 micro taper (All of this precedence was done again after the sub-spindle was re-seated). I can know put a indicator on the main spindle and clock the sub-spindel which allows me to see the sub-spindle alignment. By using the push me, pull me screws I can pull the sub-spindle into alignment and check by taking a test cut again.

As a secondary check by placing the clock on the sub-spindle and indicating the main spindle datum bar I can advance the sub-spindle and this should show any twist in the casting as the sub-spindle moves forward. The last check that was performed was placing the clock on the turret indicating the sub spindle datum bar. The turret and sub-spindle can then be walked the full length of their travel while staying in contact. This gave me a maximum deflection of +- 3.5 microns from the nominal along the full length of it's travel.

Unless I have missed something silly this all shows that the geometry is pretty good but I am still 150 microns high on the sub-spindle center height. It just really bugs me.
 
Any history of crashes on that machine? Have you run an indicator mounted on turret to check sub-spindle ways?
I believe you could adjust sub spindle ways up and down. That whole thing is screwed on to the side of main bed ( look it up in your parts list)
As to the level I did mine rough 2 extreme feet on the back (1 and 6) and number 4 on front, bolt it down and then bring rest up while watching level.
 
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Sub-spindle / tail stock slide mounting bolts

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Sorry about bronze chips.. crap is everywhere I hate it.
 
Thanks, I'll have a look at how the ways mount in the morning, I haven't run an indicator along the sub spindle ways.

I know the machine has been crashed, it was one of the reasons for re doing the sub spindle. Their is a heavy gouge in the sub spindle chuck. When I inspected the machine the sub was parallel but over 0.75mm off the center line. (how they used it like that I don't know.) This might coincide with Mazak replacing the X axis rails 2 years ago. Apart from the height issue I haven't seen any hump ect in any of the rails while setting the thing up, so maybe the whole sub assembly gave a bit.

The chuck mark shows that it was in a clockwise motion when looking at the chuck face which would want to push the sub spindle down rather than try and pick it up?
 
OK , you are very close. Ones you indicate your sub-spindle way and they turnout straight just grind the spacer to size.
The SQT is one of best machines Mazak made. I love mine.
Good luck with it.
 
I love the SQT's, I've had a 10M with T32 and that is great, this is a beast compared to it. I did some test machining on some EN24T alloy steel and it just chewed through it with 3.5mm depth of cut, 110sfm and 0.15mm feed. This machine has high pressure coolant on it as well which really clears the chips.

I measured the sub-spindle ways today and got a slight movement, 30 microns on the top and 10 microns on the side as shown. I re-checked the levels as well in case the machine has settled a bit but they are spot on. Is this acceptable?
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Does anyone have a picture of the rear Z axis guard leafs, I am missing one or more. The mechanical parts diagrams are very crowded and don't show these in much detail. I need to fill this hole. I know it has a top bearing which runs in a track but how is the bottom supported and where/how does the rearmost portion bolt onto the main sheet metal work as there are no obvious bolt holes left. I have sourced all the wipers and parts needed etc but I am just struggling on the exact geometry that I need to laser cut.

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Stage two today was stripping off, inspecting and cleaning the door and main spindle area.

I am always amazed at the amount gunk and rubbish you find in the back of these machines.

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It's not perfect but 99% better than before.

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Stage three today was sorting out the parts catcher.

Half the screws were out of it, the center shaft wasn't seated correctly.
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Pulled the whole assembly out of the machine and took it apart, like everything else it was mess inside which explains why the whole thing was jammed.
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Once cleaned it wasn't in to bad a condition. The parts catcher consists of a welded tube assembly that bolts onto the front wall, the cast aluminium head rotates on this in a bronze bush and seal. A toothed gear is then attached to the tube assembly with a belt running down the length of the head to the output shaft that the bucket bolts onto. The main shaft runs through the whole assemble with the input end being keyed to a hydraulic cylinder next to the spindle. The output end bolts on to the aluminium head. When you command the the parts catcher the hydraulic cylinder rotates the inner shaft which moves the head into position under the chuck, as the toothed pulley is held stationary by the outer tube the output shaft therefore rotate as the head moves round thus bringing the bucket into the correct orientation ready to catch your part. You can choose which side the catcher is on by flipping the out put shaft 180 degrees.

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Does any one have a few good pictures or even dimensions of the bucket and catch box as I need to make these as well. I am also looking for details on the older version of parts catcher for my QT8N as that is missing the bit that bolts onto the shaft. the one that has a single rotating shaft.

A couple of issues now that the parts catcher is back in, I tried to run it and according to the manual there are two sets of M codes to operate it M48/M49 and M90/91 but I just get an invalid M code alarm, the manual also shows that there are two soft keys under options but these are not displayed either. Looking in the books PLC data R52 bit 3 sets the parts catcher, this was set to 0 where 1 is valid. There is a big hand marked arrow next to it, so it has been turned off by someone. Setting this to 1 still won't let me operate it.
 
The parts catcher I was being stupid with, reading the PLC bit's back to front, Once the right one had been selected and the prox switches set on the cylinder, it all worked nicely with correct M codes.
 
Picture of covers inside machine. Mine is a SQT 250 1998 with a tail stock, turret is moved all the way to the main chuck. Covers are made by Hening

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(somehow this picture wont upload in correct orientation it is upside down)

Back side of sliding covers

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Outside parts box, if you going to make one yourself i would make it a little shorter
It mounts from inside.

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Thanks, those pictures are excellent.

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Pulled the back of the machine off and removed the remaining leaf. All the parts are drawn up ready for cutting this week. I am going to remake the remaining leaf rather than try and fix it and have it not fit correctly with the new ones.

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