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Rotary table help

CJD

Aluminum
Joined
Aug 28, 2019
I have what was originally a Boss Bridgeport mill that I just finished upgrading to Centroid’s Allin1DC system. The install went well for the X,Y and Z, but I am a bit stumped on the W...or rotary axis.

The rotary table I have is a substantial item, weighing at least 150 pounds. It is hooked up to a Centroid DC1 driver, so it does spin with the Jog panel, but I am not sure where to go from there. I’m a complete newby to this. There are 3 lone wires coming out of the side of the table, which I assume are for the home sensor. It also has 2 fittings that leak oil if I turn the table on its side. The Centroid rep was asking me about “clamps” and such...and I have no idea.

If any of you can help me with the basics of a rotary table I would really appreciate it. Namely, how does the homing sensor work? It has black,/red/and blue wires, but which is what and what kind of voltage will it want? Then, are the fittings for an oiling system, or a pneumatic clamp?

Thanks...
 
Most homing sensors are proximity switches that sense presence of a steel protrusion or magnet on the rotary ring gear. This is not always true but in general red or brown=24v, blue=0v (ground), and black is the signal wire which will be either NPN (sinks to ground when switch active) or PNP (provides 24v signal when switch active). Again, this is generalizing, the best thing to do is find a part number on the switch and google the datasheet for the pinout. Not all systems are 24VDC also but it's very common in CNC.
 
Just to be picky or pedantic: with X, Y and Z the normal axes for a vertical mill then the rotary associated with the X is A, in like manner Y & B and Z & C. W is movement of the table either closer to the z eg. up or farther away down. HTH

ps. it gets worse... check this link:
Horizonal boring mill, Z vs W axis
 
Thanks, Troy. The switch is buried inside the table, so trial and error is going to be my only option. I will likely start with 5v input to the prox switch and work up to prevent damaging it. Working on the table is difficult when I cannot even lift it! I will have to build a table for it so I can slide on and off the mill table.

SS, you answered a question I had during setup, but even the Centroid guy had no answer. I tried labeling the rotary table as “4”, 4th”, “R”, etc, but the Centroid software kept rejecting it. At the time “W” was all I could think of that the program accepted. I will try re-labeling “A”. Another issue I have along those lines is the DRO displays rotary movement in inches, instead of degrees. I am still trying to figure that out too.
 
A follow-up. I decided that since my rotary table was originally a Centroid factory install...or so the PO believed...I went with the parameters right off the current Centroid schematics. I used 24vDC to the red and black wires, and connected the blue to the rotary input on the Allin1DC. Succcess! The rotary table now homes and 99% of the position error messages went away. The system test finally completed so the obnoxious warning about the set-up not being complete has disappeared from every start up.

Changing the 4th axis to “A” solved the DRO issue, so the rotary now measures degrees. Thanks again!

That’s the good news.

On the other side...I still cannot figure out the nuances of the rotary table. It weighs at least 200lbs and has no markings at all. I have googled for days trying to find any similar tables, and there simply are no pictures of similar ones. I blew air into the 2 tube fittings. Absolutely nothing happens. No air escapes anywhere, and the table does not clamp. The air that comes out when I remove the pressure smells like heavy gear oil. I have to assume they are oil feed lines to the 2 ball bearings for the rotor.

Another option is the hoses may be for a hydraulic clamp, and I am not using enough air pressure to activate it. The pneumatics on the Bridgeport are all 3/8” lines, and the tubes into the rotary table are 1/4”. I am at a loss. I may have to tear down the entire unit to figure out how it works if nobody has any ideas?!? The table has no perceptible backlash at all...are there tables that do not require clamping features? What keeps going through my mind is that the X,Y and Z do not have clamps??
 
Many smaller rotaries down have brakes... and lots of people disconnect brakes to speed up performance. It kinda depends on how your gonna use it. Big difference between hogging steel on a large diameter tombstone; versus small cutters on small diameter parts held near the centerline of the rotary.
 
Thanks! I am coming to the conclusion that the lines must be for a hydraulic brake. I find it difficult to pull any info about how these tables work. It looks like there are many manufacturers, but little actual production volume when it comes to rotaries...making the documentation hard to find. The PO used the rotary to turn walnut rifle stocks...and since no pneumatics or hydraulics came with the machine, and going from what you say, I bet he did not use the rotary brake for that kind of work.

Can anyone give me an idea of how a typical hydraulic brake is setup? I assume they use a pump with accumulator and pressure switch, and then a solenoid valve for the actuation? What kind of pressures are normal? The two lines would have to be one for brake on, and the other for brake off...?
 
Can anyone give me an idea of how a typical hydraulic brake is setup? I assume they use a pump with accumulator and pressure switch, and then a solenoid valve for the actuation? What kind of pressures are normal? The two lines would have to be one for brake on, and the other for brake off...?

I think you're right about one line being clamp and one unclamp. My Tsudakoma has a self contained air over hydraulic unit mounted right to the rotary table on the side. An M code sets off a 24v air solenoid that sets off the air over hydraulic system. (plunger) This is a fixed quantity reservoir. There is no supply pump. The air connection is on the unit. The hydraulic connections are likely what you're seeing. Not sure all tables work like this. I think if you had some air and hydraulic components sitting around you could rig something up. This thing is handy though in that it's compact and part of the unit. You're dangling only an added air supply hose into the CNC machine with your electrics, not a couple heavy hydraulic hoses.

Dave
 
I think you're right about one line being clamp and one unclamp. My Tsudakoma has a self contained air over hydraulic unit mounted right to the rotary table on the side. An M code sets off a 24v air solenoid that sets off the air over hydraulic system. (plunger) This is a fixed quantity reservoir. There is no supply pump. The air connection is on the unit. The hydraulic connections are likely what you're seeing. Not sure all tables work like this. I think if you had some air and hydraulic components sitting around you could rig something up. This thing is handy though in that it's compact and part of the unit. You're dangling only an added air supply hose into the CNC machine with your electrics, not a couple heavy hydraulic hoses.

Dave

I wonder if you could check if it locks with a grease gun... down and dirty, but it would be quick to setup.
 
Thanks, guys. I found that Harbor Freight has a $150 air pump that I will try and see if I can get the brake to energize. The Centroid Allin1DC has a clamp output, so, assuming the lines are a brake, the brake should be easy to integrate with an air valve. I’ll report back with pics once I give it a shot.

Also...the more I Google the more impressed I am with this table. Most this size (about 12”) with hydraulic brakes are going for over $4k. Has me motivated to get this thing working.

One last question. The Centroid controls come with basic Intercon Cam software. I am new to the latest CNC software, but have been studying the Intercon. It seems very basic, and doesn’t look like it is optimized for a rotary table. It seems Fusion is the next CAM up the ladder, with much better options, but a few Cloud issues. Can anyone recommend a decent CAM option? Most of my design work will be with Autocad. I don’t mind paying for a good program...but not excited paying $7k for a program if it is only marginally better than free Fusion for my hobby machine shop.
 
Thanks, guys. I found that Harbor Freight has a $150 air pump that I will try and see if I can get the brake to energize. The Centroid Allin1DC has a clamp output, so, assuming the lines are a brake, the brake should be easy to integrate with an air valve.

With your air only idea, you might be barking up the wrong tree without a paddle, or something like that. It could work for a basic test of the brake mechanism, but operationally I think air alone is not enough. Also you're saying "air pump." If you really mean "air pump," I'd say don't bother. I'm very doubtful it will do anything, at least not without taking all day about it. If you really mean air compressor (like with a tank) then you have a better shot, but still I'm thinking "nah... ain't gonna work." But remember I don't know everything.

I dug around in some rotary table literature and see that a 72psi air input on an air/hydraulic brake unit yields 500psi braking pressure. You'll never get anything close to that with air only.

The worm gear setup within the table has natural braking tendencies and much work can be done without applying the brake. Braking is more for when you're doing say heavy duty milling or working near the periphery of large diameters.

Just sayin,
Dave
 
Thanks, Dave. Air pump was the wrong term. It’s actually an air driven hydraulic pump. It just arrived, so tomorrow will be the test to find out once and for all what the tubes are for!?!
 
Alright, tried the hydraulic input to the fittings on the table. The left fitting clamped the table. Releasing pressure did not release the table. I switched the pressure to the right fitting and hydraulic fluid is seeping out of every bolt on the table. The table is still clamped solid.

Has anyone seen this table before? There are no markings or tags anywhere. Any ideas about the hydraulic clamping, i.e. what are the 2 fittings for?

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Hi CJD,

Man that thing looks almost home made. It might be that it's been so long since the thing has clamped that it's just stuck. Why don't you try taking that panel off with the two holes in it that is adjacent to the hydraulic fittings. Seeing as it looks like it's held on with nothing but four button heads, I seriously doubt it's anything more then an access plate to limit switches or trip dogs. I mean put a pan under it when taking it off, but four button heads doesn't strike me as a panel with consequence. Maybe you could see some piping in there or something. On closer inspection I see that it is the top panel. Even more reason it has access to the inner goodies. Still I'd tilt the table upright before taking it off. Perhaps you've already had it off.

Dave
 
that looks loads like the Hass table i have here. can you turn the pully?

looked again, 100% thats Hass, mine here if you disconnect all the break parts it still turns, i think one port is air purge and one is to put the break on. there might be a air over oil system for what its worth i havent had the break connected on mine for about 2 years and use it most days without a problem!
 
that looks loads like the Hass table i have here. can you turn the pully?

looked again, 100% thats Hass, mine here if you disconnect all the break parts it still turns, i think one port is air purge and one is to put the break on. there might be a air over oil system for what its worth i havent had the break connected on mine for about 2 years and use it most days without a problem!

Hass...I’ll do some googling to check it out.

I decided I had to take it apart to figure it out. This is indeed a severe duty piece of industrial hardware!! The casting alone is over 100lbs. Like you say, I am pretty sure the brake is air actuated...as the bolts on the table were all blown out. I may have done it when I used the hydraulics, but as I never heard any bang, I assume I was not the first to over pressure it. All the bearings are USA. How long has it been since you’ve seen that?!? The main bearing is 9”.

I’ll update once I get more info
 
Yep...definitely an older version of the Haas HRT310. Thanks for solving the mystery! Even used they are going for $7k+, so hopefully I can save her. It’s apart down to the table spindle, but I still don’t see how the brake works. It’s so small yet weighs so much that it is very hard to work on.

Thanks again! If you can give me any insight as to pneumatic pressure envelopes and which air fitting does what I’d really appreciate it...
 
Well, with the entire table apart I still cannot figure out how the brake works. I even have a copy of the operator’s manual, which adds no light to the brake. It’s magic. The best I can figure is the air fittings pressurize the entire interior of the case, thereby forcing large o-rings to jam between the rotors and the case.

In it’s original form the servo, air, homing switch, and controls are all internal in an attached box. It turns out I have the box...but assumed it was for the coolant pump. In factory form the table is operated separately from the other axis. The conversion to the Centroid system envolved just removing the original controls and switching the servo.

Get this...the tolerance for backlash on the table is .0002”. True to form, Haas does not sell any seals for the table, so I will have to source every o-ring individually. Or I could let them rebuild it for a hefty $2500. I’ll post pics and let everyone know how the reassembly goes...
 








 
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