[adrianni]

Hello,

I recently purchased a BT30 chinese spindle. I'm having problems understanding how is the tool holder locked and unlocked from the spindle.
The manual says I need an inductive switch and they give schematics for connecting the three wires that come out of the spindle to the inductive switch so that "the light is on when the tool holder is up"... Actually they say handle instead of tool holder. Anyway, I was hoping someone can tell me exactly what I need to be able to manually change the tool. That is to say, I want to be able to push a button to release the tool holder and then push the button again to lock the new tool holder in place.
I attached the spindle manual. The diagram is on page 5 of the pdf. I suspect that depending on the switch type (npn/pnp) you wire the switch to the respective wires (+ or -) but this is just a guess as my knowledge in electronics is very limited. Should I understand that the 24 volts are coming from the spindle or is it a voltage I need to supply? Again, if you would like to help me, explain how to connect the three wires that come from the spindle. By the way, the wires are black, brown and blue.
Thanks, Adrian
ADS .pdf

[jstiltner]

Looks like to release or hold the collet, you apply air pressure between 80 and 100psi to the air fittings on the top. Apparently there is a pneumatic cylinder on the top of the spindle. Dunno what its talking about on the 24vdc though, it looks like a 3 phase motor?

[TOTALLYRC]

It looks like the tool change is acomplished by using an air solenoid to put the pressure to and then release the tool change mechanism.

Should be easy enough with either a manual air valve or electrical air solenoid.
The pnp and npn seem to be a way to trigger an indicator light to tell you when the tool is released or not.

I like the part of the manual that says use high grade gasoline to clean the parts. It was definitley not review by OSHA.

Mike

[H.O]

As others already stated the tool is released by means of air-pressure (6-7 bar). You can use a manually or electrically actuated valve to supply the air to the spindle.

I suspect that the proximity switch can/should be used as an interlock for the VFD so that the spindle drive can not be started when the tool is not locked. The english translation of the manual do have some room for imrovement though ;-)

May ask where you got the spindle and how much it costs?

/Henrik.

[Starleper1]

When they refer to the PNP or NPN they are talking solid state which more then likly is the indication LED (Light Emitting Diode) Diode=Solid State.

I'm also interested in $$ and where you got it.

Thanks

[adrianni]

As others already stated the tool is released by means of air-pressure (6-7 bar). You can use a manually or electrically actuated valve to supply the air to the spindle.

I suspect that the proximity switch can/should be used as an interlock for the VFD so that the spindle drive can not be started when the tool is not locked. The english translation of the manual do have some room for imrovement though ;-)

May ask where you got the spindle and how much it costs?

/Henrik.

Hi, thanks everybody for answering. I got the spindle from a chinese manufacturer. I attached a pdf that contains among other things the name of the manufacturer and the web address. However, the manual is a disaster in itself as it is full of mistakes, rendering it almost unusable.
Price is 3000 USD including inverter. Before you judge this price, consider that it would cost almost the same to build your own bt30 spindle. I think this forum allready has an example.
The motor is 3 phase 220 volt but I supply 220 volt 1 phase to the inverter. The spindle runs quiet and fast. At 18.000 RPM (maximum speed - 600 Hz) it hums nicely and without vibration. So, the spindle can be ran without the tool inside allthough not recommended. It is heavy so I built a sturdy z axis for it equiped with a gas spring to support its weight. I had to build the holder also. I will attach some pics with it...
The spindle does have a pneumatic system for changing the tool. It takes 45 degrees retention knobs. I hooked the spindle up to the air supply (6 bars and 7 bars respectively for tool change and 0.8 bars for positive air pressure inside to keep the chips and coolant from entering the bearings). I also did it for the water cooling circuit.

I am left with three wires. They are very thin (they shouldn't take current in the range of amps). I translated the color symbols from chinese using a website that shows you the pictograms when you select a coloured circle.
I need an induction switch that must be coupled to these wires. As the manual shows, depending on what type of switch you have, you choose the PNP or NPN configuration. That is to say, you connect the light bulb and the switch to positive or negative, final result being that when the tool is loaded, the bulb lights. However, I tried to find out about these switches. Ran a search for inductive switch and all I can find is "proximity induction switch". It might be that the spindle can use some sort of proximity switch so it releases the tool when in certain position (tool changing position) when you want to use an ATC. I don't, so I want a manual switch. I do not know how to build it.
I am convinced that this switch is used for releasing and locking the tool holder in place. Just don't know what it is...

Here is the other manual: The instruction book of the electric spindle ..pdf
Spindle and the z axis:
Closeup of spindle in the holder:
Started to collect bt30 holders:

I look forward to receiving an answer,
Adrian

[H.O]

Hi Adrian,
I'm pretty sure that the proximity switch already IS inside the spindle and the three thin wires (Black, Blue & Brown perhaps?) are coming FROM / going TO this switch.

When the spindle is used with an automatic toolchanger the ATC controller needs to know when it can retract the tool from the spindle (or retract the spindle from the tool). It's not good enough to simply "know" that the solenoid has been activated because the air might actually never reach the drawbar mechanism or it might have jammed or whatever. Trying to retract the tool in such situations might damage the spindle/tool/changer.

The proximity switch is located inside the spindle in such a position that it is "activated" by the drawbar when it is in such a position that the tool can be extracted from the spindle. The wires from the proxmimty switch is routed outside for you to connect to whatever you need.

So, IMHO, you really should not need to connect anything else than the air in order to activate the drawbar mechanism and change the tool. At least that's what I believe.

/Henrik.

PS. It might be my BT30 spindle thread you've seen here. Building one was/is NOT a walk in the park. $3000 for spindle motor and inverter sounds like quite a deal!

[Starleper1]

I have a hard time believing that a spindle like that could not be built for under $3k

[H.O]

Perhaps, if you have the knowlege, time and neccessary machines. I didn't and still don't have the required knowlege and no access to the proper grinding machines but I still tried it. You can read about it in this thread. Can't say I've spent $3000 on it but remember, he got the spindle, motor AND converter for $3k. Being one who has tried building one I still say it's a fair deal - if it works properly of course.

/Henrik.

[adrianni]

Hi Henrik,

It's nice to hear from you. I read your threads over and over for the last month or so, I really admire your work and dedication. You do have access to some serious tools though. I was hoping you would see this post as you showed us in the video some tool changing on your BT30 spindle. Anyway, you might have a point here... Went to the manufacturer website to check, the description says " ... have sensor and broaching tool". Now, I can understand how the spindle has sensor, but I cannot understand how could a spindle have broaching tool. I remember asking the seller, in fact they believe the broaching tool is the power draw bar... So, what can the sensor be? Could it be a refference to the "sensor or sensorless brushless motors"? Or maybe it is about the sensor that you were talking about?

Why do I need the wires for? Why does the diagram in the spindle manual show a NPN or PNP induction switch connected to the wires?

I have to be honest with you, I haven't even checked to see if there are 24 volts on the wires. I'll do that first thing in the morning and let you know. If this is the case, I might still need the switch or else how could I unlock the tool from the spindle?
Kind regards, Adrian.

[H.O]

Hi Adrian,
Well, thank you! Someday I hope to sort out what is cauing the runout on my spindle, then I'll update my thread. Anyway, back to YOUR spindle....

Can't say what the mean by broachingtool... But agian, all you should have to do is connect pressurised air to the correct fitting on the back of the spindle and the drawbar should activate. Insert the tool and remove the airpressure and the springs inside the spindle will psug the drawbar back up, clamping the tool in the spindle. That's really all you should have to do as far as I can see.

Again, the proximity switch is there to tell an ATC that it can retract the tool from the spindle. Simply leave the three wires unconnected for now.

/Henrik.

[adrianni]

Henrik,

I've been thinking about it for a few minutes, I think I might have missed your explanation by a mile or so... What you were saying was that if I want to manually change the tool in this spindle, I only need some sort of an air switch to be able to cut the air supply to release the tool and of course a switch (maybe the same) to allow the flow when I want to lock the tool. The wires are in fact black, blue and brown. These wires might only be needed when the spindle functions in an ATC environment so the system knows when to initiate the movement of the spindle/gripper so as not to be in a situation when it tries to remove the tool without the tool being actually released... Interesting! I thought that the ACTUATOR is inside the spindle and the switch controls this actuator...

One piece of information though: the spindle has 3 air inputs - 2 for tool changing and one for positive air pressure. One input says 6 bars, the other says 7 bars, and the positive air supply input says 0.8 bars. Does the spindle needs 2 air inputs for tool changing? One supply is for locking the tool holder and the other is for tool holder release? I am asking this because I thought there is some sort of a spring involved in the drawbar mechanism, so why the need for the second air supply? Am I way offroad here?

Thanks, Adrian

[TOTALLYRC]

On my bridgeport, the power drawbar uses to air inputs, the highpressure one to release the tool and the low pressure one to knock it out of the taper.
Mine actually uses one input pressure and 2 different size diaphrams, but you get the picture. So if yours is the same, it might require 2 solenoid valve or 2 maual valves. Put the high pressure one on first and then the second. when releasing the air, turn off the low first and the the high second.
In mach3 I set up a brain to control this so it is always done in the right sequence.

Mike

[H.O]

Adrian,
I knid of guess that you missed my point, I'm glad though that you now realise what I mean - that doesn't mean that my right though.

There definitely should be springs insife the spindle to provide the locking-force for the tool, simply counting on air-preassure for the locking action would be very dangerous. I'm not sure why there are two air-inlets for the drawbar though...It might be like Mike has on his machine or it's simply to retract the actuator completely.

My guess is that you need an air valve (electrically or manually actuated) that takes air from your compressor and routes it to either one of two "high pressure" inlets depending on the state of the valve.

Air in on one "side" and the drawbar releases the tool, put in a new tool and switch the air to the other inlet and the drawbar is retracted, locking the tool. Kind of like a toggle switch.

I'm pretty sure you won't destroy anything by simply trying a few combinations. Look up inside the spindle and connect the pressure to one of the two inlets, if it's the right one you will see the drawbar being pushed down. Now remove the pressure and you should see the drawbar being retracted by the force from the springs. Finally try the "other" inlet and see what happens, my guess is that it will simply back the piston off of the top of the actual drawbar so they won't rub against each other when the spindle rotates.

If you then wan't to play a bit with the proximity switch connect +24V to the brown wire, 0V (GND) to the blue wire and you should get 24V on the black wire when the drawbar is either locked or relased.

Again, I've no personal experience with this spindle so this is only what I "think".

Hope it helps!
/Henrik.

[adrianni]

I would like to thank you all again for viewing this post and for all your replies.
Using the information exchanged here, I managed to load a tool in the spindle and release it in good conditions without breaking anything.

@Henrik

After a day of experiments in my shop, I can confirm you were right all along about everything. As you can see in the picture, there are three air inlets in the back of the spindle, and you can tell them by the quick disconnects.
The one in the center says 7 bar. I applied pressure to it and the draw bar was pushed towards the nose of the spindle allowing the pull stud to enter. I didn't have an air valve so i disconnected the hose form the air compressor. The tool holder was immediately pulled all the way inside. So far, so good.

To all that are concerned about the quality of the spindle:
I turned the spindle on at full speed to see if there is any vibration in the endmill or the tool holder itself. All I can say is that the spindle performs beautifully. I was a bit concerned because I thought that any object in the nose of the spindle that is not perfectly balanced will induce some serious vibrations. The tool holders that I use are all Lyndex, and although they are balanced to 12000 RPM, there was no problem turning them at 18000. NO VIBRATION AT ALL! Using a dial indicator, I found that the runout measured on the tool shank is 2 microns. That's about 0.0001 inch. I'd say it is well within parameters.

Back to the rest of air inlets:
I will disregard the left inlet, that's the one maintaining positive pressure inside the spindle, it says .8 bar, and when I hooked the air to it, I could feel the air exiting somewhere in the nose of the spindle BUT NOT THROUGH THE CONE.

However, the inlet in the right of the picture does something interesting.
I hooked 6 bar of air pressure to it with the tool out of the spindle (simply didn't have two air supplies). I could feel the air exiting through the cone of the spindle. I held a 1/2" bt30 endmill holder WITHOUT the pull stud inside the cone, to see if the air leaks anywhere else beside the spindle cone. The air couldn't have leaked through the cone anymore (I checked if I could blow ait through the tool holder before, and I couldn't). But the air can still leak somewhere in the spindle nose, between the rotating ring and the fixed parts. Also, it leaks somewhere in the back near one exit of the inductioin switch wires. But it does not leak through the left inlet (the one that is for positive air pressure) I couldn't feel anything there. So, it must be a separate chamber. What puzzles me is that allthough this inlet says 6 bar, when I applied pressure to it the leaks that I was talking about are very weak. Only the leak through the spindle cone is stronger. The others, are really, really weak. So, it might be that this inlet is only for keeping the spindle cone clean between tool changes? But if this is the case, why the need for 6 bar of air pressure? To tell you the truth, I still need to check what's happening when I apply pressure to both inlets in the same time. I will do it tomorrow, and let you know. Anyway, if the air will exit the spindle through the cone at 6 bar, there goes my Silentaire air compressor. It will not keep up with the air demand...

@Mike
I could set up a system with one valve that has two exits. I could supply 7bar of pressure to the valve, I could use the 7bar on one exit for the drawbar and on the second exit I could mount a regulator first to reduce the pressure to 6bar and use this air for the low pressure inlet. But in this case the valve will supply air to both inlets at the same time. If it is important to do it in a certain sequence...
Regards, Adrian

[H.O]

Hi Adrian,
I'm glad you got it working. Perhaps the other inlet is for pushing the tool out of the taper, just like Mike says, and blowing the taper clean from any coolant or whatever. If your tools come out by them self when activating the drawbar you might not need to connect the 2nd inlet at all. Just play with it for a while....

If the above is true it might be hard to insert a new tool in the spindle if you connect both inlets in "parallell". Then there will be air blowing out the nose of the spindle as you try to insert the new tool, not handy.....

Either get a second valve and just purge/"splash" some air when releasing the tool or simply disregard it all together.

In any case, it looks like you've got a killer spindle there, hope it holds up under use as well! Good luck and keep us posted!

/Henrik.

[adrianni]

Hi guys,

As promised, I'm back with the latest results after the second test.
I connected both air inlets (6 bar and 7 bar) and the results are as expected. That is to say, the air from the 6 bar inlet exits ONLY through the spindle cone and NOWHERE else. There is no leak whatsoever. With the drawbar in the "down" position, I inserted a bt30 tool holder without pullstud to block the air from exiting through the spindle and I could not hear or feel any leak anywhere. I don't know what's going on inside the spindle but the fact that the drawbar is in the down position blocks all air form the 6 bar inlet from leaking anywhere else BUT the spindle cone. Now I can say I am happy with the results.

What remains to be done, is to set up a valve system to control the air inlets in such a way that the air form the 6 bar inlet only briefly is allowed to exit through the spindle cone to clean it, just after the tool holder is ejected. I don't think that tool holder ejecting depends on that pressure, the draw bar itself is enough to push the tool holder out of the cone. But I suppose it is important to do it, so I will take the time to set up such a system. Any comment will be highly apreciated.

@Mike: I would really apreciate if you could show us your setup, as I understood you managed to control this sequence from Mach3 using electric valves. Again, thank you for your time.

To all that may be concerned: I was browsing ebay for some BT30 tooling, and I came across these:

http://cgi.ebay.com/KL-1500-CNC-Mill...QQcmdZViewItem

http://cgi.ebay.com/KL-4500-6-0hp-CN...QQcmdZViewItem

These spindles look almost the same as mine. You can check the link at the bottom of the pages but there is no documentation at all for them. Instead the docs are somehow mixed and you get some specs from a different, cheaper spindle.
I requested the documentation for these spindles from the seller, I hope he will send it to me. Maybe the manual is better translated in this case...

Have a nice weekend, and hope to hear from you soon!
Adrian

[TOTALLYRC]

I would like to thank you all again for viewing this post and for all your replies.
Using the information exchanged here, I managed to load a tool in the spindle and release it in good conditions without breaking anything.

@Henrik

After a day of experiments in my shop, I can confirm you were right all along about everything. As you can see in the picture, there are three air inlets in the back of the spindle, and you can tell them by the quick disconnects.
The one in the center says 7 bar. I applied pressure to it and the draw bar was pushed towards the nose of the spindle allowing the pull stud to enter. I didn't have an air valve so i disconnected the hose form the air compressor. The tool holder was immediately pulled all the way inside. So far, so good.

To all that are concerned about the quality of the spindle:
I turned the spindle on at full speed to see if there is any vibration in the endmill or the tool holder itself. All I can say is that the spindle performs beautifully. I was a bit concerned because I thought that any object in the nose of the spindle that is not perfectly balanced will induce some serious vibrations. The tool holders that I use are all Lyndex, and although they are balanced to 12000 RPM, there was no problem turning them at 18000. NO VIBRATION AT ALL! Using a dial indicator, I found that the runout measured on the tool shank is 2 microns. That's about 0.0001 inch. I'd say it is well within parameters.

Back to the rest of air inlets:
I will disregard the left inlet, that's the one maintaining positive pressure inside the spindle, it says .8 bar, and when I hooked the air to it, I could feel the air exiting somewhere in the nose of the spindle BUT NOT THROUGH THE CONE.

However, the inlet in the right of the picture does something interesting.
I hooked 6 bar of air pressure to it with the tool out of the spindle (simply didn't have two air supplies). I could feel the air exiting through the cone of the spindle. I held a 1/2" bt30 endmill holder WITHOUT the pull stud inside the cone, to see if the air leaks anywhere else beside the spindle cone. The air couldn't have leaked through the cone anymore (I checked if I could blow ait through the tool holder before, and I couldn't). But the air can still leak somewhere in the spindle nose, between the rotating ring and the fixed parts. Also, it leaks somewhere in the back near one exit of the inductioin switch wires. But it does not leak through the left inlet (the one that is for positive air pressure) I couldn't feel anything there. So, it must be a separate chamber. What puzzles me is that allthough this inlet says 6 bar, when I applied pressure to it the leaks that I was talking about are very weak. Only the leak through the spindle cone is stronger. The others, are really, really weak. So, it might be that this inlet is only for keeping the spindle cone clean between tool changes? But if this is the case, why the need for 6 bar of air pressure? To tell you the truth, I still need to check what's happening when I apply pressure to both inlets in the same time. I will do it tomorrow, and let you know. Anyway, if the air will exit the spindle through the cone at 6 bar, there goes my Silentaire air compressor. It will not keep up with the air demand...

@Mike
I could set up a system with one valve that has two exits. I could supply 7bar of pressure to the valve, I could use the 7bar on one exit for the drawbar and on the second exit I could mount a regulator first to reduce the pressure to 6bar and use this air for the low pressure inlet. But in this case the valve will supply air to both inlets at the same time. If it is important to do it in a certain sequence...
Regards, Adrian

On my machine I have it setup with 2 24v solendoids controlled with a brain inside Mach3.
I have a button wired to an input that starts the tool change sequence. It looks at the limit switches to see if they are in there proper state. It applies air to the first one, then it looks to see if the first solenoid has moved all the way, if so it then applies air to the second solenoid to knock the tool loose.

My machine also has a similar setup to blow the chips off of the tool during tool changes, but I have not yet implemented it.
I don't think that I would have the air on the whole time for the chip blowing as it might interfere with the tool insertion, but that's just me.

Let me know if I can help out in any other way.


Mike