List of milling machine features I am seeking

Here's a list of things I want to get from my mill. They all seem individually doable. I can already use my mill for basic 3D
machining.
So, here's what I want.
1) All panel buttons and jog buttons work properly 2) Spindle Speed control from G code using solenoids that actuate the vari-drive (and not VFD), so that I get full power output at all speeds, all the while operating at 60 Hz 3) Flood and mist coolant working, including from G code 4) Jog mode, VFD at 5 Hz 5) 4th (rotary) axis based onthe Troyke CNC rotary table 6) Rigid tapping, based on synchronization to spindle speed (G33)
Once I do all of the above, I think that it wil be a Mercedes Benz level mill, loaded with useful features, with everything accomplished without modifying the hardware of this machine, and without incurring expensive costs.
Am I missing anything in this picture?
i
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Iggy, I know this is fun. You have really done well and I am envious. I know this is a hobby and part of the hobby is increasing your skill set, but those six goals cost your time and some money. Yeah, I know, spend to save, but those changes are impractical. I suggest you step back, look at the bigger picture, establish a closure point and do another machine. My two cents. Steve

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"Steve Lusardi"wrote...

Hey, I'm with Iggy on this one - 1,3 and 4 are just parts of a proper VFD and CNC installation?
2 and 6 sort of come together once you have a spindle encoder (maybe a fine-resolution slotted opto?) and a few solenoids to work the vari-drive, the rest is just programming and Iggy seems to have that cracked :)
No. 5, the rotary axis will take the machine's capabilities into a whole new ballpark - need a custom gear wheel? program it. Need a custom splined shaft? program it, etc. etc.
My two penn'orth,
Dave H.
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This is what I think too.
i
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Steve, the cost is really close to zero on these, speaking in comparison the "newe prices"..
i

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Steve Lusardi wrote:

Ummm, he's already done the hard stuff, most of this is REALLY easy, just a few lines of HAL code to hook up most of this stuff! REALLY!
The only thing that requires some work is adding an encoder to the spindle. What the heck is impractical? Jog on the VFD is just one more SSR connected to a terminal on the VFD. Most of the mist vs flood is just a couple of SSRs that drive a solenoid valve for mist and turn on the pump for flood. VERY easy, everything except the actual SSR is already present in EMC. G33.1 rigid tapping is already supported, too, and I have it on my Bridgeport as well. Works like a charm! The spindle speed scheme to seek the right speed with the air valves has already been done, I think, and just needs a little bit of adapting to make it work. Iggy's a software guy, so this shouldn't tax his abilities at all. Spindle braking by VFD is easy, it is just setting some parameters in the VFD. Actuating the brake in the head is just another air valve, and either rig it to a delay, so it engages the brake a couple seconds after a spindle stop, or add a button to the PyVCP (virtual control panel) to add a manual brake. Or, for the sole purpose of locking the spindle for tool change, it could be a manual-only button.
Jon
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Yep, most of these new improvements involve routing wires properly and writing configs and commands.
The "hard stuff", however, involved more of same. The whole project was not mechanically challenging, it was mostly about learning how to use various functions and connecting wires and cables. It was complicated, but required no big physical efforts or mechanical knowledge.

I agree.

Jon, practically speaking, how fast do you run your spindle when rigid tapping with small taps?
Say you are tapping with 10-32 taps, how fast would you run your spindle.

It should be a manual button, I think, I have not yet figured it out. I thought about it last night, all the delays etc, it was painful to think about. This is also a somewhat riskier function to debug (compared to, say, flood), because of how a brake may fight the VFD.
I have to look at the brake fuction more closely.
My current thinking about the brake is that the pneumatic system is already made, such that that the brake engages with a delay, but withdraws instantly. If so, then, the built in delay may be sufficient to let the VFD stop the spindle.
I recently put a brake resistor on the VFD, and can stop faster than I used to.
i
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FWIW, I do all tapping at 200 RPM in back gear. I'm sure you can go faster.
...

FWIW, I use the VFD and resistor to stop spindle, then bring in brake to hold it there.
Karl
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Karl, I want to do the same thing. Using whatever you used, how did you specify brake delay?
i
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On Mon, 09 Aug 2010 11:55:09 -0500, Ignoramus29207

here's my logic: (different language than yours)
[[STOPSPINDLE]] #34=0 'make sure CCW is off #35=0 'make sure CW is off SPINSTOP LIGHT 4;OFF SLEEP 1.0 IF #66=1 THEN #44=0:\122=0:LIGHT 10;ON 'if brake is in ON position, turn off brake release or brake on, flag for brake \121=0 'flag for spindle off
looks like I just wait 1 second after turning the out off.
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Ignoramus29207 wrote:

I have wimpy servo drives, about 5 A peak. I also was still learning how to set the thing up, and hadn't put a filter in the velocity command to the VFD. I was having a couple problems. The VFD slammed to a stop so suddenly the Z axis couldn't always follow it, and I got following error trips. Also, the electronic motor protection was enabled, and was tripping the VFD offline. The Bridgeport "pancake" motor is insanely derated, and is meant to do plug-reverse tapping all day. I just turned the motor protection off, and added a filter to soften the reversing action of the VFD. So, after these fixes, I was happily tapping 4-40 at 1000 RPM. I suspect I could go even higher now.

Hmm, I think I did some 10-32 tapping at 800 RPM. I made a 12 x 24" fixture plate with 288 holes. Rigid tapping is WAY cool on a tedious job like that! I mounted the plate on spacers, indexed the position, and then did spot, drill through, and tap in one setup, then moved the plate and did another section.

You could interlock them, so the button doesn't work when the motor is on. I have turned on my VFD when the manual brake is locked, nothing horrible happens, and the belt slips. This may be less desirable with a varispeed drive. If it takes you too long to react, the VFD will just fault. I have the VFD fault relay wired into my E-stop chain.

EMC1 had a delay built in for the brake, this has been removed, I think. But, putting in a delay would be easy in HAL.
Jon
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Ignoramus14749 wrote:

Noting but some wiring and EMC2 configuration here.

You need to get your spindle encoder installed for this one since EMC2 will need to be able to measure the spindle RPM if it's going to control the vari-drive. As long as someone has already written the modules to control a vari-drive, the rest is just more wiring so EMC2 can control the up/down solenoid valves (and VFD if you haven't already done that).

More wiring and EMC2 configuration. Nothing more than wiring up a couple outputs to relays to control the coolant pump, and a solenoid valve for mist.

Wire up yet another output from EMC2 to your VFDs speed select input, and program the VFD to select between 5 Hz and 60 Hz based on that. I presume you'll also need to wire an output or outputs to control the gear range shift mechanism.

Install your 4th axis drive, resolver converter, and a home switch on the RT, and configure EMC2.

This should come along with the spindle encoder you need for #2.

More like a nice pickup with all the options. You'll see the "luxury" mills and whatnot at IMTS.

Iggy, you ripped all the original controls out of the machine, that *is* modifying the hardware of the machine.

That's the important bit.

Just the need to spend some time working with CAD and CAM software and milling some wax to get familiar with them.
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Yep.
Correct. I will put an encoder on the spindle.

Yes, I think that it should work, it is simpoly a configuration issue for EMC.

Yes. I already have flood working 100% from G code, GUI or from panel. Mist amounts to one more relay and a pneumatic valve.

Something like that. I may use an ADC for this (desired speed). It would be at 10v or 1v dependong on what I want.

Yep
Right-o!
Correction taken.

TO me, modifying hardware is drilling new holes (except on the enclosure) replacing moving parts etc

I will start with plain G code at first.
i
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Our older cnc lathes with gear boxes require a M41 or M42 command to switch gear ranges. Perhaps you could implemnet something similar where the command emits an output you use to shift the sheave. IRRC M41-44 are typical gear change M codes.
Wes
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Wes, yes, I would like to find some good G code number and then implement it. I got some suggestions on emc-users on how to do it, with comparator elements of EMC. But speed change should only happen during speed change, and not at any other moment, like reversal or whatnot. If I get it to work, it will be much better than VFD, and will let me tap with relatively larger taps.
i
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I have a question, does your lathe have a back gear much like a manual Bridgeport? I've never seen a mill like yours.
To some degree automating the sheave displacement should be lower on your list unless you implement a tool changer. After all, you got to change a tool manually now, not much effort to adjust the sheaves.
Are you planing a tool changer?
As far as keeping the varidrive, I went through a lot of effort to repair the varidrive on my Clausing 6903 so I know where you are coming from. How hard my lathe can work is limited by how hard I'm willing to push the thing.
Wes
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My Clausing lathe does not have a back gear.
My Bridgeport Interact CNC mill does have a back gear, lowest it goes is 60 RPM.

Yes, but I could forget to change speed.

Definitely not, too complicated.

My own opinion, after the fact that I did it like you, is that it was too much work and cost for not as much benefit. I did it too. Varidrive on this mill, though, is workin well.
i
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Really? I find this hard to believe.
Joe Gwinn
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Joe, I have a feeeling that I am wrong, but I am away from home.
I
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    [ ... ]

    Which model of Clausing is this one? Mine has a back gear, as does every other Clausing that I have seen. On most of the 12" swing ones, it is a knurled knob which comes out of the front of the headstock which you pull out, swing down (or up) and swing back in. But you also have to open the cover over the belts and gears and pull out (until it clicks) a pin coupling the bull gear (big one at the right of the headstock) to the pulley sheaves. With the pin pressed in, the bull gear is coupled to the pulley sheaves for "direct drive". With it pulled out, the pulley sheaves rotate independently of the bull gear (which rotates with the spindle nose). Then operating the lever engages the back gear which is below the spindle instead of behind it as is common for back gears. The small end of the back gear engages the bull gear, and the large end of the back gear engages a gear on the other end of the pulley sheaves. I think (without looking it up) that the ratio is somewhere near 5:1.

    If there is a back gear (my Bridgeport Series-I BOSS-3 has one) Add a switch to sense the position of the back gear lever and have the CNC sense that switch to see whether back gear is engaged. The computer needs to know this anyway because the spindle reverses in back gear, and you need to have the computer command the VFD for the opposite direction in back gear.
    And even without a back gear -- have the computer sense the spindle speed to advise you to change the speed until you get it all automated.

    I would *like* to have one, but I agree. You would also have to change the spindle to one which accepted the CAT/BT styles of tool holders instead of the NTMB/NMTB (one of those is right. :-)

    And as long as it is kept in good condition (replace the Delrin bushings in the movable pulley halves, and the Delrin-covered steel key which rides in a keyway in the motor spindle -- and I believe also in the mill's spindle every so often.)
    Enjoy,         DoN.
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