Intercon - rigid tapping

[frijoli]

especially because I can’t see exactly what is in the canned cycle, i.e. how quickly it commands the reverse

You can't see it, but you can understand it.
Look in the manual for G84,M29, Parameter 74 and 84.
This should give you a pretty good idea of what is going on.

Clay

[DICKEYBIRD]

""Theoretically" the encoder keeps the Z-axis motion "geared" to the spindle rotation & should follow any move it makes. Reversing spindle directions manually "shouldn't" cause any problems.(?) Professional Centroidians may have to answer that one.

[frijoli]

If it’s hidden in the canned cycle, that would explain how it works. I have only manual spindle control at this time so I can’t test much.

It sure sounds like I need a spindle controller that is completely automatic and that my original plan to use a relay won’t work for rigid tapping?

I'm confused. Can you reverse the spindle automatically or at all?

Clay

Hi Clay,
I can reverse it but only using the original manual switches on the machine. Nothing for the spindle is wired to the Acorn at this time. I was trying to figure out all this stuff beforehand. So my issues are:
Sorting out the Intercon programming
Spindle control - what do I need and how to wire it up

Intercon/Acorn always uses the same outputs to change direction whether they are in the tap cycle, or you are manually switching it on the VCP screen. So if you configure output 2 for forward, and 3 for reverse AND it works electrically, it will "function" the same way while tapping. I don't know whether it will work with the relay setup you are contemplating but it will function.

Not sure if that's what you're looking for or not.
Are you contemplating switch the input of the drive or the output? I don't think I would try and switch the output.

Clay

[ScotY]

especially because I can’t see exactly what is in the canned cycle, i.e. how quickly it commands the reverse

You can't see it, but you can understand it.
Look in the manual for G84,M29, Parameter 74 and 84.
This should give you a pretty good idea of what is going on.

Clay

Are parameters 74 and 84 the dwell time before a reverse? M29 is the tap direction, if I understand correctly.

[ScotY]

""Theoretically" the encoder keeps the Z-axis motion "geared" to the spindle rotation & should follow any move it makes. Reversing spindle directions manually "shouldn't" cause any problems.(?) Professional Centroidians may have to answer that one.

That’s how I assume it works. I’ll have to experiment more when I have some free time. Busy at work this week, unfortunately.

[ScotY]

I'm confused. Can you reverse the spindle automatically or at all?

Clay

Hi Clay,
I can reverse it but only using the original manual switches on the machine. Nothing for the spindle is wired to the Acorn at this time. I was trying to figure out all this stuff beforehand. So my issues are:
Sorting out the Intercon programming
Spindle control - what do I need and how to wire it up

Intercon/Acorn always uses the same outputs to change direction whether they are in the tap cycle, or you are manually switching it on the VCP screen. So if you configure output 2 for forward, and 3 for reverse AND it works electrically, it will "function" the same way while tapping. I don't know whether it will work with the relay setup you are contemplating but it will function.

Not sure if that's what you're looking for or not.
Are you contemplating switch the input of the drive or the output? I don't think I would try and switch the output.

Clay

Hmmm...can Acorn be set up so one state of one output (say output 2) will be forward and the other state is reverse? Or do both outputs need to be used?

My plan was to switch the output from the speed controller where it attaches to the motor. I think this is the only way to do it with my lathe setup now. Using a DPDT relay, I’m thinking I cannot use two outputs from Acorn to change direction? Maybe it’s possible but wiring something like that is beyond my understanding. I can easily understand how to control the relay using a single Acorn output.

However, for this to work, the code would need to remove power to the motor, allow time for it to stop, then flip the relay, then reapply power to the motor. I’m not sure this can be done easily?

Does this make sense?

[frijoli]

can Acorn be set up so one state of one output (say output 2) will be forward and the other state is reverse? Or do both outputs need to be used?

I don't know the answer to this. This is what I will trying to do as well. You still have to have 2 outputs one for enable and one for direction. I don't see why Acorn cares if you use reverse, BUT, when it commands reverse in the program will it fault for not having reverse configured. Worst case you waste an output. Which isn't a big deal since if you went the VFD route you would have used it anyway.

I am going to speak to DMM tomorrow about your situation and mine as they are similar and need to be resolved at the same time in my opinion.

Incidentally I attempted to wire mine like your schematic with and without the enable pin and my drive didn't work.

Clay

[ScotY]

Curious to hear what you find out.

I’m puzzled by this rigid tapping stuff. I am experimenting with the reversing tapping in Intercon. I turned on the diagnostic screen and I don’t see any outputs changing state while running it. If I run the spindle forward (this is full manual control, I have to turn it on), it will move the imaginary tap into the hole and back right out. It doesn’t seem to care that the spindle doesn’t reverse. If I manually slow the spindle and reverse it, it will sometimes pull back out, and sometimes keep going forward...depends when and where I reverse the spindle. It’s very strange and I just don’t get it. I obviously have no idea what I’m doing. Confused.

I guess I really just need to know exactly what I need to make this work. I can’t get a VFD because I’m dealing with a brushed motor. I could get one of those KBCC-125R controllers but that’s about halfway to a DMM servo and drive (I assume this will work).

[cnckeith]

I have summarized setting up Rigid Tapping for Mills and Lathe using Acorn CNC12 in the document attached, this is a draft document.
The parameter settings are exactly what i used in the Techno Lathe Video Threading and Rigid Tapping seen on this forum.
Each machine will be a little different so some experimentation is needed but this document will get you in the ballpark.
When preparing a machine for rigid tapping, the number one item is to setup the machine with quick spindle Accell and Decell rates. As quick as possible is good. This means using a braking resistor if you are using and VFD and setting up the VFD braking parameters and adjusting for best performance. The better the VFD and Spindle motor can accelerate and decelerate the spindle the easier it is to Rigid tap with good consistent results. Typically achieving under 3 seconds decell rates from maximum rpm is a good idea.

Acorn Rigid Tapping Setup-Draft 5.pdf

(214.05 KiB) Downloaded 113 times

(edited with updated spell checked version)

[ScotY]

Wow, thanks Keith! I’ve read your guide will attempt to digest over time. Do you think a KBCC-125R will work for my DC brushed motor equipped lathe or is a VFD drive setup required?

Also, I have a lathe pro license but the only choices in the tap menu are reversing and floating. Is there supposed to be a third option for rigid tapping?