Threading issues..still < SOLVED, proper encoder required for threading>

[mcbr549]

Can anyone tell me the encoder that Centroid recommends? I have tried about 6 different ones.

[tblough]

The * being alwasy on means the index pulse is always on. CNC12 uses the index pulse to determine when to start the threading pass. If it's always on, CNC12 just starts the thread pass whenever it gets to the diameter position and does not wait "for the number on the thread dial to come around" before "closing the half nuts".

Either you have a wiring error on the index lines, or the index circuit on the encoder is bad.

I always use genuine Omron encoders. If it's less than $200-$300, then its a counterfeit. As Marty likes to say, buy once; cry once.

[cncsnw]

If the * was always present before you swapped the wires on pins 3 and 6; and is still always present after you swapped those wires, then -- as Tom just said -- you have a faulty encoder, or an encoder that does not actually have a Z channel output, or your wiring is broken somewhere between the encoder and the Acorn.

Assuming that the Acorn encoder input is the same as MPU11, Oak, and Allin1DC encoder inputs, it has internal pull-up / pull-down circuitry that makes the index appear to be present (causes the * to appear) if nothing is connected to pins 3 and 6. The only way to make the * go away is to connect a line-driver encoder that, through most of its rotation, drives pin 3 (/Z) high and pin 6 (Z) low.

[suntravel]

Related reading:

https://centroidcncforum.com/viewtopic. ... der+basics

Omron E6B2-CWZ1X works fine, or get one from Centroid.

Uwe

[cnckeith]

and open loop steppers are not recommended on a lathe that you intend to thread with, especially larger lathes. as they don't have the power/speed to keep up with basic threading requirements.
if you are on a budget consider close loop stepper which have way more power/torque at speed (than an open loop stepper) which is required to keep the threading tool up with the spindle. but it is best to install AC servos like clearpath or others.

[mcbr549]

Thanks to everyone for your input. THe problem has been solved...yep, Centroid encoder did the trick. That was a very expensive lesson for me, but one well learned.

Mike

[cnckeith]

great glad you got it going. for anyone else reading this post here is a summary for Threading machine/control setup.


Threading is simple and impressive on how it works so well with Acorn, but you got to get the details right!


1.) correct encoder. https://centroidcncforum.com/viewtopic. ... der+basics

2.) 1:1 mount

3.) Z axis motor sized so it can actually move the Z axis fast enough to keep up with the threads. (remember the Z is electronically locked to the encoder while threading! you can test this as well before doing your first test thread)

4.) Use intercon until you get it working only then introduce yet another unknown.

Test with simple threads using Intercon at slow RPM speeds using brass or wax.

Watch out for unrealistic g code program speeds and feeds during testing.