Rigid Tapping parameter 78 ?

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Rigid Tapping parameter 78 ?

Post by cut2cut »

So far I really like the Acorn and want to get my 3 axis mill to rigid tap. Hoping for some help from ya'll. To "enable" rigid tapping with a spindle encoder am I required to set parameter 78's bit to " 2.00 " ? Should I use 4.0 in parameter 78 or is 2.0 the appropriate setting for rigid tapping ?

From the wording ( see enclosed picture of parameter 78 ) , it appears that the spindle is the master and Z feed "rate" is the slave.

p.s. I'm using the "cheap" Omron knockoff that Marty reviewed on youtube. Thanks Marty !!!

Jake
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Re: Rigid Tapping parameter 78 ?

Post by DICKEYBIRD »

Hi Jake,

I don't have answers for your questions but I think your thread over on the Hobby-Machinist forum is well worth sharing with other Acorn users. I stumbled onto it early yesterday morning & read every word. You & your buds over there make an awesome problem-solving team! :)

https://www.hobby-machinist.com/threads ... orn.65196/
Milton in Collierville, TN

"Accuracy is the sum total of your compensating mistakes."
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Re: Rigid Tapping parameter 78 ?

Post by cut2cut »

I’m wondering if I need to set parameter 78 to 4 instead of 2?

Thanks Dickey, yeah, we try to help each other out the best we can !

Jake
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Re: Rigid Tapping

Post by martyscncgarage »

Keith reminded me he made a post and a draft on Rigid Tapping:

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.
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Re: Rigid Tapping parameter 78 ?

Post by cut2cut »

Thanks Marty! That should do the trick ! I'll post back when I get it tuned in. Sounds like I should get some machinable wax first, though.

Cheers,

Jake
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Re: Rigid Tapping parameter 78 ?

Post by martyscncgarage »

Good luck. Be sure.to post pictures and do a video showing the machine rigid tapping and the control running the code.
Marty
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Re: Rigid Tapping parameter 78 ?

Post by Dave_C »

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.
So having mine at .5 for accel and .5 for decel with an oversized braking resistor should be able to handle rigid tapping? :)

Edited: I changed my accel and decell to 1.0 sec. I wasn't having any faults but .5 is faster than necessary. I may change to even slower once I start testing.

Dave C.
Last edited by Dave_C on Sat Feb 10, 2018 10:41 am, edited 2 times in total.
Grizzly G0678 Mill ,CNC conversion with Acorn. G4004G Lathe, Mach 3 conversion to Acorn.
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Re: Rigid Tapping parameter 78 ?

Post by cut2cut »

martyscncgarage wrote: Mon Feb 05, 2018 8:27 am Good luck. Be sure.to post pictures and do a video showing the machine rigid tapping and the control running the code.
Marty
Hey Marty,
For sure I'll post when I get it going, hopefully by Sunday night.

I do have one question regarding parameter 37. Everything in the draft document for rigid tapping with the Acorn says to use the fastest deceleration time possible without causing faults, however Parameter 37's value *range* states 3 to 10 seconds. Basically, is 3 seconds the "sweet spot" or is < 3 seconds something someone should strive for ? My mill is now capable to stop in a mere tenths of a second ( after I worked on the settings to optimize the brake resistor ) I should set the parameter 37 value to a few tenths ? I haven't checked to see if it can be set below 3 seconds... but I'm assuming it can be. ( I'd check but I'm not at the mill now )

Best Regards,

Jake
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Re: Rigid Tapping parameter 78 ?

Post by martyscncgarage »

Jake, I think you are going to have to experiment with the machinable wax.
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
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Re: Rigid Tapping parameter 78 ?

Post by cut2cut »

martyscncgarage wrote: Sat Feb 10, 2018 11:35 am Jake, I think you are going to have to experiment with the machinable wax.
After applying the parameter settings in the draft document wrt rigid tapping, I'm getting an error when it gets to this line ( the tapping section ) :

Line 51 : N260 G84 X-0.0817 Y0.0169 Z-0.35 R0.2 F25.

Here is the error code :

509 Option not available , line 51

Enclosed is a picture of the screen, the G-code (below), and also my current machine report

Hopefully someone can lend a hand figuring out what might be at issue.

Thanks,

Jake

%
O01001 (tap test 2005)
(T4 D=0.125 CR=0. TAPER=118deg - ZMIN=-0.0476 - center drill)
(T42 D=0.1563 CR=0. TAPER=118deg - ZMIN=-0.3969 - drill)
(T43 D=0.19 CR=0. - ZMIN=-0.35 - right hand tap)
N10 G90 G94 G17
N15 G20
N20 G28 G91 Z0.
N25 G90
(Drill11)
N30 T4 M6
N35 T42
N40 S1500 M3
N45 G54
N50 M8
N60 G0 X-0.0817 Y0.0169
N65 G43 Z0.6 H4
N75 Z0.2
N80 G98 G81 X-0.0817 Y0.0169 Z-0.0476 R0.2 F10.
N85 G80
N90 Z0.6
N100 G28 G91 Z0.
N105 G90
(Drill9)
N110 M9
N115 M1
N120 T42 M6
N125 T43
N130 S1500 M3
N135 G54
N140 M8
N150 G0 X-0.0817 Y0.0169
N155 G43 Z0.6 H42
N165 Z0.2
N170 G81 X-0.0817 Y0.0169 Z-0.3969 R0.2 F7.
N175 G80
N180 Z0.6
N190 G28 G91 Z0.
N195 G90
(Drill12)
N200 M9
N205 M1
N210 T43 M6
N215 T4
N220 S600 M3
N225 G54
N230 M8
N240 G0 X-0.0817 Y0.0169
N245 G43 Z0.6 H43
N255 Z0.2
N260 G84 X-0.0817 Y0.0169 Z-0.35 R0.2 F25.
N265 G80
N270 Z0.6
N280 M9
N285 G28 G91 Z0.
N290 G28 X0. Y0.
N295 M30
%
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