I need some help with taping feed rate

[mike.carlson]

Hi everyone!

I have a Freedom 4020 VMC with syntec 22MA controller. 

I am trying to rigid tap a 3/8-16 and I can not figure out how to fix the feedrate. 

Here is my code, can somebody tell me what I am doing wrong? 

%

O0055

(AK POST VERSION - 1.6 44094)

(T27 D=0.5 CR=0. - RIGHT HAND TAP)

G90 G94 G17 G49 G40 G80

G70

M36

G28 G91 Z0.

G90

G00 A0.

(DRILL8)

T27 M06

S500 M03

M38

G17 G90 G94

G59

G00 A90.

G00 X5.0616 Y4.5121

G43 Z2.0604 H27

M08

G00 Z1.6604

G98 G84 X5.0616 Y4.5121 Z0.0365 R0.9865 P0 F38.5

X1.9383 Y4.5122

G80

Z2.0604

M09

M05

G49

G28 G91 Z0.

G90

M37

G00 A0.

G28 G91 X0. Y0.

G90

M30

%

[leo.castellon]

For inch taps, I have always used (1/threads per inch) x spindle speed = feed rate. So, in your case, 1 divided by 16= .0625 x spindle speed that you picked which was 500, then your feed rate should be 31.25, not 38.5.  If your spindle speed was 750, then your feed rate would be 46.875. 

LeoC

[mike.carlson]

So I changed the RPM and the PP output is F12.5.
This is 200 x .0625=12.5
When I run the program it goes down in Z,coolant comes on, then the RPM
changes to 13!
Any idea why?

[leo.castellon]

Did you mean that the feed rate changed to 13 or the RPM? I have no idea what machine you are running this on nor what post processor you are using. Perhaps your post is rounding up the feed rate? If your post is acting up and keeps wanting to change it, then leave the feed rate at 13 and use math to change the spindle speed to correlate with the thread pitch, which if you keep the feed rate at 13, change the spindle speed to 208. With the problems you are having, perhaps it would be best to practice on a piece of scrap material to check the tapping? Keep in mind that 208 is a pretty slow spindle speed to use for tapping. What material are you tapping?

LeoC

[DarthBane55]

Usually with rigid tapping you don't start the spindle with M3, there is usually a prep code before tapping where you set the RPM, so it keeps the sync with the actual feed on the machine.  Maybe your controller is an exception though, but I've never seen it done like that before.

[leo.castellon]

With the older Haas I use, there is no prep code, here is code for 1/4x 20 tapped holes:

(Drill4)
T10 M6
S500 M3
G54
G17 G90
G0 X1.1788 Y-0.3835
G43 Z3. H10
M8
G0 Z1.
G98 G84 X1.1788 Y-0.3835 Z-0.625 R0.2 F25.
X1.6683 Y-0.5855
X2.1827 Y-0.3835
G80
G0 Z3.
G53 G0 Z0.

But realistically, to better help the OP, we really need to know what post and machine he is using.

LeoC

[DarthBane55]

His machine and controller are in his initial message.  No mention of the post though.

[mike.carlson]

I apologize everyone. The machine is a Freedom 4020 with the 22MA controller. 

I realize speed is too slow. I am using 500 while I try to figure this out. Just tapping 6061. Using Syntec post that has been modified but no changes to tapping yet. 

[leo.castellon]

As Homer Simpson likes to say, "D'OH", not sure how I missed that, LOL. 

LeoC

[leo.castellon]

I am not familiar with that machine nor controller. I see that the company is located in Anaheim, perhaps give them a ring to see if there is some sort of preparatory command required for tapping as Darth suggested? I remember a Fanuc machine that I used to run required an M29 command issued first.  Home | Freedom CNC Machine Tool Co. (freedomcnctool.com)

LeoC

[mike.carlson]

I will reach out again to them. I went there and met the guys running the place before I bought the machine. They likely will not be much help on this though. 

[mike.carlson]

That didn't work. The guy I knew no longer works there and he thinks they are only doing service, no more sales. 

I sent an email inquiry so I will be hand taping while I wait. Just a few holes for now but this is a big problem for future jobs. 

[DarthBane55]

The machine didn't come with a controller manual?

[mike.carlson]

Attached is what I found in the manual.

Once program gets to N65 the RPM mysteriously drops to 13 RPM. 

Code I have:

%

O00071

(Using high feed G1 F650. instead of G0.)

(T28 D=0.375 CR=0. - right hand tap)

N10 G90 G94 G17

N15 G20

N20 G53 G0 Z0.

(Drill7)

N25 T28 M6

N30 S200

N35 G17 G90 G94

N40 G59

N45 G0 A-90.

N50

N55 G1 X5.46 Y-4.5121 F650.

N60 G0 G43 Z3.3596 H28

N65 G0 Z2.9596

    S200

    G95

N70 G99 G84 X5.46 Y-4.5121 Z0.4635 R2.7135 F.0625

N75 X1.54

N80 G80

N85 G0 Z3.3596

N90 M5

N95 M9

N100 G53 G0 Z0.

N105 G53 G0 X0. Y0.

N110 G0 A0.

N115 M30

%

[DarthBane55]

If you don't need the spindle sync code, that looks good, but a couple of things:

-Are you supposed to put sequence numbers on each line?  If so, the 2 lines S200 and G95 don't have a sequence number, that could be a problem, if not, then no worries.

-Maybe the G95 should be set before the S200, I'm shooting in the dark a bit, but sometimes things are weird.  Just replace the G94 you have at the beginning by G95, and delete the G95 you added after S200.  You have 2 G94, just replace the 2nd one.  But then you need to use G0, not G1 for the approach move.  If you want to keep that feed at 650, then don't replace the G94, but immediately after that G1 line, add G95.  Still delete the one after S200.

It may/may not work, but if not, the sync code might be the problem.  Try that 1st.

[DarthBane55]

I found a manual from Syntec, but it may not be your particular controller, it didn't say which one it was, it just says Syntec.  There is a P and a K value there, not sure what they do, but probably better find out...

And they put the G95 on the same line as the M3 line (which you removed), looks like you need the M3.  The rest looks standard, but P and K... not sure... they might be optional. 

It says at the top "use 1000 revolution to tapping three times" lol, whatever that means.  Tapping 3 times what!  Good luck sir, I'm gonna step out of this one, not familiar with this controller at all to be honest and when I see manuals this clear, I lose interest, sorry!  Good luck!

[mike.carlson]

Hi, 

Is this what you mean?

%

O0060

(AK POST VERSION - 1.7 44094)

(T28 D=0.375 CR=0. - RIGHT HAND TAP)

N10 G90 G95 G17 G49 G40 G80

N15 G70

N20 M36

N25 G28 G91 Z0.

N30 G90

N35 G00 A0.

(DRILL7)

N40 T28 M06

N45 S200 M03

N50 M38

N55 G17 G90 G95

N60 G59

N65 G00 A-90.

N70 G00 X5.46 Y-4.5121

N75 G43 Z3.3596 H28

N80 M08

N85 G00 Z4.3385

N90 G95

N95 S200

N100 G98 G84 X5.46 Y-4.5121 Z2.0885 R4.3385 P0 F0.0625

N105 X1.54

N110 G80

N115 Z3.3596

N120 M09

N125 M05

N130 G49

N135 G28 G91 Z0.

N140 G28 Y0.

N145 G90

N150 A0.

N155 M37

N160 M30

%

[leo.castellon]

I would suggest that you post your question to this forum also: Practical Machinist - Largest Manufacturing Technology Forum on the Web . You might find someone there with the same type of machine as yours that can answer your question and help you with tapping. As Darth said, we are both kind of shooting in the dark here as to why it isn't working as we are both not familiar with your controller. One thing that I don't understand in your tapping code line, is why is there a P? Usually, a P in g code is for a dwell. 

LeoC

[mike.carlson]

Yeah< P is a dwell.
I don't know what to do with this.
I have a post processor magician looking into this for me. I am hopeful he
will figure this out because I sure can't.

[leo.castellon]

You can always thread mill the threads 😊.

LeoC