Post Mod: Metric Ridgid Tapping

[Rory]

Dynapath must have a feed rate signed negative according to the taps lead in millimeters/thread.

Example: M8x1.25

Feed would be -1.25

Mastercam does'nt allow negative feed rates to be entered.

 

Does anyone know how I could modifiy the post to out put a negative number.

Thanks in advance,

Rory

[bryan.davis]

Dont worry about the negative number inside the operations manager, modify the post processor to convert the output F1.25 to F-1.25, there are a number of ways to do it, simply multiplying the pitch by -1 inside the post may work.

As I think about it you did say feedrate. You can use the actual pitch of the tap as its defined inside the tool definition (variable is n_tap_thds) , I dont know if you can enter a -ve value for the pitch, but multiplying it by -1 inside the post should still work.

another more hamfisted option is to alter the post to output "F-" as literal characters and then tack the feedrate/pitch value after it

[ 09-07-2001: Message edited by: bryan.davis ]

[Rory]

Bryan,

I see what you are saying and i'm sure it will work, but:

I did a search inside the post for the variable "fr" which is defined as the feed rate of current tool movement.

Its all over the post, so I don't really know to put the calculations you described.

Any ideas?

Thanks,

Rory

[bryan.davis]

OK, here is the kit for solving your problem, I couldnt give it to you before because I didnt have access to my post, if your post is very far removed from the FANUC post you may have problems finding these sections.

1 find the fmt statements and add this line below them

fmt F 1 frtap # feedrate in Tapping Cycle

2 find the ptap section under the drilling cycles and modify it to look like this

 

ptap # Canned Tap Cycle

frtap = n_tap_thds * -1

pdrillref

n, *drillref, *sgdrill, pdrlxyrot, *depth, *refht, *frtap

What you have now done is created a new variable (frtap) given it a value (n_tap_thds*-1), and then altered the output on the post line to frtap

This should use the taps pitch as defined in the tool definition and not the feedrate as defined in the operation, if you have any problems the mail me the post and Ill take a look

[ 09-11-2001: Message edited by: bryan.davis ]

[Rory]

Bryan,

It works great, except for one thing.

Now it always outputs the feed as negative.

I think i will set it up as a misc. integer.

and togle it on and off.

Thanks much for the help!

Rory

[bryan.davis]

There must be a more elegant way of solving this, under what conditions do you require a -ve sign of not?

[Rory]

I guess I don't understand the question.

I am doing both inch/metric tapping.

[bryan.davis]

so you need the - sign to indicate a metric tap and pitch -1.25 = 1.25mm NOT 1.25" yes?

Whats needed then is a way of getting mastercam to identify that you are using a metric tap...

Im not familiar with how mastercam defines the pitch for imperial taps but a variant on this may work

if n_tap_thds<=5, frtap=n_tap_thds*-1

if n_tap_thds>5, frtap=n_tap_thds

instead of frtap=n_tap_thds*-1

This assumes that imperial tap pitch is TPI and that you wouldnt use a tap bigger than 5tpi or pitch 5mm

[Rory]

This is a much more elegant way, and it does work. I also dont have to remember to toggle it on and off.

Way to go!

[Allan Brown]

You should be able to use the 'met_tool' variable as your logic check. This snippet of code is from Mpmaster:

code:

---

if met_tool, pitch = n_tap_thds # mm/thread

else, pitch = 1/n_tap_thds # in/thread

---

[ 09-11-2001: Message edited by: Dave Thomson ]

[bryan.davis]

yup that looks to be an even better way of doing it, I tried to find such a variable or switch, but alas failed

[Rory]

Dave Thomson,

quote:

---

You should be able to use the 'met_tool' variable as your logic check. This snippet of code is from Mpmaster:

---

How do I get MC to recognize that the tool is Metric?

Rory

[bryan.davis]

I would guess that mastercam would recognise the tool is metric if you were to use a tool from a metric tool library

[Rory]

Inside the Mpmaster.pst at ptap, at the line that reads: "if met_tool, pitch = n_tap_thds".

It does not seem to matter if I use a metric tap it reads the next line: "else, pitch = 1/n_tap_thds".

This doesnt seem correct.

code:

---

ptap #Canned Tap Cycle

pdrlcommonb

#tool_typ = 4 - RH, 5 - LH

if use_pitch, pbld, n, "G95", e

if use_pitch = 0,

[

pcan1, pbld, n, *sgdrlref, *sgdrill, pxout, pyout, pfzout, pcout,

prdrlout, *feed, strcantext, e

]

else,

[

if met_tool, pitch = n_tap_thds # Tap pitch (mm per thread)

else, pitch = 1/n_tap_thds # Tap pitch (inches per thread)

pcan1, pbld, n, *sgdrlref, *sgdrill, pxout, pyout, pfzout, pcout,

prdrlout, *pitch, !feed, strcantext, e

]

pcom_movea

tapflg = 1

---

[ 12-28-2001: Message edited by: Dave Thomson ]

[Allan Brown]

met_tool refers to the config file units (metric or inch) that were loaded when the NCI file was generated. e.g. If I take a fully inch file with inch tools and Regen after a metric config is loaded, then met_tool with be 1 for metric. The post is basically roughed out to handle inch tapping in inch, and metric tapping in metric. We tend to use converted 'metric equivalent' tools in inch and converted 'inch equivalent' tools in metric.

A parameter call 'metric' is also captured in Mpmaster (from the 20007 tool parameter line in the NCI file). This should represent the metric/inch flag for the actual tool, but you may have to use it in conjunction with met_tool. i.e. if met_tool is 1 and metric is 1, then the flag may mean inch values for the tool. You'd have to run some tests to confirm the proper use for your purposes.

[ 10-09-2001: Message edited by: Dave Thomson ]