multi start threading

[k_barry]

Hi

I am trying to cut a 4 start thread.

In the thread cut parametrs dialogue box when I select the NC code format as Longhand, the number of starts field is active and I can add 4 to this.

When I change the NC code format to Canned the Number of starts field goes dull.

I thought this may be a post problem but I had a quick look (not knowing much about posts) and find the variables listed below, so I assume my post does support multi start threads.

 

thd_vlen = thdlead/ nstarts

 

fmt Q 15 thdfrsts #Save initial value of 'thdfirst'

fmt R 2 thdfinish #G76 thread finish allowance

fmt Q 2 thdlasts #Save initial value of 'thdlast'

 

pg76nstart #G76 threading, for multiple starts

if old_new_sw = zero, pg76old

else, pg76new

nstart_cnt = nstart_cnt + one

if nstarts <> one & nstart_cnt <> nstarts,

pbld, n, *sgcode, thd_dirx, thd_dirz, e

 

I am using an Okuma OSP 7000L which uses G71 as its thread cycle and Q is the number of starts.

The Post I am using is basically a slightly modified MPLOSP7C.PST which came with my V9.

 

Any help would be appreciated

Kevin Barry

[mmonica]

Kevin, I recently cut a 3 start thread using the MPLFAN.pst and I had no problem with the start setting. When I loaded the MPLOSP7C.pst the start setting was gray but my 3 was still there. I posted the op and it looked OK although I'm not that fimilar with OSP controls. I'm no post writer so I can't help you, you may want to load the MPLFAN.pst, set your parameters, then switch to the MPLOSP7C.pst. It worked on my V9 lathe.

Mark Monica

[Roger Martin from CNC Software]

Kevin,

 

Lathe posts have some "enable this" options,

Check you your PST for these Post Numbered Questions ->

 

3050. Enable canned thread equal depths? y

3051. Enable canned thread equal area? y

3052. Enable canned thread multiple starts? y

3053. Enable canned thread anticipated pulloff? y

 

IF your post does support these features you can enable the options on the dialog box in MC.

[k_barry]

Thanks Roger, the "enable this" options for threading were disabled and it now produces code for the 4 starts.

It does not use the Q for the number of starts but it produces 4 separate G71 cycles with a W move a distance equal to the pitch in between each cycle.

 

This should work OK although I am not sure if Okuma use W as incremental Z.

 

I will try it shortly when our lathe has finished this current run.

 

To Mark, I did try using the 'Longhand' option and entering the 4, then changed to the 'Canned' option but it did not post the 4 starts.

 

Thanks again