Inverse time feed

[John Morris]

I am putting the finishing touches on a post modification for a new machine (VMC with 4th axis). This machine has inverse time capability and I am trying to take advantage of it. Thanks to a lot research here on the forum I have been able to incorporate inverse time into the CD, MD and post to get code out and it is running on the machine as I type. The last little issue I’m getting is an anomaly on the “Lead In/out” portions; the feed does not change over to inverse (G93) until it is past the Lead in/out.

 

<snip>

T27 M6

N100 G0 G90 G54 X-.7859 Y0. A39.247 S10000 M3

G43 H27 Z6.

Z4.2

G94 G1 Z3.75 F80. (IPM down in Z )

X-.641 A39.803 (NO change to inverse yet even though we have A output)

X-.6188 A39.916

X-.5981 A40.077

X-.5795 A40.282

X-.5633 A40.527

X-.55 A40.805

X-.5398 A41.109

X-.5331 A41.432

X-.5301 A41.766

X-.5307 A42.103

X-.535 A42.434

G93 X-1.3114 A83.942 F28.3 (begins Inverse here, although this is a fairly long move at a slow rate)

X-1.321 A84.353 F1000.

X-1.3339 A84.744 F1000.

X-1.35 A85.109 F1000.

X-1.3691 A85.444 F1000.

X-1.3909 A85.744 F1000.

X-1.415 A86.003 F1000. ( F1000. I may end up bumping my max allowable inverse time feed in the CD)

<snip>

 

To get this I am creating basically a cam track (slot) using contour (with a lead in/out line/arc at 90°) then using axis substitution. I am getting good results off the machine but the really slow in and out is aggravating. I’m not really sure where to look to track this down?

 

In addition, I was running one yesterday with very small radius on an inside bend and was getting some really slow feed around the radius compared to rest of the path.

 

_______________________

 

Still on X5

[NOTW Programmer]

MPMaster or IHS based POST. What machine is this for someone might have the mods specific to your machine already.

[Chris Rizzo]

Just curious, try getting inverse time using any of the 2d hst dynamic toolpaths.

[John Morris]

Greyman,

 

Machine is a Mazak VCN510C with the removable fourth axis. The post I started with was a post originally supplied by my vendor for my Haas VF with the fourth (it is not Mpmaster). I have been modifying it to work for my Mazak.

 

Chris, 2D highspeed DOES NOT output any G93 (inverse) code at all? What are you thinking?

[Colin Gilchrist]

John,

 

Inverse time output in CNC Software's generic posts is dependent on Contour Flag positions. These flags indicate to the post where certain actions take place (lead in, cut motion, lead out, and other information).

 

You will need to modify the post block that calls the inverse time post block to include the lead in/out motion.