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kendo
10-17-2008, 09:53 AM
I run a VMC 4024 and was wondering...
why does it pause everytime between two feed moves?
is it something to do with the look-ahead?
cutter comp works fine every time I use it so I'm confyoozed

neilw20
10-17-2008, 10:48 AM
Are you able to select between exact position and constant velocity mode?

kendo
10-17-2008, 12:53 PM
I've never seen those modes in the controller, and the programming manual doesn't contain those terms at all.
Its Acramatic A2100

neilw20
10-17-2008, 10:55 PM
3.5.14 Set Path Control Mode - G61, G61.1, and G64

Program G61 to put the machining center into exact path mode, G61.1 for exact stop mode, or G64 for continuous mode. It is OK to program for the mode that is already active. See Section 2.1.2.16 (http://www.isd.mel.nist.gov/personnel/kramer/pubs/RS274NGC_3.web/RS274NGC_32a.html#1009724) for a discussion of these modes.


2.1.2.16 Path Control Mode

The machining center may be put into any one of three path control modes: (1) exact stop mode, (2) exact path mode, or (3) continuous mode. In exact stop mode, the machine stops briefly at the end of each programmed move. In exact path mode, the machine follows the programmed path as exactly as possible, slowing or stopping if necessary at sharp corners of the path. In continuous mode, sharp corners of the path may be rounded slightly so that the feed rate may be kept up. See Section 3.5.14 (http://www.isd.mel.nist.gov/personnel/kramer/pubs/RS274NGC_3.web/RS274NGC_33a.html#1013869) and Section 4.3.5.3 (http://www.isd.mel.nist.gov/personnel/kramer/pubs/RS274NGC_3.web/RS274NGC_34a.html#1009980)
The canonical machining functions share with the RS274 language the simplifying assumption that machine dynamics can be almost ignored. That is, in this model, acceleration and deceleration do not occur. Components of the machining center can be told to move at a specific rate, and that rate is imagined as being achieved instantaneously. Stopping is also imagined as instantaneous. This model obviously does not correspond with reality. The control modes provided here provide some compensation for this lack of consideration of dynamics.



Link for this document may be useful.

http://www.isd.mel.nist.gov/personnel/kramer/pubs/RS274NGC_3.web/RS274NGC_3TOC.html


Mach3 also supports this.

kendo
10-20-2008, 07:58 AM
Thanks Neil,
G64 isn't used on my control, but you led me in the right direction
my control uses G60/G61

G60 is "Positioning Mode", or exact stop mode
G61 is "Contouring Mode", or continuous

now I'm cutting like I should have been all along
no more quadrant marks!
thanks again