wow i have not used any high speed paths on my mill as its top is only 60 ipm . so i havent noticed this , but being that mastercam does exactly as you staed above i do not know if it will be an issue unless contouring . although all the programming i do at work tends to be high speed paths on machines with infinite look aheads i am certain that as my machine evolves to a higher level of performance im likey to see issues with the one block look ahead . now as i really do not wish to consider this a gripe what would it take to implement infinite look ahead ? I ask this as i prepare to move everything back to mo and see this machine actually produce for me instead of slowly get better . And i intend on doing some serious 3d profiling it could be an issue. in light of all else i do not know what the look ahead in mach is but it is highly likely this is the observed concern. thanx for the response jon
On Wed, Apr 10, 2013 at 10:06 PM, Jon Elson <el...@pico-systems.com> wrote: > jeremy youngs wrote: > > so how far does lcnc actually look ahead????? > > > One block! It always operates at a speed such that it can come to a full > stop on the next G-code block. Some users who do high-speed > contouring need more lookahead, and then it becomes arbitrary > how far ahead you have to look. I proposed a scheme a long time > ago where you would look ahead and mark points where you needed > to slow down to avoid exceeding the machine's acceleration limits, > then run backward through the program to a point where the slowdown > needed to begin. It effectively would add an F word on every block, > even when the actual G-code didn't specify one. I also posited > that this couldn't be done in real time as the distance back you had > to go to begin the slowdown was arbitrary. But, such an operation > doesn't sound extremely difficult. Basically, you don't do anything > different until you spot a block where the speed needs to be reduced > below the commanded feedrate, then you have to run back to put > in the lowered speed. Maintaining a queue of past moves that > runs back for 100 or so blocks might make it easier to figure out > where the slowdown needs to begin. > > Jon > > > ------------------------------------------------------------------------------ > Precog is a next-generation analytics platform capable of advanced > analytics on semi-structured data. The platform includes APIs for building > apps and a phenomenal toolset for data science. Developers can use > our toolset for easy data analysis & visualization. Get a free account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- jeremy youngs ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
