These are probably more Mach3 questions but I'll ask anyway, they could be machine related.
Question 1:
Why does the spindle speed change when the S is entered twice? For example, I have a program that repeats, but after the first run when it encounters the S900 for the 2nd time, the spindle slows down 20% to around 700. I duplicated this in the MDI. When I command an S900 M3 the spindle starts and reaches 900rpm, then if I command S900 again it slows to 700, and if I command S500 it slows to 300rpm. So to get it back to 900rpm I must command an S1075.
Here is an example of the code I would like to use:
G90
M8
S900 M3
G0
X0 Y0
G1
F12
G91
Z-.005
G90
X-15.4
G91
Z.005
G90
G0
X0
G91
G1
Z-.005
G90
M0
G47
Here is the code I must use to fix the spindle speed
G90
M8
S900 M3
S900
S1075
G0
X0 Y0
G1
F12
G91
Z-.005
G90
X-15.4
G91
Z.005
G90
G0
X0
G91
G1
Z-.005
G90
M0
G47
Question 2:
How much travel can you get if you turn off the limit switches, and how do you turn them off? I have a job that requires 9.7" in the Y and 21.3 in the X.
Question 3:
How do you use the M98/M99 in mach? I tried it and it just hangs and says something like processing toolpath...please wait.
Example of code from above but using M98/M99 to try and bypass the double S900 lowering the spindle speed.
G90
M8
S900 M3
M98 P1
O1
G0
X0 Y0
G1
F12
G91
Z-.005
G90
X-15.4
G91
Z.005
G90
G0
X0
G91
G1
Z-.005
G90
M0
M99
Question 4:
In the above example say I wanted to have the program repeat to a certain Z depth such as facing a 2.433" block down to 2.250 in .005 increments and maybe a .0015 finish pass how would I write that code? I want to zero on the vice bed, put in my stock and lower the tool until it contacts the piece, then hit start on the program and come back when it is at Z2.250.
Question 5:
Why does the spindle take so long to spin up to speed it takes a full 8sec. Is it possible to speed this up?
Question 6:
I don't quite understand G54 work offsets but what does it mean when I close down Mach and it asks me if I want to fixture save?
Question 7:
If I have a long program but I only want to run from a specific point in the program like if all the previous machining has already been done and I don't want to wait a long time for it to cut air, what is the best way to do this? I've tried the run from here and it has ruined some parts and crashed tools. I have no idea what this feature is thinking when I've used it, I cut a spiral pocket once that took 10 min, then realized it was slightly undersized. I tried to simply re-cut the same geometry but start from further along in the program. Without doing anything else, it reapplied the x,y zero and attempted to cut a whole new circle somewhere else. I've also tried the set next line feature but can't figure that one either. I thought the run from here ran through the program up to that point to find out modal commands and position then move to the appropriate location based on its current position then begins the program from there. To me it appears it does all that then when it starts the program it just does whatever it wants. Could someone please explain how this is supposed to work?
Thanks