Hi,
I was out of town for the holiday weekend, so a bit of a delay in responding...
Hello,
I've been using MSM for awhile now and I absolutely love it compared to the standard 1024.
However my questions lie within the MTM. I don't have a touch plate so I don't use the auto TLO option. Just a normal 1-2-3 block is what I use to touch off. Does this mean I have to measure the PTL of each tool and manually enter them into each register in the MSM tool table?
This can get to be a complicated topic - so I'll be referring you to sections of the MSM user manual so that I don't get tempted to type something in a hurry that is incorrect....
The real purpose of TLOs is to allow gcode to be written without requiring the gcode program to have any knowledge of tool lengths at the time the program is written. TLOs are measured before gcode execution and the TLO values are applied as the program runs.
There are multiple ways to set TLO values. Before one goes to use MTM, it's important that one have a firm understanding of the general concept of TLOs and the varuous way to set them.
Section 5.2 of the MSM user manual covers non-MTM TLO techniques. Pay particular attention to 5.2.4.1 (touching off to part Z0).
Touch off to part Z0 is probably the most common method for setting TLOs. It has the characteristics that all tools need to be touched off so that each tool has a good TLO value. Typically, each tool is touched off, for each job, as each job has a slightly different Z0 level in machine coordinates (as each piece of stock is slightly different).
In contrast MTM only requires that the TLOs for all tools be set (relative to the master tool) once. The master tool is then used to set the Z0 level for the stock. The tool TLOs are good
****as long as the PTL of the master does NOT change***.
This can save a lot of touch off time over multiple jobs. But.... the counter argument is that if the PTL of the master tool changes, all the other TLO values will be incorrect.
You can use MTM without using a TCP TP (manul section 9.1.2) - but you have to have a constant PTL for the master tool, and you must know the PTL value accurately. Any error in the MT PTL value will show up as TLO and hence cut height error for all other tools.
This pretty much pragmatically mandates that the Master tool better be in a RH holder - or you'll be banging your head against the wall trying to figure out what happened.
The details of MTM are in user manual section 9.
Now I will delve into a small but important detail....
With MTM, all Tool TLOs need to be set relative to the master PTL.
This implies that they are set
after the master PTL is known.
This is why if the MT PTL changes, all the other TLOs must be redone also.
The use of a TCP TP to measure tools is not required, but it does make life much easier and it pretty much guarantees that the above conditions are always met...
If all tool are measured, ever time they are mounted, the MT PTL is measured evry time it is mounted; and the MT PTL value is then stored whenever it changes.
Thus whenever any non-MT tool is mounted, it also gets a new TLO, which is calculated using the most recent MT PTL value.... thus all tool TLOs come out "right" as any change in MT PTL will be handled by the Tool change sequence and MSM logic.
This "measure all when mounted" approach also lets one get away with having the MT in NRH holder - because if the MT PTL changes, the system finds that out.
However, if tools are not measured each time they are mounted, then the system can only assume that the MT PTL value is correct... so it had better be right. That means that putting the MT in a NRH holder will cause one grief!
This is why I recommend MTM and TCP TP together - it tends to keep people out of trouble (and they don't get all frustrated and blame MSM for cut height errors).
Does this mean I have to measure the PTL of each tool and manually enter them into each register in the MSM tool table? And if that's the case, then I would think I would have to figure out each TLO and enter that as well?
Nope, you will need to measure the MT PTL accurately. The other tools can be touched off to the a surface set by the master tool. This will set Tool TLOs in MTM to be relative to the master tool.
Also how does MSM know what 'H' value to use for each tool? i.e. in the G-Code G43 Hxx.
MSM does not know that.... a control only applies TLO offsets when it is told to. It is the gcode that tells the control when to apply TLO values (this is the G43 preperatory command) and the gcode also tells the control what TLO value to use (this is the Hxx word).
from the MSM user manual (Section 5.2.4.1):
"The real purpose of TLOs is to allow gcode to be written without requiring the gcode program to have any knowledge of tool lengths at the time the program is written. TLOs are measured before gcode execution and the TLO values are applied as the program runs."
Also note the footnote on that sentence:
"Future versions of Mach3 are anticipated to have improved support for this situation. For Mach3 V3, it is
recommended that G-code make T#=H#=D# to avoid known Mach3 V3 issues (mach3 V3 does not fully support Gcode
D and H registers)."
I just want to be sure before I start slamming tools into work pieces, vises, clamps etc...
Thanks
Its an excellent idea to understand this stuff before eating tooling!
I suggest careful manual reading, followed bunch of manual tool mounting and TLO application. it's much easier to get familiar with how TLOs by using MDI command than it is to wonder why a gcode program did not do what you expected....
You can try all this out in various TLO modes via mdi commands of
T# M6 (to mount a tool)
G43 H# to apply the TLO for entry # in the tool table.
and jogging to a scrap part surface.
Mount a tool, turn TLOs off, jog to a surface, look at the DROs on a WC offset page (where you can see all the offset values and see the TLO value also), then turn on TLO with G43 H# and see how the DROs change.
Note that applying a TLO value does not result in movement in Z - it only changes where the control thinks the current position is.
By playing with it this way, you'll begin to get a firm understanding of what TLOs are doing - then the differences between non-MTM and MTM will stop being as mysterious.
Dave
