MSM RTH Setup?

MSM Mill mode support
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BBuckle
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Joined: Tue Jun 16, 2020 1:41 pm

MSM RTH Setup?

Post by BBuckle »

Hello,

I just bought MSM and I currently have a hobby G0704 cnc conversion running mach3 and MSM. I currently use a Drewtronics probe and Tormach tool holders. I also have a granite surface plate with digital dial indicator for measuring tool heights for the tool table. What is the proper procedure for getting MSM working with a master tool as a probe and only using RH Tool? Do I still need to use a TCP every time in the beginning of each project? I've watch all the video but don't see how to use MSM without going to a touch off plate. Even though I'm using a probe and RH tools, do I still have to touch off the master tool probe to a TCP at the start of each job?
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DaveCVI
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Re: MSM RTH Setup?

Post by DaveCVI »

Hi there are two different topics here -
1) TLO values:
In master tool mod, the TLO value is the difference between the physical length of the master tool and the physical length of the tool being used. The easiest way to get that value into the tool table, is to use a TP to measure the tool.
To do that you
a) measure the Master tool (MSM remembers the PTL for the master tool so it can do this calc). IF the Master PTL is wring, all the non0master TLOs will also be wrong.
b) measure all your tools (this gets the calc dine and the difference value put in th tool table as the TLO value).

if all tools are in RH holders, you don't have to measure them each time they are used. Since the PTL doesn't change in a RH holder, neither does the TLO value.

Caution: If you ever change the MT PTL, you then have to remeasure all the non-master tools! Not just the master... (the TLO values are not calculated each time a tool is mounted, they are calculated only when it is measured).

Now then, you don't have to use a TP to measure tools, You could measure them off line and enter the data into the tool table. You just have to calc the delta in PTLs and enter that into the tool table as TLO.
BUT - that is a repetitive, error prone process, so I find it much easier to just let the machine measure tools for me.

2) Setting Z0 for a job:
Since you have a probe, I suggest that you set the probe to be the master tool. It just makes life easier. Then you can simply use the probe with any of MSM's zero finding routines and the zero for the part will be set. Example: most often, I use a corner finding routine to set Z0 to the corner of a block of stock.

Dave
Productivity Software for Personal CNC Machinists
http://www.CalypsoVentures.com
BBuckle
Posts: 2
Joined: Tue Jun 16, 2020 1:41 pm

Re: MSM RTH Setup?

Post by BBuckle »

Thank you for the reply. I think I understand what you're saying. To measure the Master Tool Probe's PTL with the touch plate, do I first have to set the TCP TP MCz position of the spindle bottom with the touch plate first or can I bypass that step?
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DaveCVI
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Re: MSM RTH Setup?

Post by DaveCVI »

Hi,
before any use of the TCP TP for measuring tools, you will have to calibrate the location of the plate. Doing that teaches MSM used the location of the plate in Z machine coordinates and the location is used whenever the plate is used to measure a tool. You want the location to be accurate, because if it is off, that amount of error will show up in every tool measurement.
Dave
Productivity Software for Personal CNC Machinists
http://www.CalypsoVentures.com
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