QTDragon offsets question

On this screen I don't understand why the "Height from the bed to the top of the work piece" field would be here. The top of the workpiece would be constantly changing with each part. I don't see it being filled when I probe the top of the work. If it did then it would make sense so the operator could see the value. Also, wouldn't we be working from Z zero rather than from the bed since the machine doesn't really know where the bed is? That is unless we probe it and store the value somewhere. I think I stll have a lot to learn.



On this screen would it make sense to display the tool length as set in the tool table or as measured when touched off on the touch plate?


I have been playing with a M6 remap macro and it consistently thinks the top of the stock it .65 inches higher than it is. I can get that number to change buy changing some of the values on the above screens but I would have to lie on the value to hit the target. I'm pretty sure it is something I just don't understand. For now I would just like touch off the stock with my 3D probe to get the stock height. And to have zeros in the tool table for the Z measurement and touch off the on tool setter at each tool change and have it calculate the tool length. I have entered the length of the probe in the tool table for tool 99 but I am not sure that is being taken into account.

Thank you.

QtDragon has 2 possible methods for setting Z0. The first is a touchplate, where a metal plate of known thickness is placed on top of the workpiece and then the tool is lowered until it touches the plate, triggering the probe signal. Z0 is set to probe height - plate thickness.
The second method uses a tool setter in a fixed position and a known height above the table where the probe signal will be triggered. In order to set Z0 to the top of the workpiece, it has to know how far above the table the probe trigger point is (tool setter height) and how far above the table the top of the workpiece is. This operation has to be done every time the tool is changed as the tool length is not saved. I realize that for an ATC or MTC, the operation is different, where each tool length is compared to a reference tool and stored in the tool table. I'm working with a simple collet spindle. HTH.
Jim

For touching off with a touch probe, whether you use the touchplate operation with thickness set to 0 or use a probing routine, the height from table to top of workpiece parameter is not taken into account and can be ignored. It is only for the tool setter.
Jim

i haven't tested the probe routines in Qtdragon - Jim the screen builder did them.

They appear to be based on work from Qtpyvcp which looks based on wersaProbe v2:

vers.by/en/blog/useful-articles/probe-screen

I have been working/tested on qtvcp's version of this code.
(Qtvcp'd versaprobe_dialog) but haven't finished to toolsetter code yet.

Anyways it looks that the pre process is :
probe the the top of the tool setter and recording that height - it should never change.

Then the usual process is: probe the top of work set 0
change tool and probe it using the toolsetter.
The routine calculates the tool offset using the toolsetter height, work height and probed tool height.

The remap automates the tool change probing process.

I assume qtdragons process is similar - I'm not sure if it requires remap.

What Jim said
Thanks Jim

i noticed that many people cook their own soup in processes and routines. and this leads to problems, confusion and misunderstandings.

Perhaps, so that there is no more confusion and / or there are several different routines for certain processes, one could agree on and establish standard routines

sorry that i'm posting it here too, unfortunately it fits here too

persei8 wrote:

QtDragon has 2 possible methods for setting Z0. The first is a touchplate, where a metal plate of known thickness is placed on top of the workpiece and then the tool is lowered until it touches the plate, triggering the probe signal. Z0 is set to probe height - plate thickness.
The second method uses a tool setter in a fixed position and a known height above the table where the probe signal will be triggered. In order to set Z0 to the top of the workpiece, it has to know how far above the table the probe trigger point is (tool setter height) and how far above the table the top of the workpiece is. This operation has to be done every time the tool is changed as the tool length is not saved. I realize that for an ATC or MTC, the operation is different, where each tool length is compared to a reference tool and stored in the tool table. I'm working with a simple collet spindle. HTH.
Jim

The first method is how I have always done it until now.

Between what you and Chris are working on it sounds like a solution. Thank you both. I will gladly volunteer to do testing.

In my mind this would be the work flow:
I would do a one-time setup where I would enter the length of the probe in tool 99. Then with the spindle nose sitting on the sensor I would enter the ABS Z value into tool zero in the tool table.

Then for each setup I would probe the work for XYZ.
Then each time I put in a new tool in it would touch off on the sensor and record the tool length.

The remap automates the tool change probing process.
I assume qtdragons process is similar - I'm not sure if it requires remap.

It is similar, but not complete. But it should be. To minimize duplication of effort, perhaps we could collaborate on this M6 remap issue. It seems that this would also be applicable to the basic_probe widget.
Jim

persei8 wrote:

The remap automates the tool change probing process.
I assume qtdragons process is similar - I'm not sure if it requires remap.

It is similar, but not complete. But it should be. To minimize duplication of effort, perhaps we could collaborate on this M6 remap issue. It seems that this would also be applicable to the basic_probe widget.
Jim

How is the progress on this?

I don't know what the status of any official work is but my remap has been working pretty well for me. I have a cheap tool-setter and a nice HALLMARK ITTP - Impact Tolerant Touch Probe. I have a mix of fixed length tools using TTS holders and non-repeatable length tools (e.g. drills and rarely used tools). I have two scripts. One records the value of the spindle nose touching the tool-setter.in G59.3. I used G59.3 because I will never need it as a work location offset. The other records the length of a tool that I mounted in a TTS holder and stores the length in the tool table. I only need to run this when I mount a new tool. When I am going to start a job I touch- off the XYZ using the 3D probe. The Z value plus the length of the probe is stored in parameter 4001 for G54 and 4002 for G55 and so on. So this is effectively as if I touched off the nose of the spindle on the work piece. I made parameters 4001-4008 persistent by adding then to the linuxcnc.var file. Then when I run my job if there is a tool length greater than zero in the tool table then it just uses that length. If the value in the tool table is zero then the tool goes to the tool-setter and touches off there to get a tool length to use. This way repeatable tools only need to be measured once and non-repeatable tools are measured each time they are used. I am using Linuxcnc 2.8 and QTDragon. I am looking forward to see the version of QTDragon in 2.9 but I'll wait until 2.9 becomes the current version.