Feature Request: Mapping of DXF Layers to Toolpath/Tool List

[Dacicusan]

Hi all. I am using a CAM software called Maestro that comes with a SCM CNC machine. This program have a feature that can associate automatically the imported DXF layers to predefined Toolpaths mechanizations that I predefined in some configuration files.

For example, the layer called "XLYP1H18" it is instructing Maestro that the part for machining will have a thickness of 18mm. The layer called "XLYP1T$CutThrough_E7$" it is instructing that all the geometries in that layer will be associated with a 10mm cutter and the cutter will perform an outside contour operation. The layer "XLYP1T$Drill_Through_3$" it is automatically associated with a pass-through drill operation using the 3mm drill of the machine, etc.

I attach a sample video that demonstrate how this works.

Will be very useful such a feature in QCAD/CAM because can save a lot of time, especially in heavy production environments. Basically I made once the setup and after that I am just importing the DXF files and all the required mechanizations are automatically created. I can provide further assistance if there it is willing to implement this feature.

Best regards.

P.S: Forgot to attach a sample DXF file.

[CVH]

Yep, yesterday the movie alone didn't tell me much.

There are 2 major approaches in CAM:
- A: Z-zero is equal to the top of the machine bed.
- B: Z-zero is equal to the top of the material.
Both have their specific Cons and Pros.

For QCAD/CAM Z-zero is the top of your material ... Approach B.
Therefore something as "XLYP1H18" has no meaning under QCAD/CAM.

It really doesn't matter if the stock material is 18 or a thousand units thick.
Z above the material is positive and for engaged with the material it is negative.
The disadvantage here is when Z-nn.nnn is in fact below the bottom of your material ... Below the top of your machine bed.

Approach A has the same disadvantage when we want to mill an nn.nnn deep detail ... E.g. a slot.
That will only be nn.nnn deep if the material is in fact as thick as we said it was.
With approach B it will always have the intended depth ... If we zeroed correctly.
Approach A is then mostly used when handling flat material ... Except for engraving among others.

For the record: 18mm plywood is not exactly 18.000mm and it is not guaranteed to be uniform.
Counter example: A modern CNC Press brake bend metal sheet in a perfect 90°angle ...
... If and only if the sheet thickness is measured up to better than a micron ... And when this is uniform along the line of action.

There is an older method for configurable properties depending on layers, look up: CAM Legacy Export
An there are several custom approaches possible in a custom post processor.
You can literally adapt almost anything.
Here is an example of such: https://www.qcad.org/rsforum/viewtopic. ... 8684#p8639
Emulating approach B by adding a fixed offset in Z can also be seen as a task of your custom post processor.

Using the layer name for properties is one, I would prefer layer custom properties.
Can't help but I have seen it being used somewhere ... For the moment I am unable to locate it on the forum.

Because it is not supported "XLYP1T$Pocket_13_E7$" would also be meaningless for QCAD/CAM.

The biggest hurdle is that there is no real standardization.
Things usually depends on the mark and/or model.
Never heard that "XLYP1" was an omni-reserved dxf layer name prefix.
Automating everything blindly can be beneficial for well defined production environments with a highly trained staff.
But it can lead to very dangerous situations in less equipped shops, with less trained individuals or for a DIY environment.

Further: I see no problems in defining dxf layer names for the usage with 'Maestro'.
You really don't need QCAD/CAM for that.
To mimic 'Maestro' with QCAD/CAM is possible but it will take a lot more than acting on layer names alone.

Regards,
CVH

[artisanicview]

This is an example on how the import/layer association works on Maestro.

Code: Select all

"Therefore something as "XLYP1H18" has no meaning under QCAD/CAM."

The layers can be configurable, so there can be a layer that represent the type of material and thickness that will be used to generate the program.

Code: Select all

Because it is not supported "XLYP1T$Pocket_13_E7$" would also be meaningless for QCAD/CAM.

If the "XLYP1T$Pocket_13_E7$" have no meaning, which it is understandable, then maybe something like "Pocket_13_E7" will more appropriate. In this example, Pocket means a Pocket operation, 13 it is the depth of the pocket and the E7 it is the tool that the machine will use to machine that pocket.

[CVH]

The layers can be configurable, so there can be a layer that represent the type of material and thickness that will be used to generate the program.

Yes, I noted that in my last paragraph, in QCAD you are perfectly able to define layer names that can be processed by 'Maestro'.

The thickness of material has no meaning for the CAM Addon of QCAD because no matter what, the top of your material is always Z-zero.
The QCAD CAM Addon is essentially coded in such a way that it is intended for approach B.

You can however customize your post processor.
That may scan for the specific layer name prefix and retrieve a value to be stored in a custom parameter.
What to do with this is less simple, it involves using the stored value as a fixed offset to all exported Z values.
In such a way that the machine bed becomes the virtual Z-zero while QCAD/CAM considers the top of your material to be zero.

All is individually custom based because there is no real standardization.

... then maybe something like "Pocket_13_E7" will more appropriate.

No, as already mentioned, QCAD/CAM does not support pocketing right out the box.
The (2018) work around is explained here :
https://www.qcad.org/rsforum/viewtopic. ... 128#p20163

You need to draw the sequence of offset contours to follow yourself using QCAD methods and use plain 'CAM Profiling' for each.
Or the created offsets are the actual toolpaths using 'Side' = 'On' path.
Both are best done from the outside inwards for exterior profiles and from the inside out for interior profiles, a finishing profile may be required.
Then you also may notice that it actually retract for each offset path and plunges back for the next ... Not really pocketing.

I see no straightforward method to automate all that based on a given layer name.
Another issue that plays a role here is that creating an offset is not always 100% reliable in all cases.

Regards,
CVH