software limits prevent negative tool offset on IDEX Printer

CR3D

Unfortunately, we are currently encountering an old familiar topic again.

If you need negative values for the tool offsets because this tool is shorter than tool 0, then the bed cannot approach the nozzle of tool 1.

The software limits are set to 0 at Z to prevent any collision at tool 0.

M208 Z0:500

In my opinion, the software limit must be shifted by the negative ToolOffset so that a shorter tool can be used.

Everything else is not a clean solution in my opinion.

@PCR @dc42 what do you think therefore?

Thank you very much!

Regards Christian from @CR3D

T3P3Tony

@CR3D what are your tool offsets set to (G10 settings for both tools.)

dc42

@CR3D you can adjust the lower M208 Z limit in the tpre or tpost file for tool 1, and reset it to zero again in the tfree file. I do a similar thing for the M208 X and Y limits on my tool changer because some tools are larger than others.

CR3D

@T3P3Tony

The right tool (Tool 1) is higher than Tool 0 -> so the title is wrong... it is a positive tool offset...

Tool 0: offsets X0.000 Y0.000 Z0.000 U0.000
Tool 1: offsets X0.000 Y-0.650 Z0.724 U-0.300

@dc42

I also thought of that, but what speaks against allowing it directly in the firmware. If tool 1 was selected and it has a tool offset like this, I think you can open the software limits by this offset in this case?

Regards Christian

dc42

@CR3D said in software limits prevent negative tool offset on IDEX Printer:

I also thought of that, but what speaks against allowing it directly in the firmware. If tool 1 was selected and it has a tool offset like this, I think you can open the software limits by this offset in this case?

That assumes that your machine is constructed so that all tools can reach Z=0. That's probably the case for the vast majority of 3D printers, but may not be for other types of machine. So it would have to be yet another configuration option. It would also have to be specific to Z, because on machines like my tool changer the accessible XY locations are not the same for all tools.

gloomyandy

@CR3D Just to clarify, if tool 0 was over the bed and you command Z such that tool 1 is touching the bed would that crash tool 0 into the bed?

T3P3Tony

@CR3D I have tools with very different Z heights and when I change to them, Z=0 is adjusted using the tool offset.

What are you probing with? One option that works with multi tool systems is to set Z0 to be the probe trigger point, and then have the Z offset set for both tools. That's what i do on the tool changer at least:

e.g. these are my current G10s for each tool:

G10 P0 X-0.750 Y32.9 Z-4.43
G10 P1 R0 S0 X-8.97 Y38.97 Z-4.45
G10 P2 R0 S0 X11.80 Y43.15 Z-8.43
G10 P3 R0 S0 X11.25 Y43.6 Z-8.16

CR3D

@T3P3Tony

Yes Tony... if you use Z - ??? it works fine of course. This we use mostly.

But in some cases the Z Tooloffset of other Tools then Tool 0 is positive like T1 Z0.85 then there will be a gap like in the picture above.

We will implement it in the Toolchange macros but I think it is not the finest way... because with our easy toolchange system you can easy insert another tools with different length and then you have to adjust Tooloffset and open the software limit in the Toolchange macro...

Regards Christian

T3P3Tony

@CR3D right, ok, in that case one idea is to have all the tools with a negative offset. So set tool 0 to be (for example) -5 and tool 1 to be -4.15, then use the Z probe offset to to be whatever it is right now +5. Then after probing and tool change your tool 0 will still be at 0, and tool 1 will also be at 0 after the tool change.

dc42

@CR3D said in software limits prevent negative tool offset on IDEX Printer:

We will implement it in the Toolchange macros but I think it is not the finest way... because with our easy toolchange system you can easy insert another tools with different length and then you have to adjust Tooloffset and open the software limit in the Toolchange macro...

Why don't you change the Z limit in the tool change file to a value based on the Z offset of the incoming tool? That way you can use the same code for all tools.

OwenD

@dc42 said in software limits prevent negative tool offset on IDEX Printer:

Why don't you change the Z limit in the tool change file to a value based on the Z offset of the incoming tool? That way you can use the same code for all tools.

@CR3D
Based on DC42's advice, I think this would work in your tool change file

M208 S1 Z{min(0,0 - tools[state.nextTool].offsets[2])}  ; set Z minima to the lower of zero or zero minus incoming tool offset

But this line in the G10 documentation

Tool offsets are given as the offset of the nozzle relative to the print head reference point, so the signs are opposite to what you might expect because tool offsets are subtracted from the required printing locations during printing.

makes me wonder if the math should be
Z{min(0,0 + tools[state.nextTool].offsets[2])}

I don't have multiple tools, so I,m not 100% sure on the G10 setup.
e.g.
Let's say tool 1 is zero offset (reference) and tool 2 is 1mm higher in Z

If that means your Z offset for tool 2 is +1, then use the first example.
If it means your tool 2 offset is -1, then use the second example.