Z Axis zero position

Does anyone know if there any way to set the java host software to use the zero position as where the toolhead is furthest from the print surface as opposed to nearest? With my machine it is very impractical to use the zero position as were the extruder is at the first layer printing position, this makes it pretty much impossible to change tool heads without having to spend ages setting everything up again.

I'm assuming you want to just hit the 'home' button to give you space to change the tool head.
Someone should easily be able to make an 'away' button (get it, home and away, nvm I thought it was funny) That way home stays the same but you can have away for space to work or remove your parts etc.

that's just my 2 cents though.

Dylan

The problem is not that the tool head can't move away, but that it can't get closer than the closest position that the thermoplast extruder would get to. I.e. if you have a tool shorter than the thermoplast extruder then the z opto sensor is activated before the tool gets anywhere near the surface.

I've tried to re-phrase the original point a bit more clearly:
To zero at the 'tool down' (or table up) position, every toolhead will have to be aligned perfectly the same, so every toolhead will need to have some arrangement of adjustment screws in it (as adjusting the z flag position will adjust for every tool).

If zero is at the 'tool up' (or table down) position then then working position of each tool can be stored in software making the whole system much more flexible.

Hi

I agree.

It is also much safer the first time you set up an extruder.

It also matches the most common CNC machine standard. Which makes a lot of sense if you are using a hybrid machine (CNC mill with extruder bolted on) as I believe many are. I have suggested this in the past along with a Z - jog button and a hot key to store current position as the extruder Z offset so that Z0 can quickly be set just above work surface.

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Regards

Ian

I don't know if the software can be changed to solve your problem, but I do have a thought on the whole problem area:

Zeroing at the top of the table is probably the best plan for accuracies sake since it will minimize the affect of slippage, etc. as the table climbs back up to the starting position.

Your idea that all tool heads have the same effective height is probably the best plan for that reason.

brendanjerwin Wrote:
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>Your idea that all tool heads have the same effective height is probably the best plan for that reason.

That wasn't really an idea, I think it would be very hard to implement successfully, and it would mean an awefull lot of tedious adjustment by hand. Also, some tools you might not want to touch right up against the table every time you need to use it

I think a combination of Ians idea and mine would work well. Once a head has been made, it will always fit on the same way. Calibrate once for it, then store that number in the user prefs for toolhead #1, repeat for toolhead#2 and up.
This way, calibrate it once, and when you need to use the same one again, tell the software which one you're using and voila, it'll zero to the correct position.
I think my idea of an away position would still work well. In your example here, the new toolhead is shorter than the extruder, so if you zero home with the short one, you wouldn't have space to put on the extruder.

Dylan

Brendanjerwin


If you have slippage or missed steps the Reprap in unusable whichever end you home. Believe me, I have the evidence.......

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Regards

Ian