Difference between tPreN.g and tPostN.g



  • When changing a tool the firmware will run three scripts located in the /sys directory. The process is described in the documentation here:

    Tool Change

    They are:

    • tFreeN.g
    • TPreN.g
    • TPostN.g

    As I understand it the first script will release the old tool, which is understandable. The second script is executed before the new tool is selected and the third after.

    I can't understand why there is a Pre- and Post-script? Wouldn't it be enough with one script?



  • It's all explained in the link: tPre is executed, then temperature is set, then tPost is executed. How to use them depends on your setup. It is very flexible, and can match a lot of configurations.



  • OK, but can you give an example of when you actually need both pre and post scripts? I am trying to understand if this can be of use to me, but I can't think of a case where it actually would give an advantage.



  • I don't have a tool changer config (yet), but, for example, if you set the temperature of parked tools to standby, and need to move them to a purge area before heating them up again to working temperature (so leaking PLA goes in the purge bucket, instead the park area), then you can put the move to purge area in tPre, and the real purge in tPost.


  • administrators

    @fma @Urban I do this slighty differently on my draft tool changer too change macros. The TFree drops off a toop, TPre moves the pickup heat to the selected tool to the point it can lock the new tool. T Post locks the tool and then extracts it, moved to the purge area, wiats for temps to stabalise, purges, cleans, continues. I do this because I have different tool offsets of each tool which are applied after TPre is run, but before TPost is run.



  • OK, I understand. Thank you both!


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