Which post processor do I use for a Sienci LongMill or AltMill with gSender?

What to select

Sienci's post processor chart lists grbl (mm) for VCarve and Aspire. Their LongMill page adds that newer versions of the software may also offer a ready-made LongMill option. Sienci recommends the millimeter post even when you design in inches, and says they have seen errors from files exported in inches.

Steps

1. Go to Machine > Machine Configuration and add your machine, so the post becomes your default.
2. Associate the grbl (mm) post (or the LongMill option if it is listed).
3. For the acceleration fields, Sienci gives 750 mm/s² for the LongMill and 1500 mm/s² for the AltMill. These only affect time estimates, not the G-code.
4. Save the toolpath and open the file in gSender.

Tool changes in gSender

gSender reacts to the M6 tool change command according to Config > Tool Changing. There are six choices:

• Ignore: the default. Good for one bit per file.
• Pause: stops at the change and leaves everything to you.
• Standard Re-zero: a wizard that walks you through changing the bit and zeroing Z again.
• Flexible Re-zero: the same idea, but lets you zero Z from a different spot when the original surface has been carved away.
• Fixed Tool Sensor: the machine drives to a tool length sensor and measures each bit. It needs homing, limit switches and a sensor.
• Code: runs your own macros before and after the change.

If you leave it on Ignore and save several bits into one file, the job will run straight through with the wrong bit, so match the setting to how you save.

Pro tips

• Owners of the AltMill tool changer need Sienci's own ATC post, which is a download on their ATC setup page. The Vortex rotary axis also has its own post.
• For a simple start, save one file per bit and zero Z after each change.
• See the entry on mm versus inch post processors for why Sienci prefers millimeters.