Error Code: -6 occurs when a tool is being measured on the measuring key and an "out of tolerance" length has been measured.

Here are some possible causes and solutions for this error:

Cause:  Incorrect tool loaded into rubber tool magazine

Solution:  Insert correct tool and restart job.  For example, 4 and 5 axis machines should use  35mm and 40mm tools, respectively.  When milling titanium or cobalt chrome on 4 or 5 axis machines, 32mm and 35mm tools should be used respectively.  

Cause:  Tool is slipping upwards, inside the collet chuck

Solution:  Commonly, if collet chuck maintenance has recently been performed, and the collet chuck was not properly tightened, this error can occur.  Correctly tighten the collet chuck and restart the job.  Also, this issue may occur if the retaining ring isn't securely fastened or has been loosened.

Cause:  Tool wasn't initally picked up by the collet chuck before measuring

Solution:  The rubber tool inserts might be worn out (usually these are re-milled after 1 year or 1000 milling hours).  The easiest way to proceed is to physically and virtually move the tool to different tool slot in the existing rubber inserts and contact customer service that they should drill new rubber inserts on their next maintenance visit.  Alternatively, if you have recently re-drilled new rubber inserts and this situation occurs, this could indicate that your B axis was not perpendicular to the spindle (level) when the inserts were drilled.  In this case you might be able to use the center most tool insert slots in order to continue milling.  Customer Service should come on site to re-level the B axis and drill new rubber inserts.

Cause:  Tool tip is broken (usually because it is worn out, lifetime exceeded)

Solution:  Replace tool with new tool