Paul
The biggest plus of the PTP machine over conventional CNCs is that PTPs come with a drilling "crown" which allows multiple drilling operations. Our Biesse has 24 vertical drilling units with 8 horizontal units so in-line drilling of carcase compononents is very fast indeed, especially as the PLC has drilling optimisation built-into its software (and that is one of the few good points about it!). This sort of "crown" is available on some CNC routers, but only a limited number. With 24 vertical drill heads we can hold a reasonable number of 3mm, 5mm and 8mm dowel drills (through and flat-bottomed) together with all three sizes of hinge hole we drill, 20mm, 25mm and 35mm and we rarely change drills between jobs.
I think that there is a bias against the PTP machine in certain parts of the WW industry (at least in the USA) because it started out as a PTP boring machine with a high spindle strapped on to do a bit of profiling. Things have changed since those days (and guys, we are talking 1980s here!)
Scrit
Scrit
from the Sunny Pennines, England's Backbone