Quote Originally Posted by AlexDoran View Post
I watched one video where the guy drilled holes prior to pocketing, is this a good way approach plunging? Or is the a better / correct way to do this.
First, a word of warning about double sided tape... don't use it to attach aluminium to MDF. I don't think it is a good idea because it doesn't stick well enough and is flexing in every direction. In my opinion double sided tape is only usable for PCB or acrylic, possibly thin aluminium (maximum 2mm) for panels. It is also OK for engraving, but not when you are pocketing or milling thick aluminium or other thick material. Use a vice or drill a few holes and screw the plates firmly to the MDF.

Regarding pocketing, yes, in my opinion it is a good idea to pre-drill large holes. It saves time and material, as well as tools. It is much faster and easier to drill or saw even a very large hole compared to milling all the material, but it requires fairly accurate positioning on both the drill stand and then the CNC bed. I drill or saw a bit smaller then needed and mill it to the final dimension with the CNC. I have a set of drills and circle saws so I can drill from 0.5mm up to 70mm and if I'd need to make even larger holes I'd buy larger (note that the quality is high On aluminium I am using 4 flute 4 or 6 mm diameter cutters, 18k RPM. I am dry milling, not using any lubricant or any spray. Probably it would be better to use something, but I chose not to because of the CNC location (inside my house in an ordinary office like hobby room). Anyway, regarding the cutter, I have no issues with chips welding to the cutter, but I try to keep a fairly high feed rate and it seems to work fine.