Many times people think of using a CNC router for cutting wood and plastic and not for detailed machining.   This project is a small stamp made out of brass that you head up and then press into material such as leather.  Due to the fine detail, the job had to be machined with 5 separate end mills each getting progressively smaller.  Keep in mind that with such small tools you have to be extra careful with speeds and feeds so you get a good finish and you don't break end mills.  The wall thickness on some of these letters is only 0.1mm thick... So it takes some patience and a good understanding of the tool path programming to ensure success. 

The end mills and feed and speed settings used on this job are as follows: 

STEP 1 - Flattening The Surface 

Cutting Tool - ¼" End Mill

Pass Depth: 0.1mm  

Stepover: 15% 

Speed: 11,000 RPM

Feed Rate: 8mm/sec

Plunge Rate: 5mm/sec

Final Cut Depth: 0.3mm

STEP 2 - First Pocket

Cutting Tool - 1/8" End Mill

Pass Depth: 0.1mm 

Stepover: 15%

Speed: 11,000 RPM

Feed Rate: 6mm/sec

Plunge Rate: 3mm/sec

Final Cut Depth: 3mm

NOTE: This tool path makes a small outline of the logo to get the end mill closer without touching the text.

STEP 3 - First Profile Tool Path For Details

Cutting Tool: 2mm End Mill

Pass Depth: 0.1mm 

Stepover: 30%

Speed: 11,000 RPM

Feed Rate: 4mm/sec

Plunge Rate: 2mm/sec

Final Cut Depth: 3mm

NOTE: This tool path is the same as STEP 2 but slightly closer to the final vectors.

STEP 4 - Second Pass For More Details

Cutting Tool: 1mm End Mill

Pass Depth: 0.06mm 

Stepover: 15%

Speed: 11000 RPM
Feed Rate: 2mm/sec

Plunge Rate: 2mm/seg

Final Cut Depth: 3mm

All the way to the text

STEP 5 -  Final Detail Pass Removing Last 1mm

Cutting Tool: 15 degree V-Bit with 

Pass Depth: 0.05mm

Stepover: 4.5%

Clearance Pass Stepover: 10%

Speed: 11000 RPM
Feed Rate: 4mm/sec

Plunge Rate: 2mm/sec

Final Cut Depth: 1mm

NOTE: This tool path contains all outlines of the text to obtain all the details.

STEP 6 - Final cut made with the 1/8" end mill again, same settings

Cut with a pocket ½ diameter more of the end mill and final 1mm direct profile with tabs

Below are some images from the job including various stages of the progress as the cutting took place: