Full slot milling

Full slot milling is a milling operation with a full cut width of the end mill. You usually use full slot milling for cutting out parts.

The video on the left side shows a full slot milling process on our MINImill KIT2 with the 1000W spindle. The full cut is made in the first part of the video. You can see a small burr on the upper side of the slot and a rough slot surface finish.

The second part of the video shows a finishing process. Finishing with a 0.1 offset at 1/3 of the roughing feed rate greatly improves surface finish and reduces the burr significantly. Finishing is usually done in one pass at full slot cut depth.

We used the following cutting parameters in the video:

MINImill KIT2, Mafell FM1000 milling spindle

Roughing: 6mm MINImill Aluminum End mill, 800mm/min feed rate, 0.8mm depth of cut

Finishing: 6mm MINImill Aluminum End mill, 300mm/min Feed rate, side offset 0.1mm, Depth of cut full slot depth

Axial plunge vs. helical plunge

The video shows the difference between an axial plunge and a helical plunge into aluminum.

In the first segment of the video the end mill plunges at 1/3 of the slot milling feed into the material. The end mill vibrates slightly during the plunge process thus reducing the service time of the end mill.

The second part of the video shows the helical plunge process. The helical plunge speed is identical with the full slot cutting feed rate. However due to the plunge ramp the actual load on the end mill is greatly reduced. We recommend this operation for advanced CAM programs like Fusion 360, FreeCAD or similar CAM tools.

We used the following cutting parameters in the video:

MINImill KIT2, Mafell FM1000 milling spindle

Axial plunge: 6mm MINImill Aluminum End mill, 300mm/min plunge rate

Helical plunge: 6mm MINImill Aluminum End mill, 800mm Feed rate 0.8mm depth / helical turn

Conventional pocket milling vs. trochoidal pocket milling

Conventional pocket milling removes material layer by layer. The cutting parameters are similar to the slot milling process. The depth of cut in the video is 0.8mm with roughly 50% path overlap.

Trochoidal milling cuts the pocket at a full depth – in the video with 6mm depth. However the end mill only removes a small portion of the wall at each cut – in the video we use a 0.8mm side cut per pass.

The total cut volume / time is roughly identical in both process. Usually you can reduce cutting time for series production with trochoidal milling as there is the following advantage:

Trochoidal milling uses a much larger portion of the cutting edge in contrast to conventional pocket milling thus greatly reducing wear of your cutting tool. Conventional milling uses 0.8mm of the cutting edge / Trochoidal uses 6mm of the cutting edge in our example.

Note: for beginners and prototyping we usually use conventional pocket milling as it is much easier to setup, if you are a more experienced user we highly recommend this cutting process.

We used the following cutting parameters in the video:

MINImill KIT2, Mafell FM1000 Milling spindle

Conventional pocket milling: 6mm MINImill Aluminum End mill, 0.8mm Depth of cut, 800mm/min Feed rate

Trochoidal milling: 6mm MINImill Aluminum End mill, 6mm Depth of cut axial, 0.8mm Depth of cut on the side wall, 800mm/min Feed rate

Drilling

For drilling in aluminum on our milling machines we recommend step 1 – 1.5 at roughly 5.000rpm on the Mafell FM1000 spindle and a feed rate of roughly 30mm/min. We use good VHM drills up to a diameter of 6mm. We drill holes up to a diameter of 4.8 mm in one pass. We recommend a helical milling process for larger diameters.