The document provides guidelines for optimizing milling operations, including: 1. Ensuring the model is slightly larger than the raw material to avoid burrs, and using rest material strategies to abbreviate milling times. 2. Choosing an appropriately small tool radius to avoid vibrations, and calculating the real tool diameter based on measurements. 3. Approaching the material at an angle to reduce strain, and approaching outside the part when possible. 4. Using techniques like trochoid moves, corner roundings, and different axial/radial thicknesses to reduce tool overload and strain.

1. Enlargement of the raw block
The model should be a little bit bigger than the origin data
to avoid burr at the edge of the raw material

2. Limit of the raw block
For roughing sometimes it is possible to limit the raw block

3. Restmaterialstrategy
Use restmaterial strategies for abbreviation of milling times
the area should overlap enough to the already milled surface

4. Choice of tool radius
To avoid vibrations use a significant smaller tool radius
than the contour radius

5. Choice of tool diameter
Do not take the nominal diameter in your CAM-System
Calculate with the real diameter, that is determined by
measurements on the machine or experience figures
Consider the tool holder and the clamping system that has
influence on the working diameter

6. Approach moves in roughing strategies
To approach into the material use an angled ramp
steel 4° angled ramps max, aluminium and copper 10° angled
ramps max

7. Approach moves in roughing strategies
Approach outside, if possible

8. Rounding of cutter moves
Roundings decrease the strain of the tool

9. Avoid tool overload
Use different possibilities to reduce tool overload
Trochoid moves reduce the tool overload

10. Decrease of tool strain
Insert one move before the last one to reduce the strain
that can occur in the last move with its corners

11. Different Thickness
Use different values for axial and radial thickness
effective programming possible by making less programs

12. Safety height
Set the Safety height to large values
Low safety heights do not save much time
Low safety heights increase collision risk in special cases

13. Safety Height
Roundings of retract moves decrease the milling time
because there are often a lot safety moves
if all safety points of view are considered then lower safety
heights are allowed

14. Approach moves
Leads on surfaces are visible in most cases
better start at corners or inconspicuous areas

15. Approach moves
At steep area strategies horizontal and tangential arcs are
recommended
Take arcs as big as possible

16. Approach moves
At flat area strategies vertical and tangential arcs are
recommended
Take arcs as big as possible

17. Corner roundings
Rounding in the corners avoid vibrations of the tool
a bad grinded tool enhances these vibrations
D x 0.05 are usual values for the radiuses

18. Corner roundings
Rounding in the corners avoid vibrations of the tool
D x 0.05 are usual values for the radiuses

19. Corner roundings
If the CAM System does not offer the possibility to insert
roundings into the cutter paths you can insert rounded
surfaces an delete them afterwards

20. Start area
The start area should not be in problem areas
better work towards corners

21. Start area
Start in the middle of the surfaces if approaching outside is
impossible
only small areas are in full cut

22. Polygonic top surface
A circular hole in a top surface is in each CAD/CAM-System a polygon
The quality depends on the CAD tolerance that is used for the modeling
process
The elements of the polygon run inside the origin circle, the polygon is smaller
than the circle at several parts of the circle
The tool can not cut the origin circle
contour
If the modelling tolerance was too big
this is visible on steep surfaces
Use very small modelling tolerances
for this operation (0.001 or less)

23. Polygonic top surface
Program example

24. Milling of opposite surfaces
Default settings of CAM Systems often mill one surface
first, then the other. That causes tool strain and damage
because the tool dives under the material of the opposite
side
mill narrow slots in layers to cut the complete material from
top to bottom

25. Point distribution depends on surface angle
Point distribution alter and move distances increase

26. Milling of steep areas
Mill only the real steep areas, otherwise:
The distances of the moves become too big
The point distribution becomes non-uniform
The milling time increases

27. Milling of flat surfaces
Mill only the real flat areas, otherwise:
The distances of the moves become too big
The point distribution becomes non-uniform
The milling time increases

28. Combination of different strategies
Overlap flat area programs and steep area programs 20°-30° to get soft
program changeover
Use different thickness to makes the border of the different programs invisible
To achieve, use different thicknesses in CAM, different tool diameter, or move
programs in the command file

29. Combination of different strategies
Usual way to mill: steep area before flat area
if steep area >85° and flat area <5°the opposite can be
better. First finish the bottom with distance to the wall
Then mill the wall from top to
bottom.
The tool gets no overstraining

30. Milling of areas with objects inside
If rastering significant flat surfaces, the CAM Systems order the
moves depending on limitting objects inside these surfaces
The result is a restart at areas where the machine temporarily
ends to cut long time ago.
The restart move is visible, consolidated by the tool that is
wear out in meanwhile
better accept a lot of retract moves to have a uniform surface

31. Collision check
Determine the most stable tool with the collision check
If nessecary divide the program into several programs,
one for a short tool, one or more for longer tools
length/diameter ratio of 5 has enough stability, beyond this
ratio the stability becomes worse, more than 8 is not
process safe

32. Collision check
For milling very steep areas the tool must be grinded free
to avoid tool vibrations and contour damage

33. The Choice of the right strategy
Choose the strategies depending on the kind of surfaces
that must be milled
steep areas: Z-level flat areas: Raster, Spiral,
corner finishing: equidistant, stitching, projection

34. Specpath (Ver 3.21)
For optimizing spiral cutterpaths the specpath command
offers the possibility to raise the first paths
origin cutterpath must have only spiral contour, no circles,
no several paths
different options and switches define the type of raising
too see what happens use the RMSCut-Simulation