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MILLING
NPA 26/2017




MILLING

Expansion of the CHATTERFREE Solid Carbide Endmills Line

Highlights

ISCAR is expanding its range of EC-E7/H7-CF 7 flute endmills to include 3xD and 6xD length to diameter endmills. These are in addition to the already available 2xD and 4xD endmills.



Features
  • 7 flute, different helix and variable pitch solid carbide endmills for high speed / trochoidal milling and semi-finish and finishing operations
  • 2xD tools to start at ae 0.1xD and increase up to 0.3xD according to system stability
    4xD tools to start at ae 0.05xD and increase up to 0.15xD according to system stability
    6xD tools to start at ae 0.05xD and increase up to 0.1xD according to system stability
  • Unique patented design
  • Special tooth design that enables large chip gullets for efficient chip evacuation
  • Produced from IC902, an ultra-fine carbide grade, and TiAlN PVD coated for machining hardened steel
  • h6 shank tolerance



Advantages
  • Excellent surface finish even at maximum ap
  • Low cutting forces
  • High productivity on most material types
  • Effective in a wide range of machining speeds from 3,000 to 20,000 RPM
  • Optimal flutes and tooth geometries, delivering maximum metal removal rates
  • Maintains high accuracy


When using an endmill that is longer than necessary, it is less rigid and requires reducing the cutting conditions. The new cutting length options provide an optimal tool for each machining requirement, enabling machining at the highest machining conditions.


1. Trochoidal Milling
Milling a slot with a curve traced by a point on or connected with a circle as the circle rolls along a fixed straight line, preferably by using max. depth of cut.

The short contact times due to small width of cut (ae) and small contact arc reduce thermal impact of cutting edges. This allows very high feeds and speeds to be reached at a radial infeed from 0.1 to 0.3xD. This allows process reliable depth of cut from 2xD up to max. 6xD.


Machining engagement zone
TrochoidalTypical
contact arc
at milling cutter
Trochoidal machining cycle
Cutting direction
 


2. Characteristics
  • Less tool wear, due to optimal cutting parameter
  • Less thermal impact, due to short contact time
  • High vc and fz
  • Constant cutting conditions
  • Maximum usage of cutting length (constant wear)
  • Very high chip removal rate

Benefits
  • Shortens cycle time due to very high vc and fz
  • Increases productivity
  • Increases process reliability
  • Reduces tool cost
  • Applicable also for low torque spindles
  • Small and cost-efficient tools
  • Suitable for difficult to cut materials

Requirements
  • Programming system (CAM)
  • High dynamic machines



3. What to consider?

Diameter of milling cutter should be at least min. 20-30% smaller than width of slot, to ensure a small contact arc.
Width of cut should be set around 5 to max. 10% of cutting diameter.
This is calculated according to the number of flutes, workpiece material and contact arc.
Feed per tooth should also be considered, as the radial infeed during circular milling differs from standard trimming operations.


4. Formula and calculation basics for trochoidal milling


Slot width W:
Minimum slot width:Wmin = 1.2 x Dtool
- This avoids an overlarge tool engagement angle and problems with chip evacuation
 
Maximum slot width:Wmin = 1.5 x Dtool
- avoid too many idle movements (productivity)
 
Tool diameter Dtool:
Minimum slot width:Dtool (min.) = W x 0.6
- avoid too many idle movements (productivity)
 
Maximum slot width:Dtool (max.) = W x 0.8
- This avoids an overlarge tool engagement angle and problems with chip evacuation
 
Width of cut ae:
ae calculation:0.05... 0.1 x Dtool



EC-E7/H7-CF
7 Flute Endmills with Different Helix and Variable Pitch
for Chatter Free High Speed Finish Milling
• Can machine at radial width of cut (ae) of up to 0.10xD
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