Voltage size

Chip sizes when turning: chip thickness h, chip width b, chip cross section A. In addition, the cutting depth a _p and feed f as well as the tool setting angle k.

Chip sizes are sizes in machining that are derived from the internal sizes such as the feed rate (also known as working engagement) or the cutting depth . The chip sizes include chip thickness , chip width and chip cross-section . They are the main influencing variables on chip formation . There are mathematical relationships between the cutting sizes and the internal sizes via the tool setting angle (small Greek kappa ). The cutting sizes are set directly on the machine by the operator or the CNC program. The voltage values ​​then result automatically from this. ${\displaystyle f}$ ${\displaystyle a_{e}}$ ${\displaystyle a_{p}}$ ${\displaystyle \kappa }$

The chip width is the width of the chip perpendicular to the cutting direction measured in the cutting plane . ${\displaystyle b}$

${\displaystyle b={\frac {a_{p}}{\sin {\kappa }}}}$

With:

${\displaystyle a_{p}}$- Depth of cut (also called infeed or working width )

The chip thickness is the thickness of the chip perpendicular to the cutting direction, measured perpendicular to the cutting surface. ${\displaystyle h}$

${\displaystyle h=f\cdot \sin {\kappa }}$

The chip cross-section is the cross-section of the chip to be removed, measured in the cut surface

${\displaystyle A=a_{p}\cdot f=b\cdot h}$

Influences

Minimum chip thickness. Shown in the working plane (here identical to the normal plane of the tool cutting edge ).

The chip thickness has a great influence on the specific cutting force . It is defined as the cutting force related to the chip cross- section . ${\displaystyle k_{c}}$ ${\displaystyle F_{c}}$

${\displaystyle k_{c}={\frac {F_{c}}{A}}}$

Although the cutting force increases with increasing chip thickness, the specific cutting force decreases.

The chip width, on the other hand, has almost no influence on the specific cutting force as long as it is much larger than the chip thickness, which is almost always the case in practice.

In order to guarantee chip removal, a certain minimum chip thickness must be exceeded. This depends on the yield point of the material and the cutting edge radius . The rule of thumb is about two to three times the cutting edge radius. ${\displaystyle r_{\beta }}$

Metal removal rate

For profitability studies, it is often important to determine how productive different processes are. An important parameter for this is the metal removal rate . It indicates the volume removed per unit of time and results from the chip cross-section and the cutting speed : ${\displaystyle Q}$ ${\displaystyle v_{c}}$

${\displaystyle Q=A\cdot v_{c}}$

Individual evidence

1. ↑ Denkena, Tönshoff: Spanen - basic , Springer, 3rd edition, 2011, p. 7.
2. ↑ Denkena, Tönshoff: Spanen - basic , Springer, 3rd edition, 2011, p. 7.
3. ↑ Heinz Tschätsch: Praxis der Zerspantechnik , Vieweg, 5th edition, 1997, p. 22.
4. ↑ Schönherr: Spanende Produktion , Oldenbourg, 2002, p. 13f.
5. ↑ Infeed = width of engagement: Denkena, Tönshoff: Spanen - basic , Springer, 3rd edition, 2011, p. 7.
6. ↑ Denkena, Tönshoff: Spanen - basic , Springer, 3rd edition, 2011, p. 53.
7. ↑ Wilfried König , Fritz Klocke: Manufacturing process 1: turning, milling, drilling. 8th edition. Springer, Berlin 2008, p. 270.