CIRP Encyclopedia of Production Engineering

Living Edition
| Editors: The International Academy for Production Engineering, Sami Chatti, Tullio Tolio

High Performance Grinding

  • Mohammad RabieyEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35950-7_16720-1

Synonyms

Definition

High performance grinding (HPG) is a grinding process with an extreme high material removal rate usually with superabrasive grinding tools.

Theory and Application

High performance grinding (HPG) also called high efficiency deep grinding (HEDG) is characterized by extremely high specific material removal rates (MRR), using high wheel speed, high depth of cut, and high feed rate with superabrasive tools resulting generally in very low specific energy (6–15 J/mm3 for ferrous material) compared to other grinding processes (Table 1). HPG is known as a combination process of creep feed grinding (high depth of cut) and high speed grinding (high feed rate and high grinding speed). It can be used for both rough and finish grinding.
Table 1

Process parameters of reciprocating, creep, and HPG processes for ferrous materials (Tawakoli 1993)

Process

Depth of cut a e

Feed rate v ft

Cutting speed vc

Specific material removal rate Q′w

Reciprocating grinding

0.001–0.05 mm

1–30 m/min

20–60 m/s

0.1–10 mm3/mm/s

Creep feed grinding

0.1–30 mm

0.05–0.5 m/min

20–60 m/s

0.1–15 mm3/mm/s

HPG

0.1–30 mm

0.5–10 m/min

80–200 m/s

50–2000 mm3/mm/s

The most important requirements of HPG are:
  1. 1.

    Rigid machine tool with high stiffness (due to high grinding forces by HPG)

     
  2. 2.

    Proper coolant system to provide sufficient coolant into the contact zone (high pressure, high capacity)

     
  3. 3.

    Stable spindle at high grinding speed (generally 80–250 m/s)

     
  4. 4.

    Proper grinding wheel (low wear, capable for high feed rate 0.5–10 m/min)

     
The concept of HPG was first proposed by Guhring (1967). The principles and theoretical aspects of the process were largely developed by Werner (Werner et al. 1980) and further practically described and proved by Tawakoli (1993). Figure 1 shows one industrial application of the process.
Fig. 1

An industrial example of HEDG (Tawakoli 1993)

Figure 2 gives accurate results for the temperature trend by increasing the grinding speed. Later Rowe (2001) modeled and verified the surface temperature by HEDG with more detailed results.
Fig. 2

Effect of grinding speed on maximum temperatures at constant high removal rate for different grinding wheels (Tawakoli 1993)

In conventional grinding, as the MRR is increased the surface temperature in the grinding zone increases, and often burn results. However, if the grinding speed and feed rate are increased further, the surface contact temperature of workpiece reaches a peak value and then decreases, due to the greater amount of grinding energy going into the chip and coolant instead of the workpiece as demonstrated in Fig. 1. Tawakoli interpreted the situation by the terms of contact time between abrasive grits and workpiece which is extremely short in HPG. As the surface is not in thermal equilibrium, the heat pulse initially spreads out over the surface before penetrating into the workpiece. This heat makes the surface layer softer so the material removal by the next grits requires less forces and lower specific energy. Before the heat can spread down from the surface into the bulk, the next chip removed from the surface takes the heated material away. The wheel speed should be about 100 m/s where these effects start to be apparent. When the speed exceeds this value, the temperature is reduced. In addition, high feed rate is essential to prevent excessive conduction of heat down to the level of the finished workpiece surface.

The larger thermal conductivity of superabrasives like diamond and CBN assist the heat removal from the workpiece. Cubic boron nitride (CBN) wheels of the electroplated or metal-bonded type are mainly used for grinding of metal to withstand the high force and stresses at the high speeds involved in process and for chemical stability at high temperatures.

Proper cooling and coolant also has a great influence in HPG. In particular, it is necessary to enrich the contact zone with coolant using several coolant nozzles and/or pressurized nozzle shoes, as well as high pressure jets which employed to clean away swarf from the wheel surface to decrease wheel loading.

Cross-References

References

  1. Guhring K (1967) Hochleistungsschleifen – Eine Methode zur Leistungssteigerung der Schleifverfahren durch hohe Schnittgeschwindigkeiten [High performance grinding – a method to increase the performance of the grinding process using high cutting speeds]. Dissertation, RWTH, Aachen (in German)Google Scholar
  2. Rowe WB (2001) Thermal analysis of high efficiency deep grinding. Int J Mach Tools Manuf 41:1–19CrossRefGoogle Scholar
  3. Tawakoli T (1993) High efficiency deep grinding: technology, process planning and application. Mechanical Engineering Publication, LondonGoogle Scholar
  4. Werner PG, Younis MA, Schlingensiepen R (1980) Creep-feed – an effective method to reduce workpiece surface temperatures in high efficiency grinding processes. In: Proceedings of 8th metalworking research conference SME, pp 312–319Google Scholar

Copyright information

© CIRP 2018

Authors and Affiliations

  1. 1.Mechanical EngineeringUniversity of applied science RapperswillRapperswillSwitzerland

Section editors and affiliations

  • Konrad Wegener
    • 1
  1. 1.Institut für Werkzeugmaschinen und Fertigung (IWF)ETH ZürichZürichSwitzerland