External Cylindrical Grinding

External cylindrical grinding with vitrified bonded high-performance grinding tools

The demands on modern automotive engine and gearbox producers continue to increase. The additional requirements create capacity bottlenecks, and an increased demand for more efficient grinding solutions. FOREVER faces this challenge in external cylindrical grinding with a new generation of vitrified bonded CBN high performance grinding tools.

After intensive research,FOREVER has succeeded in developing a new bond system that makes it possible to guarantee optimal wetting of the CBN grain even with the lowest levels of bond content. Through careful choice of the composition of the bond components, the crystallization is specifically controlled under selected firing conditions. This makes it possible to achieve porous structures with high mechanical strength that exhibit maximum resistance to the effects of cooling lubricants.

The cool grinding specifications of the high-performance tools allow a reduction of the grinding forces, and make efficient use of the CBN grain. Decreasing grinding forces are confirmed in practice with a wide range of application possibilities, through minimum tool wear and maximum profile retentio

Product- and application advantages
New high-performance CBN grain qualities
Optimized chip clearance (porosity))
High bond strength
Optimal resistance to cooling lubricants
High thermal resistance
Customer-specific solutions
High process reliability
Optimal profile retention
Extended tool life
High cutting speeds
Maximum breaking strength
Optimal transport of cooling lubricantst

For camshaft

Due to the need to increase the service life of the grinding tool significantly, at first the production planners from the customer worked in partnership with FOREVER engineers to analyse the process requirements. The new bond system of the our product line was then selected as well as the use of a particularly free-cutting CBN grain. Through the optimized bond properties, it was possible to increase the number of grooves per dress cycle from 120 to 190. In addition the power consumed by the grinding spindle, and the internal part stresses were also reduced significantly.

For crankshaft

A change to the material used by the customer, as well as a significant increase in the stock to be removed on the bearing surfaces, presented a very special challenge to both the user and the TYROLIT application engineers. After a detailed analysis of the process, a grinding tool was selected from the GENIS product line with a new, especially free-cutting CBN grain quality. The process parameters were changed accordingly for use of the tool. The result: Despite the large quantity of stock to be removed, the tool life of the grinding wheel was increased from 4,200 to 5,900 shafts with good process reliability

For gear shaft

Customer requirement: Prevention of hidden grinding burns as well as simultaneous increase of the tool life. After a detailed analysis that took into account all influencing factors of the process, the rough grinding zone angle of the tool was redesigned. It was then possible to select a tool from the FOREVER product line with a specification of extremely high edge stability with which the overlay rate during grinding could be redefined. After optimization of all process parameters, it was possible to reliably prevent feed marks as well as to increase the tool life from 6,700 to 8,100 parts.

Resin bond grinding tools for high-speed external cylindrical longitudinal Grinding

With our resin bond product line, for the first time FOREVER is offering innovative roughing and finishing wheels for the peel grinding of tungsten carbide tool blanks in particular. A high-strength metal bond is used with the rough grinding wheel. This enables especially cost-effective and reliable process control. The finishing wheel is availablewith either long-life vitrified or metal bonds, which even smoothes out large allowance fluctuations after roughing and produces maximum surface quality.

Application: Grinding workpiece geometries using the contouring process

External cylindrical grinding with metal bonded high-performance grinding tools

The metal Bond Wheel having excellent heat resistance and surpasses the grinding ability of the resin bond wheel.

Features

The grinding ability has been improved significantly by employing special metal bond that has both excellent grinding ability and long tool life.
In particular, this wheel helps improve the grinding efficiency when used with oil-based coolant.

Application

Flute grinding of endmills, drills, and reamers
Chipbreaker grinding of inserts
Heavy duty grinding of various tools

Technical Data

Sketch of flute grinding

Metal bond Wheel: Grinding Resistance Comparison

1) Wheel specifications
①Resin: SDC325N100B
②CBM-L: SD325L100CBM

2) Work material
Cemented carbide

3) Grinding conditions
Wheel peripheral speed: 1500 m/min
Depth of cut: 3 mm
Coolant: Oil-based
Machine: Horizontal spindle surface grinder

CBM Bond Wheel: Resin Bond Comparison

1) Wheel specifications
①Resin: BN140-100B
②CBM-L: BN140L100CBM
③CBM-P: BN140P100CBM

2) Work material
SKH51(HRC60)

3) Grinding conditions
Wheel peripheral speed: 1500 m/min
Depth of cut: 2 mm
Feed rate: 40 mm/min
Coolant: Oil-based
Machine: Horizontal spindle surface grinder