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Hermes Superabrasives - CBN and Diamond vitrified bonded

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<strong>Hermes</strong> <strong>Superabrasives</strong><br />

<strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong><br />

<strong>vitrified</strong> <strong>bonded</strong> abrasives<br />

B o n d e d A b r a s i v e s


Contents<br />

<strong>Hermes</strong> Abrasives Group<br />

The <strong>Hermes</strong> Abrasives Group . . . . . . . . . . . 4<br />

<strong>Hermes</strong> Schleifkörper GmbH . . . . . . . . . . . 5<br />

Quality – our trademark . . . . . . . . . . . . . 5<br />

For nature <strong>and</strong> the environment . . . . . . . . . . 5<br />

Abrasives<br />

<strong>Diamond</strong> . . . . . . . . . . . . . . . . . . . 6<br />

<strong>CBN</strong> (Cubic Boron Nitride) . . . . . . . . . . . . 7<br />

The benefits of <strong>vitrified</strong> <strong>bonded</strong><br />

<strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> grinding wheels . . . . . . . . . 6<br />

Primary applications for <strong>vitrified</strong> <strong>bonded</strong><br />

<strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> grinding wheels . . . . . . . . . 7<br />

<strong>Hermes</strong> solutions<br />

Internal cylindrical grinding . . . . . . . . . . . . 8<br />

Surface griding . . . . . . . . . . . . . . . . 9<br />

External cylindrical grinding . . . . . . . . . . . . 10<br />

Roll grinding . . . . . . . . . . . . . . . . . 12<br />

The first step to success<br />

Your informations for us . . . . . . . . . . . . . 13<br />

<strong>Hermes</strong> <strong>Superabrasives</strong><br />

identification system<br />

Shapes <strong>and</strong> dimensions . . . . . . . . . . . . . 14<br />

Specification . . . . . . . . . . . . . . . . . 16<br />

Application recommendations<br />

Process- <strong>and</strong> tool parameter . . . . . . . . . . . 20<br />

Machine parameter . . . . . . . . . . . . . . . 21<br />

Cooling lubricants . . . . . . . . . . . . . . . 22<br />

Dressing methods . . . . . . . . . . . . . . . 23<br />

Key data in the grinding process . . . . . . . . . . 25<br />

Internet<br />

Why not visit our website –<br />

www.hermes-schleifkoerper.de . . . . . . . . . . 26


<strong>Hermes</strong> Abrasives Group<br />

Dr. Siegfried Blankenburg<br />

Managing Director,<br />

<strong>Hermes</strong> Schleifkörper GmbH, Dresden<br />

Dear <strong>Hermes</strong> Customers,<br />

I am delighted to take the opportunity<br />

presented by the publication of our<br />

“<strong>Hermes</strong> <strong>Superabrasives</strong> – <strong>CBN</strong> <strong>and</strong><br />

<strong>Diamond</strong> <strong>vitrified</strong> <strong>bonded</strong> abrasives”<br />

brochure to thank all our friends <strong>and</strong><br />

business partners very much for their<br />

loyalty to the company.<br />

I would like to assure you that we will<br />

continue to do everything we can to<br />

satisfy your requirements in full by<br />

developing <strong>and</strong> manufacturing quality<br />

products.<br />

You may assume that our top priority<br />

is always to have satisfied customers.<br />

Each day we start afresh, doing everything<br />

in our power to achieve this.<br />

With best wishes for our continued<br />

partnership in a spirit of cooperation,<br />

Best wishes<br />

Dr. Siegfried Blankenburg<br />

The <strong>Hermes</strong> Abrasives Group<br />

The <strong>Hermes</strong> parent factory was founded in the Lurup district of Hamburg in 1927 <strong>and</strong><br />

has remained the group‘s head office to this day.<br />

<strong>Hermes</strong> now has over 11 production facilities <strong>and</strong> subsidiaries in 4 continents throughout<br />

the world <strong>and</strong> for decades, has been a world market leader in the production of<br />

abrasives.<br />

The map of the world below illustrates our presence <strong>and</strong> our commitment.<br />

Headquarter Germany<br />

<strong>Hermes</strong> USA<br />

<strong>Hermes</strong> France<br />

<strong>Hermes</strong> Austria<br />

<strong>Hermes</strong> China<br />

<strong>Hermes</strong> Great Britain <strong>Hermes</strong> Germany <strong>Hermes</strong> Pol<strong>and</strong><br />

<strong>Hermes</strong> Romania<br />

<strong>Hermes</strong> China<br />

<strong>Hermes</strong> Singapore<br />

<strong>Hermes</strong> Canada <strong>Hermes</strong> USA <strong>Hermes</strong> Austria <strong>Hermes</strong> Bulgaria


<strong>Hermes</strong> Schleifkörper GmbH<br />

<strong>Hermes</strong> <strong>vitrified</strong> <strong>bonded</strong> superabrasives are one of the outst<strong>and</strong>ing<br />

product strengths of the <strong>Hermes</strong> Abrasives Group <strong>and</strong> its worldwide<br />

operations.<br />

The <strong>bonded</strong> abrasives activities of the group are bundled in<br />

<strong>Hermes</strong> Schleifkörper GmbH in Dresden, with two production<br />

facilities located in Dresden <strong>and</strong> in Uetersen, near Hamburg.<br />

In both plants are working over 160 employees. This means that<br />

<strong>Hermes</strong> Schleifkörper GmbH is the third largest manufacturer of<br />

<strong>bonded</strong> abrasives in Germany.<br />

Since 1986, <strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> <strong>bonded</strong> abrasives have complemented<br />

the innovative range of precision ceramic <strong>and</strong> resin<strong>bonded</strong><br />

abrasives, honing rings <strong>and</strong> PUR-<strong>bonded</strong> polishing abrasives.<br />

Quality – our trademark<br />

On the one h<strong>and</strong>, we owe a great deal to tradition, but on the<br />

other, we are pioneers in the development of innovative products;<br />

<strong>Hermes</strong> places enormous value on the production of high-quality<br />

abrasives to the latest state of the art.<br />

To maintain <strong>and</strong> exp<strong>and</strong> this high quality st<strong>and</strong>ard in future, the<br />

TÜV CERT testing body has awarded the <strong>Hermes</strong> Group the quality<br />

seal for satisfying the requirements of DIN EN ISO 9001 <strong>and</strong> thus<br />

confirmed it.<br />

<strong>Hermes</strong> is a founder-member of the Organisation for the Safety<br />

of Abrasives – oSa, the members of which have undertaken to<br />

manufacture <strong>and</strong> sell safe <strong>bonded</strong> abrasives which prevent<br />

accidents. <strong>Hermes</strong> <strong>Superabrasives</strong> accordingly satisfy all the<br />

safety requirements of DIN EN 13236 <strong>and</strong> all the precision requirements<br />

of DIN ISO 22 917.<br />

Our customers – in other words you – derive great benefit from<br />

this security.<br />

For nature <strong>and</strong> the environment<br />

Compliance with national <strong>and</strong> international laws <strong>and</strong> regulations<br />

is one of the most important principles of <strong>Hermes</strong>‘ environmental<br />

policy.<br />

The “Environmental protection” department at <strong>Hermes</strong> takes<br />

painstaking care to ensure that every business process saves<br />

natural resources. This makes protection of the environment a<br />

cornerstone of <strong>Hermes</strong>‘ commercial policy <strong>and</strong> a key component<br />

of our corporate responsibility.


Abrasives<br />

<strong>Diamond</strong><br />

<strong>Diamond</strong> has the greatest hardness <strong>and</strong> resistance to wear of all known<br />

substances <strong>and</strong> is therefore suitable for machining (grinding) hard <strong>and</strong> brittle<br />

materials such as hardened metal, cermets, glass <strong>and</strong> ceramic. Syntheticallyproduced<br />

diamond is mainly used for abrasives nowadays.<br />

The starting material is carbon (graphite) which, under the effects of temperature,<br />

pressure <strong>and</strong> catalysts, is synthesized into the diamond crystal lattice. <strong>Diamond</strong><br />

has a high affinity for carbon, i.e. carbon-containing material such as steel draws<br />

carbon out of the diamond under the action of heat, destroying the crystalline<br />

structure of the diamond in the process. <strong>Diamond</strong> is therefore suitable only in<br />

special cases, if at all, for the economic grinding of steels <strong>and</strong> grey cast iron.<br />

Material properties<br />

Hardness 10 on the Mohs scale<br />

Thermal<br />

the highest of all<br />

conductivity<br />

substances at room<br />

temperature<br />

Coefficient of friction extremely low<br />

Chemical<br />

to acids <strong>and</strong> bases<br />

resistance<br />

up to 800°C<br />

Density 3.51 g/cm³<br />

Chemical symbol C<br />

Unit of weight carat (1 carat = 0.2 g)<br />

The benefits of <strong>vitrified</strong> <strong>bonded</strong><br />

<strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> grinding wheels<br />

In contrast to other bond systems, it is possible to dress <strong>vitrified</strong><br />

<strong>bonded</strong> grinding wheels (reset the bond) without subsequent<br />

sharpening which is why the dressing process can be both<br />

reproduced <strong>and</strong> automated.<br />

In the production of these <strong>bonded</strong> abrasives, the porosity of<br />

this material can be set from closed to very open. Among other<br />

features, the optimized porosity of <strong>vitrified</strong> <strong>bonded</strong> <strong>CBN</strong> <strong>and</strong><br />

<strong>Diamond</strong> grinding wheels means that they also generate cool<br />

grinding because the pores guide the cooling lubricant to the<br />

point of grinding <strong>and</strong> transport the chips which form away from<br />

the contact zone.<br />

Specific adjustment of the volumetric ratio between abrasive <strong>and</strong><br />

pores allows grinding forces to be kept low <strong>and</strong> higher performance<br />

parameters to be achieved in the grinding process.<br />

6<br />

Carbon atom<br />

Crystal morphology<br />

The possible shapes (morphology) of synthetic diamond crystals extend from<br />

the cube to the octahedron.<br />

Octahedron Cube<br />

The use of materials which are difficult to machine <strong>and</strong> which<br />

cannot be ground economically using conventional abrasives has<br />

increased significantly in recent years.<br />

More <strong>and</strong> more steels produced by the powder metallurgy method<br />

are being used, for example <strong>and</strong> these are ground with <strong>vitrified</strong><br />

<strong>bonded</strong> <strong>CBN</strong> grinding wheels; the use of hardened metals <strong>and</strong><br />

oxide ceramics is also increasing <strong>and</strong> consequently so is the use<br />

of <strong>vitrified</strong> <strong>bonded</strong> <strong>Diamond</strong> grinding wheels.


<strong>CBN</strong> (Cubic Boron Nitride)<br />

<strong>CBN</strong> (Cubic Boron Nitride) has the same crystalline structure as diamond <strong>and</strong> is<br />

therefore likewise extremely hard. In <strong>CBN</strong>, boron <strong>and</strong> nitrogen atoms, rather than<br />

carbon atoms, form the crystal lattice.<br />

Cubic boron nitride does not occur in nature <strong>and</strong> is therefore produced only<br />

synthetically in a similar process to that for synthetic diamond. In 1957,<br />

General Electric was the first company to synthesize <strong>CBN</strong>.<br />

Because <strong>CBN</strong>, in contrast to diamond, is free of carbon, it is particularly suitable<br />

for grinding hardened steels containing carbon.<br />

Material properties<br />

Hardness 9.5 on the Mohs scale<br />

Thermal<br />

conductivity<br />

high<br />

Coefficient of friction low<br />

Chemical<br />

resistance<br />

very high<br />

Density 3.48 g/cm³<br />

Chemische Elemente B (Boron), N (Nitrogen)<br />

Unit of weight carat (1 carat = 0.2 g)<br />

Octahedron<br />

Primary applications for <strong>vitrified</strong> <strong>bonded</strong><br />

<strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> grinding wheels<br />

Boron atom Nitrogen atom<br />

Crystal morphology<br />

Its more complex atomic structure means that <strong>CBN</strong> has more crystal shapes.<br />

In addition to the shapes between cubes <strong>and</strong> octahedrons already known<br />

from diamond, <strong>CBN</strong> has other crystal morphologies between octahedra <strong>and</strong><br />

tetrahedra.<br />

Cube<br />

Tetrahedron<br />

<strong>CBN</strong> <strong>Diamond</strong><br />

• Iron/carbon materials with a high proportion of alloy which are • Hard, brittle, short-chipping materials which do not contain iron<br />

hard to machine, especially steel; hardness primarily >55 HRC • Hardened metal, glass, ceramic, quartz, semiconductor<br />

• High-speed steel (HSS), cast steel, rolling bearing steel, grey materials, plastics, glass fibre-reinforced plastics, natural<br />

cast iron, stainless steels, tempered cast iron, heat-resistant<br />

steels, steels produced by the powder metallurgy method<br />

stone, concrete, composite materials <strong>and</strong> plastic in general<br />

7


<strong>Hermes</strong> solutions using <strong>CBN</strong> <strong>bonded</strong> abrasives<br />

Internal cylindrical grinding<br />

Applications<br />

<strong>Hermes</strong> solutions for bores<br />

Specifi cation 20B 76 M-N4-5 V24 200<br />

Operating speed 63 m/s<br />

Dimensional example 1A1W 40 x 55 x 16 - X5<br />

Material 16MnCr5<br />

Applications:<br />

• Automotive <strong>and</strong> automotive supplier industry<br />

(e.g. rockers, valve bodies)<br />

• Transmission engineering<br />

(e.g. bores for gear wheels, guide rings)<br />

• Electrical industry<br />

Specifi cation 12B 64 X4 V31K 240<br />

Operating speed 63 m/s<br />

Dimensional example 1A8 7 x 12 x 4.5<br />

Material 16MnCr5<br />

Applications:<br />

• Rolling bearing industry<br />

• Mechanical engineering<br />

(e.g. bores for hydraulic parts, nozzles, bushes)<br />

<strong>Hermes</strong> solutions for rolling bearing races (outer rings)<br />

Specifi cation 28B 64 X4 V31K 240<br />

Material 100Cr6<br />

<strong>Hermes</strong> solutions for bore bushes<br />

Specifi cation 20B 46 P3 V24 175<br />

Material 100Cr6<br />

8<br />

Product description<br />

<strong>Hermes</strong> <strong>CBN</strong> <strong>vitrified</strong> <strong>bonded</strong> abrasives for internal cylindrical<br />

grinding have proved outst<strong>and</strong>ing in medium to large-scale<br />

production.<br />

In the course of intensive research work, we have developed<br />

an extraordinarily sharp, high-performance bond for internal<br />

cylindrical grinding.<br />

This bond enables our <strong>bonded</strong> abrasives to achieve longer tool<br />

lifes (chip volume) <strong>and</strong> its excellent self-sharpening properties<br />

reduce grinding times.<br />

Bonded abrasives can also be supplied with a steel or hardened<br />

metal shaft. <strong>Hermes</strong> offers customers an additional service of<br />

gluing <strong>bonded</strong> abrasives to shafts provided by the customer<br />

(e.g. when abrasive coatings are worn).<br />

Product benefits<br />

• Considerably reduced dressing times<br />

• Long tool lifes means reduced tool costs<br />

• Very good surface qualities<br />

• Shorter grinding times increase productivity<br />

Comparison of performance, <strong>vitrified</strong> bonds<br />

Tool life<br />

130%<br />

120%<br />

110%<br />

100%<br />

90%<br />

80%<br />

70%<br />

60%<br />

50%<br />

Reference V31<br />

at conc. > 200<br />

V24<br />

at conc.


Surface grinding<br />

Applications<br />

<strong>Hermes</strong> solutions for reciprocating grinding<br />

Specifi cation 23B 126 N6 V24 125<br />

Material 16MnCr5<br />

<strong>Hermes</strong> solutions for creep feed grinding<br />

Specifi cation 23B 91 N6 V24 100<br />

Material X155CrVmo12-1<br />

Product description<br />

<strong>Hermes</strong> surface grinding wheels are characterized by the ideal<br />

balance between the three main components: abrasive, pores <strong>and</strong><br />

ceramic bond.<br />

This facilitates cool grinding, high relative metal removal rates <strong>and</strong><br />

outst<strong>and</strong>ing tool lifes.<br />

<strong>Hermes</strong> surface grinding wheels are <strong>vitrified</strong> <strong>bonded</strong>, so can be<br />

dressed. They can be used for a broad range of materials requiring<br />

machining.<br />

<strong>CBN</strong> <strong>bonded</strong> abrasives for high-performance surface grinding from<br />

80 m/s operating speed are available with metal core bodies.<br />

Product benefits<br />

• Prevent thermal overload of the workpiece<br />

• Flexible with regard to the material for grinding<br />

• Save retooling time<br />

• High degree of profile stability<br />

• Long tool lifes<br />

• Increased productivity<br />

• Reduced workpiece costs<br />

9


<strong>Hermes</strong> solutions using <strong>CBN</strong> <strong>bonded</strong> abrasives<br />

External cylindrical grinding using Quickpoint method<br />

Product benefits<br />

• Long tool lifes<br />

• Considerably reduced dressing times<br />

• Low wear on grinding wheels<br />

• Increased productivity<br />

• Very good surface qualities<br />

10<br />

Productivity comparison<br />

%<br />

140<br />

120<br />

100<br />

80<br />

60<br />

40<br />

20<br />

0<br />

St<strong>and</strong>ard bond V241<br />

Product description<br />

Segmented <strong>Hermes</strong> <strong>Superabrasives</strong> for peel grinding allow<br />

operating speeds of up to 140 m/s.<br />

Their outst<strong>and</strong>ing grinding properties were achieved by a<br />

newly-developed, <strong>vitrified</strong> bond matrix in conjunction with<br />

specially-selected <strong>CBN</strong> grit qualities.<br />

The tools are used on Junker‘s Quickpoint machines,<br />

for example.<br />

<strong>Hermes</strong> solutions for das Hochleistungs-Schälschleifen<br />

Specifi cation 23B 126 R4 V241 161<br />

Operating speed 125 m/s<br />

Dimensional example 3A1 400/J297.5 x 25 x 127-U8-X5<br />

Material tempering steel, sintered metal<br />

Workpiece camshaft<br />

Specifi cation 10B 126 T3 V42 161<br />

Operating speed 125 m/s<br />

Dimensional example 3A1 406/J342 x 18 x 127-U6-X8<br />

Material tempering steel<br />

Workpiece camshaft<br />

Applications<br />

Diagram illustrating<br />

the principle of peel<br />

grinding<br />

Grinding<br />

radii<br />

Surface<br />

grinding<br />

Grinding prooves <strong>and</strong> infeeds<br />

External<br />

cylindrical<br />

grinding<br />

• Automotive <strong>and</strong> automotive supplier industry<br />

• Cutting tool industry<br />

• Transmission engineering<br />

• Machine tool engineering<br />

• Textile machine engineering<br />

• Printing press engineering<br />

• Electrical industry<br />

Direction of grinding


External cylindrical grinding of crankshafts<br />

Product description<br />

<strong>Hermes</strong> crankshaft grinding wheels with segmented <strong>CBN</strong> coatings<br />

can be manufactured in external diameters up to 750 mm.<br />

Further optimization of high-performance bond V24 has significantly<br />

improved grinding properties. The significantly increased<br />

profile stability of the <strong>CBN</strong> coating in particular leads to shorter<br />

grinding times <strong>and</strong> longer tool lifes.<br />

<strong>Hermes</strong> <strong>Superabrasives</strong> for external cylindrical infeed grinding can<br />

be used at operating speeds of up to 160 m/s.<br />

<strong>Hermes</strong> solutions<br />

Specifi cation 30B 126/181 R6/T6 V04 150/125<br />

S<strong>and</strong>wich design<br />

Operating speed 125 m/s<br />

Dimensional example 1L1-450 x 24 x 127-U21-R1.8-X5<br />

Material tempered steel<br />

Specifi cation 23B 151 N7 V241 161<br />

Operating speed 125 m/s<br />

Dimensional example 3A1-600/J275 x 40 x 140-U20-X8.5<br />

Material tempered steel (e.g. 16MnCr5)<br />

Applications<br />

• Grinding pins <strong>and</strong> journals on crankshafts<br />

Also:<br />

• Grinding bearing seats on transmission shafts<br />

• Other external cylindrical infeed grinding processes with<br />

extremely high Requirements with regard to reduced grinding<br />

time with tightest adherence to surface <strong>and</strong> dimensional<br />

tolerances on the workpiece<br />

Product benefits<br />

External cylindrical grinding of pump cams<br />

Grinding process<br />

Workpiece pump cams on camshafts<br />

Operating speed 125 m/s<br />

Material 16MnCr5 (1.7131), 58 HRC<br />

• Prevent thermal overloads on the workpiece despite<br />

extremely high metal removal rate<br />

• Save retooling time<br />

• High degree of profile stability<br />

• Long tool lifes<br />

• Increased productivity from reduced workpiece costs<br />

<strong>Hermes</strong> solutions<br />

Specifi cation 23B 126 M7/6 V241 125<br />

Dimensional example Form 14A1<br />

400/J192 x 27 x 127-U25-X5<br />

11


<strong>Hermes</strong> solutions using <strong>CBN</strong> <strong>bonded</strong> abrasives<br />

Roll grinding<br />

12<br />

Product description<br />

High-alloy materials require suitable high-performance abrasives<br />

for roll grinding.<br />

Our newly-developed <strong>CBN</strong> grit mixture meets this need. The<br />

performance potential of <strong>CBN</strong> required is exploited to the full in<br />

combination with a high-performance bond.<br />

<strong>Hermes</strong> solutions for high-performance peel grinding<br />

Specifi cation 73B 107 P7/6 V04 100<br />

Operating speed 50 m/s<br />

Dimensional example 1A1-600 x 40 x 203.2-X3<br />

Material e.g. ASP 2023<br />

Product benefits<br />

• Surfaces are stable in the long term, yet can have varying<br />

designs (adjustable by means of the appropriate dressing <strong>and</strong><br />

grinding parameters)<br />

• Save retooling time<br />

• Generate surfaces without twists or patterns<br />

• Long tool lifes<br />

• Increased productivity<br />

Applications<br />

• Working <strong>and</strong> back-up rollers in cold-rolling applications<br />

• Highly suitable for servicing Sendzimir st<strong>and</strong>s<br />

• Grinding high-alloy, wear-resistant steels, e.g. high-speed tool<br />

steel with 12% Cr (e.g. 1.2379) <strong>and</strong> high-performance highspeed<br />

steel produced by the powder metallurgy process<br />

(ASP 2023)


The first step to success<br />

Your information for us.<br />

Note<br />

Your process data <strong>and</strong> optimization objectives form the basis for us applying our expertise <strong>and</strong> thus for our shared success.<br />

Please fax the form to +49 (0)351 2801-390<br />

Company name<br />

Address<br />

Street<br />

Town/Postcode<br />

Shape <strong>and</strong> dimensions of grinding wheel (if not ISO st<strong>and</strong>ard, please send a drawing as well)<br />

Grinding method (e.g. surface, internal cylindrical or external cylindrical grinding)<br />

Grinding machine<br />

Operating speed v C in m/s or grinding spindle speed of rotation n S in rpm<br />

Description of workpiece (e.g. valve)<br />

Material, hardness of material<br />

Surface quality required (R a or R z or R t in μm)<br />

Grinding overmeasure, infeed control in mm<br />

Wet or dry grinding<br />

Specification used to date<br />

Optimization objective<br />

Annual requirement for this item<br />

13


<strong>Hermes</strong> <strong>Superabrasives</strong> Identification System<br />

Shapes <strong>and</strong> dimensions<br />

14<br />

14L1R D/J x T x H - U - R - X<br />

Shape of wheel Diameter of wheel Thickness of wheel Bore diameter Coating dimensions<br />

Core body basic shape Grinding coating shape<br />

14 L<br />

1 2<br />

3 4<br />

6 9<br />

10<br />

12<br />

14<br />

>30° bis


The shapes of <strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> <strong>bonded</strong> abrasives are described in DIN st<strong>and</strong>ard 69 800.<br />

The shapes of grinding wheels are described by means of 4 primary characteristics:<br />

1. Basic shape of core body; 2. Shape of grinding coating; 3. Arrangement of grinding coating; 4. Modification.<br />

Arrangement of grinding coating Modifi cation<br />

1<br />

On circumference<br />

3<br />

On the side, two sides<br />

5<br />

Outer chamfer or outer curve<br />

7<br />

Part of the side surface<br />

9<br />

Corner<br />

1 R<br />

2<br />

On the side, one side<br />

4<br />

Inner chamfer or inner curve<br />

6<br />

Part of the circumferential surface<br />

8<br />

Continuous<br />

10<br />

Inside<br />

B<br />

Countersink for<br />

cylinder bolts<br />

Q<br />

M<br />

Continuous <strong>and</strong><br />

threaded bores<br />

Inside<br />

K<br />

With keyway<br />

NEW<br />

S<br />

Segmented<br />

C<br />

Countersink for<br />

countersunk bolts<br />

P<br />

Coating relieved on<br />

one side<br />

Y<br />

Concave on inside<br />

W<br />

With shaft or spindle<br />

NEW<br />

H<br />

Continuous<br />

bores<br />

R<br />

Coating relieved on<br />

both sides<br />

V<br />

Concave coating<br />

SS<br />

Segmented <strong>and</strong> slit<br />

15


<strong>Hermes</strong> <strong>Superabrasives</strong> Identification System<br />

Specification (e.g. 23B 126 P5 V241 150 125 m/s)<br />

Manufacturers mark <strong>vitrified</strong> <strong>bonded</strong> <strong>CBN</strong> <strong>and</strong> <strong>Diamond</strong> abrasives in accordance with a company-specific code.<br />

On the following pages, we show the <strong>Hermes</strong> Identification System using the example specification mentioned above.<br />

Type Application<br />

<strong>CBN</strong><br />

11B<br />

29B<br />

12B<br />

22B<br />

28B<br />

13B<br />

16B<br />

23B<br />

10B<br />

20B<br />

30B<br />

<strong>Diamond</strong><br />

12D<br />

14D<br />

10D<br />

11D<br />

16<br />

Grit type Grit size <strong>and</strong> surface quality<br />

23B 126<br />

High performance<br />

e.g. for external cylindrical <strong>and</strong><br />

internal cylindrical grinding<br />

High performance<br />

e.g. for internal cylindrical grinding<br />

High performance<br />

e.g. for for external cylindrical <strong>and</strong><br />

surface grinding<br />

St<strong>and</strong>ard<br />

e.g. for external cylindrical, internal cylindrical<br />

<strong>and</strong> surface grinding<br />

High performance<br />

e.g. for external cylindrical, internal cylindrical<br />

<strong>and</strong> surface grinding<br />

St<strong>and</strong>ard<br />

e.g. for external cylindrical, internal cylindrical<br />

<strong>and</strong> surface grinding<br />

FEPA Nominal<br />

mesh width<br />

[µm]<br />

6.3 6 - 12<br />

10 8 - 15<br />

25 20 - 30<br />

46<br />

64<br />

76<br />

91<br />

107<br />

126<br />

151<br />

181<br />

213<br />

38 - 45<br />

53 - 63<br />

63 - 75<br />

75 - 90<br />

90 - 106<br />

106 - 125<br />

125 - 150<br />

150 - 180<br />

180 - 212<br />

US-Mesh R Z<br />

[µm]<br />

3000<br />

1800<br />

800<br />

325/400<br />

230/270<br />

200/230<br />

170/200<br />

140/170<br />

120/140<br />

100/120<br />

80/100<br />

70/80<br />

0.17<br />

0.30<br />

0.43<br />

0.52<br />

0.65<br />

0.77<br />

0.86<br />

1.00<br />

1.07<br />

1.20<br />

1.45<br />

1.70<br />

1.95<br />

2.20<br />

2.45<br />

3.45<br />

4.60<br />

5.45<br />

6.35<br />

7.10<br />

301 250 - 300 50/60 8.45<br />

11.20<br />

15.10<br />

19.40<br />

20.60<br />

R t<br />

[µm]<br />

0.10 - 0.30<br />

0.20 - 0.50<br />

0.30 - 0.70<br />

0.40 - 0.80<br />

0.50 - 1.00<br />

0.60 - 1.20<br />

0.65 - 1.40<br />

0.70 - 1.60<br />

0.80 - 1.70<br />

0.90 - 1.90<br />

1.10 - 2.30<br />

1.30 - 2.70<br />

1.50 - 3.00<br />

1.70 - 3.40<br />

1.90 - 3.80<br />

2.70 - 5.20<br />

3.70 - 7.00<br />

5.20 - 9.50<br />

4.50 - 8.20<br />

6.00 - 10.00<br />

7.10 - 12.50<br />

9.60 - 16.50<br />

13.00 - 22.00<br />

17.00 - 28.00<br />

18.00 - 30.00<br />

R a *<br />

[µm]<br />

0.02<br />

0.04<br />

0.06<br />

0.08<br />

0.10<br />

0.12<br />

0.14<br />

0.16<br />

0.18<br />

0.20<br />

0.25<br />

0.30<br />

0.35<br />

0.40<br />

0.45<br />

0.65<br />

0.90<br />

1.10<br />

1.30<br />

1.50<br />

1.80<br />

2.50<br />

3.50<br />

4.50<br />

5.00<br />

External cylindrical method, further dependent on dressing conditions, materials.<br />

This information is only intended as a guide! The surface values which can be<br />

achieved are significantly affected by the grinding method, the conditions of use <strong>and</strong><br />

the concentration of hard substance in the coating specification.<br />

* CLA (Centre Line Average) [µ"] = R a [µm] / 0.0254<br />

RMS (root mean square average) [µ"] ~ CLA [µ"] / 0.85


Code<br />

letter<br />

H, I, JOT,<br />

K<br />

Hardness Use<br />

Hardness Structure<br />

P 5<br />

soft primarily for heat-sensitive<br />

materials<br />

L, M, N, O medium st<strong>and</strong>ard<br />

P, Q, R, S hard for very good profile <strong>and</strong><br />

edge stability<br />

T, U, V,<br />

W, X<br />

very hard for high profile <strong>and</strong> edge stability<br />

(e.g. Quickpoint)<br />

Explanation of surface values<br />

R t<br />

R a<br />

R max<br />

1 2 3 4 5<br />

R Z1<br />

R Z2<br />

R RZ3 Z3<br />

Area R arithmetical mean roughness value<br />

a<br />

R averaged surface roughness<br />

z<br />

R maximum surface roughness<br />

t<br />

maximum individual surface roughness<br />

R max<br />

R Z4<br />

R Z5<br />

Code numbers Description<br />

2 - 3 dense structure<br />

4 - 7 medium structure<br />

8 - 10 open structure<br />

Number / 2 ... 8 with artifical pore-former<br />

Reference profile<br />

Actual profile<br />

Mean profile<br />

Base profile<br />

17


<strong>Hermes</strong> <strong>Superabrasives</strong> Identification System<br />

Specification (e.g. 23B 126 P5 V241 150 125 m/s)<br />

18<br />

Bond Concentration<br />

V241 150<br />

Name Hardness Grinding process<br />

V04 Moderate<br />

Universal<br />

V31 Internal cylindrical grinding<br />

V24 Internal cylindrical <strong>and</strong><br />

surface grinding<br />

V42 External cylindrical grinding<br />

V242 Internal cylindrical grinding<br />

V41 External cylindrical grinding <strong>and</strong><br />

surface grinding<br />

V241 Extremely External cylindrical grinding<br />

strong e.g. cam shape<br />

Concentration Per cent by<br />

volume of<br />

<strong>Diamond</strong>/<strong>CBN</strong><br />

<strong>CBN</strong><br />

in carat/cm 3<br />

<strong>Diamond</strong><br />

in carat/cm 3<br />

25 6.30% 1.09 1.10<br />

50 12.50% 2.17 2.20<br />

75 18.80% 3.26 3.30<br />

100 25.00% 4.35 4.40<br />

125 31.30% 5.44 5.50<br />

150 37.50% 6.53 6.60<br />

175 43.80% 7.61 7.70<br />

200 50.00% 8.70 8.80<br />

220 55.00% 9.57 9.68<br />

240 60.00% 10.44 10.56


Maximum operating speed<br />

(m/s)<br />

below 50 none<br />

50 1x blue<br />

63 1x yellow<br />

80 1x red<br />

100 1x green<br />

125 1x blue + 1x yellow<br />

140 1x blue + 1x red<br />

Permitted circumferential speed<br />

125 m/s<br />

Number of stripes Coding colour of stripes<br />

19


Application recommendations<br />

Influence of process <strong>and</strong><br />

tool parameters on outcome<br />

Grindability<br />

of steel (x)<br />

Cutting speed (x)<br />

Metal removal rate<br />

(Infeed control,<br />

feed rate) (x)<br />

Lubricity of cooling<br />

lubricant (x)<br />

Effective<br />

roughness from<br />

dressing (x)<br />

Concentration (x)<br />

Grit size (x)<br />

Hardness (x)<br />

Structure<br />

Bond<br />

20<br />

high<br />

Grinding force (y) Wear (y) Roughness (y) Burning risk (y)<br />

y<br />

low<br />

difficult<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

poor<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

easy<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

y<br />

low<br />

difficult<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

poor<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

easy<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

y<br />

low<br />

difficult<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

poor<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

easy<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

y<br />

low<br />

difficult<br />

Structure is specified mainly by the process <strong>and</strong> should only be varied within narrow limits. In general, it<br />

holds true that the longer the contact length, the more open the structure (the higher the structure number).<br />

<strong>Hermes</strong> uses the bond best suited to the process.<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

x<br />

x<br />

high<br />

high<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

poor<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

high<br />

y<br />

low<br />

low<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

x<br />

easy<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high<br />

high


Selecting machine parameters<br />

for <strong>CBN</strong> grinding<br />

Grinding process und machine parameters Settings<br />

External cylindrical grinding<br />

Traverse grinding<br />

Cutting speed vC 30 - 140 m/s<br />

Workpiece speed vW 15 - 200 m/min<br />

Workpiece advance vfa 0.5 x b x n S W mm/min<br />

Infeed ae Plunge grinding<br />

0.005 - 0.05 mm<br />

Cutting speed vC 30 - 140 m/s<br />

Workpiece speed vW 100 - 200 m/min<br />

Advance speed vfr Centerless grinding<br />

0.1 - 2.0 mm/min<br />

Cutting speed vC 30 - 100 m/s<br />

Workpiece speed vW 30 - 150 m/min<br />

Workpiece advance vfa 50 - 2000 mm/min<br />

Infeed ae Surface grinding<br />

Reciprocating grinding<br />

0.005 - 0.05 mm<br />

Cutting speed vC 25 - 60 m/s<br />

Workpiece speed vW 10 - 20 m/min<br />

Infeed ae


Application recommendations<br />

Cooling lubricants<br />

Note: In principle, <strong>vitrified</strong> <strong>bonded</strong> <strong>CBN</strong>/diamond abrasives should be used only in wet-grinding methods.<br />

Conventional cooling lubricants perform the tasks “lubricate”, “cool” <strong>and</strong> “flush” to varying degrees of satisfaction.<br />

A distinction is generally made between three types of cooling lubricants:<br />

1. Grinding oils with EP additives<br />

In addition to their cooling action, their good lubricating properties have a favourable impact primarily on friction forces, thus allowing<br />

longer tool lives to be achieved for better surface qualities.<br />

2. Emulsions (water with 0.2 - 15% oil fraction)<br />

Good wettability, high level of heat dissipation <strong>and</strong> consequently good cooling action.<br />

Suitable for <strong>CBN</strong> <strong>and</strong> diamond grinding wheels at elevated metal removal rates <strong>and</strong> moderate roughnesses.<br />

3. Transparent solutions of synthetic products with EP additives<br />

In addition to good wettability, their transparency should be mentioned as a particular benefit.<br />

It allows the grinding process to be observed better.<br />

Suitable for <strong>CBN</strong> <strong>and</strong> diamond grinding wheels at elevated metal removal rates <strong>and</strong> moderate roughnesses.<br />

Product comparison<br />

Cooling lubricant Lubricating action Cooling performance Cleaning effect Resistance to ageing<br />

Mineral oil, pure very good poor moderate good<br />

Emulsion 15% good moderate good poor<br />

Emulison 5% moderate good good moderate<br />

Synthetic solution 3% poor very good very good very good<br />

Semi-synthetic solution 3% good good good good<br />

Comparison of applications<br />

Material Abrasive Grinding process Cooling lubricant<br />

Recipro- Creep<br />

recommended<br />

cating feed<br />

grinding grinding<br />

<strong>Diamond</strong> X Emulsion 98 - 95%<br />

X Emulsion 95 - 90%<br />

X Fully-synthetic solution 98 - 97%<br />

X Semi-synthetic solution 98 - 97%<br />

Hardened metal<br />

Hardened metal + steel<br />

Ceramic<br />

Spray-on alloys with<br />

tungsten carbide<br />

HSS<br />

Chrome steel<br />

Metal spray-on alloys<br />

Long-chipping types of steel<br />

e.g. 100Cr6, 16MnCr5<br />

Special materials<br />

22<br />

Water fraction<br />

<strong>CBN</strong> X Emulsion 98 - 95%<br />

X Fully-synthetic solution 97 - 95%<br />

X Semi-synthetic solution 97 - 96%<br />

X Fully-synthetic solution<br />

X Semi-synthetic solution<br />

X Mineral oil with EP<br />

if appropriate<br />

<strong>CBN</strong> X X Emulsion<br />

Mineral oil with EP<br />

if appropriate<br />

95 - 80%


Dressing methods <strong>and</strong> parameters<br />

Note:<br />

It is generally necessary to dress the <strong>bonded</strong> abrasive after changing the tool (to generate concentricity) <strong>and</strong> during the<br />

grinding process once the tool life criterion (surface quality, profi le deviation) has been reached.<br />

Dressing method<br />

V R<br />

<strong>Diamond</strong> profile roller dresser<br />

1 2<br />

V frd<br />

<strong>CBN</strong> grinding wheel<br />

3 4<br />

7°<br />

Application recommendations<br />

V frd<br />

V R<br />

V sd<br />

<strong>Diamond</strong> dressing wheel<br />

<strong>CBN</strong> grinding wheel<br />

V fad<br />

V sd<br />

<strong>Diamond</strong> form roller dresser<br />

V rel = 0<br />

Variables affecting dressing outcome Dressing method Formulae<br />

Dressing/speed ratio qd 1, 2, 3 Transverse overlap ratio<br />

V R<br />

V frd<br />

<strong>CBN</strong> grinding wheel<br />

V sd<br />

Steel profile roll<br />

V fad<br />

<strong>CBN</strong> grinding wheel<br />

Semi/counter direction 1, 2, 3<br />

Peripheral grinding<br />

wheel speed<br />

vsd 2, 3<br />

Peripheral dresser speed vR 1, 2, 3 Dressing/speed ratio<br />

Transverse overlap ratio Ud 2, 3<br />

Dressing infeed aed 2, 3<br />

Dressing feed rate vfrd 1, 4<br />

Contact pressure 4<br />

Dressing contact width bR 2, 3<br />

Recommended settings for dressing methods 2 + 3<br />

q > 0.5 d<br />

a = 2; a = max. 10% of grit diameter<br />

ed ed – total<br />

U = 5 (U : number of times dressing tool contacts a point on the circumferential surface of the abrasive tool)<br />

d d<br />

U d = b R<br />

v fad<br />

q d = v R<br />

v sd<br />

. nsd<br />

23


Effective surface roughness (µm)<br />

Application recommendations<br />

Dressing methods <strong>and</strong> parameters<br />

Effect of speed ratio <strong>and</strong> dressing infeed on effective surface roughness<br />

16<br />

14<br />

12<br />

10<br />

8<br />

6<br />

4<br />

2<br />

Same direction<br />

Counter direction<br />

0<br />

2 1.5 1 0.5 0<br />

Speed ration q<br />

-0.5 -1 -1.5 -2<br />

24<br />

Radial feed<br />

for dressing<br />

[µm/revolution]<br />

frd = 0.72<br />

frd = 0.54<br />

frd = 0.36<br />

frd = 0.18<br />

Source: Schmitt, R. – Dressing grinding wheels with diamond-coated rolls - dissertation from the Technical University in Braunschweig, Germany


Key data in the grinding process<br />

G ration<br />

The G ratio allows a direct comparison to be made between two different grinding wheels in the same grinding process<br />

with identical parameters.<br />

The ratio is calculated as follows:<br />

G =<br />

General guidelines<br />

Volume of workpiece reduced [mm 3 ]<br />

Wheel coating consumed [mm 3 ]<br />

<strong>Diamond</strong> on hardened metal <strong>CBN</strong> on HSS<br />

50 - 300 150 - 800<br />

Relative metal removal rate Q' W<br />

The relative metal removal rate describes the removal rate of a grinding wheel per second per millimetre of grinding wheel thickness.<br />

This allows a direct comparison of different grinding processes to be made.<br />

Formulae for calculating Q' W [mm 3 /mm . s]:<br />

Q' W = a e . v t<br />

60<br />

Q' W = a e . n W . D W . π<br />

60<br />

Q' W = v f . D W . π<br />

60<br />

Surface <strong>and</strong><br />

creep feed grinding<br />

External cylindrical<br />

longitudinal grinding<br />

External cylindrical<br />

infeed grinding<br />

Key<br />

ae vt DW nW vf Infeed control [mm]<br />

Advance speed [mm/min]<br />

Diamater of workpiece [mm]<br />

Speed of rotation of workpiece [rpm]<br />

Radial advance speed [mm/min]<br />

25


Internet<br />

Why not visit our website?<br />

26<br />

Virtually all the information<br />

useful for planning <strong>and</strong> purchasing<br />

<strong>Hermes</strong> Bonded Abrasives<br />

is available on our website which<br />

is based on a database <strong>and</strong> is<br />

equipped with numerous other<br />

functions:<br />

• New products<br />

• Detailed product information<br />

• Application solutions<br />

• Information about the company<br />

It goes without saying that the<br />

<strong>Hermes</strong> site is multilingual, so it<br />

can be used all over the world.<br />

This website is constantly being<br />

updated <strong>and</strong> is an important<br />

information platform.<br />

www.hermes-schleifkoerper.de<br />

You have the option of downloading<br />

information material<br />

via the Web for instant<br />

availability.<br />

Our website also lists all your<br />

relevant contacts, whether fi eld or<br />

offi ce-based staff.


For more information<br />

about <strong>Hermes</strong> <strong>bonded</strong> abrasives<br />

<strong>Hermes</strong> Schleifkörper GmbH<br />

Lohrmannstrasse 21<br />

01237 Dresden, Germany<br />

Phone +49 351 28 01-0<br />

Fax +49 351 28 01-390<br />

info@hermes-schleifkoerper.de<br />

www.hermes-schleifkoerper.de<br />

33 E 21.30 . The right to make amendments is reserved.

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