Drilling rocks and/or sawing reinforced concretes are important for modern societies in fields like mining as well as state-of-the-art building.
Diamond tool – that are used for those drilling/sawing applications – are generally made of impregnated diamond inserts. Depending on the application, different geometries, metal bonds, diamond grades and diamond concentrations are used to optimize cutting performances.
It is therefore essential to develop good multilateral information exchanges between manufactures and customers. Those exchanges might – for instance – include investigating and understanding the active wear mechanisms through characterization of worn surfaces as well as of deeper layers in cross-section.
Laboratory testing and wear modeling are also essential for developing tools with improved cutting efficiencies (or Rate of Penetration).
This is with those objectives in mind that we strive to maintain close and discreet partnerships with all our customers.
Partner relationship that include for example :
Applications :
Oil & Gas – High wear resistant impregnated diamond inserts for PDC bits
Oil & Gas – High ROP cutting impregnated diamond inserts for matrix bits
Mining – High ROP cutting impregnated diamond inserts for core bits
Shapes :
Pagode
Mammouth
Standard
Reinforced
Sandwich
Diamond concentrations :
Sandwich Inserts
Sandwich Inserts
Transversal Width Cut
Transversal Width Cut
Encapsuled diamond types :
Laboratory wear tests :
Preliminary wear resiStance tests
Each new composition is preliminary tested :
– in dry and wet conditions
– on SiC and on granite class 5 grinding wheels
Rotational speeds are controlled
Applied pressures range from 1 bar up to 8 bars
Analysis :
Metallography
| Worn Segments | New Segments | |
|---|---|---|
| Number of segments | 21 | 21 |
| Analysis | ||
| Iron (Fe) | 36 % | 36 % |
| Colbalt (Co) | 54 % | 54 % |
| Copper-Silver-Titanium | 10 % | 10 % |
Porosity
Opened
Closed
High
Fractography
Fractures around diamonds
Fractures Foot - Matrix
Diamond Clusters
Welding
The segment can be welded onto steel blades by conventional method ( i.e. brazing alloys in strips, in wire, in paste, etc. ) or by laser. A defficient welding can be at the origin of cutting defaults such as deviation cuts, loosed segments, etc. Therefore, it is important to verify the welding.
The welding analysis includes the control of :
– the parallelism of segments,
– the method used,
– the porosity,
– the presence of a foot,
– the composition of the brazing alloys.
Diamonds analysis
The most important part of the cutting tool performance evaluation consists in an analysis of :
– the working surface,
– the aspect of the diamond,
– the diamond concentration,
– the quality and the grit sizes of the diamonds
Working surface :
The working surface analysis covers the general aspect of the surface ( e.g. tails, protusions, glazing surface, etc. ), the diamonds distribution ( e.g. presence of clusters ), the diamond retention ( e.g. number of pull-outs ) and the ratio between :
– pull-outs
– polished crystals
– intact crystals
– crushed crystals
Diamond aspects :
All factors such as cutting parameters, manufacturing parameters, diamonds’ quality, diamonds’ sizes and the concentration have an impact on the diamonds’ behaviour and on the tools’ performances. Indeed, during the cutting operations, the diamonds will be submitted to heavy constraints and will :
– stay intact
– clive or crush
– polish
– leave the matrix
Diamond crushed at the matrix level.
There is no protrusion anymore.
Diamond has lost its cutting properties.
Diamond is crushed but still shows a protusion.
Diamond still keeps its cutting properties.
concentration :
The concentration is measured according to the FEPA norm. By definition, the amout of diamond present in a segment is calculated on a scale in which a concentration of 100 corresponds to 4.4 carats per cm³ or to 25 % in volume.
| FEPA | ||
|---|---|---|
| Concentration | Carats/cm³ | % in volume |
| C10 | 0.4 | 3 |
| C20 | 0.9 | 5 |
| C25 | 1.1 | 6 |
| C30 | 1.3 | 8 |
| C35 | 1.5 | 9 |
| C40 | 1.8 | 10 |
| C50 | 2.2 | 13 |
| C60 | 2.6 | 15 |
| C75 | 3.3 | 19 |
| C100 | 4.4 | 25 |
quality and grid sizes :
The segments are dissolved into acid bath and the diamonds are cleaned.
Then, the same diamonds are sieved according to FEPA mesh sizes and each class is submitted to a battery of test in order to estimate the qualities of the diamonds.