The Abrasives Hub

24 November 2010

As one of the sponsors of the new European Diamond University, Carbodiam recently opened its manufacturing plant at Tilly in Belgium to visitors. This plant is specialised in the manufacture of diamond segments that are used in grinding wheels and core drilling application for the stone, construction and road sectors.

As well as its own branded products, Carbodiam also manufactures for other leading companies. Tilly boasts a highly flexible production facility and keeps more than 1,000 different diamond segments in stock at any one time. Research and Development is a major activity as tooling customers have diverse needs when it comes to end user applications. Developing tools to suit a specific task requires considerable experience and in-depth knowledge of materials, machines and tools.

Development is also supported by extensive testing and Carbodiam has a various stations for testing diamond cables, wall and floor saws, asphalt discs, concrete drilling, floor treatment and surface machines.

All of the company’s tool matrixes are produced on site. This means that it has the capacity to create specific designs and develop segments that are optimised for a particular application. The more complex moulds for the segments are electro-cut from steel and each die can produce between 2,000 – 6,000 segments.

Diamond considerations

When designing a diamond segment, the main parameters to consider are the hardness, density, thickness and radius. Carbodiam uses synthesised diamond in its production from a number of suppliers either coated or uncoated dependant on the application. A thin coating on diamond adds protection to improve performance in certain applications. For a perfect cut in various materials, diamonds of specific size, quantity and concentration are employed. To ensure that the diamond particles perform optimally in the tool, design engineers need to understand the wear and breakdown characteristics of diamond and to maximise those phases where the diamond presents the best cutting edge. It is also important that the diamond is properly distributed throughout the segment and the company has developed its own mixing technology to ensure material consistency when blending diamond in the matrix material.

For any tooling application, bond composition does have a dramatic impact on performance which is why Carbodiam has so many different segment designs, each design is specific to the application and the material to be cut. Softer materials require a harder bond, while harder materials demand softer bond types. Again, to optimise performance, Carbodiam employs proprietary and specific bonds types based in bronze, carbide and cobalt metal powders.

Often, the segments developed by Carbodiam are made up of layers – this sandwich construction is created in CNC hydraulic presses each with a capacity of around 14,000 segments a say. Simpler presses producing single layer segments have double this capacity.

Once the segments have been formed, they are transferred to the furnace section where are variety of sintering process are employed dependant on the bond mixture. Free sintering is a 36 hour process carried out at temperatures up to 1200 oC and hot pressing is used for segments that need to be more flexible in operation. Thermal cycles are carefully monitored as performance stability of final tools is dependant on this part of the process. After sintering, all segments are subject to strict quality control procedures with each batch given a quality control number to ensure that production can be tracked.

Diamond segments then need to be matched to their steel bodies. Prior to mounting the segments, each core is assigned a unique identification number. Carbodiam maintains a stock of more than 3,000 steel cores of different shapes and sizes.

For most steel cores, segments are attached using high frequency brazing; however, for dry cutting discs, laser welding is employed as this reinforces the solidity of the segment joint to the steel core. Every brazed segment is flexion tested to avoid potential problems in use. For the larger sized discs, the steel core is checked for flatness using computer inspection and then corrected individually to ensure a straight cut in operation.

Quality control and testing are key activities within the plant. Raw materials such as powders and diamonds are checked prior to production and each finished tool undergoes scrutiny before being painted, engraved and packed for shipping.

Also for any current or future European Diamond University members, the Tilly plant has extensive testing facilities for tools and equipment. Its test stations can handle diamond cables, wall and floor saws, asphalt discs and concrete drilling, and machines for floor treatment and surfacing.

One of the company’s ambitions is to work closely with end users and partner companies to develop tooling solutions that will meet new market needs novel application areas.