Loose Abrasive Applications
Diamond and PCD Drawing Dies
Micron powders up to approx. 15µ are used for the ultrasonic shaping of diamond and PCD dies. The sizing and fine polishing operations are very quality-sensitive. Van Moppes has acquired a world-wide reputation with its sub-micron sizes, such as 0-0.25, 0.25-0.5, 0-0.5, 0.25-0.75 and 0.5-1.
Jewel bearings originally prompted the development of precision graded micron diamond powders, due to the high surface finish ans accuracy requirements. This explains why Switzerland has developed into a major centre for micron diamond powder production. Sapphire crystals for watches have become the largest single application, but the industry uses its know-how to produce numerous other components for many industrial applications, as well as many special parts made of hard materials and ceramics. Polycrystalline powders are generally preferred for their superior cutting properties on monocrystalline or sintered ceramic materials.
Electronics are large users of micron diamond powders, mainly in the following applications:
Magnetic heads, which are made of composite materials and are polished using micron powders ranging between 0-0.5µ and 1-3µ.
Hard disk media surfaces are textured with submicron powders such as, for example, 0-0.2µ to achieve an Ra surface roughness in the order of 4 Angstrom and more recently with special products in the nanometer range. The quality requirements are very high, to guarantee an accurate, controlled and consistent surface roughness.
Compounds, Slurries, Suspensions
Micron powders up to approx. 40µ are obviously a vital ingredient for the manufacture of liquid or paste based diamond lapping compounds. Pasty compounds are mainly used to polish metallographic samples, or to polish tools and dies. Liquid compounds, suspensions or slurries are often replacing powders in a variety of applications, to alleviate the powder dispersion problem and the difficult choice of the correct carrier liquid. Better surface finish, production efficiency and lower cost are often achieved. In certain markets, the use of ready-made slurries is significant, whilst others prefer to blend their own abrasive media.
This title includes a variety of applications, such as writing balls, gauge balls, bearings, printer needle guides, or other components such as cutting tools, tap joints, electronic circuit substrates or automotive parts. Polycrystalline powders are used, as well as monocrystalline powders in both loose or bonded form.
Lapidary Industry and Diamond Polishing
Diamond is cut and polished with diamond. Gem diamond polishing is the largest application, mostly using monocrystalline powders between 0 and 40µ.
Another exotic application for fine submicron powders is the polishing of microtome knives.
This list is obviously incomplete, as diamond powders continuously find new applications, as a result of ever increasing technical and productivity requirements.
Advice on Micron Powder Applications
Many years of experience have shown that complaints regarding the performance of our micron powders or the surface finish usually find their origin in one of the following causes:
- The powder is no longer suitable for the application, as a result of a change in the working environment or the work-piece material. It may thus be necessary to change for a slightly different powder size.
- There is an application problem. The most frequent one is the incomplete dispersion of the micron powder in its carrier. Dry powder pockets or agglomerates can cause scratching.
We are always available to help our customers resolve application problems. Each complaint is thoroughly investigated. No complaint may be filed before the problem is solved to the customer's entire and confirmed satisfaction. No time may be saved on Product Quality and Customer Service matters.
Observations and Recommendations
Before attempting to resolve a micron powder application problem, please observe the following points:
- Product definitions and inspection limits are defined and interpreted differently, depending on where the evaluation is taking place.
- Inspection results from different sources are therefore rarely comparable, as each manufacturer works to his own product definitions and his own quality inspection concept.
- It has been widely established that products of different origins may be different in many respects, even though they may bear the same description.
- As a result, shopping around for a given nominal diamond powder size may be very misleading. It is often useless to compare products that are just different, for reasons unknown to the user. Van Moppes offers its customers a free advice and inspection service, which helps to establish the exact characteristics of a satisfactory or unsatisfactory product.
- This evaluation, together with detailed application data, allows a suitable product recommendation to be made, at no cost and in a short amount of time.
- Once a product has been tested satisfactorily, it is fully documented for future reference. Each subsequent delivery will be identical in its performance, saving the user a considerable amount of time and money.
Take the safe and simple route: Let us deal with your micron diamond powder quality and inspection problems.
Important advice on the mixing of micron powders with a liquid carrier
- Initially, disperse the powder in concentrated form. Dilute the mix to the required concentration only after its complete dispersion.
- It is easier to disperse diamond powder in a low viscosity and low surface tension liquid. If the slurry includes more than one liquid, first disperse the powder in its most suitable component.
- Consider using a wetting agent to help powder dispersion: alcohol for water-soluble slurries, acetone for oil-based slurries.
- After thorough mechanical mixing, it is highly recommended to further disperse the mix by means of a powerful ultrasonic bath.
- Check the possible presence of residual agglomerates through sedimentation of a slurry sample in a test tube.