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How do I select the correct CV Nanotechnology polishing product(s) for my application?

On the Applications pages of this website there is a guide for which CV Nanotech products are used for specific polishing applications. If you don't find your application there or need additional information please call our technical support team 1-516-935-4000 or contact our scientists and we will be glad to assist you.

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How do I know which CV Nanotechnology polishing products to use for the surface finish I desire?

In almost all cases, for each abrasive type the smaller the particle size, the better the surface finish. However because with some abrasives, particularly Aluminum Oxide/Alumina (Al₂O₃, CVA- series), the crystalline phase is very important as well. For example, alpha-phase alumina (Al₂O₃) is much harder than gamma-phase Al₂O₃, so a larger gamma Al₂O₃ may give a better finish than a smaller alpha Al₂O₃.  As a guide the general hardness of the abrasives in our four abrasive-material series is: Al₂O₃ is harder than a comparable size ZrO₂ (zirconia), which is harder than a comparable size CeO₂ (ceria), which is harder than a comparable size SiO₂ (silica) - Al₂O₃ > ZrO > CeO > SiO₂.  Although particle type and size are the primary factors affecting surface finish, other polishing compound characteristics can play a significant role, especially pH and reactive chemical additives. Additionally, the pad type and roughness and polishing down-pressure are important variables. To a lesser degree polishing slurry tribology (viscosity, lubricity, etc.), slurry concentration, and polishing temperature need to be considered. But they and other minor material and process conditions may provide the final "touch" to optimize the finish desired.  Should need additional information please call our technical support team 1-516-935-4000 or contact our scientists and we will be glad to assist you.

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Which is better to use, a polishing powder or manufactured slurry?

As a rule-of-thumb powders give better stock removal rate and slurries provide better surface finish. The better surface finish is due to the fact that manufactured slurries have better abrasive particle dispersion and narrower particle size range. Additionally manufactured slurries are better filtered than slurries made from powders at the customer site. Also, manufactured slurries usually have better suspension than made-from-powder slurries to reduce or eliminate particle agglomerates as used.

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How do I choose what lapping compound or lap plate/pitch to use prior to polishing with your recommended CV Nanotechnology precision polishing compound?

There are many considerations, but in general, the better the surface finish BEFORE you polish the better off you will be in terms of throughput and cost. Some general rules are:

1) NEVER use a lapping abrasive or plate that will imbed particles in a softer substrate that you are polishing! Examine the substrate closely for "imbeds" when evaluating lapping compounds otherwise you will destroy your polishing efforts.

2) NEVER mix lapping compounds with polishing compounds in order to try to get "the best of both worlds" - removal rate and final surface finish in one operation step.

The lapping compound(s) depend on how much material you need to remove to get to the proper substrate thickness and, if the substrate is not flat, the curve you desire. Assuming the part has been tool-ground (e.g. CNC, diamond turning) very close to the thickness and ,if applicable, curvature you want most precision polishing operations will require only one lapping step before a one or two step polish completes the process. If the final surface finish is not too demanding, and there hasn't been too much subsurface damage to be removed, as is the case with crystalline substrates, a one-step lapping with one-step polishing may be adequate. Experience combined with testing are usually required, especially with new substrate materials.  A CV Nanotechnology process engineer will be glad to assist you, please contact us at 1-516-935-4000.

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Once I know what abrasive material type(s) to use, how do I know what particle size to use?

When selecting particle size it is VERY important to remember that measurement of particle size and distribution of sizes (PSD) is a relative inexact science. There are many methods of measurement, e.g. the oldest method, settling, to the most common method, light-scattering. And the different methods, even when measured properly will have different results. And even within any method there can be a significant difference in results depending on a host of variables, most importantly sample dispersion and pH.  When consideration of how well the sample of the specific drops used in the PSD instrument are obtained from the bulk of the slurry, i.e. how representative of the entire slurry is it, and how well was the bulk slurry dispersed prior to sampling, huge differences can occur. The message is: Be cautious when comparing PSD between different methods and different slurry manufacturers.
Having said this, if a two-step polishing process is used:

  • The first step is primarily a stock removal process which improves the finish from the lapping step.
  • The second step is the final "finishing" step to achieve the final surface finish. It generally does not affect substrate thickness or curvature enough to take those out of specification.
As an example, for most precision optics the first step polishing slurry has a mean particle size (d50) of 1 - 3 microns (µm) and the final step has a d50 of 1 µm or less, usually 0.5 µm or less.

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What concentration of slurry do I use?

There are general guidelines but as with most aspects of polishing these can vary significantly. For cerium oxide/ceria polishing compounds, CVC- series, a weight concentration of 2-5 % is desired for first-step stock removal. This is the equivalent of a 5-10 Baume (Be) specific gravity measurement. Specific gravity measurement is the least accurate because other factors such as slurry viscosity can greatly affect the Baume reading, mostly in the higher concentrations. For final finish step a smaller particle ceria, e.g. 0.5 µm, or a colloidal silica, e.g. 50 µm, is used. The concentration of the ceria can be in the range of 1-2 weight percent (< 5 Baume). Here the Baume reading is very difficult to read and thus unreliable for reproduction.  A good method to obtain reproducible slurry abrasive concentration is to measure the amount of slurry by volume with added volume of water. It's important that the slurry not be thick and foamy to ensure a reasonable accuracy. A CV Nanotech process engineer can help you with this, please contact us at 1-516-935-4000.

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How do I clean the polished surface after using your polishing compounds?

The surface will probably contain a mixture of the CV Nanotechnology polishing compound, the polishing pad (or other material), and the swarf (debris from the action of the polishing compound on the substrate that was polished). The polished surface can be cleaned using surfactants and/or chelating agents such as citric acid, either with a soft brush or lint-free cloth. There are many commercial laboratory cleaning agents available. Ultra- or megasonic baths with these cleaning materials may also be used alone or as a separate step. Another method is, when possible, to etch the substrate with a dilute mineral acid (e.g. 0.01% hydrofluoric acid) or caustic solution (e.g. 0.1% sodium hydroxide). CARE must be taken in handling these acids or caustic solutions: goggles and acid/base resistant gloves are required and inhalation of fumes avoided.

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How do I obtain a data sheet and/or MSDS?

Fill out an online technical data & MSDS request form and our technical support team will email/contact you, or call CV Nanotechnology Customer Service at 1-516-935-4000 for info.

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How do you guarantee your product?

Our products are guaranteed to be of the composition and physical and chemical specifications listed on CV Nanotechnology data and MSDS sheets. Because we cannot control usage and processing by the end user of CV Nanotechnology products we cannot quarantee specific results such as removal rate and surface finish. Be assured we will provide assistance in achieving your desired results.

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What quantities do you offer?

Our manufacturing facility can support quantities from a minimum of few gallons up to high volumes of 10,000+ gallon batches. For ordering information please contact the CV Nanotechnology Sales team at 1-516-935-4000.

SHIPPING

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Does CV Nanotechnology offer express delivery?

We always strive to meet our customers' needs, so we offer both FedEX and express delivery for sample and/or product shipments. For ordering information please contact the CV Nanotechnology Sales team at 1-516-935-4000.

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Do you accept customer's FedEX account for shipping?

For the convenience of our qualified customers, we do accept customer's FedEx account for shipping.  To verify if you are qualified, please contact our customer service department at 1-516-935-4000.

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What shipping carrier do you use?

We use worldwide shipping carriers, i.e. FedEX, DHL, UPS, etc.  If you have a specific carrier that you would like to use, please contact our customer service department at 1-516-935-4000 for arrangement.

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Do you ship to international addresses?

Yes, CV Nanotechnology Inc. does business all over the world. So we are experienced with shipping to international commercial address(es). Please contact our customer service at 1-516-935-4000 for details.

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Do you accept credit cards?

For customer convenience, we accept many forms of payments including credit cards.  Please contact our Customer Service department at 1-516-935-4000 for details.


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