Ceramic vibratory media
Preformed ceramic mass-finishing media, supplier grades, geometry, density bases, wear and compound-dependent limits.
Tags: abrasives, mass-finishing, deburring, reference
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Identity and process boundaries
Washington Mills lists ceramic DURAMEDIA 20/F at 85 lb/ft³ and DURAMEDIA 40 at 100 lb/ft³ bulk density. Both use alumina, with 20/F described as mildly abrasive and 40 as fast cutting. Bulk volume includes spaces between bodies. The same ceramic range includes abrasive-free burnishing grades. Washington Mills ceramic media DURAMEDIA product descriptions
The supplier examples separate cutting, burnishing, and impact blasting.
| Product family | Distinction |
|---|---|
| Abrasive ceramic bodies | DURAMEDIA 20/F contains aluminum oxide; 50/SC is silicon-carbide based. These are supplier formulations, not loose-grain designations. DURAMEDIA descriptions |
| Nonabrasive ceramic or porcelain | Vibra Finish P has no abrasive and can drive separately added loose abrasive. AFT identifies AF-P as porcelain with no added abrasive. "Nonabrasive" describes the media formulation, not every possible combined process. Vibra Finish formulations, AF-P porcelain |
| Resin-bonded media | DURAMEDIA Plastic uses polyester resin. A similar cone or triangle does not establish the same body material. DURAMEDIA Plastic |
| Ceramic blasting beads | Zirblast is an impact-blasting product with crystalline zirconia in a glass matrix. Its bead size is the projectile size. Its composition and blasting claims do not describe vibratory chips. ZirPro Zirblast |
| Loose abrasive | Separately added abrasive and abrasive incorporated inside a body are different process inputs. Vibra Finish explicitly lists driving loose abrasive as an application for P. Vibra Finish formulations |
Composition and manufacturing evidence
A ceramic body is not necessarily a single mineral. The Washington Mills shared SDS for Duramedia 10, 20, F, FB, PK, PK-20, and Duralite II calls these fired ceramic mass-finishing media. Section 3 discloses aluminum oxide at 10–40% by weight, titanium dioxide at 0–2%, and trace cristobalite at no more than 0.1%, with nonhazardous additions. These family-level disclosures do not assign the same abrasive content to every listed grade. Shared SDS, revision printed as 11.02.2015, sections 1 and 3.
Vibra Finish's VF-M SDS discloses kaolin at 40–50%, aluminum oxide, feldspar, and silica each at 10–20%, and talcum and wollastonite each at 0–10%. Its composition note concerns possible dust generation. These intervals are not a complete recipe or a measured fired-phase assay. VF-M SDS, revision September 4, 2017, section 3.
Synthesis: an ingredient list, a mineral phase analysis, and the amount of free abrasive exposed at the working surface answer different questions. Neither SDS establishes an exact abrasive loading, absence of crystalline silica, or a contamination-free finished part. A firing description also does not establish a universal sintering temperature or matrix composition.
Exact grades and supplier labels
The examples below preserve each supplier's terminology. They are not substitute grades.
| Supplier and grade | Documented description | Color and stated bulk density |
|---|---|---|
| Vibra Finish M | General-purpose deburring formulation | Grey; SDS gives 85–90 lb/ft³ |
| Vibra Finish SF | Fast cutting; tough bond | Grey; formulation page lists bulk rate 85–90 |
| DURAMEDIA 20/F | Mildly abrasive, aluminum-oxide based | White; 85 lb/ft³ |
| DURAMEDIA 40 | Fast cutting, aluminum-oxide based | Tan; 100 lb/ft³ |
| DURAMEDIA 50/SC | Mild cutting, silicon-carbide based | Beige with blue/black grain; product page gives 85 lb/ft³ |
Sources: Vibra Finish formulation table, VF-M SDS, section 9, and DURAMEDIA product page. The Vibra Finish table labels its last column "CU. FT. Bulk Rate" without stating the mass unit there; the M SDS supplies an explicit unit for M.
Supplier documents can disagree. Washington Mills' public brochure gives 50/SC a bulk density of 90 lb/ft³, while its product page gives 85. Vibra Finish's formulation page calls LC tan and DF's bulk rate 100–105; its separate descriptions page calls LC gray and gives DF 95–100 lb/ft³. These undated pages do not establish which value applies to a supplied lot. Washington Mills brochure, page 3, Vibra Finish descriptions.
Synthesis: "fast cut," "good wear," color, and formula numbers are supplier labels. They do not define a shared FEPA grit size or a cross-vendor hardness scale. A measured hardness requires its test method and conditions. Cut level, body hardness, abrasive grain size, and chip dimensions are separate properties.
Shape, supplied dimensions, and lodging
Vibra Finish's shape table lists M among the formulations for a 22° angle-cut cylinder designated 1/4 × 5/8 and a straight-cut triangle designated 1/4 × 1/4. Its 5/8 × 1/4 angle-cut tristar row omits M but includes SF. Availability therefore belongs to a particular shape, size, and formulation combination. These are catalog size designations, not measured distributions or manufacturing tolerances. Vibra Finish ceramic shape and formulation tables.
Synthesis: a two-dimension chip designation is not an abrasive grain grade, maximum diagonal, or guaranteed passing size. For example, 1/4 inch converts exactly to 6.35 mm, but conversion adds no tolerance information. An angle-cut body can enter a feature in different orientations. Nominal dimensions alone cannot establish a universal bore clearance or freedom from lodging.
Walther Trowal describes ceramic media becoming smaller through abrasion and identifies removal of undersize media as a way to limit lodging in holes or cut-outs. That statement concerns worn media as well as fresh charge geometry. Walther Trowal ceramic media.
Synthesis: worn shapes and possible broken fragments change the population that contacts the part and reaches the separation screen. Contact geometry and accessibility do not establish a final edge radius, uniform treatment of internal features, or a specified roughness.
Density, ratios, and measurement bases
The Washington Mills brochure lists DURAMEDIA 20/F with specific gravity 2.46 and bulk density 85 lb/ft³. Specific gravity is a dimensionless relative-density quantity. Bulk density describes a quantity of media occupying a bulk volume, including spaces between pieces. A poured or tapped result additionally depends on packing method; the cited brochure gives no such method. Washington Mills brochure, page 3.
The following are definitions and illustrative arithmetic, not loading recommendations:
| Quantity | Defined basis |
|---|---|
| Media-to-part volume ratio | Media bulk volume divided by the stated part-volume basis. Solid displacement volume and a container of loosely packed parts are different denominators. |
| Media-to-part mass ratio | Media mass divided by part mass. It equals the volume ratio only under additional, matching density assumptions. |
| Abrasive mass fraction in a chip | Incorporated abrasive mass divided by total chip mass. It is unrelated to the fraction of the bowl occupied by media. |
| Working-liquid concentration | Compound amount divided by an explicitly stated final-liquid amount, using mass or volume consistently. |
Hypothetical synthesis: at an assumed bulk density of 85 lb/ft³, 0.20 ft³ of media weighs 17 lb. With 10 lb of parts, the mass ratio is 1.7:1. No volume ratio follows without a defined part volume. Separately, 20 g of compound in 1,000 g of final working liquid is 2% by mass. Adding 20 g to 1,000 g of water instead gives about 1.96% compound by final mass. Neither example specifies a suitable charge or liquid recipe.
Wear, cutting, and working-liquid limits
Washington Mills' brochure reports "Metal Loss" percentages and qualitative grinding-performance graphics. It does not give a complete test basis for machine, workpiece, load, compound, water, duration, or loss denominator. Those figures cannot establish transferable removal rates or a controlled cut-to-wear ranking. Washington Mills brochure, pages 2–3.
Synthesis: workpiece mass loss and media mass loss are distinct measurements. A removal rate needs the workpiece quantity and time basis. A cut-to-wear ratio needs both losses under comparable conditions. Lower media consumption alone does not prove faster deburring or better geometry retention.
Compounds are separate from the solid media. Walther Trowal describes compounds for cleaning, corrosion protection, and other application-dependent functions. Its process description treats the machine, media, and treatment agents as a combination. This does not establish a universal liquid, concentration, pH, or compatibility with a workpiece or coating. Walther Trowal consumables.
The VF-M SDS says that the product should not be used dry and discusses dust and mist exposure. The shared Washington Mills SDS distinguishes the supplied non-inhalable form from inhaled particles and reports reaction with strong acids and alkali. These dated safety statements do not qualify a finishing process or establish current exposure limits for a workplace. VF-M SDS, sections 2, 7, and 11, Washington Mills shared SDS, sections 10–11.
Source coverage and applicability
This draft reviews public supplier pages, the six-page Washington Mills Products & Services brochure, and the cited VF-M and shared Washington Mills SDS documents. The brochure and product pages have no explicit technical revision date. Upload-directory dates are not document revisions. Individual Washington Mills technical sheets are behind its login boundary and are outside this coverage. Technical-sheet access page.
The evidence does not establish lot tolerances, complete formulations, standardized grain-size distributions, comparative test conditions, or a qualified finishing cycle. It establishes no customer capability or standards compliance. Publication remains separate from this research review.
Related references cover Finishing process references, ceramic blasting beads, and resin-bonded vibratory media.