An aluminium valve body for medical devices that will be hard-anodised after finishing must arrive at the anodiser free of embedded media, residue and rounded seal lands. A buyer in Kobe, Japan can send representative bodies to SurfacePolish, a cross-border supplier of finishing machines, media and compounds, for a free sample trial and a scoped discussion. This brief is written for a buyer in Kobe working on medical devices; it describes equipment, media and a scoped sample review, not a local polishing service.
Who defines and verifies the cleanliness, residue and any regulatory requirement, and by what method and limit?
What edge radius or chamfer is allowed at each mating, sealing and press-fit feature, and how will it be measured?
Which surfaces on this aluminium part carry a cosmetic grade, which are functional seating or sealing faces, and which are indifferent?
Begin by marking up the drawing surface by surface. An aluminium device housing may carry a visible cosmetic face, several machined mating faces that set a seal or a press fit, threaded ports, dowel holes and a thin outer wall, and each has a different finishing tolerance. Cosmetic zones can accept a uniform satin or bright finish; sealing faces and dowel bores need the edge left close to sharp or rounded to a stated radius, and a heavy media cycle destroys that. Note where the customer sees the part after assembly, because a face that meets a cosmetic grade on its own can still look wrong beside an untreated neighbour. A drawing that names, per surface, whether it is cosmetic, functional or indifferent is the cheapest document in the whole finishing project.
A rotary barrel tumbles the load under gravity at comparatively low energy, which makes it a reasonable route for small precise aluminium parts that must not be peened, distorted or made to impinge on each other. It suits high-volume small components such as connector bodies, pins, small fittings and thin machined parts where the requirement is a consistent light deburr and surface refinement rather than heavy stock removal. Two costs come with that gentleness: cycles are longer for the same result, and parts with flats, pockets or low mass can slide rather than tumble, so one face may receive almost no work. Barrel loading, rotational speed, media-to-part ratio and compound quantity all change the result, and an overloaded barrel simply rotates with the mass instead of working it.
| Machine route | Where it fits | What it will not do |
|---|---|---|
| Grinding finishing machine | Higher material removal on aluminium parts that need a heavy burr or a pronounced chamfer removed before a gentler finishing step | Aggressive on soft aluminium, difficult to control on cosmetic faces and functional edges, and not a finishing step on its own |
| Dry polishing machine and dryer | Post-wet drying and dry polishing of aluminium parts before anodising, laser marking, bonding or packaging | Does not remove a burr or refine a surface on its own; residual media dust and incomplete drying still cause marking and coating defects |
| Vibratory bowl finishing machine | Small to medium aluminium components that tumble freely: ferrules, handles, brackets and cover plates needing uniform deburring or satin finishing | Long, tall or heavily recessed parts shadow themselves and finish unevenly; part envelope must fit free circulation in the bowl |
| Disc finishing machine | Fast burr removal and edge radiusing on robust aluminium parts where a short cycle and high material removal matter most | High part-on-part contact and impingement risk; smears soft 6061, is hard to localise, and adds fixturing labour to every cycle |
Media is a consumable that changes as it works, and that change alters the finish. As media wear down they lose mass and edge definition, the charge volume drops, the cut rate falls and the surface result drifts, so a finish that was correct at the start of a media charge may not be reproducible after a week of running. Screen and grade media for size, top up the charge, and replace a fraction on a schedule rather than waiting for the result to move. Cross-contamination is the sharper risk on aluminium: steel media or steel machine parts in the same loop deposit iron on the soft surface, which later shows as black staining, as a galvanic couple under a coating or as an inclusion visible after anodising. Keep media and barrels dedicated to aluminium where finish matters.
| Media | Best fit | Watch out for |
|---|---|---|
| Alumina-based ceramic media, low-density, cylindrical and pin shapes | Internal bores, slots and cross-holes on small aluminium components that a rounded tumbling body cannot reach | Pin and cylinder shapes can wedge in a bore or a slot; confirm retrieval and inspection before running a production batch |
| Ceramic media, spheres and low-density ceramic, fine size class | Bright surface development and light edge work on small aluminium components with mixed cosmetic and internal features | Fine media lodges in blind holes, cross-drillings and thin-wall pockets and is harder to screen out of the load |
| Plastic-bonded media, light to medium abrasive grade, cone and triangle shapes | General deburring and satin finishing on 6061 and 7075 where galling risk rules out dense ceramic | Wears quickly and loses edge definition; cut rate drops as the charge ages and the cosmetic result drifts unless media is screened and topped up |
| Ceramic media, angle-cut triangles, medium size class | Heavy-cut deburring on cast or robust aluminium parts where the machined surface will be finished again or is not appearance graded | Rounds functional edges quickly and can chip or peen thin walls; not suitable where a sealing land or press fit is exposed |
Small media, abrasive grit and magnetic pins can lodge in a blind hole, a cross-drilling, a thread root, an undercut or a thin-wall pocket and stay there through rinsing. A lodged fragment is a functional defect, not a cosmetic one: it can score a mating bore during assembly, come loose inside a device, or sit under a coating. Thin walls make it worse because the pocket deforms slightly under load and grips the fragment. Detect it with a borescope on internal features, by weighing parts against a known-clean reference, by controlled tapping over a white surface, or by an ultrasonic clean followed by inspection of the bath residue. Design the route around it: plug or shield the features that trap media, change the size class, or choose a route whose loading geometry differs. A visual pass is not proof that a cavity is clean.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Galled, smeared or picked surface with transferred aluminium | Media too heavy or too dense for the alloy, insufficient compound lubricity, hot or overloaded charge, aluminium parts rubbing against each other | Inspect under low-angle directional light for smears and cold welds, then wipe with a white lint-free cloth to reveal transferred metal |
| Sealing land or dowel bore edge rounded past the drawing limit | Long or energetic cycle on an unprotected functional edge, sharp-edged media, cumulative material removal across repeated passes | Measure the edge with an optical comparator or radius gauge on a cross-section, or compare a CMM scan of the feature before and after finishing |
| Water spotting, rings or mineral staining after drying | Hard rinse water, slow or incomplete dry, droplets trapped in blind holes or under a flange, no final deionised rinse | Inspect the dried part in raking light against a reference, and check rinse-water hardness and conductivity records for the shift |
| Damaged thread or media wedged in a thread root | Threads left exposed to the media field, sharp media entering the crest, insufficient plugging or masking of ports before the cycle | Run a go and no-go gauge through every sampled thread and inspect the root with a borescope or a thread impression |
Kobe's manufacturing is concentrated in food, transport equipment and general machinery. The city's 2020 Census of Manufacture report counts 1,394 establishments with four or more employees, 67,951 workers and 3,421.1 billion yen of manufactured goods shipments, with value added up 3.3 per cent. It states that food manufacturing and metal products together account for about a quarter of all establishments, and that food, transport equipment and general machinery together account for just over half of employment, with Hyogo ward especially strong in transport equipment and Nishi ward in production machinery and metal products. The city also publishes an economic census and industrial statistics series, and the port has been the city's trade gateway since it opened to foreign trade in 1868.
The nearest part of that base to this brief is machinery: Kobe's 2020 Census of Manufacture report lists general machinery among the three industries making up just over half of manufacturing employment, and records Nishi ward as having high shares of production machinery and metal products.
Kobe's three largest manufacturing employers by industry are food, transport equipment and general machinery, so the surface requirement splits between hygienic, cleanable finishes for food equipment and dimensional, burr-controlled finishes for transport and general machinery parts. General machinery and metal products are concentrated in Nishi ward, where small firms supplying machined components need a finish specification that travels with the drawing rather than a verbal agreement.
A Kobe buyer should separate the two cases before choosing a process: transport and general machinery parts where edge and burr limits govern, and food-equipment parts where cleanability and surface condition govern, because the same media and compound choice will not serve both.
Freight context: Port of Kobe (神戸港), open to foreign trade since 1868, Kobe Airport (神戸空港), opened in 2006. Kobe City records that after the 1995 Hanshin-Awaji earthquake the port's facilities were restored within two years, and that the 2006 opening of Kobe Airport established a combined sea, air and land transport system. Customs clearance in the Kobe area is handled by Kobe Regional Customs, one of Japan Customs' regional offices.
The national standards body is the Japanese Industrial Standards Committee (JISC), which states that JIS covers industrial and mineral products, data, services and management systems under the Industrial Standardization Act. Its technical divisions include mechanical engineering, ferrous materials and metallurgy, nonferrous materials and metallurgy, ceramics, medical equipment and safety appliances, and aircraft and aviation, which are the divisions a finishing or deburring requirement is normally read against. Product certification runs through the JIS Mark Certification Scheme, operated by accredited certification bodies compliant with ISO/IEC 17065; as of March 2019 there were 24 JIS-accredited bodies, three of them outside Japan, with about 8,700 certifications issued, and the scheme explicitly covers foreign manufacturers, processors and exporters.
Documentation and technical communication are Japanese-language in practice: JISC states that the documents submitted for JIS certification-body accreditation must be written in Japanese, and drawings, inspection sheets and purchase specifications from Japanese buyers are normally issued in Japanese. Import declarations are filed in triplicate and importers commonly use licensed customs brokers, so the commercial invoice, packing list and origin documents must be complete and consistent with the declared commodity code. As general industry practice in Japan, industrial buyers qualify a supplier on documentation, quality-management evidence and a defined inspection standard before volume orders, and expect a named Japanese-speaking contact for technical and commercial follow-up.
SurfacePolish supplies from Xiamen, China. The buyer's own destination rules, conformity marking, tariff classification and documentation responsibilities stay with the buyer; confirm them against the authorities named above before ordering.
Residue requirements on a device component come from the buyer's own specification, not from a finishing route, and they should be stated as a measurable limit before parts are accepted. Practical checks include visual inspection of internal features under magnification or with a borescope, a wipe test with a defined solvent and a white substrate, a gravimetric non-volatile residue determination on a rinse sample, and a rinse-water conductivity or particulate count where the assembly is sensitive. Blind holes, threads and press fits are the features that retain residue, so sample them specifically rather than only a flat exterior face. If a validated cleaning process, biocompatibility data or a sterility claim is needed, that work belongs to the buyer's own quality system.
The first good batch is not the hard part; holding the finish over weeks is. Media wear, the charge volume falls, fines accumulate in the compound, screens clog and the rinse water changes, so the same timer produces a different result as the charge ages. Drift shows first as a slightly duller surface, a burr that reappears at a bore exit, or a finish that no longer matches the retained reference. Control it with a media top-up and replacement rule based on screening rather than the calendar, a compound concentration and pH check each shift, a rinse-water quality check, and a first-article comparison against the retained reference at the start of every batch. Any change of media supplier, compound, water supply or machine setting invalidates the previous baseline and should be treated as a new first-article event.
It does. Anodising is partly transparent over the underlying texture, so machining marks, media direction and any residual film remain visible, and embedded media or a silicate deposit can show as a bloom or speckle. Aluminium also needs a clean, freshly finished surface, because a slow dry or a contaminated rinse leaves an oxide or residue layer that shows through the coating. A buyer planning a cosmetic anodised finish should evaluate appearance on an anodised sample rather than on bare metal, and should specify the rinse, dry and handling expectations to the finishing supplier. Acceptance of the coating itself remains with the buyer and the anodiser.
No. SurfacePolish is a cross-border supplier of finishing machines, media and compounds and runs a free sample trial on parts the buyer sends. A trial reports observations on the parts tested under the settings used; it does not qualify, approve or validate a process, and it does not create biocompatibility, cleanability, sterility or regulatory documentation. Any requirement of that kind must be defined by the buyer and verified by the buyer's own engineering and quality functions, usually with the help of specialist testing providers. For a device programme in Japan, treat the finishing route as one input into the buyer's own verification plan rather than as evidence for it.
Send representative parts, including the worst case: the thinnest wall, the tightest sealing edge, the deepest tool mark, a casting with visible porosity, the smallest hole and the feature most likely to trap media. Include two or three pieces of each condition, an untreated reference part, and a note of the alloy and temper, the part number, which surfaces are cosmetic and which are functional, and the edge radius or chamfer allowed at each critical feature. State the current process, the defect that prompted the enquiry and the downstream operation, whether anodising, laser marking, bonding or assembly. The clearer the part definition, the more useful the observations returned.
Use Kobe, Japan as the destination on the enquiry and state whether the deliverable is equipment, media and compound, a representative sample review or a line concept. A destination does not imply local stock, a local service point or a local delivery time.
Kobe buyers reference JIS, maintained by the Japanese Industrial Standards Committee, whose mechanical engineering and ferrous materials divisions cover the city's machinery and transport-equipment output, with the JIS Mark scheme available for third-party product certification. For food-equipment work the additional reference is the customer's hygiene and cleanability requirement, which is specified on the drawing rather than by a general finishing standard.
Sources were retrieved on 2026-09-29 and describe the local industrial and trade context only. They do not evidence any SurfacePolish project, shipment, installation or service in Kobe.
The buyer needs the deburring cycle to leave the sealing land flat and the thread clean, and to leave a surface that anodises without a visible bloom.
Send the material, dimensions, approximate weight, batch quantity, the incoming condition and photographs of the difficult features. Mark which features must not be contacted by media and state how the result will be inspected. This form carries source reference PSEO-0853; quote it if you prefer an additional manual reference.
Open the SurfacePolish enquiry form Email a prepared enquiry
No price, lead time, certification or result is promised here. Confirm whether a sample trial is available for the specific part and what the trial can and cannot show.
Page PSEO-0853 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
Email : info@surface-polish.com
IPv6 network supported 
+86-592-2381506 