A buyer in Tokyo, Japan finishing a 6061-T6 instrument housing for medical devices has to hold two requirements at once: a satin face the customer will see, and an O-ring groove edge that must stay within a stated radius. SurfacePolish supplies finishing machines, media and compounds across borders and runs a free sample trial on the parts the buyer sends. This brief is written for a buyer in Tokyo working on medical devices; it describes equipment, media and a scoped sample review, not a local polishing service.
What are the alloy and temper, and has machining, casting, welding or heat treatment already changed the surface hardness and porosity?
Who defines and verifies the cleanliness, residue and any regulatory requirement, and by what method and limit?
What is the minimum wall thickness and unsupported span, and which internal features could trap media?
Controlled edge rounding is where a finishing route earns or loses its place. Every machined aluminium edge carries a burr and a stress concentration, and a deburring cycle removes both, but it also moves the edge position. On a mating face, a seal groove, a bearing seat or a dowel hole that movement is a functional change, not a cosmetic one. Establish the allowed edge radius or chamfer per feature, then measure the finished edge against it rather than judging by eye, using an optical comparator or a radius gauge on a sectioned or replica sample. A part with generous cosmetic edges and one tight sealing edge usually needs a shielded fixture or selective hand finishing after the machine cycle. Deciding this after the first batch has run is how an assembly ends up with a leak path.
Aluminium reacts to both strong acid and strong alkali, so compound chemistry deserves more care here than on steel. A mildly alkaline or near-neutral cleaning and burnishing compound with a suitable inhibitor is the usual starting point for aluminium, because a strongly alkaline product etches the surface, darkens it and attacks exposed edges, while a strongly acidic one can pit it and leave smut. The compound also carries debris and controls foam, lubricity and rinsing, so concentration and flow rate matter as much as family. Water quality is part of the chemistry: hard water leaves mineral spotting and deposits, chloride content in the supply raises a corrosion concern on aluminium, and a recirculated system concentrates fines and dissolved metal over time. Set a working range for concentration, pH and flow, then monitor and correct it during the shift.
| Media | Best fit | Watch out for |
|---|---|---|
| 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 |
| Plastic-bonded media, ball and ellipsoid shapes | Surface refinement and blending on cosmetic aluminium faces where edges, seal lands and dowel bores must stay close to drawing | Removes very little edge material, so a burr at a bore exit or a thread crest may survive the cycle and need a separate step |
| 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 |
| Dry media, walnut shell, fine grade | Dry polishing, light surface cleaning and preparation before anodising or laser marking on aluminium parts | Shell dust must be extracted and the part cleaned, or the residue interferes with marking, bonding or a later coating step |
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 |
|---|---|---|
| Magnetic finishing machine | Small aluminium parts with fine internal features such as cross-holes, slots and recesses that tumbling media cannot reach | Small working envelope and low throughput; pins and fine media can lodge in blind features, and mixed part families are awkward |
| 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 |
| Tub vibrator | Long and large aluminium parts such as extruded frames and housings that can be oriented in a linear working channel | Slower uniform coverage, a tendency for parts to settle in one attitude, and greater floor space and media volume than a 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 cannot tell a cosmetic edge from a sealing edge, so a cycle that breaks a burr nicely on the outside of a housing can round a seal land, a dowel bore or a press-fit shoulder until it no longer functions. The drift is gradual and cumulative: each pass removes a little more material, and a batch that was within tolerance at the start of a media charge may be outside it by the end. Watch for a seal face that has lost its flat land, a bore edge closed to a radius, or a chamfer grown past the drawing. Detect it with an optical comparator or radius gauge on a cross-section, or by measuring the feature with a CMM before and after. Protection comes from shielding the functional edge, rounder and lighter media, and a first-article check.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Finish bloom or speckle, or poor laser mark contrast, revealed after anodising or marking | Embedded media, a silicate or residue film, a directional texture that marks unevenly, or an oxide layer from a slow dry | Evaluate the appearance on a coated or marked sample rather than bare metal, and compare marking contrast on parts from different positions in the load |
| 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 |
| Media or abrasive fragment lodged in a blind hole, cross-drilling or thin-wall pocket | Media size class too small for the feature, unshielded pockets, flexing thin wall gripping the fragment, no dedicated retrieval step | Borescope the internal features, weigh against a known-clean reference, tap over white paper, and inspect the residue from an ultrasonic clean |
| 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 |
Tokyo's manufacturing is concentrated in the eastern wards rather than spread evenly across the metropolis. Ota City states that the number of manufacturing establishments in Tokyo is largest in Ota, and describes itself as a metalworking town of small and medium firms; about 3,500 manufacturing establishments are counted there (2021 Economic Census). The ward's core 'base technologies' are cutting, pressing, forming, grinding, casting, forging and plating, and it reports that these support fields extending from automobiles to medical equipment and aerospace, with Naka-Ikegami concentrating industrial equipment makers and Omori-nishi concentrating electro-mechanical manufacturers. Multi-product, small-lot production and prototyping and R&D work are named as strengths of the district.
For this brief the relevant part of that base is medical: Ota City states that the ward's base technologies support fields from automobiles to medical equipment and aerospace.
Ota's base-technology list explicitly includes grinding and plating, and the ward reports that its firms are specialised by process step and linked across steps to achieve high-precision, compound machining and short lead times. In a district built on multi-product, small-lot work and prototyping, deburring, edge condition and pre-plating surface cleanliness are process-step decisions rather than finishing afterthoughts, because each downstream firm in the chain inspects what the previous step delivered.
Because Ota's supply chain is organised by process step, a Tokyo buyer should decide first which step owns the edge condition — the machining shop, the grinder or the plater — and specify burr and edge limits on the drawing so the requirement is not re-negotiated at each hand-off.
Freight context: Port of Tokyo (東京港) — container terminals including Oi, with the port's hinterland covering the 40-million-person Greater Tokyo area, Shinetsu and southern Tohoku, Haneda Airport (羽田空港, Tokyo International Airport), located in Ota City's waterfront. The Port of Tokyo is described by the Tokyo Metropolitan Government as an urban general port handling goods needed by the metropolis' industry and residents, with imports accounting for two thirds of cargo volume by in/out direction. The Tokyo Metropolitan Government reports Port of Tokyo container throughput of 4.86 million TEU for 2025, 3.3 per cent above 2024, so containerised receipt of machines and dispatch of sample parts runs through the same port complex.
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.
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.
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.
A roughness number without a location and a cut-off is not a specification. On an aluminium device component, name each surface that carries a roughness requirement, the direction of measurement relative to the machining or polishing marks, and the cut-off and evaluation length to be used, since a profile measured over a short length with a short cut-off reads differently from one measured across the full face. ISO 4287 and ISO 4288 describe profile parameters and the rules for selecting cut-off, ISO 25178 covers areal texture if a three-dimensional description is needed, and ASME B46.1 is the equivalent North American reference. Aluminium is soft, so stylus force and tip radius can mark the surface being measured; agree the instrument and the force, or use an optical method, and retain the measured part as the physical reference.
A sample trial is most useful when it isolates one change. If media family, size, compound and cycle time all change together, a difference in the result cannot be attributed to anything and the trial cannot be repeated. Ask for a small matrix: the same parts run with two media families at the same cycle, or the same media at two cycle times, with every other condition held constant and a record of the settings used for each cell. Photograph or measure each result on the same features under the same lighting, and keep an untreated reference beside them. Reproducibility deserves attention too: one good part proves little, so ask whether the result repeated on the other pieces in the charge. A trial yields observations on the parts tested, not a guaranteed production result.
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.
Lodging is a geometry problem before it is a media problem. Blind holes, cross-drillings, thread roots, undercuts and thin-wall pockets trap fragments, and a pocket that flexes under load grips them harder. Options include shielding or plugging the trapping features, changing the media size class so pieces cannot enter, moving to a route whose loading geometry differs, and adding an inspection step with a borescope or a weighed reference part. A visual pass on an exterior face proves nothing about a cavity. For parts made in Japan, agree with the buyer which internal features are checked and how, before the first batch is run.
Laser marking interacts with surface texture, so contrast depends on whether the surface is directional, random satin or bright. A strong directional finish from a tub or a linishing step can produce a marking that reads differently when the part is turned, while a uniform random texture marks more consistently. Residue and embedded media also interfere, because the marking energy meets a contaminated surface. For a marked cover plate in Japan, the practical sequence is to fix the finish first, then qualify the marking programme on finished parts, and to check the mark under the lighting the end user will use rather than a bench lamp.
Use Tokyo, 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.
Tokyo buyers work to JIS, maintained by the Japanese Industrial Standards Committee, with the mechanical engineering and ferrous materials divisions covering machined metal parts; the JIS Mark scheme provides third-party product certification, and foreign exporters are eligible to apply. Drawings and inspection sheets issued by the customer, not a generic finishing standard, define the acceptance criteria for burrs, edge radius and surface texture.
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 Tokyo.
The buyer needs a uniform satin cosmetic face without rounding the O-ring groove edge or driving media into the threaded bosses.
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-0803; 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-0803 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
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