An aluminium stage plate for medical devices is mostly datum: dowel holes, a tapped pattern and a flatness callout leave very little room for rounding or distortion. A buyer in Saitama, Japan can send a representative plate to SurfacePolish, a cross-border supplier of finishing machines, media and compounds, for a free sample trial. This brief is written for a buyer in Saitama working on medical devices; it describes equipment, media and a scoped sample review, not a local polishing service.
What is the minimum wall thickness and unsupported span, and which internal features could trap media?
What are the alloy and temper, and has machining, casting, welding or heat treatment already changed the surface hardness and porosity?
What edge radius or chamfer is allowed at each mating, sealing and press-fit feature, and how will it be measured?
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.
Disc finishing machines generate high energy at the disc face and remove material and round edges quickly, which is attractive when a batch of aluminium parts needs a burr gone in a short cycle. That same energy is what makes them risky on soft wrought aluminium and on thin castings. Part-on-part contact is high, so parts impinge, peen each other and develop a hammered or uneven surface, and 6061 will smear rather than cut if the compound is wrong or the load too heavy. Fixturing helps: a carrier that holds each part in a fixed attitude reduces random contact but adds load and unload labour to every cycle. Disc routes are also unforgiving on edge control because removal is neither uniform nor easy to localise. Use them where a robust part needs a fast radius.
| 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 |
| 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 |
| 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 |
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 |
|---|---|---|
| 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 |
| 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 |
| Dry media, corn cob with a polishing compound charge | Final dry polish and drying assistance on small aluminium parts where a wet rinse and dry would leave spotting | Compound loading saturates with use and the media cakes; the charge needs regular replacement, and soft aluminium can still smear |
| 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 |
Parts that do not circulate freely receive uneven work. In a bowl or barrel a long part, a heavy part or a part with a deep recess can sit in one attitude, shelter its own face, or trap a neighbour against the wall, leaving a bright band beside a dull one. Impingement is the more visible version: two parts strike each other repeatedly and produce dents, peened patches, scratches or a hammered texture that will not polish out without further material removal. The cause is usually charge geometry rather than media: wrong load ratio, media too large to flow around the part, insufficient compound lubricity, or a fixture that holds parts where the media field is weak. Check under directional light and compare several parts from different positions in the load, not one sample from the discharge gate.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Uneven finish with bright and dull bands on the same face | Part settling in one attitude, self-shadowing on a long or recessed part, wrong load ratio, media too large to flow around the geometry | Compare several parts taken from different positions in the load under directional light rather than sampling only the discharge gate |
| 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 |
| Bloom, bleed-out or staining appearing days after finishing on a casting | Porosity holding compound or rinse water, an as-cast skin opened by the cycle, incomplete drying before packaging or anodising | Hold finished castings for a defined period and re-inspect, and section a rejected part to confirm whether the residue originates in the pores |
| Etched, darkened or chalky surface after wet finishing | Compound pH or concentration outside the aluminium working range, over-alkaline product, long dwell in a hot solution, exhausted compound | Compare a dried part against a retained reference under the customer's lighting, and log compound pH, concentration and temperature for the batch |
Saitama City positions itself as a Greater Tokyo business and logistics location: its official investment guide states that the city supports the siting of research facilities, manufacturing plants and distribution facilities with one-stop administrative service, and that it is preparing new industrial accumulation sites as receptacles for incoming companies in ten districts. The guide also cites the city's medical-device manufacturing initiative (さいたま医療ものづくり都市構想) as part of its location support. The city has a dedicated policy for creating logistics-facility induction districts, justified in part by securing supplies and logistics during disasters. A separate municipal project relocates and rebuilds the central meat wholesale market together with a roadside-station-based agri-food distribution and tourism hub.
For this brief the relevant part of that base is medical: The city's investment guide lists medical-device manufacturing support (さいたま医療ものづくり都市構想) among its business-location services.
Medical-device manufacturing in the area puts cleanliness, edge quality and surface integrity on the critical path, because burrs or embedded media on a diagnostic or device component are a quality and documentation issue rather than a cosmetic one. General machinery and sheet-metal fabrication in the city's industrial parks needs consistent deburring and edge break before coating, welding or assembly, so one process specification rarely fits both groups.
A Saitama buyer should first decide which regime the part falls under - medical-device-related work where cleanliness and surface integrity must be documented, or general machinery where edge break and roughness callouts dominate - because that choice determines whether the sample trial has to include cleanliness verification as well as dimensional and visual checks.
Freight context: Designated 物流施設誘導地区 (logistics-facility induction districts) in Saitama City. Saitama City creates logistics-facility induction districts for facilities meeting the legal definition of a specified distribution business facility (特定流通業務施設), and it requires disaster-resilience measures and a disaster-time cooperation agreement - a sign of the city's role as a metropolitan distribution base. The city has no seaport, so freight for machines and samples moves by road and rail.
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.
Chinese industrial machinery entering Japan is classified under the Customs Tariff Law, whose harmonised schedule sets the classification and the General Rate; the Temporary Tariff Measures Law sets a Temporary Rate for certain products, and where the WTO rate or an EPA rate for the goods is lower, that lower rate is applied. The applied rate therefore depends on the exact commodity code, and on whether an economic partnership agreement covers the goods and their origin, so a landed-cost figure has to be confirmed against the specific machine before it is quoted. Japan Customs' monthly country table for August 2026 records exports to China of 1,809,133 million yen and imports from China of 2,361,239 million yen, the largest single-country line in the Asian table, with imports from China up 22.5 per cent year on year.
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.
Treat the first finished part of every batch as a first article and hold it until it has been checked against the agreed criteria. Record the part number, alloy and temper, the machine and route, the media charge identity and its accumulated hours, the compound and concentration, the cycle time, the load ratio and the drying step. Retain a reference part from the accepted first article, and when a later batch differs, compare the two physically before adjusting anything. Segregate batches by alloy and part number, and keep the aluminium loop separate from steel work so iron cannot transfer onto a soft surface. This discipline, not the machine settings, is what makes a finish reproducible. Who performs the checks and who signs the release is a buyer decision, but the record of what was run is worth keeping.
A sample trial produces observations on the parts that were tested, under the settings that were used, on the equipment that ran them. It does not guarantee a roughness value, an appearance grade, an edge radius, a dimensional result, a cycle time, a capacity or a production cost, and it does not qualify, approve or validate a process for a medical device or any regulated application. It cannot prove biocompatibility, cleanability, sterility, corrosion life or a cleaning validation, and it does not create a specification the buyer can rely on for regulatory purposes. Those determinations belong to the buyer's own engineering and quality functions, working to their own requirements. What a trial can do is show whether a mechanical route is plausible for a part and which media and compound direction is worth pursuing.
No. A trial shows what happened on the parts tested, with the media, compound and cycle used at that time. It does not guarantee a roughness value, appearance grade, edge radius, dimensional result, cycle time, capacity or cost in production, and it cannot cover the drift that comes from media wear, compound carry-over, water changes or a different machine. What it can do is indicate whether a mechanical route is plausible, which media and compound direction deserves a closer look, and which features need protection. A buyer in Japan should plan a first-article routine and retain a reference part before releasing a production batch.
A bowl vibrator circulates a load through a media field at moderate energy, with good uniformity on small parts that tumble freely and easy discharge. A centrifugal barrel presses media and parts together at high force in a much shorter cycle, producing a fine finish and controlled edge quickly, but bending thin walls, distorting light sections and rounding edges faster. Bowl routes suit mixed small parts and gentle work; centrifugal routes suit a narrow part family that fits the barrel and accepts the energy. Parts made in Japan should be trialled in the specific geometry before a machine size is fixed, because barrel dimensions limit part length and load size.
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.
Use Saitama, 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.
Japanese buyers work to JIS (Japanese Industrial Standards) administered through the Japanese Industrial Standards Committee (JISC), which also maintains the market-creation standardisation scheme run with METI; drawings normally cite JIS or customer standards for surface finish and material conformity. For medical-device-related work, customers add their own cleanliness and quality-system requirements on top of ISO 9001 as general industry practice.
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 Saitama.
The buyer must remove machining burrs from the hole pattern without moving the dowel hole edges or disturbing the plate's flatness.
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-0883; 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-0883 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
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