A robotics manufacturer in Saitama, Japan working in robotics and automation has an aluminium joint housing whose bearing bore, shoulder and dowel holes must survive deburring intact. SurfacePolish supplies finishing machines, media and compounds across borders and runs a free sample trial: representative parts travel to the factory in Xiamen and come back with observations and a proposed media, compound and cycle direction for the buyer's own review. This brief is written for a buyer in Saitama working on robotics and automation; it describes equipment, media and a scoped sample review, not a local polishing service.
Which alloys and tempers run through the shop, and how will media, machines and compounds be purged between aluminium, stainless and steel work?
What is the size and mass spread inside one part family, and does one machine have to cover both a heavy casting and a small gripper jaw?
Which surfaces on the part are functional, such as bearing bores, dowel holes, seal lands, ground mounting faces and threads, and which are only cosmetic?
Two housings made to the same drawing can need different routes because of alloy and temper. A 6061-T6 machined body is soft enough to smear and peen under a heavy ceramic charge, and it marks where a steel charge has transferred iron. A 7075 part is stronger and cuts differently. Austenitic stainless work-hardens at the surface and responds to media pressure rather than to sharp cutting. Hardened 4140 or a nitrided seat may tolerate only a light edge break, because the finishing step cannot be allowed to remove the case. Castings can open porosity that machining had closed. Record the temper, the hardness range and the heat treatment, and establish whether an anodise, passivation or paint step follows, because that step usually sets the residue and smut limits the finishing cycle has to respect.
Rotary barrel finishing is the gentle end of the range. Parts tumble in a closed drum, usually with plastic or light ceramic media and a generous compound flow, so direct impact is limited and small fragile components such as spools, pins, bushings and screw-machine parts survive. Cycles are long and the drum hides the work while it runs. Magnetic finishing works differently: a small charge of pin-shaped or fine media is driven by a moving field into narrow gaps, small bores and fine internal radii that tumbling media cannot enter, which suits precise items such as orifice plates, small valve spools and fine slot arrays. Its working envelope is small, the pins are a lodging risk in the features they are chosen to reach, and the surface signature differs from tumbling, so a roughness value from one route does not transfer to the other.
| Machine route | Where it fits | What it will not do |
|---|---|---|
| Dry polishing machine and dryer | Removing residual moisture after a wet cycle and reducing water spotting on aluminium and stainless surfaces with pockets and threads | A finishing step only; a dry part can still carry compound film, fines and media dust, so it is not a cleanliness release |
| Tub vibrator | Long parts such as linear-axis beams, manifolds and welded frames that cannot rotate in a bowl | Lower energy per unit area so heavy burrs take longer, and large tubs need floor space and a reliable part support method |
| Grinding finishing machine | Taking off a heavy machining burr, dross or a defined stock layer before a refinement pass on robust steel and stainless work | High removal energy cuts functional edges fast and demands a tighter assessment of what may be removed and how much |
| Disc finishing machine | Fast, high-energy edge breaking and surface refinement on small robust parts and uniform batches of gripper jaws, blocks and fittings | High impingement and edge-loss risk on thin, soft or aluminium parts, and the geometry must suit the disc working gap |
Steel media produces the brightest appearance of the common charges and the highest contact pressure, and it brings a contamination question with it. On aluminium it can embed iron-bearing fragments that show up later as rust spots or as particles in a wiped sample, so a shop that runs both materials needs a changeover discipline, dedicated charges or a different route for the aluminium work. Separation at unload matters as much as the choice: steel media is dense, retains in blind holes and slots, and can only be recovered magnetically if the equipment and the procedure are set up for it. The compound has to keep the charge clean and inhibit corrosion on the parts. A bright result from a steel charge is an observation about a surface, not evidence about cleanliness or fitness for a downstream process.
| Media | Best fit | Watch out for |
|---|---|---|
| Magnetic finishing pins and fine magnetic media | Small precise items such as spools, orifice plates, small valve parts and fine slot arrays where tumbling media cannot reach the feature | Limited working envelope, pins lodge in the same fine features they are chosen to reach, and the surface signature differs from tumbling |
| Plastic cylinders and cones in a harder, denser grade | Longer cycles on mixed batches of small fittings and screw-machine parts where a repeatable light edge break is wanted without ceramic impact | Can float or segregate by shape in a bowl, and cylindrical forms can wedge in slots, keyways and cross-drillings |
| Fine ceramic or porcelain shapes in a small size class | Edge blending and surface refinement after a cutting stage, and reaching tighter external geometry on machined housings and brackets | Small sizes enter and retain in tapped holes and fine slots, and media wear shrinks the charge so the finish drifts over its life |
| Plastic triangles, cones and pyramids in a soft to medium grade | Deburring aluminium housings, gripper plates and other soft alloy parts where surface marking and edge rounding must be kept to a minimum | Slow cut rate, media deforms and wears, and a worn charge behaves noticeably differently from a fresh one |
Parts can pass a finish check and still fail because something moved. Thin machined webs, long beams and unsupported walls relax or distort under tumbling loads, so a housing that measured flat before the cycle fails a flatness or position check afterwards, and a soft aluminium part can pick up a bow that only shows on a surface plate. At the same time, media that cannot reach deep pockets, internal corners or the shielded side of a flange leave the original machining marks intact while the exposed faces are fully refined, and the difference becomes obvious once the part is assembled against a mating surface. Both outcomes are caught by measurement rather than by looking harder at the finish: record flatness, wall thickness and critical dimensions at the same points before and after, inspect at defined locations, and treat the batch record as the first place to look for the cause.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Bearing bore, bore lip or dowel hole edge rounded past the drawing limit | High-energy route, over-long cycle, dense or coarse media, or a functional edge run without masking or a shielding fixture | Measure the defined edge feature before and after with an optical comparator, radius gauge or moulded replica, and compare it with the maximum radius on the drawing |
| Thin plate, cover or housing distorted, bowed or dimensionally drifted after the cycle | Tumbling load on an unsupported thin section, part-on-part contact, or heat and pressure from a high-energy route | Measure flatness, wall thickness and critical dimensions at the same marked points as the pre-process baseline, on a surface plate or CMM |
| Threads rounded, galled or opened out by edge finishing | Media working the thread crest during a long or high-energy cycle, with no plugging or masking on the hole | Run go and no-go thread gauges on every sampled hole, inspect the crest at magnification, and confirm that plugs or masks were fitted and removed |
| Colour change or darkening on an aluminium face after the cycle | Compound chemistry unsuitable for aluminium, no effective corrosion inhibitor, or a delay between finishing and drying | Compare the finished face with an unprocessed coupon of the same alloy under the agreed light, and review the compound product, dose and rinse sequence for the lot |
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.
The nearest part of that base to this brief is machinery: The city's investment guide states that it 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 in ten districts as receptacles for incoming companies.
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.
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.
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.
Ask for a record that says what was actually done, rather than one that asserts a result. A useful batch record lists the part numbers and quantities in the lot, the machine used, the media type and size class, the charge mass and its age since the last screen or top-up, the compound product and dose, the rinse water source, the cycle time and any interruption, plus the inspection results and the lot disposition. Request the media and compound data sheets offered by the supplier. Where aluminium and stainless run in the same shop, ask for the changeover note covering media purge, machine cleaning and compound replacement. This is process documentation from a finishing operation, not a certificate of compliance with any standard, and it supports the buyer's own traceability.
Send parts that represent the real range rather than one convenient sample. Include the part with the tightest hole, slot or cross-drilling, the thinnest unsupported section, the functional surface that must not be touched, and at least one part in its normal as-received condition with the usual burr, chips and cutting oil. Cover every alloy and temper in the family, because aluminium and stainless behave differently under the same charge. Add a coupon of the same material with a known starting roughness so a measurement can be compared before and after. Supply a marked-up drawing naming the controlled surfaces, edge limits and any cleanliness requirement, and a short note on what the part does in service. Several pieces let more than one stop point be examined; one part answers one question.
Cycle time depends on the starting burr, the alloy and temper, the media size class, the compound and how much edge refinement is wanted, so no figure can be quoted in advance. A part that needs only a light edge break runs very differently from one that must shed a milled burr or a recast layer before refinement, and a two-stage route has to count both stages. The useful approach is to test one or two defined stop points on representative parts and record what changed at each. SurfacePolish does not promise cycle times or capacity; treat any timing on returned parts as an observation from that run rather than a production commitment.
There is no single best medium, because aluminium is soft and the trade-off is between cut rate and surface damage. Plastic media is often the safer starting point where a machined face, a thin wall or a bore lip must be preserved, while a fine ceramic cuts faster if the edges tolerate more energy. The deciding variables are the smallest opening a medium could enter, the smallest radius that must not be rounded, and the surface condition the next operation needs. Media size class usually matters more than the broad material name. Send a marked-up part with its tightest feature and one controlled face, and let the trial compare two size classes.
Ask for a record that identifies what was done rather than one that asserts a result. A useful record lists the part numbers and quantities in the lot, the machine used, the media type and size class, the charge mass and its age since the last screen or top-up, the compound and dose, the rinse water source, the cycle time, any interruption, the inspection results and the lot disposition. Request the media and compound data sheets. Where aluminium and stainless are processed on the same site, ask for the changeover note covering media purge, machine cleaning and compound replacement. This is finishing process documentation, not a certificate of compliance.
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 needs the milled edges broken and the external faces evened out without touching the bearing bore or closing a dowel hole.
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-0890; 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-0890 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
Use this local checker to identify missing part and inspection information. It prepares a technical-review brief; it does not approve a machine, process recipe or production result.
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