A gripper and tooling maker in Kobe, Japan working in robotics and automation has a recurring batch of small machined jaws where the edge break has to be consistent without losing the pivot hole or the serrated face. SurfacePolish supplies finishing machines, media and compounds across borders and runs a free sample trial, returning a representative batch with observations and a proposed media, compound and cycle direction for the buyer to compare. This brief is written for a buyer in Kobe working on robotics and automation; it describes equipment, media and a scoped sample review, not a local polishing service.
What is the smallest hole, slot, keyway or cross-drilling the charge must not enter or plug, and how will a lodged medium be detected and removed?
What does the finishing step actually have to deliver before the next operation, whether that is assembly, anodising, painting or a functional test, and who defines that requirement?
How much of the incoming contamination, cutting oil, machining chip and handling damage is expected to be removed by finishing rather than by an earlier operation?
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.
Long parts and heavy parts both fall outside a round bowl. A tub vibrator uses a rectangular chamber, so the working length extends along one axis while the bed stays shallow, which suits linear-axis beams, long manifolds and welded frames that cannot tumble end over end. The part is immersed or supported rather than turned, which removes bending risk from a divider, but energy per unit area is lower and a heavy burr takes longer. A grinding finishing machine works the other way, using higher removal energy to take off a defined layer or a heavy machining burr before refinement. That route cuts functional edges quickly and needs a tighter assessment of what may be removed. The deciding questions are part length, mass, how the part can be supported, and whether the critical face can be presented to the media at all.
| Machine route | Where it fits | What it will not do |
|---|---|---|
| Magnetic finishing machine | Fine deburring and light refinement of small precise features such as small bores, narrow slots and fine internal radii | Small working envelope that excludes housings and long parts, with pin media that can lodge in the fine features it reaches |
| Barrel finishing machine, rotary barrel tumbling | Gentle deburring of small fragile parts and mixed batches of screw-machine components with a generous compound flow | Long cycles, no visibility while running, and internal features can collect media and compound that must be retrieved at unload |
| 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 |
| 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 |
Compound carries debris away, keeps the media from loading and buffers the chemistry against the metal. Alkaline and neutral families are common for general deburring and cleaning; acidic families may be chosen where a descale or brightening effect is wanted; silicate-bearing products can leave a tenacious film that is hard to remove from a bore or a sealing land. On aluminium an effective corrosion inhibitor usually matters, because the wrong chemistry darkens the surface during or after the cycle. Concentration, flow and temperature shift the result, so dosing should be metered rather than judged by eye, and rinse water hardness, chloride content and suspended solids all affect foaming and what remains behind. Where an anodise or paint step follows, the film and smut left by the cycle become the buyer's problem, so define how the surface will be checked.
| Media | Best fit | Watch out for |
|---|---|---|
| Steel media, including balls and shaped pins | Bright finishing and edge blending on stainless automation components where appearance and a burnished surface matter | Transfers iron to aluminium and carbon steel, needs a corrosion-inhibiting compound, and must be separated magnetically or by screen at unload |
| 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 |
| 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 |
| Aluminium oxide grinding media in a dense ceramic bond | Heavier stock removal or a more consistent cut on robust steel and stainless parts with thick edges and a defined layer to remove | High removal energy rounds functional edges quickly and is a poor match for thin aluminium plates, cast housings and bore lips |
A medium left in a tapped hole or a cross-drilled passage usually escapes the finishing area and is found later at assembly or at a functional test. It happens when the size class is too close to the opening, when a charge has worn or fractured into smaller pieces, or when a passage was never mapped as a retention risk. Tapped holes, keyways, seal grooves, cross-drillings and slots whose width approaches the media section are the usual places. Retrieval has to be designed rather than assumed: count the charge in and out where practical, use a pin or thread gauge on sampled holes, borescope the smallest passages at an agreed angle, and rinse through a filter for a visual check. Any medium found is a non-conformance to record, not something to wipe away and release.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Uneven finish with unrefined pockets, internal corners or the shielded side of a flange | Media cannot reach the feature at the chosen size or orientation, charge circulation is blocked, or the part was never repositioned during the cycle | Inspect at defined locations rather than judging the whole part, photograph the same feature before and after, and measure roughness only at the surfaces the drawing controls |
| Water spotting, mineral rings or haze left after wet processing and drying | Hard or high-chloride rinse water, slow or uneven drying, or parts stacked wet so moisture is trapped in pockets and threads | Inspect dried parts under angled light for rings and haze, check the rinse water source and the drying method, and confirm that pockets and tapped holes drain before packing |
| 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 |
| Burr remaining inside a cross-drilled intersection or an internal corner | Media too large to enter the intersection, part orientation that shields the feature, or a cycle stopped before that feature was reached | Borescope the intersection at a fixed angle, compare with a first-article reference, and use a pin or probe to feel for a lip on sampled parts |
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 automotive: Kobe's 2020 Census of Manufacture report lists transport equipment manufacturing among the three industries that together account for just over half of manufacturing employment, and records Hyogo ward as having a high share of transport equipment.
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.
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 customs authority is Japan Customs, the Customs and Tariff Bureau of the Ministry of Finance, with regional customs at Tokyo, Yokohama, Nagoya, Osaka and Kobe. Any person importing goods must declare them to the Director-General of Customs and obtain an import permit after examination and payment of customs duty and consumption tax. The declaration is normally filed by the importer or by a customs broker acting as proxy, on a triplicate import (customs duty payment) declaration form (Customs form C-5020) supported by the invoice, the bill of lading or air waybill, a certificate of origin where a WTO rate applies, certificates of origin for preferential rates, packing lists and freight and insurance documents where required, plus any licence or certificate demanded by laws other than the Customs Law. More than 90 per cent of import procedures are computerised. A JIS Mark certificate is a separate, voluntary third-party scheme; foreign exporters are eligible to apply, and certification bodies must comply with ISO/IEC 17065.
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.
A sample trial answers a narrow question: what happened to these parts under these settings on this equipment. It does not prove that a production lot will be uniform, because load ratio, media age and operator practice all shift the outcome, and it does not transfer a result from a coupon to a complex housing. It cannot establish a particle count, a cleanliness level or fitness for any regulated application, and it does not show whether a machine or medium is approved or qualified for a buyer's process. It cannot establish a cycle time, a cost per part, a capacity or a delivery schedule, and it says nothing about how the surrounding handling or automation should be arranged. Treat the returned parts and the settings record as evidence for the buyer's own engineering and quality decision, and plan the production route with its own first-article and sampling discipline.
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.
A trial shows what a given machine, charge and setting did to the parts tested, which is useful evidence but not a sizing study. Machine size depends on the largest envelope and mass in the family, the smallest part that must meet the same appearance, the load ratio you intend to run, and how many stages the part needs. Those are planning questions that belong in a line-concept discussion alongside the trial result. A part tested on a small machine may behave differently in a larger chamber, and a part run in a full production load may come out differently from one run in a light trial batch. Record both the settings and the load.
A bore cannot be protected by the cycle alone; it is protected by what is decided before the cycle. Masking or plugging the bore, keeping the part out of contact with heavy neighbours, choosing a lighter route and shortening the cycle all reduce the load the bore sees, but none of them guarantees a dimension. That is why the bore must be measured before and after at the same points, with a bore gauge or CMM, and compared with the drawing limit. SurfacePolish does not promise a tolerance or a result; the trial reports what was observed on the parts tested, and the dimensional acceptance decision stays with your own metrology and quality functions.
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 a consistent light edge break across the batch without rounding the pivot hole or blunting the serrations.
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-0860; 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-0860 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
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