A buyer in Tokyo, Japan working on energy equipment has an Inconel turbine disk whose broached rim slot edges need a consistent break without disturbing the profile. SurfacePolish supplies finishing machines, media and compounds across borders and runs a free sample trial, sending representative parts to Xiamen and returning them with an observation record plus a proposed media, compound and cycle direction for the buyer's engineers. This brief is written for a buyer in Tokyo working on energy equipment; it describes equipment, media and a scoped sample review, not a local polishing service.
What must the part be clean of, and what method and limit does the buyer use to verify cleanliness before assembly, welding, coating or a leak test?
Does the drawing state an edge break or an edge round at each controlled edge, and what maximum radius applies where over-rounding is the risk?
Which edges on this part are functional, such as gasket lands, seat bands, stem guides, metering lands and thread entries, and which only need to be free of a sharp edge?
Treat the batch, not the individual part, as the unit that gets controlled. A charge holds a defined mass of parts sharing a material family, a burr condition and an edge requirement. Mix a thin heat-exchanger plate with a heavy valve body and the light part absorbs energy it did not need while the heavy part shields its own critical edges. Batch definition also fixes traceability. If two heats of duplex stainless or two casting lots run together, a defect found later cannot be tied back to a charge, a media age or a compound batch. Keep part numbers, material grades and heat-treatment states in separate runs, label the charge, and record how many parts were loaded and in what orientation.
Shape and size class decide where the charge can go and how it cuts when it gets there. An angle-cut triangle presents a point and a sharp edge, so it works into a corner or a thread entry and cuts hard; a sphere rolls and makes softer, more uniform contact; a cylinder or oval lies along a face and blends rather than digs. Size then sets the access limit: the medium must be comfortably smaller than the smallest opening it is expected to clear, and comfortably larger than any opening it must never enter. Those two constraints are often only a size class apart, which is why thread entries, cross-drillings and slot widths need listing before a charge is ordered. Media that fractures in service defeats the original sizing, so screen the working charge.
| Media | Best fit | Watch out for |
|---|---|---|
| Heavy-cut ceramic, angle-cut triangles in a coarse size class | Removing a substantial or thick burr root from open external edges, flange corners, cast bosses and large tapped entries on steel and stainless parts | Cuts controlled edges and gasket lands as readily as burrs, leaves a coarse surface, and lodges in slots whose width approaches the media section |
| Alumina-bearing grinding media in a dense ceramic bond | Heavy stock removal and consistent cutting on hard or work-hardened parts with generous edge limits, such as robust flanges and heavy fittings | High removal energy rounds functional edges quickly and is a poor match for thin plates, thin-wall castings and lapped sealing faces |
| Hardened steel media, balls and pins | Burnishing and bright finishing of stainless and hardened parts, and light edge consolidation where a cutting action is not wanted | Changes the surface by deformation rather than cutting, can work-harden or smear a soft surface, and needs corrosion protection and separation from acidic compounds |
| Magnetic pin or needle charge | Reaching small internal intersections, radial holes and thread entries on small precision parts such as spools, sleeves and drilled fittings | Limited by part size and shape, pins must be retrieved and inspected for breakage, and the result depends heavily on fixture and field design |
Geometry decides the machine frame before any setting does. A bowl vibrator needs the part to move freely in the charge; a long manifold body, a shaft or a stacked plate set cannot tumble that way and belongs in a tub where it can be carried, rotated or supported along its length. Mass matters as much as length: a heavy valve body sinks in a small charge and stalls the part-on-media motion, so either the charge grows or the machine size grows. Thin plates need the opposite treatment, a low load ratio and separation so they are not driven into each other. Before comparing machines, list the largest and smallest envelope in the batch, the heaviest single part, the longest unsupported span and any feature that cannot bear load. Those four numbers eliminate most of the catalogue.
| Machine route | Where it fits | What it will not do |
|---|---|---|
| Grinding finishing machine | Heavier stock removal and thick burr roots on robust parts where clearing material in a shorter cycle matters more than the surface result | Aggressive edge rounding and a coarser surface, so it fits lapped seats, thin sections and tight edge bands poorly |
| Barrel finishing machine and rotary barrel tumbler | Gentle, low-impingement deburring of small, fragile or precision parts and mixed fitting batches where edge protection matters more than speed | Long cycles, no visibility while the barrel runs, and internal features can collect media and compound that must be retrieved at unload |
| Tub vibrator | Long parts such as manifold rails, shafts, long housings and stacked plate sets that cannot tumble in a bowl, with support or rotation along their length | Lower energy per unit area so heavy burrs take longer, and the tub needs floor space plus a defined part support method |
| Disc finishing machine | Fast, high-energy cycles on small to medium robust parts, including batches of fittings and small housings that need a quick cut | High contact pressure rounds edges quickly and can mark or deform thin and soft parts, with results sensitive to load and disc condition |
Media lodging is a geometry and media-condition problem, and it concentrates at intersections. A cross-drilling breaking into a bore, a blind tapped hole, a keyway, a snap-ring groove and a slot whose width approaches the medium section are all traps. The usual causes are a size class chosen against an average feature rather than the smallest one, a charge that has fractured into smaller pieces, and a secondary burr or fold that closes part of the opening while the part is running. Retrieval often costs more than the deburring itself, especially where the trap is inside a body that cannot be opened. Plan detection before the run: which passages are borescoped at an agreed angle, which holes are pin gauged, how a flush through a filter is collected, and how the part mass is compared.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Ferrous specking, rust staining or graphite smearing on stainless parts after a shared run | Carbon steel or cast iron fines carried over in the charge, machine, rinse tank or drying cloth, or a purge that was too short between material families | Compare against a retained reference part, inspect suspect areas at magnification, examine the charge and rinse for embedded ferrous fines, and review the changeover record against the batch history |
| Staining, pitting or a corrosion question on a hardened high-strength part after a wet cycle | Acid-bearing compound or contaminated rinse water, long dwell between finishing and drying, or no protective rinse for the interval before the buyer's next operation | Inspect within an agreed interval after drying, wipe a defined area with a white cloth, compare against a retained reference, and route any embrittlement question to whoever owns the downstream coating or plating specification |
| Media fragments or abrasive fines embedded in a soft surface or machined groove | Impingement from excessive energy or charge mass, fractured media left in the working charge, or cross-contamination from a previous material family | Inspect at magnification under angled light, use a tape lift or solvent wipe on the suspect area, and screen the charge for broken media and accumulated fines |
| Tenacious compound film or reaction residue left in a gasket groove, thread or blind hole | A film-forming or silicate-bearing compound, insufficient rinse volume or temperature, or drying the part before it is genuinely clean | Wipe a defined area with solvent against a clean reference, check for a continuous water film on a rinsed sample, and inspect recessed features at magnification before packing |
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.
The nearest part of that base to this brief is automotive: 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.
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.
Edge acceptance needs a reference object, because words like lightly broken or slightly rounded mean different things to different inspectors. Build a physical or photographic master at a stated magnification: a part or coupon showing the acceptable edge, the borderline case and the reject. For each controlled edge, express the requirement as either an edge break, meaning the sharp corner is removed to a small defined size, or an edge round, meaning a controlled radius band the edge must sit inside. Give a maximum where over-rounding is the risk, and a minimum where the edge must not stay sharp. State how the edge will be checked, whether by radius gauge, optical comparator, moulded replica or tactile comparison against the master, and at what frequency.
The value of a sample trial comes from the range of parts sent, not from the quantity. A box of identical nominal parts tests one geometry and one burr condition; it cannot show how the proposed route behaves on the tightest passage, the thinnest wall or the hardest material in the family. Send a small set chosen to cover the extremes: the part with the smallest internal opening, the part with the longest unsupported section, the part with the most protected edge, one part in the hardest heat-treatment state the family sees, and one as-received reject that already fails. Label every part so its identity survives the trip, and send enough pieces that some can be sectioned or measured destructively.
Size the charge well below the smallest opening it could enter, and treat every passage as a retrieval point rather than assuming it stays clear. List the tightest hole, slot, thread and cross-drilling first, then choose a size class against that geometry instead of the average part. Screen the working charge, because fractured media produces smaller pieces that defeat the original sizing. Plan detection: a borescope at an agreed angle, a pin gauge in every tapped hole, a count of the charge in and out where practical, a flush collected through a filter, and a part mass check. For Tokyo buyers preparing a trial, include the smallest passage.
Use more than one method, because each misses something. Visual inspection under angled light at magnification catches obvious sharp edges, wire edges and remaining burr fragments. A tactile check with a probe, a fine needle or a lint-free wipe drawn along the edge catches lips that have been folded flat. A radius gauge, optical comparator or moulded replica gives an edge size, and a profilometer or surface roughness tester with a suitable cut-off and traversing direction gives a profile across the edge when the geometry allows it. Microscopy helps on small features and when documenting a dispute. Compare against a master agreed before the batch.
Protect it deliberately rather than relying on a gentle setting. Options include masking or plugging the face, fixturing the part so the land is held out of the mass, orienting the part so the land sees less contact, or choosing a media shape and size that blends rather than digs. Each has a cost: a masked face keeps its as-machined condition and can show a boundary line, a fixture shields the area behind it, and fixturing reduces how many parts fit in a load. Mark the land on the drawing, give it a maximum edge radius, and agree how it will be checked. Test the arrangement on the real part.
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 must break the sharp slot edges consistently around the disk without reworking the broached profile or rounding the bolted flange face.
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-0808; 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-0808 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
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