A steelwork fabricator in Yokohama, Japan supplying architectural metalwork holds 4 m lengths of 88.9 mm stainless pipe at 5 mm wall with a heavy mill seam and a transit scratch, and needs the metal cut back without thinning the wall past the buyer's own limit. SurfacePolish supplies finishing machines, media and compounds across borders and runs a free sample trial on parts shipped to Xiamen. This brief is written for a buyer in Yokohama working on architectural metalwork; it describes equipment, media and a scoped sample review, not a local polishing service.
Which faces of each profile are actually seen when installed, from what distance and under what light, and which faces can be finished to a coarser standard without it showing?
What is the longest length in the order, and how will it be supported, carried and packed at every stage between finishing, fabrication and installation?
How much of the incoming mill seam, joint weld or transit scratch must be removed, and what minimum wall thickness has to remain after that removal?
Once a length runs past roughly a metre and a half, handling stops being a detail and becomes the deciding constraint. A six-metre handrail cannot be turned in a chamber, cannot be stacked with its finished face against another part, and cannot be lifted by two people without risk of a bow. The screening questions are: what is the longest length in the order, how is it moved to and from finishing, is it cut to final size before or after finishing, and what supports it at every stage. Answering these sets the machine class, the cradle design and the inspection points. A buyer who fixes the finish specification first and the handling plan later usually discovers the finish cannot be held on the long lengths that matter most.
When an order repeats the same profile in volume, an arrangement that moves either the part or the working heads along the length can hold direction better than any batch chamber. A roller or belt conveyor carrying the length past fixed heads, or a carriage moving heads along a stationary length, produces a texture whose direction is set by the machine axis rather than by media motion. That is what makes the grain on adjacent lengths line up. The trade-offs are floor space, changeover when the profile or the length changes, and the need for reliable support of thin sections over the full travel. It is a line concept to be scoped against a real order book rather than a catalogue item.
| Machine route | Where it fits | What it will not do |
|---|---|---|
| Magnetic finishing machine | Small precise parts and localised areas that are difficult to reach with loose media in a conventional chamber. | Size and mass limits keep it away from architectural lengths and large diameter profiles. |
| Grinding finishing machine | Higher material removal where a mill seam, a joint weld or a deep scratch has to be cut back before surface refinement. | Removal is aggressive, so depth control and wall thickness limits have to be set before the cycle is run. |
| Barrel finishing machine, rotary barrel tumbling | Gentle, precise batch processing of small parts, finials, sleeves and short connector pieces. | Part length and part-on-part contact restrict it to short fittings rather than long architectural runs. |
| Disc finishing machine | Fast, high-energy cycles for small to medium fittings and hardware where a short cycle is the priority. | The high energy that makes it fast will distort, mark or bend thin and long parts. |
Ceramic media cuts harder, holds its shape longer and is the usual choice when a previous scratch or a weld seam has to be removed from stainless. Plastic media is gentler, lighter and less likely to mark a thin or soft section, at the cost of a slower cut and a shorter texture. Steel media produces a bright appearance and strongly linear marks, but it is heavy, it needs well-controlled compound to keep it clean and separated, and it raises a question about whether any iron-bearing debris is acceptable in the buyer's own cleanliness or contamination control. That last point is a requirement for the buyer to define and verify, and it is not something a supplier can decide on their behalf.
| Media | Best fit | Watch out for |
|---|---|---|
| Plastic media, cylindrical | Light surface refinement on thin rectangular sections where holding the shape matters more than cutting power. | Little cut power, and the size class changes quickly as the media wears, which shifts the texture pitch over a run. |
| Plastic media, cones and triangles | Gentle work on thin-wall sections and softer alloys, and where marking or distortion is the main risk to be managed. | Slower cut and shorter media life, with limited effect on a deep scratch or a heavy seam. |
| Steel media, pins and balls | Bright, strongly linear appearance on stainless where a higher-lustre finish is wanted on accessible faces. | Heavy, needs tight compound control to stay clean and separated, and any iron-bearing debris is a contamination question the buyer has to define and verify. |
| Grinding media, alumina-based | Higher material removal where a mill seam, a joint weld or a deep transit scratch has to be cut back before refining. | Aggressive on thin wall, can over-round edges and change cross-section geometry, and needs tight depth control. |
Straight scratches running along the length are the signature defect of tube finishing. They come from three places: the incoming coil or straightener, media or swarf dragged along the surface during the cycle, and the handling between operations, when a finished length slides over a steel support. The first cannot be removed without cutting back real wall, so it has to be identified before the cycle is set. The second is controlled by media cleanliness, compound filtration and keeping the bed free of tramp metal. The third is controlled by padded cradles and a rule that nothing finished ever touches bare metal. Detection is by raking light along the axis at a low angle; a scratch invisible under diffuse light can be the first thing an occupier sees on a sunlit elevation.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Bow along the length | Unsupported part in the bed, resting on hard supports, or lengths stacked while still wet. | Place on a surface plate or straight reference and measure the gap with a feeler gauge at several stations, against the incoming straightness record. |
| Compound residue weeping from a hollow section | Incomplete rinsing of the interior, or a drying step that does not reach inside a closed section. | Stand the length on end over a clean cloth for a set period, then inspect the bore interior for residue after drying. |
| Media or swarf trapped in a bore or channel | Open ends left unplugged, a media class smaller than the opening, or no defined retrieval step at the end of the cycle. | Endoscope or internally swab every sample length, and count media into and out of the batch as a routine check. |
| Visible band or line along the mill seam | The seam crown was not cut back evenly, or the media class was too small to reach the seam root without over-working the surrounding surface. | Look along the seam line under raking light from both sides, and measure the remaining crown with a depth gauge on a sectioned sample. |
Yokohama combines a waterfront heavy-industry zone with a large base of small and medium manufacturers. The city lists eight separate industrial accumulation areas, including the Keihin coastal zone, which it calls a major industrial region representing the Greater Tokyo area, and LINKAI Yokohama Kanazawa, where more than 1,000 companies and offices are located. The city's investment material states that Yokohama has clusters of automotive and other manufacturing, IT and life-science industries, together with R&D bases of global companies, and that it ranks first among Japan's designated cities for both the number of academic and R&D institutions and the number of engineers and researchers. The port's designated zones are predominantly industrial: of a 2,936.8 ha waterfront district, 1,712.1 ha is classified as an industrial port zone.
The nearest part of that base to this brief is medical: Yokohama City names life-science industries among the clusters in the city and lists life sciences among the fields in which global companies locate R&D bases.
Yokohama's manufacturing base mixes automotive and general machinery production, in which deburring and edge quality affect fit, fatigue life and coating adhesion, with life-science and R&D activity, where cleanliness and documented surface condition matter. A dense supplier base across eight accumulation areas means an incoming parts specification is likely to pass through several subcontractors, so a shared, measurable finish requirement reduces rework at hand-offs.
A Yokohama buyer sourcing from an eight-area supplier base should fix one measurable edge and surface specification for the whole chain and agree who inspects it, rather than letting each subcontractor apply its own visual standard.
Freight context: Port of Yokohama (横浜港) — piers including Minami-Honmoku, Honmoku, Daikoku and Osanbashi, Haneda Airport, about 24 minutes from Yokohama Station by the city's own access description. The Port of Yokohama has a 7,218.3 ha port area and a 2,936.8 ha waterfront district, of which 1,712.1 ha is an industrial port zone, so both break-bulk and container movements of machinery sit alongside industrial waterfront users. The city publishes the Yokohama Port Statistics Yearbook and fast-report series for throughput data used in freight planning.
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 six-metre length cannot be examined in every square millimetre, so the acceptance plan has to say where the checked zones are and how often they are checked. Define stations along the length, for example near each end and at one or two intermediate points, decide whether the visible face of every length is checked or only a percentage of the batch, and set the reaction when a station fails: quarantine the lot, measure the rest of the lot, and record the finding. Keep the first accepted length as a physical reference and re-photograph it under the agreed light whenever the lighting setup changes. Photographs taken on different days with different cameras are a poor substitute for the retained part, though they are useful supporting evidence when the setup is fixed.
The first production batch is usually the best one, because the media charge is fresh and the fluid is at its set point. What changes over a run is media wear, which reduces cut and shifts the surface toward a finer and dimmer appearance; the build-up of swarf and fines in the fluid; and the arrival of material from a different heat or mill finish. Plan for it: a media top-up and screening routine with a defined interval, a fluid change criterion based on measurement rather than appearance, and a check length kept from each lot for comparison. Agree in advance what will be done if a later lot does not match the retained reference, so the decision is procedural rather than improvised.
Start with a physical sample: if a short section can be removed without damage, send it, together with the retained reference panel from the original order if one exists. An installed surface has aged, been cleaned and possibly scratched, so a new length will not reproduce it exactly, and the visible difference is usually easier to manage by finishing a group of adjacent lengths than by matching one piece in isolation. A trial reports what the tested settings produced on the sample you sent; deciding how close is close enough remains with your own acceptance process and the people who will look at it daily.
No. A sample trial produces observations on the parts that were tested under the settings used; it is not a guarantee of a roughness value, a surface class, an appearance or a repeatable production result. Media wear, compound concentration and the condition of incoming material all move the finish over a run. What we can do is show what a given media, compound and cycle direction did to your part, and describe what would need to be controlled to hold that result. Acceptance criteria and any promise made to a client or specifier remain your own.
Ra is a two-dimensional amplitude average taken along one traverse, and it says nothing about the pitch of the texture, its direction, or whether the surface reflects light evenly. Two surfaces with the same Ra can look quite different: one can carry a directional brushed grain and the other a mottled, hazy appearance with a broken reflection. That is why an architectural callout normally needs both a numeric limit with its measurement conditions and a physical reference viewed at an agreed distance under agreed light. The number controls the process, and the panel settles the argument.
Use Yokohama, 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.
Yokohama buyers reference JIS, maintained by the Japanese Industrial Standards Committee, with the mechanical engineering and ferrous materials divisions covering machined metal parts, and the JIS Mark scheme available for third-party product certification, including to foreign exporters. For finishing, the customer's drawing and incoming-inspection sheet define burr, edge and roughness acceptance.
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 Yokohama.
The seam and scratch have to be cut back to an even grain without reducing the wall below the buyer's own minimum.
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-0837; 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-0837 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
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