A buyer in Hiroshima, Japan in semiconductor equipment has a machined showerhead housing with fine gas passages that must be deburred without plugging a passage or contaminating the seal face. SurfacePolish supplies finishing machines, media and compounds across borders and offers a free sample trial, returning tested parts to the buyer with observations and a proposed media, compound and cycle direction. This brief is written for a buyer in Hiroshima working on semiconductor equipment; it describes equipment, media and a scoped sample review, not a local polishing service.
Which surfaces on this part are functional, such as seal lands, gas passage walls and locating bores, and which are only cosmetic?
How will a production batch be identified, segregated by material family and documented so a result can be traced to its settings?
Can the required finish be reached in one mechanical route, or does the part need a cut stage followed by a refinement stage?
Treat every internal feature as a potential media trap and map it before selecting a media size class. Slot widths, blind tapped holes, cross-drilled intersections, tapered gas passages, O-ring groove corners and the annular gap behind a flange are the usual retention points. A useful first pass is to measure the narrowest opening a medium could enter and the depth behind it, then compare that with the smallest medium in the proposed charge. Sharp internal corners and stepped bores hold media differently from through-hole patterns that drain freely. Where a passage cannot be avoided, the process needs a defined retrieval step such as a controlled rinse, an ultrasonic bath, a borescope inspection at an agreed angle or a pin gauge, rather than an assumption that parts come out clean. The exit of the smallest gas passage is often the hardest place to inspect.
Centrifugal barrel finishing multiplies the effective gravity acting on the media charge, so cycle times shorten and contact pressure rises sharply. That combination can deburr and refine small precise parts such as fitted inserts, small valve bodies and gas distribution components efficiently, and it can also round an edge or distort a thin plate within a minute of over-running. Parts usually sit in compartments or barrels, which limits part-on-part damage but concentrates media at the compartment walls. Process control matters more than on a bowl: charge weight, barrel speed, fill level, compound dose and stop time all change the outcome, and a short trial cycle is easier to overshoot than to under-run. Ask whether the geometry has thin unsupported spans, a knife edge or a soft aluminium section, because those features decide whether this route is usable.
| Machine route | Where it fits | What it will not do |
|---|---|---|
| Disc finishing machine | Fast, high-energy edge breaking and surface refinement on small robust parts and uniform batches of fittings | High impingement and edge-loss risk on thin or soft parts, and geometry must suit the disc working gap |
| Centrifugal barrel finishing machine | Small precise parts and short cycles with high contact pressure, such as inserts, small valve bodies and distribution components | Rounds edges and can distort thin unsupported sections quickly; results are sensitive to charge weight, speed and stop time |
| Tub vibrator | Long gas rails, tubular manifolds, weldments and linear electrode assemblies that cannot rotate in a bowl | Lower energy per unit area so heavy burrs take longer, and large tubs need floor space and a suitable part support method |
| Vibratory finishing machine (bowl) | General deburring and refinement of chamber bodies, plates and housings that fit and can tumble without racking, with easy mid-cycle inspection | Continuous part-on-part contact and no access to deep internal passages; thin plates and finished mating faces need separation |
Ceramic media is the workhorse for deburring machined aluminium and stainless, and its shape and size class matter more than the broad material label. Angle-cut triangles and cylinders in a coarse size class cut quickly and reach open pockets, while smaller sizes follow tighter geometry but lodge more easily and can load passages with chips. A heavy-cut ceramic leaves a coarser surface than a fine ceramic or a plastic medium, so a route that starts coarse has to plan a refinement stage and a compound change rather than simply a longer cycle. Size selection should be driven by the smallest opening a medium can enter and by the smallest radius that must not be rounded. Wear is continuous: ceramic media break down and shrink, so the charge changes character over its life unless it is screened and topped up on a defined schedule.
| Media | Best fit | Watch out for |
|---|---|---|
| Steel media, including balls and shaped pins | Bright finishing and edge blending on stainless 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 |
| Aluminium oxide grinding media in a dense ceramic bond | Where a heavier stock removal or a more consistent cut is needed on robust stainless parts with thick edges | High removal energy rounds functional edges quickly and is a poor match for thin aluminium plates or knife-edge seal lands |
| Plastic triangles and pyramids in a soft to medium grade | Deburring aluminium and other soft alloys 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 |
| Magnetic finishing pins and fine magnetic media | Small precise items such as nozzles, orifice plates 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 |
Uneven results are common when part geometry or charge behaviour prevents media from reaching all surfaces equally. Deep pockets, blind recesses, internal corners and the shielded underside of a flange come out with 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. At the other extreme, part-on-part contact in a dense charge produces bright impact marks, dents on thin plates and flattened corners. Both outcomes trace back to the same variables: charge mass, part mix, whether fragile parts were separated, cycle time and media circulation. Checking means inspecting at defined locations rather than judging the part as a whole, photographing as-received and finished condition of the same feature, and measuring roughness at the surfaces the drawing actually controls.
| Failure mode | Likely cause | How to catch it |
|---|---|---|
| Bright impact marks, dents or flattened corners from part-on-part contact | Dense charge, high load ratio, thin or light parts left loose among heavy neighbours, or a cycle run longer than the edge condition required | Look for repeating mark patterns on exposed faces and edges, compare an unsupported part with a racked or compartmentalised one, and review the batch mix and load recorded for the lot |
| Compound film or tenacious residue left on a sealing face | A film-forming or silicate-bearing compound, insufficient rinse volume, or drying the part before it is genuinely clean | Magnify the sealing land and wipe a defined area with solvent, comparing the wipe against a clean reference; confirm with the buyer's own cleanliness method |
| Water spotting or mineral residue 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 grooves | Inspect dried parts under angled light for rings and haze, check the rinse water source and drying method, and verify that pockets and grooves drain before the part is packed |
| Burr remaining in 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 against a first-article reference, and use a pin or probe to feel for a lip on sampled parts |
Hiroshima Prefecture's industrial base is organised around automobiles and their supply chain: the prefecture's industry department describes a Hiroshima automotive industry-academia-government collaboration council founded in 2015 by six organisations with a 2030 vision, together with a car-technology innovation centre that supports automotive suppliers, and a separate division for automotive industry promotion and for advanced manufacturing and new technology development. Aircraft is a second organised cluster: the prefecture's Hiroshima Aircraft Industry Promotion Association (エアクラフトひろしま) builds an aircraft supply chain with more than 150 member companies and organisations, mainly manufacturers in the prefecture, and the prefecture also runs a carbon-neutral manufacturing business programme. Hiroshima Port is designated an international hub port (国際拠点港湾) serving the Hiroshima Bay industrial zone.
The nearest part of that base to this brief is aerospace: The prefecture established the Hiroshima Aircraft Industry Promotion Association (エアクラフトひろしま), and states that more than 150 companies and organisations, mainly manufacturers in the prefecture, take part in building a strong aircraft-related supply chain.
Automotive parts produced around Hiroshima - machined, stamped and cast components - are deburred and edge-conditioned before assembly, painting or inspection, and the prefecture's supplier-development programmes put supplier process capability under review. Aircraft supply-chain work adds documented process control and cleanliness expectations, so surface condition and edge quality have to be repeatable and recordable rather than merely visually acceptable.
A Hiroshima buyer should first settle which customer regime governs the part - automotive drawing tolerances for edge break and burrs, or an aircraft flow-down requiring documented process control and cleanliness - because that determines how much of the finishing process has to be specified, recorded and verified rather than judged by eye.
Freight context: 広島港 (Hiroshima Port), 国際拠点港湾. The prefecture's port authority office states that it manages and promotes the international hub port Hiroshima Port together with the ports in Etajima City, serving the Hiroshima Bay industrial zone; that makes Hiroshima Port the natural route for incoming finishing machines and for outbound sample parts.
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.
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.
Acceptance has to be written before the trial, on the drawing and in the purchase specification, not agreed verbally afterwards. Name the controlled surfaces individually, for example a seal land, a gas passage wall or a mating flange face, and state the parameter, the cut-off length, the direction of measurement and the number of readings. A single global roughness call-out on a chamber body is not enough, because the sealing face, the outer wall and the bore will not respond the same way to one media charge. Where an edge limit applies, express it as a maximum radius or a required chamfer at a named feature. Add the cleanliness requirements the part must meet and the method by which they will be judged. Settling these points early prevents the common dispute in which a supplier reports a finish and a buyer rejects on cleanliness.
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 bowl size, load ratio, media age and operator practice all shift the outcome. It does not establish a particle count, a cleanliness level or fitness for a cleanroom or any regulated process environment, and it does not transfer a roughness value from a coupon to a complex geometry. It cannot guarantee a cycle time, a cost per part, a capacity or a delivery schedule, and it does not qualify a machine, medium or compound for a semiconductor application. Treat the returned parts and the settings record as evidence for the buyer's own engineering decision, and plan the production route with its own first-article and sampling discipline.
It can change a surface, but whether it lands inside a specified band is something to measure rather than assume. The parameter, the cut-off length, the measurement direction and the reading locations all have to be fixed first, because a seal land, a bore and an outer wall respond differently to the same charge. A trial result applies to the geometry and settings tested, not to every part in the family. SurfacePolish does not guarantee a roughness value. Send parts with a marked measurement plan, ask for readings at those points, and set your own acceptance band from data you can verify in Hiroshima.
Thin plates are governed by distortion and media lodging as much as by finish, so plastic media is often the conservative first choice because it is lighter and imposes less impact. A fine ceramic may cut the hole exits faster, but it also increases edge rounding and part-on-part damage unless the plates are separated. Either way, the plate needs support and separation in the charge, and the hole exits need an inspection that can see inside them. Send several plates so more than one cycle time can be examined, and state the flatness requirement you will verify afterwards.
Size the medium well below the smallest opening the charge could enter, and treat every passage as a retrieval point rather than assuming it stays clear. Map the tightest hole, slot or cross-drilling first, then choose a size class against that geometry instead of an average part. Add a defined check such as a borescope at an agreed angle, a pin gauge on holes, and a rinse collected through a filter. For Japan buyers preparing a trial, send the part with the smallest passage so the media choice is tested on the real feature. SurfacePolish reports what was observed on tested parts; the cleanliness release remains the buyer's decision.
Use Hiroshima, 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); the official JIS database allows standards to be read but not printed, so buyers normally work from purchased or licensed copies and from the JIS number cited on drawings. Management-system certification to ISO 9001 is commonly required as general industry practice, and aerospace customers flow down their own additional process and documentation requirements.
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 Hiroshima.
The buyer must deburr the rib edges and passage entries without blocking a passage or leaving compound film on the sealing 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-0865; 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-0865 · revised 2026-09-29 · cross-border equipment, media and scoped sample review. City context is sourced and cited above.
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