Small-part finishing for factories in 304 Industrial Park, Prachinburi
One road inside this park carries a circuit-board plant and an automotive parts plant, and those two trades want opposite things from the same screw. This page is about what happens when both drawings land on the same lot.
We run one plant, and it is in Samut Sakhon. This page covers collection and delivery for customers in Prachin Buri — it is not a branch or a facility in Prachin Buri.
This estate at a glance
| Province | Prachin Buri |
|---|---|
| Road corridor | — |
| Nearest sea port | — |
| IEAT-designated | No |
| Eastern Economic Corridor | No |
| Industry mix | electronics, automotive & parts, general manufacturing & SMEs |
IEAT-designated covers both estates operated by the Industrial Estate Authority of Thailand and joint-operation estates run with a private developer. A dash means we could not confirm a single status for the whole area — some of these names describe a factory district rather than one designated estate.
A dash in the port row means the estate sits inland between two ports and we will not guess which is nearer. Nothing on this page is a distance, a drive time or a delivery-time promise.
Reviewed:
What this estate is
304 Industrial Park sits at Tha Tum in Si Maha Phot district, Prachinburi. It is privately developed and privately run — it is not an estate designated under the Industrial Estate Authority of Thailand, which is why the IEAT row in the glance table reads No. Read that No narrowly: it describes the legal status of the land and nothing else, and it says nothing at all about the size, the quality or the standing of the plants inside it. The number in the name comes from Highway 304, and it is worth knowing that the name collides: there is an IEAT-designated นิคมอุตสาหกรรม 304 ฉะเชิงเทรา at Phanom Sarakham in Chachoengsao, a different park in a different province. The mix here leads with printed circuit boards and electronics, then automotive parts, then a general tail broad enough that this page will not itemise it. This site’s end-market axis has no separate entry for circuit-board work, so that work sits inside the electronics category — we would rather say so than let the table look finer-grained than it is.
What this estate asks of a small part
The recurring problem here is not a hard specification. It is two specifications pulling in opposite directions. The electronics side wants a coating that is thin, even and clean, that sheds no loose particles, and that survives the restricted-substance list its own customer imposes — which is why every zinc line we run is finished with trivalent-chromium (Cr3+) passivation. The automotive side wants hardness held inside the band an ISO 898-1 property class sets, an embrittlement relief bake wherever the class or the hardness crosses the ISO 4042 trigger, and salt-spray hours that can actually be measured to ISO 9227. When one drawing asks for both, we do not split the difference, because the average satisfies neither. We ask which clause is the one your customer actually audits, work to the tighter of the two in writing, and where they genuinely cannot coexist we split the lot into two works orders with two certificates. Each certificate names the document it was run against rather than carrying a sentence that could be read either way. The other conversation worth having early is material: a great deal of circuit-board hardware is brass or austenitic 300-series stainless, and neither hardens by heat treatment — that is what the material is, not a limit of our furnaces. Send the material designation with the drawing and we will tell you at quotation which parts can take the route and which cannot.
Services for factories in this estate
Hardening, Cr3+ zinc plating, phosphate coating and in-house lab testing, all on small parts at bulk volume.
Steel grades behind those parts
End markets on this estate
Each end market has its own spec drivers — property classes, salt-spray hours, governing standards.
The corridor row on this page is blank on purpose, and it is a slightly self-mocking blank: the park is named after Highway 304, and neither Highway 304 nor Highway 33, which also serves this province, is one of the eight roads this table names. We would rather leave the row empty than pin the park to a corridor it does not sit on. The port row is blank for a different reason — Si Maha Phot is inland in the east, between Bangkok Port and Laem Chabang, and we will not guess which of the two is nearer. If your lot has to leave through one of them, tell us and the paperwork will be written to match that route. One more question that comes up often: whether a lot moves under a customs free-zone arrangement is a fact about your own plant, not about the park, and we will not assume it either way. Tell us how the documents have to read and we will issue them that way. Collection and delivery are arranged per lot and confirmed with sales when the job is booked; no transit time and no completion time is published on this page.
Questions we get from this estate
Is this page about the 304 in Prachinburi or the one in Chachoengsao?+
This page is the Prachinburi one, at Si Maha Phot, which is a privately developed industrial park. The other is นิคมอุตสาหกรรม 304 ฉะเชิงเทรา at Phanom Sarakham in Chachoengsao, an IEAT-designated estate. Different province, different legal status, same number. We take work from plants in both, but if you are in the Chachoengsao park this page is not describing your location — name the site when you ask for a quote so we are not talking about two different places.
Our drawing carries an electronics restricted-substance clause and an automotive property class at the same time. Which one wins?+
Neither by averaging, because an average passes neither clause. We ask which one your customer actually audits, work to the tighter requirement, and get that choice from you in writing. Where the two genuinely cannot be met in one route, we propose splitting the lot into two works orders with their own certificates, each naming the document it was run against instead of a general sentence that could be read either way.
We order one large campaign a year rather than a monthly repeat. What has to be agreed before you start?+
The first article, in full, because there is no next lot to adjust on. Send the drawing, the material designation, the thread class and whatever specification document your customer imposes. We will propose running samples from the real lot first — hardness measured, coating thickness checked, and the thread tried against your own mating part — and the full run starts only after you confirm those results in writing. The cost and the scheduling of that step are in the quotation from the beginning, and we reply to a quote within 24 hours.