Re: [TECH]:: Advice sought on 10 and 000 quantity manufacture of tubular plastic products

Another great project!

Measuring a piece of DN40 DWV PVC tube lying nearby... ID is 38, OD is 43mm. A 
5.8m length for NZD19 from trade depot would break down to maybe 47 or 48 
pieces of 120mm @ ~NZD0.40ea. Food for thought, though I can't imagine you 
haven't had this thought already :-) 
https://tradedepot.co.nz/upvc-dwv-drainage-pipe-40mm-x-6m/

Additionally/alternatively wondering if this plastic component could be "crowd 
sourced" by "makers" with 3D printers at home. E.g. use PLA material 
(cheapest/easiest) but over engineer to get the mechanical qualities required, a 
community of volunteers each prints a bunch of say xx or more pieces at a time and 
donates material/time/shipping to the cause. Or perhaps give them a free reel of 
filament and they return a percentage of it in printed parts.

I like the idea of no transparent end cap as lesser parts count has merits, and rely 
on internal lens... secondary lens might be a struggle to improve light characteristics 
and soak up lumens or milli-lumens that you don't have in abundance. That said, a 
degree of sealing may be a consideration you haven't mentioned yet.

I imagine this thing is fixed/hung high up and the light will point straight down?

Brent

On 9 Apr 2026 at 3:43, RussellMc wrote:

> The following is from posts to Stack Exchange and Facebook engineerings
> groups.
> I'm sure that there are people here just as capable :-).
> Main concern is suggestion how to manufacture 1000 and 10-20 tubular
> plastic items at low cost.
> I'm asking Chinese and local manufacturers these questions.
> Local manufacture has minimal chance of being viable, sadly.
> 
>      Russell
> _______________________
> 
> I'm looking for advice on
> 
> How to make the following in quantities of:
> 
>    - Prototype (10-20 volume)
>    - Small volume (say 1000) <-- this is the main concern
> 
> For larger volumes plastic injection moulding is liable to be most economic.
> 
>    2.
> 
>    Order of cost for labor (labour to me - I'm a Kiwi)
>    3.
> 
>    Thoughts on material choices.
> 
> In volume production (and maybe 1000 quantity) a mounting "foot" will
> probably be added.
> 
> This is a light for use in women's toilets (initially) in refugee camps.
> The light level is VERY low but vastly better than utter darkness, and it
> will operate from a single Alkaline D cell all night for 5 years.
> An optional version with a PIR person sensor allowing brighter light only
> when occupied.
> 
> Target cost is $US3 (or less) complete (electronics, housing, battery).
> 
> Ideally the device would be highly theft and vandalism resistance BUT this
> is probably unachievable given cost constraints.
> Metal is not an option: ANY metal parts are liable to be removed for
> "recycling" :-( . At least for the prototype and maybe the first 1000
> lights durability and vandal resistance are not a major factor, although eg
> PLA plastic is probably not robust enough.
> ------------------------------
> 
> 3D printing may be acceptable for the first prototypes.
> I have 3D printing facilities. PLA filament and Resin printers at present
> but strength is very poor. ABS filament and carbon fibre filled resin MAY
> be an option.
> 
> I have a lathe, milling machine and router and may yet chew the prototypes
> out of tube and sheet.
> 
> Diagram shows possible plastic choices but other suggestions welcome.
> 
> A, B: Body and end cap ABS PC PE ... Black (ideally) opaque.
> 
> C, D: "Lens" (just a light "port") Actual lens is internal.
> 
> 
> *Diagram is just to convey concept.Dimensions shown are conceptual only and
> need work.*
> Some parts are too thin. TBD.
> 
> Please excuse bad diagram - after too long away I'm learning a new graphics
> package and this was quicker :-) :-(
> 
> 
> *Diagram here <https://i.sstatic.net/GkUWD6QE.png>(Stack Exchange):  *
> 
> *And here (Dropbox)
> <https://www.dropbox.com/scl/fi/3ldxj6zl4x2sfpak4v4oj/5YL-body-design-conceptual-Cambrian-prototype-dimensioned-V321-FF.jpg?rlkey=r84hgb7mr3c1i2skkd6hhwq1k&dl=0>*
> 
> C & D are both transparent.
> *Ideally D is not needed and C fits as a cap on A.*
> 
> In volume C&D can be one part but that's harder in small volume.
> 
> A-B join can be permanent.
> C-D pinned / grub screws / thread / magic.
> 
> Ideally opened maybe twice at start of life.
> Thread may be nice but not if costly/hard.
> 
> Adhesive use acceptable.
> 
> BONUS if C & D pass IR light well - allowing PIR to work inside and not
> need a custom "port" for its lens.
> 
> Acrylic/PMMA - good light transmission.
> Not robust.
> Polycarbonate - slightly less light transmission. Robust. Expensive.
> ------------------------------
> 
> Manufacture:
> 
> 3D print
> "Screw machine"
> Other ... ?
> 
> Also on: https://www.facebook.com/share/p/14ZCy9T4FVv/
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