Decent products but - mechanical design - fail!

[bruce]

Wet day, family all out, nothing planned. thought I'd make a start to the pile of "needs minor repair" stuff. I'm sure we've all got one - a box (or in my case, a big plastic bin) full of stuff that needs a minor repair or a check before re-using.

First out of the bucket - some LED pars. Unbranded, Aliexpress 18x3W RGBW units. Quiet fan, reasonably bright, I've got half a dozen of them, and they've proven quite useful and reliable.

The weak point(literally) is the casing. Plastic, injection moulded. Pretty normal for the price. And the brackets had come off.

But the bit I don't understand. They have two metal threaded nuts moulded into the case, for attaching the bracket. If I was designing it, I'd probably make the casing a little thicker at that point, or strengthen it in some way. But the designer of these units has chosen to put ventilation slots right beside them (and nowhere else on the case), so the mounting bolts are in the weakest point of the casing.

Repair attempted, with replacement inserts, some large washers, and epoxy glue. Let's see if it holds.

Image before:

 

 

[David Duffy]

That does defy all common sense. Surely the vents could have been at 90° to the mounts.

[sunray]

14 hours ago, David Duffy said:

That does defy all common sense. Surely the vents could have been at 90° to the mounts.

I would have though:- Should have been top and bottom.

[Tomo]

It may well be an incorrectly manufactured injection moulding tool that the 'real' customer rejected.

Then someone picks up the tool dirt cheap, and bangs out a load of generic LED par casings.

I've seen more than a few items where the casing manufacturer looks to have picked up an injection mould out of a skip to bang out a load of 'free' widgets. Sometimes it's very obvious where the tool was badly worn or defective and a bit's missing, filed down or simply left out-of-tolerance for the purchaser to deal with...

[Stuart91]

52 minutes ago, Tomo said:

It may well be an incorrectly manufactured injection moulding tool that the 'real' customer rejected.

Then someone picks up the tool dirt cheap, and bangs out a load of generic LED par casings.

I've seen more than a few items where the casing manufacturer looks to have picked up an injection mould out of a skip to bang out a load of 'free' widgets. Sometimes it's very obvious where the tool was badly worn or defective and a bit's missing, filed down or simply left out-of-tolerance for the purchaser to deal with...

I bought some suspiciously cheap LED Pars a few years ago. They had cast metal casings, which looked as if they had rusted and been hastily painted over. Did make me wonder if the casings had just been sitting in a pile in a field before some enterprising person married them up with some cheap innards. 

To be fair, the casing looked fine from a few feet away and the handful we put into a very low-budget install have given stalwart service with no failures or niggles. The fans are a bit on the noisy side but that comes with the territory at this kind of price point.