3
$\begingroup$

For personal usage, indoor, I'm doing some experiments with following lamp (v0.1):

enter image description here

Lamp is a led bulb enclosed in a methacrylate tube and with a 3D printed finish at the top using PLA (my first 3d print ;-).

In some www pages (by example, here) I've read that the led buld radiator can reach 90º C. Experimentally, the methacrylate and the PLA feels only slightly hot, I suppose around 40ºC.

According to www info, PLA has a melting point of 150ºC, far from this usage, but a continuous operative temperature of only 40ºC ( !? this made 3d printing unable in a country as my own one, where ambient in summer is around 40ºC).

So, my question, is PLA a valid material for this application? If not, some other one better?

Thanks a lot.

$\endgroup$
  • 2
    $\begingroup$ Note that if (as it appears) your "3D printed finish" is blocking airflow for the LED radiator, it will negatively impact LED lifetime (the hotter they run, the faster they fail) $\endgroup$ – Ecnerwal Aug 13 '17 at 15:53
  • $\begingroup$ @Ecnerwal: it is true, to minimize this effect, the narrow part of the piece has some margin around the cable, allowing some airflow. Taken into account your comment, I will add some holes in the horizontal layer of the piece to increase airflow. $\endgroup$ – pasaba por aqui Aug 13 '17 at 15:56
5
$\begingroup$

EvilTeach's answer is correct, ABS is a more reliable plastic for any kind of work which may get above what feels "hot to the touch."

Just to elaborate on the why: the property you're looking for in the thermoplastic (which will determine the continuous operating temperature) is glass transition temperature. This is the point at which the plastic begins to flow, and becomes deformable as EvilTeach described. PLA reaches this state at around 60 °C, whereas ABS is around 105 °C, just suiting your specifications. To go a bit further, polycarbonate offers a glass transition temperature of around 150 °C, and Ultem at 217 °C. So there's a thermoplastic for everyone, you just need to know what you're looking for!

| improve this answer | |
$\endgroup$
2
$\begingroup$

I had a PLA print that would weaken and deform when sitting in the car on a hot day. I think you should try it with ABS.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.