6
$\begingroup$

I want to contain a very small PCB (roughly a square centimetre) in a casing. For demonstration purposes I want to 3D print a couple of those casings as well.

The most obvious method available would be using ABS for the printed casings. However, nylon appears to be smoother and tougher. Those traits are often a plus during demonstrations. However, since the PCB contains a S band antenna I'm slightly worried about the RF properties of the material used.

Are there any downsides to switching from ABS to nylon that I'm not seeing? I'm especially interested in the RF characteristics in 2-4 GHz range. Cost is not an issue.

$\endgroup$
1
  • $\begingroup$ Generally nylon is fairly strong but brittle and has low impact resistance: see this chart (select tensile strength amd izod impact, respectively). ABS is pretty tough stuff, but nylon is stronger. At least from a purely materials standpoint under standard conditions and processing. Many consumer products have ABS shells and casings because they resist damage when dropped, stepped on, thrown, etc. Legos are a good example. $\endgroup$ – wwarriner Dec 10 '15 at 3:26
3
$\begingroup$

I am not sure if this will help, but when I have used any plastic in antenna designs, or RF power amplifiers, I would put them in a microwave oven and see if they heated up. Most would stay cold, but every now and then some would get warm, and sometimes I could hear some audible arcing. My only experience is at Ham Radio frequencies but I think it may still be a valid test for what you are doing. After all, a microwave oven works at 2.450 GHz. This has always worked for me to see if any insulating material would react to RF.

$\endgroup$
1
  • $\begingroup$ As an addition to this answer, which it reminded me of: nylon absorbs water (hydrogen bonding causes hydrophilic behavior, all aminated polymers do it to some degree), and microwaves interact with water. Nylon may therefore cause some attenuation compared with ABS, which is hydrophobic. $\endgroup$ – wwarriner Dec 10 '15 at 3:18

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.