First experiences with "Alumide" 3D print

[HartmutG]

Hello everybody,

I was happy to have my PCB-Housing being shipped, designed with FreeCAD, 3D-printed in Alumide.
It is my first time to have a housing 3D-SLS-printed. I chose Alumide because of its properties superior to other common 3D materials.
In the last 20yrs, all housings I designed have been based on raw milled aluminium for heavy duty industry applications.

Also being excited, I have to say, that now I am a little bit disappointed from the comparing results:

1.) It is light, I mean really light. Reason is the material, sure. Other more important reason is that for 3D you have a different approach, you want it to be light because the material is (really) expensive. Whereas milled aluminium during the design you have always on mind to mill as easy and as few as possible, therefor ending up with more material.
Oh did I mention: IT IS LIGHT! First time my wife (who is an industrial sales man) picked it up, the only response was: "That feels so freaking cheap, you cant sell that expensive". So the haptic experience is a failure, except in case you want it light for mobility/flying modells etc...

2.) The surface: Is rough, from the haptic standpoint exceptable, maybe you might want to call it a feature. Although the roughness has a drawback, it can tend to collect dirt, oilly fingerprints and is harder to really clean it.

3.) The look: It's very rough which looks nice, grey and has a very nice shimmer from the aluminium particles, see below.

4.) Electromagnetic absorption: Although the material is supposed to be absorbing due to the included metal particels (but it is not conducting), in my case it didnt as I needed it. In fact, my application turned out to be very critical and the Alumide didnt help on that issue. If I really wanted to use it, I would have had to use silver-copper-coating paint on the inside.

5.) Tolerances: The overall small details were really good. Problem is the length (~250mm), over the total length the SLS process let it bend, just inside the manufacturers tolerances but in total you can see it that it's bend.

6.) Price: For small series up to 5 pieces, cheaper than comparable design in milled aluminum (at least in this case).

My conclusion: My expectations were set too high, probably due to my new enthusiasm for 3D print. Plenty of drawbacks and few advantages for my personal application. I ended up doing a redesign in raw milled aluminum with FreeCAD. Your needs might vary, just wanted to share what you might want to look out for.

regards, Hartmut

P.S. What really sucked: The application included infrared lightbarriers, therefore you see the gaps in the front. Although 3,5mm wall thickness with metal particles, IR still shine slidely through the material, very very small almost not measurable but it does, I would not have expected that.

[triplus]

It depends on the purpose of use. I think the result does look good from the Alumide point of view. If that is what you are after. But if it would need to look like "fancy" ionized aluminium using Alumide i guess won't do.

[HartmutG]

It depends on the purpose of use.

Absolutely, and I really dont regret that I gave it a try. Money worth the experience to really have it in your hands for a judgement what's it good for and what's not. Maybe in the future I stumble over a project where I need excatly those properties.

[bejant]

Hi Hartmut, and thanks for the interesting essay. Your wife's comment about the light weight reminded me of an article I read about what someone found when they took apart a set of beats headphones:
http://www.huffingtonpost.com/ben-einst ... 39618.html
(Weights were added to make them feel more substantial.)

[kkremitzki]

I've never heard of alumide before but that sounds very intriguing! It'd be cool to do some tests on it to find out some mechanical and thermal properties.

As far as the rough finish... you know how acetone vapor can be used to smooth out 3D printed plastic? I wonder what kind of finishing processes could be used on alumide on account of its metal composition. Hmm.