Best plastic for this application, and possible pointing toward suitable specialist/consultant

[StuSmith]

Hi guys,

My first post here.

I am currently designing a new product which I plan to injection mould.

You can see renders and prototypes (3d printed) here:

http://www.rocksolid-tech.com

The parts surround brushless electric motors which move the axes.

Usually these 'gimbals' use carbon fibre parts or CNC aluminium parts:

http://www.goodluckbuy.com/index.ph...rds=Y&cid=0&q=3+axis+brushless+gimbal&x=0&y=0

My product is an attempt to productise for the end user, enclosing components, etc.

The key property required from the frame/arms/etc is stiffness. Any flex dramatically reduces the effectiveness of the device. It also allows vibrations to build up from the motors, resonating around the frame (the current problem with my cheap 3d printed abs parts).

I'm thinking that a polycarbonate would be ideal, but I'm also really looking for someone to pat me on the back and tell me not to worry, and that it will be all alright

 

[marcunator]

* pat pat*

Dont worry about vibrations/resonating the viscoelastic properties of plastics will take car of that.

As far as your material selection.

Why do you design your product first, and then think about your material? Your "flow" should be like this:

Requirements -> Material selection -> product design.

PC will be ok, although it can be better for your application.

http://promolding.nl/materiaal-munt.php?lan=nl&c=107

Website is in dutch but have a look at it with google translate.


And have a look @ my thread, i need some help too

 

[StuSmith]

Thanks.

Why do it the way I did it ?

Well.. I'm an electronic engineer who has spent the last 20 years in IT.

I haven't a clue about any of this and am just mucking in and learning as I go. 4 months of home 3d printing, teaching myself CAD and fitting that all around the electronics and component choices I've been making.

I knew I wanted it injection moulded, but wasn't sure exactly what plastic. So I figured it wouldn't be big changes to decide that later (shrinkage, etc). Talking to injection moulding companies has so far confirmed that impression ?

I think ideally, in the next month I'll need to source a plastics specialist perhaps on a consulting basis who can take this forward for me. I've already got a professional CAD guy on the books.

I'll have a look at your questions.. but as you will now be aware from my background, it might be as much use as a chocolate teaspoon

 

[CoryPad]

For stiffness, you should probably consider glass reinforced plastics like polyamides (nylons), polyesters (PET/PBT), PEEK, LCP, etc. Other properties like environmental resistance, resistivity, fire retardance, etc. will be very important.

 

[marcunator]

Thank you STUsmith

As already mentioned,

You probably end up looking @ PA6 30% Glass filled

 

[StuSmith]

Yes, I am looking at PA6 GF.

It has the benefit that it can be SLS printed.

I will be SLS printing several prototypes with it with a view to seeing if it could provide an alternative to injection moulding (it is price competitive for this application).

I've had some regular PA6 SLS prints done and they are pretty stiff, though nothing like PC stiff (based on the unscientific method of flexing it in my hands and comparing it to PC stuff I have lying around the house).

Obviously it could be moulded too.

But reading specs sheets, it still looks like GF nylon will be significantly less stiff than PC ? POMs seemed to be worth a look too - looking at the sort of products they are used for - they seem to have similar technical requirements to my product.