Enclosure design review 2

[ivan1237]

Hello Engineers!

I'm working on the design of an enclosure for electronic stuff.

Being an electronic engineer, I've check tips and articles on plastic injection to get something realistic and not too expensive to produce. But now I'm getting to a point where i need some help to review my design.

If you check the attached drawing you'll see a flat bottom with many ribs (do I need all of them?). The electronic pcb is holded on the side ribs (+ few points inside). Behind you'll see the holding "ring".

I plan to use 2 screws and some "snap" stuff (in the front) to close the enclosures...
I'm also worring about the tightness of the assembly (shall I add an "o-ring" in the assembly profile?)

But now my question is about the draft angle on the ribs and walls. Where should I take the reference plan from? Would it be the top assembly face? Or the flat bottom face?

Please give me some comments!

Any link to technical documentation (or example) would be welcome too!

Thanks in advance for your replies!

Ivan

 

[ivan1237]

Thanks again it helps me to build some basic knowledge!

The lens is supposed to be glued on the upper shell...

Regarding flexible button, what sharpness could be rubber?
Any idea about the unit?


Ivan, Owner
STEIMER ROBOTICS

 

[SincoTC]

I think that maybe you mis-heard it as sharpness! Rubber hardness is usually specified as "Shore Hardness" A through D and the lower the number the softer it is.

Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK

SW2007x64 SP3.0 Pentium P4 3.6Ghz, 4Gb Ram ATI FireGL V7100 Driver: 8.323.0.0
SW2007x32 SP4.0 Pentium P4 3.6Ghz, 2Gb Ram NVIDIA Quadro FX 500 Driver: 6.14.10.7756

 

[ivan1237]

Indeed I misundestood! Now it is more clear!

Sorry for my poor english!

Thanks for your correction!



Ivan, Owner
STEIMER ROBOTICS

 

[patprimmer]

I had me confused.

Hardness of rubber required can be very subjective, to use an idiom, sometimes you just need to suck it and see which means you need to try it out to get the taste or feel of undefinable qualities.

The suppliers of the elastomers should be able to advise and supply samples of the correct thickness for you to get a feel for it.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ivan1237]

You're right.It's not possible to describe rubber hardness!

I've touched samples but they were not the right shape neither the correct thickness.

Hopefully I'll get some samples in time...



Ivan, Owner
STEIMER ROBOTICS

 

[patprimmer]

You can describe the hardness, elongation and elasticity, but yoy can't describe the "fell"

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ivan1237]

Hello Advicers!

I've got the protoypes done. It looks very good and luckly the hardness of the button was ok (I did guess a hardness Shore A 40). The buttons are easy to assemble, it makes a water tight interface and it can even push to activate the swicthes!!!

Now I've a new problem: the lense's reflexion... When the sun shines straight on it, there's no way to see the lcd...

I thought it's due to 2 reasons:
a. the PC lense is not coated
b. the lense shape (flat)

What can I do to improve the visibilty?

I'm not sure I can afford the coating (the part should be very cheap to produce) and if I change the shape then the LCD will looks deformed...

Thanks for your help, my success is yours too!

best regards

Ivan

Ivan, Owner
STEIMER ROBOTICS

 

[ivan1237]

Well, in fact after looking at similar product, I found out that the reflection is the same. The only difference is that with my flat protection glass, it does not add the optical effect of the shape (anyway the lcd under the glass is flat!).

I'm still interested in treatment for hardness and reflection...

I will ask our supplier what they can do to improve reflection and hardness!

Thanks everyone for your help!

I'll give some feedback when injection machines will be running!

Best regards

Ivan

Ivan, Owner
STEIMER ROBOTICS

 

[SincoTC]

Good to hear that the project seems to be progressing well. You could try getting the windows cut from some pre-treated polycarbonate sheet similar to this, available in the UK but I guess it can be sourced anywhere if you know what to ask for:

http://www.visionteksystems.co.uk/polycarbonate.htm

Is it possible to get the LCD with a built in back-light, it may not cost a lot more in quantity, but it would improve the readability and is a bonus if it ever needs to read in the dark!

Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK

SW2007x64 SP3.0 Pentium P4 3.6Ghz, 4Gb Ram ATI FireGL V7100 Driver: 8.323.0.0
SW2007x32 SP4.0 Pentium P4 3.6Ghz, 2Gb Ram NVIDIA Quadro FX 500 Driver: 6.14.10.7756

 

[patprimmer]

A slight dome on the window should help with reflection without to much distortion. Thermoform from sheet to test.

I am not up to date on scratch resistant coatings, but the coatings used for car headlights should do. Your PC supplier can probably give advice as to the current state of the art suppliers

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.