Telephone project

[plastics-studen]

Hi guys

I am up to create telephone components, based on
delivered PCB. This is non-commercial project which I must finish due
to my studies. The final grade depends on complexity of developed
parts, so it is not mystery I want to push it hard.

I am not that experienced in plastics as I wish I would, so I thought it is wise to ask for tips first.

So, just to start it I am curious how ussualy such project is managed? what is first:

*design - sketches, models?

or

*PCB and mechanical layout?

p.s

I am using Pro/E, thus I decided to put these questions here. Yea they`re not Pro/E related yet, but I suppose there will be time for it either

 

[design-engine]

Development is almost always a team effort. Your instructor should hook your engineering group up with ID department like Purdue does. Usually the industrial designers are given a PCB layout from an existing product (similar) and told PCB designers can move stuff around if necessary on the board if they like.

Concept design is usually without much thought to draft and what have you... Concept sketching ... it is best to leave the concept sketching up to experienced designers.... then let the engineers problem solve how to separate the parts into moldable components. That's what I try to teach however there are some who might argue.
Edited by: design-engine

 

[Jacoolo]

usualy I do the mech layout - investigation of snaps, drafts, cuts for connectors, tol chain, offstes etc - before ID is hired

but our products are not that desgin focused


Edited by: muadib3d

 

[[-Skint-]]

take an already existing pcb and base your initial designs of components around it, if you find the constraints of the pcb limit your designs you can then start to think about moving the pcb components about, which is usually pretty standard aslong as you have the room to keep ALL the parts on the pcb. When modelling your plastic components in pro-e make sure you are aware of how you are going to produce them, google injection moulding techniques etc. Keep wall thickness the same throughout and Im sure you`ll be off to a fine start

 

[plastics-studen]

I`ve remodeled PCB to have it flexible for necessary changes.

I did assembly with prelimenary curves for driving all components.





the design is going to be based on existing telephone, which is not a problem to project, becasue I am not considered to be responsible for design.

More - I can even take advantage of already available telephones to use them as guide, but all introduced solutions must be well understanded, becasue there is going to be no mercy during final confirmation of project.

So first question that have raised to me are:

*what are the conditions to develope right thickness?

*where can I find materials regarding size(tol dims) of battery

*which fixture / assembly joining approach should I consider regardning telephone device?

 

[design-engine]

you skipped the concept sketching part and jumped right into Pro/ENGINEER. A typical mistake of an engineering student.

[url]http://images.google.com/images?q=concept%20sketching&oe=utf -8&rls=org.mozilla:en-USfficial&client=firefox-a&um=1&ie=U TF-8&sa=N&hl=en&tab=wi[/url]

I hope your not taking a product design course!Your instructor should be teased a little.
Edited by: design-engine

 

[plastics-studen]

well, I guess I am not that "manual" skilled...

So far, rather than designing I would like to focus on mechanical side of project.

Consider this as borring, but there are not that much ID related buisness around me.

My intention is to be involved in surfacing and plastic parts development - houseware, consumer goods, automotive etc.

So regarding my project I will follow existing design, instead of creating new. There is to much time effort behind it, and project time constraints push me hard.

Wall thickness develpment, tolerancing issues, fixing solution are things I want to address as fast as possible.

 

[design-engine]

Be process drivin... and realize there are multiple personalities involved with 'process dirvin' design.

So you are going to pretend the design is completed by a seasoned industrial designer... now you want to wrap the product around the motherboard you created. (its hard to move forward because you don't have a pencil concept of your product) Your going to have to look thru google images for cellphone images. Pick something from Japan .. they have the coolest phones on the market.

If you decide to have a stab at creating your own concept sketch, (which is a good idea) create a plan and side view doodle plus perspective doodle (one every 10 minutes create one set until you have been drawing for at least 8 hours. The experienced will want to give up because your not practiced and dedicated. Keep going and consider drawing with a friend to keep the momentum.At design engine we offer this 16 hour workshop specifically to engineers:

[url]http://www.proetools.com/courses/design/marker_renderings.ht m[/url]

You can also refer to this 'sketching' forum on Core77
http://boards.core77.com/viewforum.php?f=27

In plastic part design world thin wall design is big in hand held products. This is the most difficult part of plastic part design because where you shave off material from the plastic for the lithium battery creates a smaller void for the mold which causes difficulties in the tool for filling the cavity.

The hardest part of concept sketching for engineers is to let go of the physical constraints of reality for tooling and such. Consequently the design often suffers. Plastic Engineers need to be pushed hard to play problem solvers.

The thin wall material thickness often does not exceed 1mm (.039) or approximately 40 thousands of an inch and for the large side 2mm (.078) or approximately 90 thousands of an inch. This contrast makes if very difficult to fill/gate/eject the mold however there are tricks to manage filling for the experienced designer and mold shop team. I said team because often times purchasing does not allow proper communication between part designer and mold shop.

Ribs... Depending upon the specific type of plastic chosen your ribs will want to be approximately 70% of the nominal wall thickness.

Consider taking a plastic design course. I offer this 16 hour class that integrates Pro/ENGINEER ...

http://www.proetools.com/courses/plastics/plastics.htm

When your all said and done you end up at some point learning about research. Product research and competitive analysis. This part of the process should have been the very first thing you do. You end up with a series of questions designed to get the pencil moving. I put it last to reiterate that it should be first. Why does the product need to be made of plastic? Can the product be flexible like Mylar or should it have an exoskeleton like a thin aluminum cover? What of using bamboo to create your outer shell or simply use bamboo accents? Does the product need to pass a 10 foot drop test or a four foot drop test. If the product should pass a four foot drop test onto concrete then should the product remain intact upon strike or should it pop apart so the user can place the product back together? Polypropylene is a good choice because it flexes while polycarbonate is a good choice while it offers the most strength. Almost all of the motorola cell phones use polycarbonate.



[url]http://images.google.com/images?hl=en&client=firefox-a&rls=o rg.mozilla:en-USfficial&hs=tGj&ei=qzYQStPEEYrFtgehvPCXCA&r esnum=0&q=bamboo%20cell%20phone&um=1&ie=UTF-8&sa=N&tab=wi [/url]

Try this consumer products forum on core77: http://boards.core77.com/viewforum.php?f=25

How green should the product be? to get a specific edge on the more mature US market where consumers are thinking of biodegradable materials that can also be molded... refer to these threads on Core77:
http://boards.core77.com/viewforum.php?f=14
Edited by: design-engine

 

[plastics-studen]

it all turns to be a LOT more complicated than I excpected(however I did not expected to make a real telephone within one shot).

Seeing such variety of devices among the market I tended to think the development time, thus details are much more narrowed, simple and already well ruled.


I thought there are already some rules behind i.e thickness development like:

*size of device
*snaps, fixtures
*stiffness
*etc

I would like to attend to mentioned by You Bart training, but isn`t 16 hours too less to cover such(as it appears to be) wide subject?

 

[design-engine]

Complicated? No... but a process for success will grantee a successful product and I am surprised your professor does not drill this point home.

Rules.... Your rules stem from product research and a competitive analysis. A typical product design process will have a review process and a tangible deliverable between each stage. There are many different iterations of a product development process and each product firm will have a different flavor that best suites their specific strengths and weaknesses. Search this 'product development process' in google to learn more.

1 research/competitive analysis
2 concept sketching, color/material study
3 3d forum study (could be crude Pro/E) or carved from polyfoam or CNC'd Rhen concept model
4 Pro/ENGINEER engineering model and SLA prototype.
5 management of production tooling

Another place to get product research and competitive analysis... http://welectronics.com/
Edited by: design-engine

 

[cloughna]

Lots of good advice here.

Assuming you are not a pro|e rockstar, I would advise putting off going to CAD until you have sketched or clay modeled your desitgn to the point that you know exactly how you want this thing to go together. It takes many hours logged before it becomes efficient to do conceptual work in pro|e.

There are few things more frustrating than sitting in front of pro|e simultaneously trying to figure out how you want the parts to go together, and then how to model them in pro|e.

Also, as you can see from Mr. Brejcha, you can put ALOT into product design. What I'm a little unclear on is what exactly would get you the best grade (which as I understand it, is the point of all of this). What do you think would be more appealing to your professor?

Complex (yet still manufacturable) part geometry?
Justification of design (I believe Mr. Brejcha mentioned gating. If I were a professor, a student justifying their design with respect to gating would be impressive)
Process (does he want to see research, sketching, cost analysis etc.)

I ask these because it would be a shame to spend your time researching texturing of the molds just to find out that the professor thinks your parts are too simple.

 

[mgnt8]

As far as figuring out assembly, this looks like a reverse engineering issue. My suggestion is to get a hold of the handset that you're basing your design on and cracking it open. For example



Edited by: mgnt8

 

[design-engine]

we have several cell phones taken apart at design engine. We need to glue them to a board now... Don't leave your cellphone un-attended here! We will defiantly take it apart after a few days.

 

[mgnt8]

That's how you find out how stuff works. Its been a while but during my stints at Motorola I believe we also worked with PC/ABS blends for the housings, but the design guidelines are similar. Here is another resource for that stuff

One more thing about the iPhone, the housing isn't made of plastic but apparently some kind of ceramic.




Edited by: mgnt8

 

[plastics-studen]

I would like to not expand goals I am trying to meet.

So, this is up to me what do I want to focus on - styling or mechanical concept(tooling is out of scope of project). To me development of mechanical side is much more interested.

So far I should introduce:

*good Pro/E skills

*proper fixture solution(what and why?)

*thickness investigation(why have You chosen such value?)

*PCB mounting solution

*parts must to be manufactured, thus - at least - I should be aware of all drafts and its direction vs splitting line, etc(tooling costs side in this project is not an issue)

*material investigation

*dimensions and tolerances

 

[design-engine]

dont forget texture

 

[cloughna]

I would like to not expand goals I am trying to meet.

So, this is up to me what do I want to focus on - styling or mechanical concept(tooling is out of scope of project). To me development of mechanical side is much more interested.

So far I should introduce:

*good Pro/E skills

*proper fixture solution(what and why?)

*thickness investigation(why have You chosen such value?)

*PCB mounting solution

*parts must to be manufactured, thus - at least - I should be aware of all drafts and its direction vs splitting line, etc(tooling costs side in this project is not an issue)

*material investigation

*dimensions and tolerances

for thickness, material investigation, and tolerances check out http://mpw.plasticstoday.com/imm/beall-library There is a bunch of god information there.

 

[mgnt8]

What is your modeling plan? Are you using top down master modeling techniques or skeletons?

Your goal should always be to create a design with the most efficient & optimal use of resources. You are goldilocks, not too much, not too little, but just right. You might find out something if you examine existing products - universal aspects of the designs that have been optimized such as wall thicknesses. So look at some, look at the material specifications, look at the components being supported & housed, and apply some critical thinking. Cross check with design guidelines like here & in the Machinery Handbook. Better yet, find a machine shop that has experience with molds & start asking questions.

Here is another thing I came across about materials. Samsung replaced the PC/ABS alloy with PC/PLA with some improvements to mechancial properties. The only way right now to get decent parts from bioplastics is to blend it with other resins.

 

[plastics-studen]

I was faced at start which platform to use: SE or Foundation package.

I
chose second one, because of possibility to work on commercial version.
So no TD in its pure form - no skeletons while Foundation package does
not support it.



However. as much as it is possible I try to create references in TOP
assembly to drive components. I like to Acitvate them and work in
assembly mode.



This is what I have done so far:







I disassembled real example of telephone and checked its design, fixtures, etc. I am going to introduce same solutions.

However I am curious what is general differance between the use of ordinary hooks/snap-fit and the solution one can meet often in small devices







It seems to be very popular fixture regarding remote controlers. However, to me they are "heavy" to be considered in constraint of ease of disassembling.

 

[mgnt8]

These are planar locks and are common for assembling components like this with long walls. The advantage is the entire walls deflect which eases strains. The text book cantilever snap fits require more deflection which also may not be ideal for the relatively more brittle engineering resins. As you suspect, the disadvantage is easier separation, but this can be remedied with thicker walls & ribs.

Also, dis-assembly may not be completely discouraged because of extended producer responsibility considerations & European Waste Electrical and Electronic Equipment Directive

By the way, here's another great article about taking apart phones

Edited by: mgnt8