I would like some help with blow moulding or rotational moulding

[Scarecrow]

Hi
I am designing a display unit for one of our products. Essentially it's a hollow enclosure that is made of two pieces, the upper piece (dome) needs to be clear transparent. I'm thinking PC or PET, it does not have any structural requirements.

The bottom half (base) will support the top half, and will contain water and a pump within.

The display will allow our product "the scarecrow" to activate and dispense a high stream jet of water. The water will drain down along the inside of the dome into the base.

We need to make lots of these functioning display cases (like 500 +), and they need to be CHEAP!!! I am sorry to say that unless we can make the plastic for $20 US it's gonna be canned. That leaves China as the only viable solution to cheap plastic manufacturing.

Can anybody help me out here, I'm looking for contacts in China, a good track record, ect ect

Thanks

Gerry Bolda

http://www.scatmat.com

 

[insideman]

A lot hinges on how big and how deep the parts are. Please tell us about these factors.

 

[patprimmer]

Tooling costs will be your biggest problem for a 500 off project.

The biggest cost by doing business in China will be the communication and travel cost. On a small cheap project, the costs of communicating with China might be more than the cost of getting it done close to home. I guess home is USA.

Rotational moulding can be done on very cheap tooling, so it is probably the way to go, or even fabricating from acrylic sheet. Have you talked to a local sign maker who does backlit sighns.

Regards
pat

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Scarecrow]

K hang on for a few, i'm just getting a rendering ready with some dimensions....


Gerry

 

[cpretty]

Try vacuum forming. You could create your forms out of MDF for 500 parts. You will probably have to do a bit of post processing to finish the edges etc, but for 500, your savings on tooling costs would offset it.

You will probably have to find an accomodating vacuum former to do this, but anyone with experience in prototyping parts using vacuum forming should be particularly usefull.

If the size you are talking about is approx 400mm across then I have actually seen a similar sounding item used for sprinkler demonstrations at a agricultural show in New Zealand.

Cheers,
Craig

 

[patprimmer]

Backlit sign makers normally use vacuum forming

Regards
pat

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Scarecrow]

hi guys,
here's a pdf page with my design, can you have a look and see if it's feasable. Top dome maybe PETG or PC and base LDPE.

http://www.scatmat.com/ScarecrowPOP/pop_photos.pdf

 

[cpretty]

Bottom looks ideally suited to vacuum molding. Top looks like it requires some major draw to suck that deep. It would be a matter of tuning to get something that works. Could you divide the top into two pieces ie a flat back peice, and then the curved front and top. The back shouldn't get wet, so sealing is not of prime importance.

You should be able to find some info on the web about home vacuum molding using a vacuum cleaner and household oven, that can give you an idea of what could be done.