How to attach a glass window onto a injected part 1

[cdaguet]

Hi everyone,

I'm designing a device in a startup (so we basically have little amount of money to spend) and I have to attach a rectangular and flat glass window onto an ABS/PC injected part (also flat). I'm currently thinking about a double coated adhesive + silk screen onto the glass (for aesthetic purpose) but the problem is that it costs a lot of money (laser cut the glass, die cut and apply the adhesive). Would you guys have another idea than using adhesive in order to attach a glass window onto an injected part? The shapes are simple: rectangular glass window and rectangular frame in the plastic part.

This is my first post so don't judge me too quickly

Thanks in advance

César

 

[Tmoose]

How big is the window?
Are the corners rounded, or sharp pointed 90 degrees?
T molding.

https://www.rehau.com/us-en/furniture/edgeband/t-molding-and-bullnose

Please describe the "rectangular frame in the plastic part."

If I picture the molded-in frame correctly ( which without pictures and drawings is REEEEAALLY hard to do) could the frame be reversed so the attaching ugliness be hidden on the inside?

 

[IRstuff]

Can you injection mold with the window in place?

TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529

 

[BrianPetersen]

The expected production volume and cycle time will play a role in the decision, too. How many are you making and if it's a lot, what's the cycle time? The process you use to make one, might not be the same choice used to make 100,000.

 

[MadMango]

To keep costs down, heat stake it in place, or add features that allow for snapping it into place. Foam tape could be used to eliminate rattles.


"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[hydtools]

Maybe a UV activated adhesive.

Ted

 

[cdaguet]

I didn't attach a drawing of the parts because it can be redesigned according to the way the window will be attached. The question is fully opened. Angles can be sharp or not. The only constraint I have is that the glass window thickness has to be between 0.5 and 0.75mm. Also, it needs to be attached strongly. Therefore, clips won't be strong enough. If you have any snapping features that hold strongly please share your ideas I thought about heat staking before but I wasn't sure if it was easy and low cost to stake glass on plastic. Is it really?
I attached a rough drawing of the current design: the rectangle (21.9x12.4) is the glass window while the crosshatched area represents the tape we currently use. We're planning on producing between 5000 and 10,000 part per year. We don't know the cycle time yet because it depends on the glass window production/assembly processes.

Thanks in advance guys. You help a lot

 

[hydtools]

Perhaps a rubber window seal/gasket.

https://www.trimlok.com/

Ted

 

[MadMango]

"Strong enough" is the question. You haven't told us any details like how much force the glass must withstand, if it is decorative or a safety device. There are probably many more questions that need to be answered. Depending on the shape and size of your heat staked areas, it could be "strong enough".

Adhesives like Hydtools suggested might be a good route. At 10,000 annual, that's only 40 a day. Modern car windshields are attached with adhesives as well, that are not UV cured. Manually applying an adhesive and cleaning up the product of messy goop and smears is easily achievable. Maybe look into:

http://usa.sika.com/en/industry/industry-home/01a011/01a004sa04100/01a004sa04101.html

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[BrianPetersen]

Glass thickness of only 0.5mm isn't going to be very strong. Tape it, or glue it.

 

[hendersdc]

Does it need to be made of glass? Can you increase the thickness slightly? If the answers to these questions are "No" and "Yes" respectively you may want to look into the process of in mold decorating (IMD). This could decrease your part cost, part count, and assembly time while allowing you to integrate artwork in the window. Taking this route, your window would be made of clear plastic and would be integrated into your housing. The IMD foil would include paint to cover the portions of your housing that you do not want to be clear while at the same time acting as a scratch resistant coating for your window. Down side would be an increased tooling cost for the injection molded housing with in mold decoration.

An video of the process can be found here: Link and a quick google search will give you everything you need to know about the process.