Method to Retain a Small Disk within plastic
Method to Retain a Small Disk within plastic
(OP)
I am trying evaluate methods to permanently retain a small disk, .75" x .125" in some plastic.
I have come up with 3 ideas, but not so sure of the cost effects and manufacturability of each.
Insert disk and sonic weld cap on...Needs to be strong bond.

Drop Disk into slot and Glue/Sonic weld cap to retain

Snap Latch..No so sure about designing these still.

I'd like to permanently retain the disk. I think Molding it in would also be nice, but the disk has a 170degF limit. Don't know the cost of that either..I can possibly substitute for high temperature material.
So I have 4 Options..Need good retention strength. Water tight would be a plus, but Do I have to be concerned if this is brought on an air plane and increased pressure differential causes a break at the seal? Something I have to analyze. Also, I need to be able to predict the sonic weld strength. Mostly thinking out loud here.
Thanks
I have come up with 3 ideas, but not so sure of the cost effects and manufacturability of each.
Insert disk and sonic weld cap on...Needs to be strong bond.

Drop Disk into slot and Glue/Sonic weld cap to retain

Snap Latch..No so sure about designing these still.

I'd like to permanently retain the disk. I think Molding it in would also be nice, but the disk has a 170degF limit. Don't know the cost of that either..I can possibly substitute for high temperature material.
So I have 4 Options..Need good retention strength. Water tight would be a plus, but Do I have to be concerned if this is brought on an air plane and increased pressure differential causes a break at the seal? Something I have to analyze. Also, I need to be able to predict the sonic weld strength. Mostly thinking out loud here.
Thanks






RE: Method to Retain a Small Disk within plastic
**My comments are my opinions, and results are not guaranteed**
Eugene Kim
www.eeksolutions.com
RE: Method to Retain a Small Disk within plastic
You might also spin weld it.
Adhesives will work with the right materials. Take PVC pipe for plumbing systems for instance.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Method to Retain a Small Disk within plastic
I'm kind of torn between the snap and welded cap. Welded cap Introduces another step in the process and another tool, making the Snap more viable, but the I like the aesthetic of the cap. I think I will need to review. Also, I can use a Disc with a hole in the center..and maybe use a "push-in" snap cap to retain the part.
But the center hole needs an undercut for the push-in snap cap. I'll have to think about that..
RE: Method to Retain a Small Disk within plastic
Mike Halloran
Pembroke Pines, FL, USA
RE: Method to Retain a Small Disk within plastic
Is having a pleasing aesthetics a design requirement? Is it a company goal or a personal goal?
If it's a company goal, then no one should have any issue about spending the extra money on tooling, molding, and assembly. The "push-in" snap cap or some form of molded cover as MikeHalloran suggested sounds good. By the way, for molded-in disc option, it would require at least two holes on either side of the disc package. More holes may be needed depending on what it would take to hold the disc in place during the molding op. You may even have to settle for the less productive vetical molding with operators hand-loading the discs.
If meeting an aesthetic requirement is a personal goal, during a design review, how would you justify the extra costs to produce the more asethetically pleasing part?
**My comments are my opinions, and results are not guaranteed**
Eugene Kim
www.eeksolutions.com
RE: Method to Retain a Small Disk within plastic
Another option is to screw-fix the disc into the part. I think that may be the most economical method, but not those most aesthetic.
RE: Method to Retain a Small Disk within plastic
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Method to Retain a Small Disk within plastic
I would guess that the money saved in tooling cost by going ultrasound welding (i.e. straight open and shut tooling, simple cavities) would buy you a second hand welder and tooling.
Agree with above that it would be the neatest solution by far.
Cheers
Harry
RE: Method to Retain a Small Disk within plastic
-b
RE: Method to Retain a Small Disk within plastic
That doesn't sound real watertight.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Method to Retain a Small Disk within plastic
RE: Method to Retain a Small Disk within plastic
Solvent bonding is better, imho.
Or just gob the cavity full of hot melt.
Mike Halloran
Pembroke Pines, FL, USA
RE: Method to Retain a Small Disk within plastic
Assuming it's possible to solvent bond - or even CA glue.
If it's ABS or similar, then no problem - apart from getting solvent/glue on the outside and ruining any aesthetic finish required. There is also these days the health and safety aspects of using solvents. Not loved by all.
Rgds
Harry