Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [plastic]

Plastic (material): materials consisting of any of a wide range of synthetic or semi-synthetic organic compounds that can be molded into solid objects. This includes thermos-softening & thermos-hardening plastics.

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Why do glass windows still exist? (Why haven't they been replaced by plastics?)

Glass is fragile and impractical to transport, install and repair. Even worse, glass kills and hurts people when it breaks. Falling to the streets like guillotines during earthquakes and bomb raids. During wars people put tape on their windows to…
LocalFluff
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What type of ultrasonic transducer would be suitable for ultrasonic welding?

Project background: I am working on a project where i need to weld plastic using ultrasonic transducers. Problem: Since I'm still learning engineering, I have a hard time figuring out what all the factors are in order to choose the right…
vaid
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How to determine whether plastic is ABS or Polypropylene?

I have a pump that I want to use to pump a solvent. It is hard black plastic so I'm pretty confident it is either ABS or polypropylene (it wasn't expensive enough to be some more exotic plastic). My solvent will rapidly dissolve ABS but it will work…
ericksonla
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Information regarding plastic hinges that can hold the position

I am trying to find some information regarding the design of plastic hinges that can move freely but also hold a position in any degree, like in this little camera:…
Kevin Mamaqi
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Silicon and silicones

How is it possible for silicon to be used in many engineering materials like oil (Silicone oil), grease, caulk, rubber(PDMS), resin? What property of silicon allows it to be so used?
RTh
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What should the size difference be between a lid and a container?

I am designing a box and lid (for a home-made micro computer). Using Autodesk Inventor (Student Version), I've created my box which looks something like this: I plan on 3D printing (ABS Plastic) the box and lid in the end. And I am going to create…
Thomas Gerot
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Can I seal the inside of a water well to use it as water reservoir when the well is dry?

We've had unusually dry weather and our well has run so low that we had to call in a water hauling company to refill it a few days ago. The water man told me that even though he dumped in ~ 1000 gallons, a great part of it will seep out of the well…
cannotcompute
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How are non-continuous internal threads plastic injection molded?

I'm trying to figure out how the heck some of these plastic bottle caps are injection molded. By having the thread on the inside of a cap, this obviously creates an undercut. Now I've watched some videos on Youtube on the process, and I can see…
Davbog
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Finding the pull-through capacity of a nutted bolt and washer in ASA plastic

I have a uniform load applied to the underside of a plastic sheet which is to be resisted by the combination of a bolt, washer, and nut as depicted below (the other end of the bolt is secured and will not budge). The thickness of the Luran S 777k…
Rick
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Limits of Injection Molding Regarding Overhung Edges

I'm looking to redesign a seal my company currently uses. The original task was to re-source it from a lower cost supplier with the same design as is in current production. However, the supplier doesn't work with the type of material the seal is…
Trevor Archibald
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Minimising permeation rate of hydraulic fluid through hydraulic hose

I am designing an experiment where the hydraulic hose is going to be subjected to relatively high internal pressure for prolonged period of time and it is absolutely imperative that the rate of permeation is minimised. I have found one great book…
user2820052
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How do I cut a crack into a polymer/plastic?

We need to cut a very thin crack into a polymer plate for a research project. The closest thing to what we are looking for is Wire EDM but since the polymer we are using is not conductive we cant use that method. Any suggestions? Is there an…
Murad Nazari
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Increasing torsional-stress resistance of an Auger at its motor-shaft joint

An auger is used to move plastic balls and is rotated by a stepper motor. Due to the balls getting jammed sometimes, this induces stress on the auger at the motor-shaft junction and breaks. Images below describe the issue…
Amol Patravali
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What is the composition of Arizona Ice Tea 1gal plastic jugs stamped #7 OTHER and #5 PP (PP COMPATIBLE formerly)?

I wished to know the composition of Arizona 1gal plastic jugs that I have. The bottom is stamped PP COMPATIBLE and has a #7 OTHER RIC code. I understand PP recyclable would be #5 triangle. #7 means it doesn't fit in the plastic recyclable…
Nissim Nanach
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Calculating a pull force between two pieces of plastic

I have an HDPE pin, 2 mm high, 2 mm diameter, that I impress into a flat plaque of hot HDPE. It is not hot enough to melt the pin, but still hot enough that the material will shrink 4% in 24 hours. How would I calculate the force required to…
William B.
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