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Questions tagged [injection]

16 questions
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1 answer

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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Prototype for Injection Molding

Mold for Injection Molding is very expensive and is justified for mass production. However, at Prototype stage, how we make the same part with less expensive method. I know 3D Printing is a way but it doesn't have Isotropic properties as its a…
Rehan Jamshed
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1 answer

Designing a Chilled Process Water System for Small Plant

I am designing a new, closed loop,chilled water system for our small injection molding outfit and can use some help where to begin. Here are some of my knowns: Northeast NJ, USA, no air conditioning. 4 hydraulic machines( 2x250ton, 1x310ton, 1x400…
Corey
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1 answer

Combustion Chamber Back Pressure due to gas injection

I am trying to calculate prior to testing the expected back pressure resulting from injecting gaseous oxygen through an injector orifice (choked) into a rocket combustion chamber before ignition. I have tried using the Borda-Carnot equation with the…
Justin B.
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Why does the cylinder/barrel on an injection moulding machine have such thick walls?

When you look at the cylinder on injection moulders, for instance on DIY ones on YouTube, they are all thick walled. The piston has say a 20mm diameter and the cylinder has like a 40mm diameter in which plastic is heated to 250C. Could you get away…
Lewis Kelsey
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Designing an injection molding mold for a part with a certain parting line and ejector pin location

How do you design a mold to create that part? The only way I can think of is to make the parting line horizontal to the part instead of vertical. But is there any way to design the mold so that the parting line is vertical like in the picture?
SVS
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Shear between which two fluids is better for atomisation - liquid & liquid or gas & liquid?

In designing an atomizer which generates a spray of liquid, one can adopt atomisation through shear. Shear in the following cases are to be considered: stagnant Gas- moving Liquid: in this gas case the gas is stagnant but the liquid is injected at…
karthikeyan
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Injection and lose of fluid injected and pressure drop down?

I am trying to develop a field by using water injection. I am facing a problem that the average reservoir pressure is dropping down and the BHP of the production wells dropping down as well until it reach the limit and stop producing. Therefore,…
CDplayer
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Plastic Vacuum Cleaner Part -- Why did they design it this way?

I've designed a whole lot of different parts and products in my time: Plastic, metal, lighting products, electrical products and automotive parts. I generally can look at a product and figure out why did they do that. Here's one that has me…
zipzit
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Injection molding - Probability of plastic pouring into connector

I have some metal pins that I want to be molded in parts of the final assembly. Meaning that, the mold will be made to accept those metal pins, which are positioned in the mold so that when the plastic is shot in, it will envelop the pins with…
user1584421
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Is this shape possible with injection moulding?

I want to build a DIY case with the connector shown in the pictures below. As you can see, it consists of a circular plastic that extrudes from the main enclosure. Inside there is something that can be described as "cut_circle", that again…
user1584421
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Why would these hydraulic cylinders have 3 large connections?

I am trying to work out how a recently acquired Arburg 220-90-350 from 1982 works so that I can build a new control system and get it working. It's a direct clamping machine with no toggle. The injection side is quite simple, just 3 motors or…
Newbie Noob
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How to get this hydraulic system working and help identifying parts and their function

I have recently acquired a 1982 Arburg 220-90-350 injection moulding machine, mainly just as a hobby to further my knowledge on injection moulding machines and control systems as I plan to modernise the control system by redesigning it from scratch…
Newbie Noob
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Injection nozzles and static mixers for LSR - How do i prevent an uncleanable blockage between runs?

I'm trying to implement a new material in our processes, and that's a 2 part, highly viscous (500-1000 Pa s) liquid silicone rubber. I will also be adding a pigment, so that's 3 components that need to be mixed before entering the mold. I have very…
Manohar Nayak
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Material Properties of ABS

I've been working on a design that requires a plastic snap feature. I've assumed up to this point that the material will be injection molded ABS, with material properties I pulled off of matweb. After several dozen iterations on the design, I've…
Diesel
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