The Plastics Store™

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Books: Design, Processing, Materials, Simulation, Testing

Design

How to Search for Unfilled Plastic Materials
One of our advanced features in Prospector, the Property Search, not only allows you to search for materials with a percent % filler reinforcement specified, such as 30% glass filled, but it also allows you to search for unfilled materials. It’s a pretty simple search to do with the Property Search tool.

2 Easy Ways to Search for Plastic Materials by Filler Type
To help you find the best material for your application, the Sequential Search provides 5 different properties to help you refine your search.  This tool is particularly helpful if you need to select a material based on filler content. 

By Design: A Simple Shape Creates a Complex Problem
Injection molders claim that one way or another, they can mold any shape a designer envisions. In general this is true, but some shapes are more troublesome than others.

By Design: The Roller Skate, Part 2: A Change in Material and Manufacturing Method is Troublesome
In the previous By Design article, we reviewed stress cracking around the molded-in steel insert in a roller skate undercarriage. Once this obvious defect was eliminated, our attention was drawn to two equally troublesome, but subtler, problems.

Playing the "Not Invented Here" Game Costs OEMs Many Thousands of Dollars Each Year
You don’t have to be a yes-man to a large OEM to get the job, but you do have to be diplomatic.

Processing

June '08 Design Tip: Avoid Knitting Around Your Boss
Start with a simple fact: resin cools as it is injected into a mold. This is why the leading edge of the resin flow within a mold is always the coolest area of the resin, and, therefore, the closest to solidifying.

Mold Components and Why You Should Use Purchased Ones
Mold components play a very important role in plastic injection mold making. There are numerous basic components that are common to almost every injection mold, and often some components that are specifically engineered for special applications. Both of these make up the reason you should use off the shelf mold components, whenever possible.

Is EDM Graphite Dust Dangerous?
The health and welfare of toolmakers that use graphite to make electrodes for use in the electrical discharge machining of molds should be a high priority for management. In addition to the health issues for the workers, the very expensive machinery, such as the EDM machines and milling machines, must be protected from the damaging effects of graphite dust.

The Troubleshooter, Part 100!: If he's told you once, he's told you 100 times
Although times and technology have changed, many of the problems Hatch sees today are the same ones molders and moldmakers struggled with back when he started writing this column.

Materials

The Lifecycle of Plastic - Impacts on Business and the Economy
As the cost of petrochemicals skyrockets and concern with the environment continues to grow, we ’ll have to think more about plastic’s origins and destinations, both as consumers and as producers of plastic components.

Ways in which Plastic is Substituted for other Materials
There ’s nothing new about plastic as a substitute for other materials. From its very beginnings, plastic took the place of whalebone, tortoiseshell, wood, and stone. The reasons for substitution were simple: availability and cost. Mixing up a vat of combustible celluloid had its risks, but they were small compared to those of hunting whales in tiny boats. Plastics were cheap compared to the semiprecious stones they replaced in costume jewelry, and they were easier to work than wood or stone.

The Basics of Resin Selection
You know there are tools out there to help you pick the right material for your part, but are you up to speed on the terms and technology needed to use them? Here ’s a place to start.

Simulation

Simulation of Core Shift and Injection Molding Machine Clamp Over-Tonnage Using Moldflow Plastics Insight® (MPI®)
The core shift analysis has the capability to predict the thickness changes due to core deflection, and these thickness changes are carried through to subsequent analyses; so for example, a warpage analysis can be performed to evaluate the part final form, fit and function.

A Mesh By Any Other Name - Is it Still the Same?
Computer-aided engineering (CAE) simulation of injection molding is a mathematical representation of a physical manufacturing process. As such, there are assumptions and limitations inherent in the software that users must understand in order to obtain the most accurate results.

Plastics Design Principles: Theory and Concepts
The Moldflow Design Principles are a set of rules that influence the design of a part and tools to optimize the filling of a part. When these principles are followed, higher quality parts and faster cycle times are the result. Not following these plastics design principles leads to problematic designs.

Testing

Material Stability and Performance Test
Creep experiments are a valuable method for studying the viscoelastic properties of polymer melts. The zero shear viscosity can be calculated at many temperatures and plotted as a function of temperature.

Frequency Sweep and Temperature Sweep Package
A great test package, for incoming raw material resins, and to determine the viscosity as a function of temperature. In order to successfully predict the processibility of polymer melts, it is important to characterize the viscoelastic properties and the temperature dependency.

FTIR Analysis- Fourier Transform Infrared Spectroscopy
Fourier Transform Infrared Spectroscopy (FTIR) identifies chemical bonds in a molecule by producing an infrared absorption spectrum. The FTIR generates an infrared spectral scan of samples that absorb infrared light. Metals
do not absorb infrared light, but polymers that contain metals can be scanned with FTIR.

Predicting Polyolefin Foamability Using Melt Rheology
Every polyolefin has a unique and definitive fingerprint of it's melt flow. Many different polyolefinic foams and effectively nonfoamable polyolefinic resins are successfully studied by ASTM D-4440, Standard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology techniques.