This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.
This Website Uses Cookies
By closing this message or continuing to use our site, you agree to our cookie policy. Learn More
This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.
Assembly Magazine logo
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Assembly Magazine logo
  • Home
  • Magazine
    • Current Issue
    • Digital Edition
    • Archives
    • Specs Book
    • How-To-Guide
    • Buyers Guide
  • Exclusives
    • Plant of the Year
      • About Plant of the Year
      • Nomination Form
    • Capital Spending
    • State of the Profession
  • Industries
    • Aerospace
    • Appliance
    • Automotive
    • Medical Devices
    • DFMA Assembly
    • Green Manufacturing
    • Lean Manufacturing
    • Electronics Assembly
    • Machinery Assembly
  • Technologies
    • Adhesives
    • Assembly Presses
    • Automated Assembly
    • Dispensing
    • Motion Control
    • Screwdriving and Riveting
    • Plastics Assembly
    • Robotics
    • Test and Inspection
    • Welding
    • Wire Processing
    • Workstations
  • Columns
    • Assembly in Action
    • Automation Profiles
    • Medical Device Assembly
    • On Campus
    • Shipulski on Design
    • The Editorial
    • XYZ
    • Moser on Manufacturing
    • 21st Century Assembly
    • Mind Your Ps and Qs
  • New Products
  • More
    • Web Exclusives
    • Classifieds
    • eNewsletter
    • Blog
    • Market Research
    • Store
    • Product Spotlight
    • White Papers
    • Integrated Showcase
    • Custom Content & Marketing Solutions
    • Monthly Quiz
    • Sponsored Insight
  • Multimedia
    • Assembly Radio
    • Assembly TV
    • Image Galleries
    • Webinars
    • Interactive Spotlights
    • eBooks
  • Events
    • Calendar
    • The Assembly Show
  • Contact
    • Contact Us
    • Advertise
  • InfoCenters
    • Collaborative Robot Revolution
    • Factory of the Future
Home » Molding for Medical Device Assembly: Glossary of Injection Molding Terms

Molding for Medical Device Assembly: Glossary of Injection Molding Terms

April 8, 2005
Austin Weber
Reprints

Cavity: the space inside a mold into which material is injected. Molds can contain a single cavity or multiple cavities to produce more than one part in a single shot.

Chilling: the action of removing heat from the melt to convert it from a liquid consistency back to its original rigid state. As the material cools, it also shrinks. This stage can consume 70 percent to 80 percent of the total cycle time; it is largely dependent upon the wall thickness of the part.

Clamp force: the force required by the clamp to keep the mold closed during the injection process.

Clamping unit: a device that holds the two halves of a mold in correct alignment and keeps the mold closed during injection by applying a clamping force sufficient to resist the injection force. It typically consists of a fixed platen and a movable platen, which are attached to tie bars.

Ejection: the removal of the cooled, molded part from the mold cavity and from any cores or inserts. As the mold opens, ejector bars or ejector pins make contact with the ejection mechanism and push the part out of the mold.

Ejector bars: pins that are pushed into a mold cavity from the rear as the mold opens to force the finished part out of the mold.

Flash: any excess material that is formed with and attached to the part or component along a seam or mold parting line.

Injection: the stage during which the melt is introduced into a mold to completely fill a cavity or cavities.

Injection-molding machine: a device that consists of two basic components: a plastic injection unit and a mold-clamping unit. The machines can be either electrically or hydraulically actuated.

Injection unit: a device that acts like an extruder. It consists of a barrel that is fed from one end by a hopper containing a supply of plastic pellets.

In-mold assembly: a process in which parts are molded and assembled in the mold. The combination of these two traditionally separate processes can reduce production cost, while improving quality and productivity. In-mold assembly eliminates traditional joining processes, such as bonding or welding.

Melt flow rate: a measure of the molten viscosity of a polymer determined by the weight of polymer extruded through an orifice under specified conditions of pressure and temperature.

Metal injection molding: a process similar to plastic injection molding that can produce many of the same shapes and configurations. Metal powder is mixed with a thermoplastic binder and molded into a cavity. With metal injection molding, a wide variety of flexible designs, component integration and high-performance characteristics are possible.

Micromolding: a process similar to traditional injection molding that allows manufacturers to produce tiny parts for microelectromechanical, microfluidic and nanotechnology applications. Micro parts typically have tolerances of 0.0001 to 0.0002-inch. Their geometry can only be seen by microscope. Micro parts feature wall thicknesses as low as 0.0015-inch and overall part weight as low as 0.00012-gram.

Moldability: the characteristics of being easy to mold without rupturing or developing flaws due to movement of the polymer during gelation.

Multi-shot molding: the injection of two or three materials, in sequence, into a single mold during a single molding cycle.

Nozzle: a hollow metal hose screwed into the extrusion end of the heating cylinder of an injection machine, designed to form a seal under pressure between the cylinder and the mold.

Plasticizing: the conversion of a polymer material from its normal hard, granular form at room temperature to the liquid consistency necessary for injection at its correct melt temperature.

Platen: the structural part of an injection-molding machine to which the mold is mounted.

Shot: the complete amount of melt injected during a molding cycle.

Shrinkage: a process that occurs when plastic cools in a mold, because polymers have high thermal expansion coefficients. Some thermoplastics contract up to 10 percent. However, fillers added to plastic tend to reduce shrinkage. To compensate for shrinkage, the dimensions of the mold cavity must be made larger than the specified part dimensions.

Sprue: the feed opening provided in injection molding between the nozzle and cavity.

Thermoplastic: a polymer that melts or flows when heated.

Thermoset: a polymer that does not melt when heated.

Tie-bar spacing: the space between the horizontal tie-bars on an injection-molding machine. This limits the size of molds that can be placed between the tie-bars.

 

subscribe to assembly

Recent Articles by Austin Weber

Colorado develops grid-storage battery technology

Auto Industry Drives New Vision Technology

Electric vehicle makers rethink assembly processes

2019 Assembly Plant of the Year: Refrigerator Production Heats Up at GE Appliances

Omron sponsors University of Houston robotics lab

Weber200
Austin has been senior editor for ASSEMBLY Magazine since September 1999. He has more than 21 years of b-to-b publishing experience and has written about a wide variety of manufacturing and engineering topics. Austin is a graduate of the University of Michigan.

Related Articles

Packaging for Point of Sale: Glossary of Packaging Terms

Robot Dos and Don'ts: Glossary of Robotics Terms

Some Change is Good: Glossary of Packaging Terms

Glossary of Lighting Terms

Subscribe For Free!
  • Print & Digital Edition Subscriptions
  • Assembly eNewsletters
  • Online Registration
  • Subscription Customer Service
  • Mobile App

More Videos

Popular Stories

lordstown motors

Electric Truck Manufacturer Buys GM’s Lordstown Assembly Plant

Bobcat manufacturing

Bobcat Announces Manufacturing and Assembly Facility Upgrades

Wearable Device 11-27

Wearable Lets Users Control IoT-Enabled Devices With Brain Waves

Rayovac 11-20

Energizer Moving VT Battery Manufacturing Facility to Former Rayovac Plant

Breaking and Industry News

Airstream Manufacturing Expands With $50 Million Factory

Upcoming Assembly Events and Webinars

Events

January 1, 2030

Webinar Sponsorship Information

For webinar sponsorship information, visit www.bnpevents.com/webinars or email webinars@bnpmedia.com.

View All Submit An Event

Poll

Cloud Computing

Are you using cloud computing at your assembly plant?
View Results Poll Archive

Products

Welding: Principles & Practices

Welding: Principles & Practices

This text introduces students to a solid background in the basic principles and practices of welding.

See More Products
assembly buyers guide

Assembly Magazine

assembly dec 2019

2019 December

The 2019 December Assembly features our Capital Spending Report, plus much more. Check it out today!
View More Create Account
  • More
    • Assembly Plant of the Year
    • Manufacturing Group
    • List Rental
    • Organizations
    • Connect
    • Want More?
    • Polls
    • Privacy Policy
    • Subscribe
    • Survey And Sample

Copyright ©2019. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing