Views
5 years ago

SPRING 2013

  • Text
  • Fastener
  • Fasteners
  • Products
  • Screws
  • Manufacturing
  • Metric
  • Industrial
  • Continued
  • Mechanical
  • Distributors
Distributor's Link Magazine Spring Issue 2013 / VOL 36 / NO.2

64 THE DISTRIBUTOR’S

64 THE DISTRIBUTOR’S LINK Spirol International Corporation 30 Rock Avenue, Danielson, CT 06239 Tel: 1-860-774-8571 Fax:. 1-860-774-2048 Email: info@spirol.com www.spirol.com HEAT VERSUS ULTRASONIC INSTALLATION by Christopher G. Jeznach, Application Engineer Introduction The focus of this article is on two of the most commonly used Insert installation methods in thermoplastic parts: heat and ultrasonic installation. As the usage of plastic parts has increased in a wide array of industries, the methods for fastening have become increasingly important. When screws or bolts are threaded directly into plastic components, failures can occur due to stripped threads or plastic creep 1 . In situations where joint strength and the ability to assemble and disassemble without degradation of components is required, Threaded Inserts provide a serviceable thread which satisfies both of these needs. Before going into detail on heat versus ultrasonic installation, it is important to note that there are other methods for installing Inserts, as shown in Table 1. Installation of Inserts after molding (post mold) versus molding-in reduces costs by shortening molding time. Post mold installation also reduces the chance of scrap and potential mold damage resulting from dislodged Inserts. As shown in Table 1, heat and ultrasonic installation is only used with thermoplastic parts. Thermoplastics are solid at normal temperatures and can be re-melted a number of times, whereas thermosets have a one-time reaction in their conversion from liquid to solid and cannot be re-melted. With both heat and ultrasonic installation methods, the Insert is Table 1: Installation methods for Threaded Inserts, showing installation type and material compatibility. embedded into a molded or drilled hole through re-melting of the plastic. Retention within the hole is provided by the melted plastic conforming to the external features of the Insert (Figure 1). A sufficient volume of plastic must be displaced to entirely fill these external features so that the Insert achieves maximum performance when the plastic solidifies. An accurate way of determining sufficient plastic flow into the knurls, barbs and undercuts of the Insert is to take a cross section of the installed Insert and ensure that the features are mirrored in the plastic as shown in Figures 2 and 3. It is extremely important to ensure proper plastic flow into the features of the Insert as this dictates the torque and pull-out performance. In Figure 3, the plastic did not sufficiently flow into the retention features, which will result in low Insert performance. Though they are both dependent on localized melting of the plastic, heat and ultrasonic installation methods can result in varying performance. Both installation methods have advantages and disadvantages, which should be considered before investing in installation equipment. 1Creep refers to material deformation or movement when the material is exposed to static mechanical stresses and/or elevated temperatures. (Materials Science and Engineering An Introduction, William D. Callister, 7th Edition). Figure 1: Undercuts, knurls and/or threads on the outside of the Insert improve performance LEFT: Figure 2: Proper Plastic Flow RIGHT: Figure 3: Improper Plastic Flow please turn to page 138

THE DISTRIBUTOR’S LINK 65 KEY BELLEVILLES, INC. We are the largest Disc Spring Manufacturer! • Complete size range from .236” to 36” O.D. & 3” Thick • Largest Raw Material and Finished Inventory in the World • We manufacture Metric Parts to DIN Specs • Complete Line of Stainless and Inconel Parts • 10,000 Different Sizes in Stock Call toll free from anywhere in the U.S. and Canada at: Phone: 1-800-245-3600 • Fax: 1-800-847-1672 Key Bellevilles, Inc. 100 Key Lane • Leechburg, PA 15656-9531 U.S.A. Phone: 724-295-5111 • Fax: 724-295-2570 www.keybellevilles.com • e-mail: sales@keybellevilles.com Visit Our Website or Call for a FREE Engineering CD

SHARE A PAGE FROM THIS MAGAZINE

OPTION 1: Click on the share tab above, or OPTION 2: Click on the icon (far right of toolbar) and then click on the icon (top right of the page).

View Archives

SPRING 2020
WINTER 2020
FALL 2019
SUMMER 2019
SPRING 2019
WINTER 2019
FALL 2018
SUMMER 2018
SPRING 2018
WINTER 2018
FALL 2017
SUMMER 2017
SPRING 2017
WINTER 2017
FALL 2016
SUMMER 2016
SPRING 2016
WINTER 2016
FALL 2015
SUMMER 2015
SPRING 2015
WINTER 2015
FALL 2014
SUMMER 2014
SPRING 2014
WINTER 2014
FALL 2013
SUMMER 2013
SPRING 2013
WINTER 2013
FALL 2012
SUMMER 2012
SPRING 2012
WINTER 2012
FALL 2011
SUMMER 2011
SPRING 2011
WINTER 2011

Copyright © Distributor's Link, Inc. All Rights Reserved | Privacy Policy