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24 September 2017 Tablets & Capsules microstructure, and residual stress, including microstruc- tural analysis, crack observation, scanning electron microscopy, x-ray diffraction, and chemical composition change analysis by energy-dispersive x-ray. The results showed a 35 percent decrease in the fatigue limit of the EDM samples compared to the milled samples. "This was attributed to a tensile residual stress state after EDM, com- bined with significant phase transformation and hydrogen embrittlement. The milled surfaces showed no microstruc- tural transformation or surface cracking and contained compressive residual stresses, all of which contributed to an improved fatigue resistance," according to the study. Conclusion Although monoblock and other multi-tip tooling can significantly improve production rates, there are other machine and formulation characteristics that need to be considered. The sidebar on the previous page discusses some of these considerations. Before you decide to imple- ment multi-tip tooling in your tabletting process, ask a multi-tip tooling manufacturer to assess your manufactur- ing requirements and recommend the tooling type most suitable for your operation. T&C Reference 1. Ghanem F., Sidhom H., and Fitzpatrick, M. E. Effect of near-surface residual stress and microstructure modification from machining on the fatigue endurance of a tool steel. J Mater Eng Perfor 2002 11(6): 631-639. Steve Osborn is a design and multi-tip tooling expert at I Hol- land, Nottingham, UK. Its products are distributed in the USA, Canada, and Puerto Rico by IPR, 1241 Hardt Circle, B a r t l e t t , I L 6 0 1 0 3 . T e l . 6 3 0 8 2 3 4 7 0 0 . W e b s i t e : www.iprinc.net. Factory and Headquarters: 1400 Monroe Street • P.O. Box 730 • Owosso, MI 48867 www.tri-mer.com particulate control HEPA-Level Dry Dust Collector • MERV 16 rating • Efficiencies of 99.999% on 0.5 micron & larger particles (by weight) • Filter life 3-5X that of bags or cartridges • Low cost per cfm! • 7 media options Talk with Asa Halliday (989) 723-7838 • ahalliday@tri-mer.com Low Maintenance Wet Dust Collector WHIRL/WET ® Talk with Todd Ainsworth (989) 723-7838 • tainsworth@tri-mer.com Low Maintenance Wet Dust Collector WET 99% efficient 99.999% efficient One Source for Particulate Control • Advanced collector has no internal moving parts to wear or replace • Optimum efficiency with low water use • 99% efficient in a wide range of micron sizes • Whirl/Wet units will not clog under any operating condition Since 1960 © 2017 Tri-Mer Corp. Write for Tablets & Capsules Contact: Matthew Knopp, Editor Tablets & Capsules Tel. +1 651 287 5618 Fax +1 651. 287 5650 E-mail: mknopp@cscpub.com Our articles are written by technical professionals for technical profesionals. Ask about the types of articles we're looking for as well as tips on preparing an article for consideration.