Appliance Design - January 2009 - (Page 31) PLASTICS & PLASTIC PARTS ed by drafting the sides of the clip as shown in the diagram on the right by a minimum of 3 degrees. Fig. 4. Illustration of a clip feature produced using telescoping shutoffs. At left is top view and angled view showing how the lack of draft results in sliding parallel mold surfaces. At right, top view and angled view show how draft yields improved mold shutoff surfaces. Draft and rotational symmetry There are special cases when considering the role of draft, such as when designing a plastic part with rotational symmetry. For a simple example, consider a dowel. In CAD software one might create the shape of half the cross-section — a rectangle — and rotate that shape through 360 degrees to create the solid. (See Fig. 5.) However, knowing that the part is going to be injection molded and that the parting line of the mold will run along the length of the dowel, it becomes apparent that the end faces of the dowel need to be drafted. There are two ways to draft those ends, one of which works better than the other. The obvious, but problematic, approach is to tilt the ends slightly when laying out the cross section. When rotated, this cross section makes the ends of the finished design shallow cones instead of flat disks. (See Fig. 6.) This is “rotational drafting.” The preferred method, however, from the standpoint of minimizing tooling complexity Fig. 5. Undrafted dowel. Richco World Headquarters • 8145 River Drive • Morton Grove, IL 60053 www.richco-inc.com www.applianceDESIGN.com AD01094Rich1.indd 1 applianceDESIGN January 2009 31 12/15/08 11:54:12 AM http://www.richco-inc.com http://www.richco-inc.com http://www.appliancedesign.com
Table of Contents Feed for the Digital Edition of Appliance Design - January 2009 Appliance Design - January 2009 Contents Editorial Shipments/Forecasts News Watch Supplier Spotlights Commercial Appliances Plastics & Parts Electronics Motors Design Marts Association Report: NAFEM Advertiser’s Index Appliance Design - January 2009 Appliance Design - January 2009 - Appliance Design - January 2009 (Page Cover1) Appliance Design - January 2009 - Appliance Design - January 2009 (Page Cover2) Appliance Design - January 2009 - Appliance Design - January 2009 (Page 1) Appliance Design - January 2009 - Appliance Design - January 2009 (Page 2) Appliance Design - January 2009 - Contents (Page 3) Appliance Design - January 2009 - Contents (Page 4) Appliance Design - January 2009 - Editorial (Page 5) Appliance Design - January 2009 - Shipments/Forecasts (Page 6) Appliance Design - January 2009 - News Watch (Page 7) Appliance Design - January 2009 - News Watch (Page 8) Appliance Design - January 2009 - News Watch (Page 9) Appliance Design - January 2009 - Supplier Spotlights (Page 10) Appliance Design - January 2009 - Supplier Spotlights (Page 11) Appliance Design - January 2009 - Supplier Spotlights (Page 12) Appliance Design - January 2009 - Supplier Spotlights (Page 13) Appliance Design - January 2009 - Supplier Spotlights (Page 14) Appliance Design - January 2009 - Supplier Spotlights (Page 15) Appliance Design - January 2009 - Supplier Spotlights (Page 16) Appliance Design - January 2009 - Supplier Spotlights (Page 17) Appliance Design - January 2009 - Supplier Spotlights (Page 18) Appliance Design - January 2009 - Supplier Spotlights (Page 19) Appliance Design - January 2009 - Supplier Spotlights (Page 20) Appliance Design - January 2009 - Supplier Spotlights (Page 21) Appliance Design - January 2009 - Commercial Appliances (Page 22) Appliance Design - January 2009 - Commercial Appliances (Page 23) Appliance Design - January 2009 - Commercial Appliances (Page 24) Appliance Design - January 2009 - Commercial Appliances (Page 25) Appliance Design - January 2009 - Commercial Appliances (Page 26) Appliance Design - January 2009 - Commercial Appliances (Page 27) Appliance Design - January 2009 - Plastics & Parts (Page 28) Appliance Design - January 2009 - Plastics & Parts (Page 29) Appliance Design - January 2009 - Plastics & Parts (Page 30) Appliance Design - January 2009 - Plastics & Parts (Page 31) Appliance Design - January 2009 - Plastics & Parts (Page 32) Appliance Design - January 2009 - Plastics & Parts (Page 33) Appliance Design - January 2009 - Plastics & Parts (Page 34) Appliance Design - January 2009 - Plastics & Parts (Page 35) Appliance Design - January 2009 - Electronics (Page 36) Appliance Design - January 2009 - Electronics (Page 37) Appliance Design - January 2009 - Electronics (Page 38) Appliance Design - January 2009 - Electronics (Page 39) Appliance Design - January 2009 - Electronics (Page 40) Appliance Design - January 2009 - Motors (Page 41) Appliance Design - January 2009 - Motors (Page 42) Appliance Design - January 2009 - Motors (Page 43) Appliance Design - January 2009 - Motors (Page 44) Appliance Design - January 2009 - Motors (Page 45) Appliance Design - January 2009 - Motors (Page 46) Appliance Design - January 2009 - Design Marts (Page 47) Appliance Design - January 2009 - Association Report: NAFEM (Page 48) Appliance Design - January 2009 - Advertiser’s Index (Page 49) Appliance Design - January 2009 - Advertiser’s Index (Page Cover4)
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