Appliance Design - January 2009 - (Page 30) PLASTICS & PLASTIC PARTS Fig. 3. Illustration shows the use of a telescoping shutoff without draft (left) and with draft (right). On the left, the arrows point to where tool wear will occur without drafting. parts or molds. See Fig. 1 for an example of an undrafted and drafted design. Determining amount of draft The amount of draft required will depend on geometry and characteristics such as surface texture, but, in general, more is better. Here are some suggested design guidelines for the rapid injection molding process. (See Fig. 2.) 4Use at least 0.5 degrees on all vertical (parallel to direction of mold opening) faces. 4Add 1 degree of draft for each inch of part depth: 2 degrees for a part 2-in. deep, 3 degrees for a part 3-in. deep. Texture on a vertical surface is essentially a field of small undercuts that can catch on the mold face as the part is ejected. For this reason, textured surfaces require a high degree of draft to prevent damage. 43 degrees of draft for light texture (PM-T1). 45 degrees or more for heavy texture (PM-T2). mold breakage and wear resulting in problems like flash. These problems can be prevented by drafting the mold surfaces where they meet. A telescoping shutoff In Fig. 4, the blue face of the vertical clip is created by an extension of one mold half protruding through the hole in the base of the part. The sides of this metal protrusion meet the walls of the other mold half to create a shutoff. If the sides of the clip are parallel to the direction of mold opening, metal from the two mold halves will rub as the mold opens and closes. This can be prevent- Telescoping or sliding shutoffs A telescoping shutoff, as seen in Fig. 3, is any place where metal surfaces slide against one another as the mold closes and opens. Undrafted telescoping shutoffs can lead to Join Us at the Industry Event for Advanced Design and Manufacturing February 10–12, 2009 PacDesignShow.com 30 applianceDESIGN AD01094PACI.indd 1 for free expo hall admission! REGISTER TODAY January 2009 www.applianceDESIGN.com 11/14/08 9:42:42 AM http://www.PacDesignShow.com http://www.PacDesignShow.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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