![\"416167341\"](\"https:\/\/ptfe-machinery.com\/wp-content\/uploads\/2017\/12\/416167341.jpg\")
<\/strong><\/p>\nMost screws have these three zones:<\/strong><\/p>\n Metering zone (also called the melt conveying zone): this zone melts the last particles and mixes to a uniform temperature and composition. Like the feed zone, the channel depth is constant throughout this zone.<\/p>\n In addition, a vented (two-stage) screw will have:<\/p>\n Often screw length is referenced to its diameter as L:D ratio. For instance, a 6-inch (150 mm) diameter screw at 24:1 will be 144 inches (12 ft) long, and at 32:1 it is 192 inches (16 ft) long. An L:D ratio of 25:1 is common, but some machines go up to 32:1 for more mixing and more output at the same screw diameter. Two-stage (vented) screws are typically 36:1 to account for the two extra zones.<\/p>\n Each zone is equipped with one or more thermocouples or RTDs in the barrel wall for temperature control. The “temperature profile” i.e., the temperature of each zone is very important to the quality and characteristics of the final extrudate.<\/p>","protected":false},"excerpt":{"rendered":" There are five possible zones in a thermoplastic screw. Since terminology is not standardized in the industry, different names may refer to these zones. Different …<\/p>","protected":false},"author":1,"featured_media":75513,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[103],"tags":[117],"class_list":["post-75511","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-extruder-machine","tag-screw-extruder"],"yoast_head":"\n\n
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