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How much draft angle do I need in my mold on ribs and the sides of parts for filled nylons?
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We recommend at least a quarter of one degree but not more than one degree.
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hear that nylon will absorb moisture and grow, yet I see some high tolerance applications out of both nylon 6 and 66. How is that possible?
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All parts in plastic also have molded-in stress from the molding process. As nylon parts absorb moisture, the moisture also relieves that stress and makes the parts want to shrink. These two forces in opposite directions tend to cancel each other and actually result in quite stable dimensions over time.
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What is the IV of your materials?
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1.5 to 1.8
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How can I tell if my nylon parts were properly molded and not degraded?
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Ask your material supplier to run an “RV” or relative viscosity on both a molded part and the same lot of pellets they were molded from. This test is a quick way to measure if the length of the molecules changed.
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My moldmaker asked me what type of vents I want for nylon parts. What do I tell him?
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Tell your toolmaker to use a .050 inch land and a .001 inch depth for unfilled nylon but a .030 inch land and a .002 inch depth for filled nylon. Call us or see our Processing Guide for a complete sketch.
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The warpage of my part in 33R0glass reinforced nylon is unacceptable. I’ve tried everything. What can I do?
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First, make sure your part is well-radiused where walls intersect, and then try a mineral/glass nylon like our MRGF25/15. Not only will you get a much flatter part, but you will also save money. The stiffness of both is similar while the mineral/glass has somewhat lower strength.
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How thick should I make ribs for nylon parts?
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The rule of thumb is half the thickness of the wall they intersect. If the ribs are thicker, you will get very visible sink marks on the other side of the part. If the ribs are thinner, you will get warpage since the ribs will set up quicker than the wall they attach to as the part cools after molding.
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How much radius should there be where walls intersect for nylon parts?
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The rule of thumb is to make the radius at least 60% of the wall thickness. For example, if the walls are .100 inches thick, then as a minimum you should have a .060 inch radius.
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