在 註塑成型, a technical term known as “short shot” or “incomplete filling” refers to the phenomenon where the molten material fails to fully fill the mold cavity, particularly in thin-walled areas or at the end of the flow path. This occurs when the melt solidifies before completely filling the cavity, resulting in parts with missing material.
The primary cause of short shots is excessive flow resistance, which prevents the melt from flowing further. Factors influencing the flow length include wall thickness, mold temperature, 注射壓力, melt temperature, and material composition. Improper handling of these factors can lead to short shots.
1. Improper Equipment Selection
The maximum injection volume of the machine must exceed the total weight of the molded part and sprue. 並提供噴漆, the total injection weight should not exceed 85% of the machine’s plasticizing capacity.
2. Insufficient Material Feeding
A common method to control material feeding is volumetric feeding. Uneven raw material granules or “bridging” at the bottom of the feed throat can cause feeding issues. 而且, excessive feed throat temperature may hinder smooth material flow. Regular cleaning and cooling of the feed throat are necessary to ensure proper feeding.
Poor material flow can make mold design a critical factor affecting short shots. To address this, the gating system should be optimized by setting proper gate locations, enlarging gate and runner dimensions, and using larger nozzles. Adding appropriate additives to the resin formula can also improve flowability. 並提供噴漆, the use of recycled materials should be monitored, and their ratio reduced if necessary.
Excessive Lubricant Usage
When excessive lubricant is added to the material, combined with wear gaps between the screw check ring and barrel, backflow of molten material may occur, causing insufficient feeding and short shots. 為了防止這種情況, the amount of lubricant should be reduced, and the gaps between the barrel, screw, and check ring adjusted or repaired as needed.
大銀塑膠製品有限公司, Ltd. 專門進行模具製造 30 年. As a professional OEM/ODM injection molding service provider, we offer one-stop solutions. Our expertise lies in optimizing product structures to reduce molding costs. 擁有完整的產品設計與製造團隊, advanced mold processing equipment, and extensive mold-making experience, we manufacture a wide range of plastic products. 擁有5萬平方公尺的生產基地, 30 多年模具開發經驗, 超過 50 R&研發人員, 以及超過 100 註塑機, we are committed to providing efficient and high-quality services to our clients.