Views: 1258 Author: Site Editor Publish Time: 2024-06-10 Origin: Site
The Dragon Boat Festival, the 5th day of the 5th lunar month, has had a history of more than 2,000 years. It is usually in June in the Gregorian calendar.
Every year, the Loong Boat Festival is the most traditional festival of the Chinese nation, also known as the Dragon Boat Festival.
There are many customs on Loong Boat Festival, because the"Dragon Boat Festival" is also called the "heavy five", and many customs are also associated with the number of "five".
Tie red, yellow, blue, white, and black silk threads around a childs neck, wrists, or ankles,which is called a long life strand. Each family should the "Five Ends": calamus, mugwort,
pomegranate flower, garlic, and dragon boat flower. South China will eat "five yellow" foodduring the Loong Boat Festival: yellow croaker, cucumber, Salted duck egg yolk, Zongzi
wrapped in bean petals, realgar wine. Regardless of the north or south, on this day, it is still necessary to use realgar to draw the character "Wang" on childrens foreheads and wear
colorful sachets.
On this day, the main activities are Loong Boat racing and eating Zongzi. It is said that the Loong Boat race is to save the patriotic poet Qu Yuan who died in the Miluo River. To throw
Zongzi into the river is to let fish, shrimp and crabs eat enough and stop eating Qu Yuans
remains.
Loong Boat Festival is really a colorful festival.
the wear-induced failure of screws and barrels, noting the limitations of chrome plating and nitriding. It investigates the feasibility of surface boriding treatment on 45 steel screws and barrels to enhance surface hardness and wear resistance, and validates the process through field testing.
This article introduces the working principle of ball screws, highlighting their high mechanical efficiency and load capacity, which have led to widespread adoption in all-electric servo-driven injection molding machines. It compares ball screw design philosophies for machine tools and injection molding machines, noting that injection units experience loads hundreds to thousands of times greater. Key design priorities for high-load ball screws—such as uniform ball contact pressure, optimized lubrication, and enhanced durability—are discussed, with reference to Ningbo Superior's specialized solutions.
The screw and barrel are the most critical components of injection molding machines, operating under high temperature and pressure. Wear enlarges the clearance between the screw flight and barrel, reducing melting and pumping capacity, causing product quality degradation, lower productivity, and higher energy consumption. The screw is more susceptible to damage than the barrel.
This section examines the key parameters of the venting section in vented extruder screws. Venting effectiveness depends primarily on venting section length L, melt residence time, shear rate, and the fill factor F (the ratio of melt cross-sectional area to channel area). To ensure good performance, the venting channel should be partially filled; experiments suggest L ≥ 3D, F ≤ 0.5, and a shear intensity K > 100 for optimal degassing. For screws with L/D ratios of 24–30, the venting section length is typically 4D, and its channel depth is 2.5–6 times that of the first metering section. Design verification must include fill factor, shear intensity, and screw strength.
On Labor Day, we pay sincere tribute to every hardworking professional around the world.Dedication creates value, and perseverance achieves dreams. May everyone enjoy a pleasant holiday, stay safe and healthy, and reap fruitful rewards from every effort.Wishing you all a happy and wonderful Labor Da
This section discusses the determination of channel depths H₁ and H₂ in venting screws, with emphasis on the pump ratio Ω (Ω = H₂/H₁). The pump ratio directly influences the risk of vent flooding and extrusion stability. A theoretical optimum Ω of 1.5 is derived for Newtonian fluids, while for non-Newtonian polymers like polyethylene an Ω of 1.75 yields maximum die pressure. In practice, most designs adopt Ω values between 1.5 and 2.0. The article also clarifies that the concept of a "second compression ratio" is invalid for venting screws, as the venting section is not fully filled.
This section outlines the functional characteristics of venting screws in extrusion. It identifies three main sources of gases in raw materials—entrained air, adsorbed moisture, and internal volatiles—and describes their detrimental effects on product quality and properties. While conventional methods rely on pre-drying or feed-throat venting, these approaches increase costs, risk contamination, and are often insufficient for high-speed extrusion. The text concludes that vented extruders offer superior performance in effectively removing these gases.
