Tungsten Alloy Injection Molding Technology Defects Occurring During Injection And Solutions

Affect the quality of the injection process and process parameters green lot, quite complex, due to improper control will produce injection, holes, deformation, wire, broken edges, sandwich, density gradient, surface defects and other defects of varying green singlet. Through the rational choice matching material mild mold temperature control plus quantity, adjust packing pressure, dwell time, injection speed, injection pressure, improved mold design, mold with improved accuracy and other measures, can effectively control the generation of defects injected green . The following are some common causes of defects and solutions.

(1) Owes Note (or can not be injected). Note refers to the feed in less filling process can not fill the mold cavity. Specific causes and solutions are:

1) Material temperature or mold temperature is too low, you need to increase the material temperature or mold temperature;
2) Feeding Quantity Insufficient;
3) Feed the viscosity is too large, the general approach taken by elevated feed temperature;
4) Runner improper size, gate should be wider, shorter runner should thus filling behavior of simple and easier to fill the cavity.

(2) Holes. Holes is the cross section of the green can be found in the pores. Some of the holes of a nearly circular, almost throughout the development of some of the central through hole green body, which is a common defect, be carefully controlled. Produce this defect causes and solutions are:

1) Clip person when injected gas, kneading feeding clip person filling gases and bad, will lead to, at this time needs to be adjusted or trimmed feed mold;

2) Powder with the binder separation; mold temperature and melt temperature does not match; holding pressure is too small, dwell time is insufficient. When these problems, the need to improve the mold design, mold filling process so that feeding can be evenly filled cavity; reduce mold temperature or injection temperature; reduce injection speed.

(3) Deformation. Causes and solutions are:

1) Ejection green strength is low, you can reduce the mold temperature or melt temperature, injection unit time decreases the number of blank birth, improve loading capacity, the use of higher-strength adhesive system, etc. to solve;
2) Feed mixing powder and binder uneven or separation;
3) Residual stress is too large, can be appropriate to reduce the injection temperature and also slightly elevated mold temperature, lower injection pressure and holding pressure to resolve.




Tungsten Alloy Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-alloy.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

 

• < Prev
• Next >