How the Hot Runner Systems Works The cold runner of a plastic injection mold refers to the section between the mold inlet and the gate. The molten plastic maintains its fluidity inside the runner by virtue of the injection pressure and its own heat. However, as a part of the molding material, the runner is not a product. As a result, when designing a mold, we need to consider not only the filling effects, but also the material-saving effect produced by shortening or downsizing the runner; but in actuality, it is not easy for us to have the best of both worlds. Types & Application of Hot Runners When applying the hot runner technology, the proper selection of gate type is of critical importance, because gate type directly determines the selection of hot runner components as well as manufacturing and application of molds. Therefore, the hot runner system can be classified into 3 types based on the gate type, i.e. (1) hot tip hot runner system, (2) sprue gating hot runner system and (...

The Runner Design Concept The runner refers to the melt flow passageway between the end of the main runner and the gate, which is used to change melt flow direction and allocate it to each cavity in a stable and balanced way. The basic design principle of the branch runner is little pressure/heat loss, with the minimum quantity of plastic retained in the runner. Sectional Shapes of the Branch Runner:   –Circular, with the minimum specific surface area (runner surface area/runner volume), but during production, both sides of the mold plate need to be aligned. –The commonly applied forms, trapezoid and U-shape are easy to process. –Semicircle. –Rectangle, larger specific surface area and high resistance to flow, thus seldom applied.   The Principle of the Runner Design The runner is usually designed on either half of the plastic injection mold. When considering the layout of the cavity and the branch runner, it is better to ensure that when projected on ...

Mold sprue bush,The main runner refers to the melt flow passageway from the joint between the injection molding machine nozzle and the mold sprue bushing to the starting point of the branch runner. –The design has to minimize melt temperature drop/pressure loss.   –Adopt the cone shape design, to facilitate removal of the condensed material   Forms of The Mold Sprue Bush   Fixing Methods of the Mold Sprue Bushing   The main runner is usually located along the center line of the plastic injection mold, overlapping with the axle of the injection molding machine nozzle. In horizontal and vertical injection molding machines, the runner axle should be perpendicular to the parting surface. To facilitate removal of condensed materials from the main runner, the main runner should be designed into the cone shape, with a cone angle of 2 – 6º; the diameter of the smaller end D ＞ d + (0.5~1mm), d refers to the diameter of the injection molding machine noz...

Mold inserts are the terms relative to the integrated core – when the mold core is made of a single piece of steel, it is called an integrated core, while an insert is a part that’s inserted into the mold core made primarily of the steel material. As a matter of fact, the biggest weakness of an insert is that it weakens the rigidity of the mold as a whole. However, the application of different insert materials is able to independently enhance the rigidity of the weak parts.   Now, let’s see what the circumstances for mold inserts applications are: Material Saving. The dimensioning of a mold core is defined by its highest point. If there is only one single point rising up regularly, this part can be inserted, so as to make the core shorter during dimensioning. Easy Processing for mold making. During processing, EDM is the slowest equipment with the poorest precision. As a result, an insert is selected to avoid EDM processing. Facilitate Ventilation. Inserts are us...

1, filling defect It always show uncomplete filling or edge collapse,it will dective product,waste material,labor and time.ther are many possible reason, such as nozzle temperature is too low,not enough supply,flowablity not good,injection pressure is low,the gate is too small or not right position,the mold surface is not smooth enough,nozzle is blocked,venting problem     2,flash or burr It always happen in parting line,it will increase the difficulty of machining or dishape,even defective.the possible reason such as:nozzle temperature too high,injection too much material,flowbility is very good,injection pressure too high,clamping force too small     3,sink mark It always caused by material shrink after injection molding,possible reason such as:nozzle temperature too high,resin supply not enough,shrinkage is too big,injection molding pressure too low,holding time too short,injection speed too slow,mold teperature too high,cooling time too short,the thickness of pr...

Injection molding lifters and sliders play a crucial role in achieving intricate and complex molded parts. These mechanical components are designed to aid in the ejection of molded products from the mold cavity, ensuring smooth and efficient production processes. Injection molding lifters are indispensable when it comes to creating designs with undercuts, threads, and other intricate features that cannot be demolded using conventional techniques.   The significance of lifters lies in their ability to unlock design possibilities and push the boundaries of what can be achieved through injection molding. It allows engineers and manufacturers to create innovative products with intricate details, textures, and shapes that meet the most demanding industry requirements. As we delve into the world of injection molding lifters, we’ll uncover their functionalities and explore the various types that enable the creation of visually appealing and highly functional molded parts. Let&rsquo...