The runner design
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 … Read more
Injection mold sprue bush (Main Runner) design
Mold sprue bush,AKA.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 … Read more
O-ring
What is the O-ring used for? In a mold structure, the cooling channel tends to leak at the joints between mold plates as well as those between the mold plate and the core insert due to the existence of joint gaps. To prevent this from happening, O-rings are often applied to seal the joints. Mold structure design should take the following principle into consideration in case O-rings are applied: Ensure sufficient positive pressure between the mold plate and the core/Cav insert. Please click below for O-ring detail HASCO O-Ring size and spec.
Injection mold sliders designing
1. When designing the injection mold sliders, the biggest clearance between the slider and the product should be at least 2 – 3mm. The inclination of sliders should be kept between 15 and 25 degrees, and the inclination of the guide pin should be 2 degrees smaller that of the wedge. The available diameters of the guide pin are 6mm, 8mm, 10mm and 12mm, with the min and max values being 6mm and 12mm respectively. If a slider width is larger than 60 mm, deployment of 2 angle pins needs to be considered; if the width exceeds 80mm, a guide bar needs to be placed under the slider in middle. If the injection mold sliders is too high, the starting … Read more
Guide Pins of plastic injection mold
There are many types of guide pin structures in plastic injection mold application, among which the standard structural design is shown in the figure below. A guide pin has to serve as the cylindrical surface of concentric circles of different diameters. Based on structural dimensions and material requirements, a round steel bar with an appropriate size can be directly selected as the material. In addition, the technical requirements of guide pins need to be satisfied during the machining process. Fig. 8-2 Structural Shape of a Guide Pin Technical Requirements of Guide Pins (1) At the joint between the guide pin and the fixed mold plate, the diameter concentricity tolerance should not exceed 1/2 of the diameter tolerance in the working … Read more
Mold texture
Mod texture Definition Texturing refers to the process that produces various patterns on the surface of a metal product through chemiosmosis, such as stripes, images, wood grain, leather pattern and stain, etc., while also including sandblasting, which means spraying glass sands directly onto the surface of a metal product. The Purpose of Mold Texture Improve product appearance. The texturing process is able to camouflage part of the shrinkage, welding line, parting line and steps of slider, etc. Product surface strength can be improved via texturing and sandblasting. Varieties of Mold Texture Sand Pattern Characteristics: Fast process, low cost and able to produce fine and 2D patterns. Satin Pattern Characteristics: Fast process and able to be applied to a plane surface. … Read more
A Brief Introduction to Ejector Pins Design
The Purpose of Ejector pins: Eject the molded part from the injection mold. Considerations for the ejection system: 1. Ejector pin holes should be at least 3/32” away from other holes; 2. At least a clearance of 1/32” for pin holes on the ejector plate; 3. At least a clearance of 1/64” for pin holes on the mold plate; 4. All ejector pins should adopt the standard dimensions; the ejector base cannot be ground lower; 5. During the injection molding process of nylon, LDPE or PP, the diamter of each ejector pin must be measured, because flash might occur when the clearanc between the pin and the hole is greater than 0.02mm 6. All ejector pin holes must be vertical … Read more
Commonly Seen Mainstream Injection Molding Machines Brands
The injection molding machine industry has experienced rapid development across the whole globe. Especially, in the era when Chinese manufacturing industry develops at a very fast pace, many Chinese and foreign injection machine brands are widely used in enterprises which produce plastic products. Among them, the more famous ones include Chen Hsong from Hong Kong, Victor Taichung from Taiwan, Haitian/Haitai/Bochuang from mainland China, Mitsubishi/Toshiba/Sumitomo from Japan, and Demag/KRAUSS MAFFEI from Germany. Comparatively speaking, Japanese injection molding machines enjoy the longest service life while German ones follow the highest safety standards. (1) German Demag Injection Molding Machine Demag is a world famous injection molding machine brand of the German Demag Ergotech. Its main characteristics include: the hydraulic mold clamping structure and … Read more
Lifters or Sliders for Undercuts on Four Sides?
As mold designers, we are all aware that, in normal circumstances, lifters are created for inner undercuts and sliders are created for outer undercuts. However, when we have undercuts on all 4 sides of a product, which makes it impossible to release the product by force, how should the mold be designed? See the following figure for the product. Shall we create lifters or sliders? Now, let me explain the mold design solutions for such products to all of you. Design analysis When coming across such products, we will firstly consider whether it is possible to create lifters. However, analysis shows that the undercuts in the 4 corners will not be able to be released with the help of lifters … Read more
Injection pressure,holding pressure and back pressure
1．Injection Pressure Injection pressure is exerted by the hydraulic mechanism of the plastic injection molding system. This pressure is transferred from the hydraulic cylinder to the molten plastic through the molding screw, under which the molten plastic will be pushed to flow into the mold sprue (also known as the primary runner of some molds), the primary runner and the sub-runner via the nozzle of the plastic injection molding machine, and then finally get into the mold cavity through the gate. This process is referred to as the injection molding process or the filling process. The purpose of the pressure is to overcome the resistance occurring when the molten plastic is flowing; or to put it another way, the resistance … Read more