PC/ABS injection molding defects and solutions
Seven Common Defects and Solutions for PC/ABS injection molding Products Flow Lines The flow lines are caused due to the poor fluidity of the material. Unlike silver streaks, it is not caused by moisture or material decomposition, thus resulting in a different look. Solution: The flow lines can be eliminated by raising the material temperature so as to improve the fluidity. Appropriate increase of mold temperature and decrease of injection speed can also solve the problem. Pitting The shrinkage cavities are caused by short shot in the mold cavity. Solution: Increase mold temperature and material temperature appropriately to improve material fluidity; extend the injection / pressure holding time, and raise the injection speed to improve the mold filling, or increase the … Read more
How to Control the Dimensions Tolerance of Injection Molding Products
Due to the greatly varied market demands for molds and molded products, there are many kinds of changes and thus high requirements for us in such aspects as shape, size, material, structure and more, causing us many problems and difficulties in the production process of molds and products. How to effectively control the geometric dimensions of the mold and the product is just one of them. For different types of molds and products, there are different control techniques and methods for dimensions control. Personally, I usually start from the following aspects. Mold Design Control Firstly, we have to fully understand the technical requirements for the mold structure, material, hardness, and precision, etc., including whether the shrinkage rate of the plastic … Read more
PVC injection molding plastic resin
PVC plastic is a heat-sensitive material that features a poor injection moldability, for which the reason is that an excessively high melt temperature or an excessively long heating time easily causes PVC decomposition. Therefore, the key to molding the PVC products lies in the control of the melting temperature. The heat sources for melting the raw PVC material are usually from two aspects, i.e., the shear heating generated by screw motion and the resistance wire heating provided by the outer wall of the barrel, among which, the former is the main source, while the latter is mostly provided during machine operation. Due to the unsatisfactory heat transfer property of the PVC material, although the outer portion is heated, the inner … Read more
Mold steels P20,718 and H13 comparison
P20 Mold steel Overview:The P20 Mold Steel is a type of mold welding consumable, and the earliest is P20, followed by P20H and P20Ni. The P20 Steel is applicable to the production of molds for plastic materials, as well as those for diecasting low melting point metals. This steel material features great machinability, as well as mirror polishing properties. Chemical composition： Element C Si Mn Mo Cr Ni （%） 0.28~0.40 0.20~0.80 0.60~1.00 0.30~0.55 1.40~2.00 0.80~1.20 How to Use: The P20 Steel is pre-hardened to 285-330HB (30-36HRC), which is equivalent to 618 of Sweden and GS-2311 of Germany. It can be directly used for molding, and boasts a great dimensional stability. Pre-hardened steel is able to meet the requirements for … Read more
High impact polystyrene(HIPS)plastic injection molding resin material
HIPS(High impact polystyrene) is an impact-resistant polystyrene product created by adding butyl rubber particles to polystyrene. This polystyrene product is added with micron-sized rubber particles, and links the polystyrene and the rubber particles together by means of grafting. When subject to an impact, the tip end stress of the crack propagation is released by the relatively soft rubber particles. Therefore, the crack propagation is hindered and the impact resistance is improved. HIPS Engineering Plastic Milky white opaque pellets, with a density of 1.05g/cm3, a melting temperature of 150-180°C, and a thermal decomposition temperature of 300°C. HIPS is one of the cheapest engineering plastics. When compared with ABS, PC/ABS and PC, the glossiness of the material is relatively poor, and so … Read more
Steel hardness test method and conversion table
Steel hardness describes the properties of steels that resist deformation, indentation, penetration, and scratching. steel hardness is important because the inherent resistance of the surface to withstand friction or erosion by oil, steam, and water from injection molding process,there are several harness test method as below: 1.Brinell Hardness (HB) Press a hardened steel ball of a certain size (usually 10mm in diameter) against the surface of the material with a certain load (usually 3,000kg) for a period of time. After the load is removed, the ratio of the load to the area of indentation is referred to as the Brinell hardness (HB), measured in kg/mm2 (N/mm2). 2．Vickers Hardness (HV) Use a diamond square cone presser to penetrate into the surface of the … Read more
TPE,TPR,TPU and TPV injection molding
Thermoplastic Elastomer (TPE) Domestically in China, it is usually known as “TPE”, basically referring to the styrene-based thermoplastic elastomer. The styrene-based TPE (known as TPS in foreign markets) is a copolymer of butadiene or isoprene and styrene block, so its performance is similar to that of SBR. Strengths: High elasticity of rubber and plastic injection moldability; environmentally friendly, non-toxic and safe; excellent coloring, smooth touch, weatherability, fatigue / temperature resistance, excellent processability, no need for vulcanization, and able to be recycled for cost reduction. It can be co-molded with such base materials as PP, PE, PC, PS and ABS, or molded separately. Weaknesses: The biggest problem with SBS and SIS is their low heat resistance – the temperature should not … Read more
Warpage injection molding defects causes and solutions
Warpage as one of the most common defects in a plastic injection molded product, refers to the situation in which the shape of the injection molded part deviates from the shape of the mold cavity. The following is a brief analysis of the factors that affect the warpage of the injection molded products. How the mold structure influences the warpage of an injection molded product With regard to the mold, the main factors that affect the deformation of a plastic part are the gating system, the cooling system and the ejection system Gating System The gate location, type and quantity of a plastic injection mold affect the filling status of the plastic in the mold cavity, leading to changes to … Read more
Methods for Coloring Plastics resin
A variety of plastics coloring systems can be used to get color for the plastic materials, each possessing its unique features, benefits, and weaknesses.now we share some plastics coloring process as below: Select a Color Scheme According to the plastic properties, the molding process, the toner characteristics, the color matching principles, the product requirements and other comprehensive considerations, match the various toners, and then achieve the required color requirements. Each color has a certain hue, a certain brightness, and a certain degree of saturation, so you can call up tens of thousands of different colors by changing these three factors. Therefore, during toning, it is the most basic technique to adjust the three factors of depth, hue and difference. The … Read more
RAL Color Chart
RAL COLOR CHART RAL is an European color matching system which defines colors for paint, coatings and plastics. The RAL color standard is administrated by the RAL Deutsches Institut für Gütesicherung und Kennzeichnung. ‘RAL’ is the abbreviation of ‘Reichs-Ausschuß für Lieferbedingungen und Gütesicherung’. Please click the link as below for RAL Color reference RAL Color Chart