1. Don’t just focus on product design and ignore plastic injection molding mold manufacturing.
When some users develop products or trial-produce new products, they often only focus on product research and development in the early stage and ignore communication with plastic mold manufacturing units. After the product design plan is initially determined, there are two benefits of contacting the mold manufacturer in advance:
1. It can ensure that the designed products have good forming technology, and the final design will not be modified because the parts are difficult to process.
2. The mold maker can make design preparations in advance to prevent insufficient consideration in a hurry and affect the construction period.
3. To produce high-quality plastic molds, only the close cooperation between supply and demand can ultimately reduce costs and shorten the cycle.
2. Don’t just look at the price, but consider all aspects of quality, cycle, and service.
1. There are many types of molds, which can be roughly divided into ten categories. Different types of molds are selected for molding based on different requirements such as part material, physical and chemical properties, mechanical strength, dimensional accuracy, surface finish, service life, and economy.
2. Molds with high precision requirements need to be processed using high-precision CNC machine tools, and there are strict requirements on mold materials and forming processes. CAD/CAE/CAM mold technology must also be used for design and analysis.
3. Due to special requirements during molding of some parts, the mold also needs to use advanced processes such as hot runners, gas-assisted molding, and nitrogen cylinders.
4. Manufacturers should have CNC, EDM, wire cutting machine tools and CNC copy milling equipment, high-precision grinders, high-precision three-coordinate measuring instruments, computer design and related software, etc.
5. For general large-scale stamping molds (such as automobile cover molds), it is necessary to consider whether the machine tool has a pressing mechanism, or even edge lubricants, multi-station advancement, etc. In addition to stamping tonnage, the number of punches, feeding devices, machine tools and mold protection devices must also be considered.
6. The above-mentioned mold manufacturing methods and processes are not possessed and mastered by every enterprise. When choosing a cooperative manufacturer, you must understand its processing capabilities. Not only the hardware equipment, but also the management level, processing experience and technical strength.
7. For the same set of molds, there are sometimes big differences in the quotations from different manufacturers. You shouldn’t pay more than the mold is worth, and you shouldn’t pay less than the cost of the mold. Mold manufacturers, like you, want to make reasonable profits in their business. Ordering a set of molds with a much lower quote can be the beginning of trouble. Users must start from their own requirements and make a comprehensive assessment.
3. Avoid multi-party collaboration and try to integrate plastic mold manufacturing and product processing.
1. With a qualified mold (the test piece is qualified), it may not be possible to produce batches of qualified products. This is mainly related to the selection of machine tools for processing parts, the forming process (forming temperature, forming time, etc.) and the technical quality of the operator.
2. With a good mold, you must also have good forming processing. It is best to have one-stop cooperation and try to avoid multi-head cooperation. If the conditions are not met, one party must be chosen to take full responsibility, and this must be written clearly when signing the contract.
Plastic molds are classified into the following categories:
A. Injection molding mold – TV casing, keyboard buttons, electronic product exteriors, computer peripheral plastic products, toys, household products (most commonly used)
B. Blowing mold-beverage bottle
C． Compression molding mold – Bakelite switches, scientific porcelain dishes
D. Transfer molding mold – integrated circuit products
E. Extrusion mold – glue tube, plastic bag
F. Thermoforming Mold – Transparent Forming Packaging Shell
G. Rotational mold – soft plastic doll toys
According to the different types of pouring systems, molds can be divided into three categories:
(1) Large nozzle mold: The runners and gates are on the parting line and are demoulded together with the product when opening the mold. It has the simplest design, is easy to process, and has low cost. Therefore, more people use the large nozzle system to operate.
(2) Slim nozzle mold: The runner and gate are not on the parting line, usually directly on the product, so it is necessary to design an additional set of nozzle parting lines. The design is more complex and the processing is difficult. Generally, the selection depends on the product requirements. Fine nozzle system.
(3) Hot runner mold: The structure of this type of mold is roughly the same as that of the fine nozzle. The biggest difference is that the runner is located in one or more hot runner plates and hot spouts with constant temperature. There is no cold material demoulding, runner and pouring. The port is directly on the product, so the runner does not need to be demoulded. This system is also called a no-port system, which can save raw materials. It is suitable for situations where raw materials are expensive, product requirements are high, design and processing are difficult, and mold costs are high.
Hot runner system, also known as hot runner system, mainly consists of hot runner sleeve, hot runner plate, and temperature control electrical box. Our common hot runner systems have two forms: single-point hot gate and multi-point hot gate. Single-point hot gate uses a single hot sprue sleeve to directly inject molten plastic into the mold cavity. It is suitable for plastic molds with a single cavity and a single gate; multi-point hot gate branches the molten material to various locations through a hot runner plate. The heat is divided into the sprue sleeve and then enters the mold cavity. It is suitable for single-cavity multi-point feeding or multi-cavity molds.
◆Advantages of hot runner system
(1) There is no nozzle material and no post-processing is required, making the entire molding process completely automated, saving working time and improving work efficiency.
(2) Small pressure loss. The temperature of the hot runner is equal to the temperature of the nozzle of the injection molding machine, which avoids surface condensation of raw materials in the runner and reduces injection pressure loss.
(3) Repeated use of nozzle materials will degrade the performance of plastics, but using a hot runner system without nozzle materials can reduce the loss of raw materials, thereby reducing product costs. The temperature and pressure in the cavity are uniform, the plastic parts have small stress and uniform density. Under smaller injection pressure and shorter molding time, better products can be injection molded than ordinary injection molding systems. It can show its advantages even more for transparent parts, thin parts, large plastic parts or high-demand plastic parts, and it can produce larger products with smaller models.
(4) The thermal nozzle adopts standardized and serialized design, equipped with various optional nozzle heads, and has good interchangeability. The uniquely designed and processed electric heating ring can achieve uniform heating temperature and long service life. The hot runner system is equipped with hot runner plates, temperature controllers, etc., with exquisite design, various types, easy use, and stable and reliable quality.
◆Disadvantages of hot runner system application
(1) The closing height of the overall mold is increased. Due to the installation of hot runner plates, etc., the overall height of the mold is increased.
(2) Thermal radiation is difficult to control. The biggest problem with hot runner is the heat loss of the runner, which is a major issue that needs to be solved.
(3) There is thermal expansion, and thermal expansion and contraction are issues we need to consider when designing.
(4) The cost of mold Plastic injection molding manufacturing increases, and the price of standard parts of the hot runner system is higher, which affects the popularity of hot runner molds.