plastic mould and custom injection moulding tips

China Injection Mold Cost Many buyers who purchase injection molds from China are solely focused on saving money . However, this isn’t the right attitude to take, since you’ll ultimately want a mold that works properly and is reliable, instead of just being cheap. How much a plastic mold tool will cost is dependent on several different factors. You should, therefore, request the  information when getting a quote. The checklist below details the various areas of interest that you need to consider when purchasing a mold: How many check dimensions are required on the print- this will determine the cavity complexity, as well as the part tolerances Surface finishes which will be necessary Number of necessary tight tolerances and their requirements Any required functions in mold operating, such as unscrewing or lifters. Balanced cooling requirements- these can  determine  tolerances. Part resin Number of cavities in the part, determined by tolerances and ...

The gas-assisted injection molding system directly injects inert gas (usually nitrogen) into the melt plastic in the mold cavity through the sectional pressure control system, which makes the plastic part expand and cause hollowness, but still keeps the shape of the product surface. Gas-assisted injection molding can be regarded as a variant of hollow blow molding. The process of gas-assisted injection molding is to inject an accurately measured plastic melt which accounts for a certain proportion of the mold cavity. This process is called "short-shot-injection molding", and then directly inject a certain volume and pressure of high-pressure nitrogen into the molten plastic, and the gas diffuses along the direction of minimum resistance surrounded by the plastic melt. Because the plastic temperature near the mold wall is low and viscosity is high, while the plastic melt in the center of the thicker part is of high temperature and of low viscosity, the gas can easily penetrate...

The gate is a short groove with a small cross-sectional area to connect the runner and the cavity. Therefore, the cross-sectional area should be small in order to obtain : Soon after the cavity is injected full, the gate will be solidified Simple demoulding The part ejection is completed, leaving only a few traces Makes the filling of multiple cavities easier to control Reduce excessive runner scrap Gate location and size 1) Place the gate at the thickest part of the product, and injection on the thickest part can provide better filling and pressure holding . If the holding pressure is insufficient, the thinner area will solidify faster than the thicker area. Avoid placing the gate at a sudden thickness change section to avoid hysteresis or short shots. 2) If possible, set the gate in the center of the product . Placing the gate in the center of the product can provide equal length flow. The flow length will affect the required injection pressure. The central gate mak...

In the process of injection molding, the bubble inside is a serious defect. Air bubbles in injection molded transparent parts will affect the appearance quality of products. At the same time, it will also reduce the strength of injection molded products. The bubbles are mainly produced in the process of injection molding: The raw materials are not dried enough or air mixed in the raw materials. In the injection molding process, the injection speed is too fast, the residual material inside barrel is too much, and the back pressure is too low. Poor mold venting and low mold temperature. How to solve: Raw materials should be fully dried. Reduce the screw temperature and the temperature of the feeding port. Increase the back pressure  and reduce the ejection position of screw (more residual material). Reduce injection speed and increase mold temperature. Increase the injection pressure and time and improve the venting of the mold. Retain bubbles on the nozz...

One of the important reasons for the warpage of strip flat injection molding parts is the position of the gate on the injection molding parts. There are usually three positions of the gate on the strip injection molded part,and these will cause warpage of the strip-shaped flat injection molded parts. [caption id="attachment_4417" align="aligncenter" width="563"] strip-shaped flat parts injection molding[/caption]   For example (Figure A) , the gate position of the strip flat plate is set at one end of the injection-molded part, which can make the injection-molded part obtain consistent shrinkage in the flow direction. Injection molding : Injection molding is relatively simple for long flat injection molding parts with this gate position . However, it should be noted that the distance from the gate to the end of the injection molded part couldn't be too long, so as to prevent the deformation caused by the different filling. Mold : For the long strip-...

In three forms it is important to consider how the costs of injection molding are determined:  To check if the commodity is competitive on the market, To recheck with evolving plastic fabrics, cavities, volumes or press measurements so that we can see if additional benefit is produced and To determine whether the molding costs of the out-sourcing manufacturer are appropriate.  To assess molding prices, four basic elements must be analyzed: equipment costs, labour costs, process speeds and tooling costs. The volume or expenses per cubic inch was not just the expense per pound of raw material to be obtained when measuring production quality. If necessary, regrind plastic is good to use as the cost typically amounts to around half of new plastic material. Typically 18 percent of the sum by weight is the assurance that injection molded part should be safely used. Tests demonstrate, though, that 100% regrind may be of same performance  as 100% virgin mater...

Polycarbonate injection molding Topworks is a professional manufacturer of poly-carbonates injection molding. We have more than 10 years of production experience in poly-carbonates injection molding We have rich experience in the production of extra wall thickness poly-carbonates and ABS/PC injection molding part. Our PC injection molding covers the following industries： Automobile parts Medical instruments Aerospace Packaging field Electronic appliance optical lens LED lighting The maximum wall thickness of the PC product can reach 3 cm , but the surface does not shrink and there are no bubbles inside. https://www.youtube.com/watch?v=ms2aPfCHdzc&feature=youtu.be   EXTRA WALL THICKNESS POLY-CARBONATE INJECTION MOLDING CASE #1  CASE    [caption id="attachment_3326" align="aligncenter" width="1139"] extra wall thickness 32 mm poly-carbonate injection molding[/caption] [caption id="attachment_3325" align="alignnon...

On plastic injection products, especially for raw materials such as ABS, PP and PC, you will often see shiny stress marks on the surface of products, such as injector pin stress marks, insert stress marks and stress marks of wall thickness difference . These apparent shiny, white markings are the result of internal stresses , which are nothing more than orientation and cooling shrinkage stresses. The irregular stress marks near the gate are caused by the typical orientation stress, and the difference of wall thickness is the result of orientation and contraction stress, those stress marks are made by ejector pins and sliders . Normally , with the increase of holding pressure and time, the first occurrence is the stress mark of wall thickness difference, the stress mark of ejector pin, then the stress mark of meat thickness difference, and finally the irregular stress mark near the gate (gray section will appear on the side), which of course also depends on the specific structure of the...

If want to reduce or eliminate cracking of injection molded poly-carbonate, it can take two measures: Reduce internal stress; Or improve the cracking resistance of plastics. What can do to reduce the internal stress of the PC injection molding process ? Mold Temperature Increasing the mold temperature can reduce the internal stress. When the mold temperature is controlled between 80 ~ 110 degrees, the internal stress is small. Barrel Temperature Increasing the  barrel temperature can reduce the internal stress. For the PC part injection molding, the barrel temperature can be controlled between 260 ~ 330℃, and the higher the temperature is, the lower the internal stress will be. Ejection Pressure The viscosity of PC material is high, which  requires high pressure in theory, but high pressure will greatly increase internal stress, so it is inappropriate to use high pressure here. The pressure should be kept between 800 ~ 1200 kg. Ejection speed High ejection...

PC/ABS, mixture of Polycarbonate and acrylonitrile butadiene  ,is a thermoplastic plastics made of polycarbonate and polyacrylonitrile (ABS), which combine the excellent characteristics of the two materials, the injection-ability of ABS and the mechanical properties, impact strength, temperature resistance, ultraviolet (UV) resistance   of PC. 1. Silver Streak Silver streak is the most common problem of PC/ABS materials injection. Silver streak is also called silver grain and silver splash, etc. It is a silvery white  stripe phenomenon on the surface of products along the flow direction. The source is mainly divided into three fields: (1) Air: the air involved in the melting and injection phases; (2) moisture: moisture contained in the plastic material itself; (3) decomposition: gas generated by high-temperature hydrolysis/thermal material decomposition. Solution: First, check whether the plastic material is dry enough. After confirming , adjust the injection m...

      PRECISION MACHINING? Precision Machining is a process to remove material from a workpiece like plastic mold component during holding close tolerance finishes. The precision machine has many types, including milling, turning and electrical discharge machining.  A precision machine today is generally controlled using a Computer Numerical Controls (CNC). Precision machining contributes parts and pieces from space shuttle pencils. Almost all metal products use precision machining, as do many other materials such as plastic and wood. These machines are operated by specialized and trained machinists. In order for the cutting tool to do its job, it must be moved in directions specified to make the correct cut. This primary motion is called the “cutting speed.” The workpiece can also be moved, known as the secondary motion of “feed.” https://www.youtube.com/watch?v=YrbQIN2TBhM&t=609s Together, these motions and the sharpness of the cutting tool allow the precisio...

When the mold was tested, sometimes the product had a serious appearance quality problem with radial white marks appeared on the surface. The white marks tended to be serious with the increase of the glass fiber content. This  is  known as " glass emergence on the surface(also glass fiber rich surface )" which is a surface defect most likely on the  glass fiber plastic products, which is unacceptable for automotive plastic parts with high appearance requirements. [caption id="attachment_3913" align="aligncenter" width="3200"] glass fibre rich surface[/caption] Cause The glass fiber rich surface is caused by the exposure of glass fiber. The white glass fiber appears on the surface during the plastic melt filling and molding. After condensation and molding, radial white marks are formed on the surface of the plastic part. When the plastic part is black ,it will become more obvious as the color difference increases. There are several reasons b...

A system which constant transfers heat from the melt in the mold or heats the mold to the injection temperature is called a temperature control system. Mold temperature refers to the surface temperature of the mold cavity that comes in contact with the product. It directly affects the flow of the melt, the cooling of the product, and the quality of the product. An injection mold is a production tool which can repeatedly mass-produce plastic products with the same structure and the dimensional accuracy . it is a heat exchanger. In order to ensure the molding quality and production efficiency, it is necessary to use the medium to heat or cool the mold to control the temperature within a reasonable range. The productivity of the mold depends on the speed of the mold heat exchange. The speed of the mold heat exchange depends on the mold heat exchange. The mold heat exchange depends on the temperature of the melt, the demolding temperature, and the plastic. The design of the temperature ...