Two types of injection-compression used for thin walled high aspect ratio parts. The first uses a moving side core or secondary cylinder that leaves the cavity spaced and upon injection clamps forward to compress the part stress free. This usually requires a specific capability of the press. The second method sometimes referred to as coining closes the mold under reduced clamp pressure and the cavity is filled.

In this design it is also typical to have roughly a 7 degree draft angle on the parting/vent line to avoid flashing during the injection-compression stroke depending on the material and criteria for edge definition. keep in mind other critical control parameters are melt viscosity, plastification, pellet size uniformity as the cushion is typically much lower than with standard straight injection to avoid shot to shot variance.

A book of "Mold Standards" is a detailed description of what is required to match the mold with the molding factory, their equipment, machines, clamping systems, water hook ups, hydraulics for cylinders, air hook ups and cylinders, brand and type of steels/materials that are required, Hot Runner brand, electrical hook up and wiring requirements, brand and type of components (DME, Hasco), etc. This should never come from the mold maker, he'll build you what is cheapest for him.

Mold parts that are excessively heated, like spure bushings and areas near the gates, must be cooled intensively. Rapid and even cooling is enhanced by the use of highly conductive metals, such as berylliumcopper. These metals are used to full advantage in places where it is impossible to place sufficient cooling channels. Copper transfer twice as much heat as carbon steel and four times as much heat as stainless steel. This does not mean copper mold will run 4 times faster than a stainless steel mold but they will run some thin walled parts significantly faster.

Generally, injection mold has two major components: the movable halve and the fixed halve, during injection molding process, these two halves are pressed tightly and form a sealed hollow to avoid the melt flow leakage and maintain certain holding pressure, the pressed surface are called parting surface, usually parting surface are the biggest projection outline of the part.

Flat parting surface (see figure a)
Parting surface tilt (see figure b)
Stepped parting surface (see figure c)
Curved parting surface (see figure d)

Clear plastic injection molding parts usually made in PC, POM, PMMC, AS, PET, these clear plastic kits used widely in different application, such as auto light, medical devices, cosmetic packing, food container, water tank etc.

Comparing with other colored parts, strict requirements for appearance is a must for transparent plastic parts, which makes the injection molding processing more complex. Mold design and injection molding condition are all determined factors to the final result, there are a few problems happen frequently in clear plastic molding process, we provide some solutions as below.

You can get a larger shot size out of a hydraulic injection molding machine. There are times when you are pushing the injection capacity of the injection unit that hydraulic machines are a better choice than all-electric injection molding machines. However, if the job is within the range of the injection unit and specified properly, the electric machines outperform hydraulic for repeatability and energy consumption.

The main consideration when considering an all-electric injection molding machine is energy efficiency. Electricity savings of 20%-40% are typical when compared to hydraulic machines. Also, an all-electric machine can offer unmatched repeatability due to the servo drives that are used for injection forward and clamp rather than hydraulic pumps/valves.

This technology can be very effective in eliminating or substantially reducing the stress in flatter molding. In internal gas injection, where the gas is injected into one or more gas channels. For a flattish, panel-type part such as this, this is not always the gas injection process to be recommended. The added gas channels can leave a slight witness mark on a cosmetic 'A' surface and depending on the part geometry, the gas packing pressure will probably not be equal across the whole surface area of the part, especially with thinner wall sections and wider surface areas.

Overmolding is also called 2 times injection molding in China. Compared with the third-party material bonding, overmolding process makes the process faster and more cost-effective, it has been widely employed in plastic design.

Over molding are categorized into 3 types: insert molding, double shot molding, co-injection molding.

Insert molding: The most commonly used to mold soft elastomers to rigid plastics, insert molding is the most economical way to do overmolding. In the insert design, the hard segment has been separated into tools in advance, and then eject the soft materials in.

Elastomers are adhesion bond, which can be mechanical locks, chemical and other methods. In order to achieve chemical adhesion, the elastomer must be sufficiently heat to melt the surface of the hard segment to achieve chemical bonding.

Scientific Molding to me is a bit different than having a whole lot of data studies. To me, and to many of my peers, scientific molding is an disciplined elimination of multiple variables, which yields an range of conditions/settings/protocol/things that you must do. This will yields the highest volume of acceptable parts with the least amount of cost. I.E., when you do this, and you do that - the press operates thus and you get money. Going thru the methology checklist eliminates the variables in a disciplined fashion resulting in an updated group of setting, updated methods of handling material change outs, setting up a mold, scheduling jobs, etc. and reduction of scrap. Happy customers, happy plant operators, more money.

Engineering plastic molded parts are made of engineering plastics, through injection molding process, the engineering plastics, such as ABS, PC, POM, are molded into parts with desired shape and measurement. Parts made of engineering plastics have better mechanical and thermal properties, it can be used as a replacement of metal in many applications, for example, plastic auto parts, medical parts, electronic parts, household parts etc.

Engineering plastic molded parts required firstly part design, then you need a mold making company to fabricate an injection mold, at the end, you need an injection molder to mold it. To achieve a good result, it is important to make sure that both the mold maker and molder understand the property of the engineering plastic. Unlike other ordinary plastic parts, the parts made of engineering plastic are supposed to be applicable on many aspects besides dimension or appearance; you need to do some test to make sure there are functional.

Design For Manufacturing (DFM) report, it's a bridge between product developer and mold manufacturer. It has been implemented in many manufacturing industries and proved to a sufficient way to improve efficiency. A comprehensive DFM report for mold making project would be the first step to success. As a mold maker, the more potential problems you foresee, the less risks you had in the manufacturing process. Here are a summary for it.

Many kinds of raw material are frequently used, such as PC, PC+ABS, ABS, PS, HIPS, Nylon, Material with glass or fiber filled suitability and price different of them are different. More importantly, the shrinkage rate is different, which is key factor to measurement and tolerance precision.

The process of compression molding may be simply described by reference like two-piece mold provides a cavity in the shape of the desired molded article. The mold is heated, and an appropriate amount of molding material is loaded into the lower half of the mold.

The two parts of the mold are brought together under pressure. The compound, softened by heat, is thereby welded into a continuous mass having the shape of the cavity. The mass then must be hardened, so that it can be removed without distortion when the mold is opened. If the plastic is a thermosetting one, the hardening is affected by further heating, under pressure, in the mold. If it is a thermoplastic, the hardening is affected by chilling, under pressure, in the mold.