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.

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.

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.

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.

Guiding system of injection mold works as guides to ensure precise mechanic movements. Generally the standard mold base all have guiding design, like guide pins between cavity side and core side, mold designers can just choose the proper mold base. Typical mold guiding system include, guiding between A/B plates, guiding for stripper plates, guiding for runner plates, guiding for ejector pins. All this guiding system can be customized when you order the mold base.

Plastic enclosures are plastic cases or housings manufactured by injection molding process. Usually a popular consumer product with great enclosure design catch people's eye immediately without promoting how good the function are, a very success example is Apple product, success industrial design contribute a lot to the success of Apple in worldwide.

How to make a custom plastic enclosure?
First you need to make a design for your custom plastic enclosure, a complete and professional design will includes plastic parts size, structure, selection of proper plastic materials, assembly method, finish. Then you need a plastic mold maker to make a custom injection mold for it, mold price and lead-time will be determined by the quantity demanded, complexity of structure, size finish of the plastic part. If your plastic parts are in high volume demand, then a high quality and long durable mold is a must, get a warranty for how many plastic parts the mold can produce before you sign a mold manufacturing contract with your injection mold supplier. After the custom mold produced, you need to run the mold on an injection molding machine, finally, you get your custom plastic enclosure done.

A good mold flow analysis has lots of benefits, although it is time consuming, the cost is much lower than the cost of trials during nights and days on a production injection molding machine. The difficulty is not to produce colored pictures but to explain to the customers the different results, some customers have enough knowledge to understand some others no.

In 90% of cases, I work before the injection mold is cut, so I am ready to take the responsibility of cycle time, warpage, sink marks and so others issues. I am specialized in gas assisted injection molding and I assist Chinese companies to produce plastic parts for the German automotive industry which generally use overflow. With short shot process, we can obtain a production costs reduction of 20% by simulation and 30% in practice.

After a new injection mold is construction is finished, the mold maker need to set up the injection mold to do test or molding plastics. Setting an injection mold is more than loading and fixing the mold to injection machine, there are many other important things to do after you clamp the injection molds.

This article will give you a comprehensive explain of how to setup an injection mold, and the critical checklist you should pay attention to.

Injection molding is one of the most important processing methods to produce plastic parts. Plastic injection molding techniques have been used and developed for a long time. Look around you, the case of your laptop, the case of intelligent cell phone, water filters, food containers, wash machines and quite a few components in your car... yes, we are living in a world that are full with plastic parts, most of the common plastic parts are made by injection molding. This article will show you the basics of plastic injection molding advantages and disadvantages.

Injection Molding Basic Process
Feeding raw material from the hopper into the barrel, the plunger start to push, the plastic raw materials are pushed into a heating zone and then through the bypass shuttle, the molten plastic through the nozzle into the injection mold cavity, then water or oil run through the designed cooling system to cool down the injection mold to get a plastic article.

Mold flow analysis is widely employed in mold making industry, utilizing data simulation software, the injection molding process can be simulated and presented on the computer, you can improve part design or mold design base on the out put results. Moldflow, Moldex3D are very popular mold flow analysis software used by many mold makers.

Advantages of mold flow analysis
Mold flow analysis will advise if the cavity is fulfilled, it can also provide other useful information such as the required injection pressure and clamping pressure.

You can know whether the filling problem exists. Many filling problems, such as short shot, bubbles and imbalances, can be predicted by a careful analysis of the filling curve. Mold flow analysis allows you to change the position of the gate, injection speed, and other processing conditions, so you would know if these problems can be improved or corrected.

Soft tool is the tool made of pre-harden steel, it is an economic solution for a small volume production. It has advantages of low cost and fast turn around, but pre-harden steel is a lower grades steel that process lower hardness and wear resistance, so the soft tool can only stand molding cycles no more than 500k shots, it's also difficult to maintain tight tolerances.

Hard tool is a high quality tooling for mass production, it's made of the best quality steel, like H13,420 etc. Hard tool requires more procedure and longer time to manufacture.

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)