Injection Molding Machine

ARBURG’s injection molding machines are renowned for their well tried and tested modularity. When it comes to the ALLROUNDER ALLDRIVE (A) series, the principle of modularity also applies to the drives.

The ALLROUNDER A offers the choice of combining the electric main axes with either electric or hydraulic auxiliary axes, depending on which solution is best suited to any specific application. 
The first example of the electric ALLDRIVE series is the ALLROUNDER 420 A 800-400. It has an 800 kN clamping force, 420 x 420 mm distance between tie bars, 400 series injection unit, screw diameters of 35, 40 and 45 mm as well as electric main axes and also an electrically driven five-point toggle system to provide the highest degree of positional accuracy. 
Following the successful introduction of the first ALLDRIVE machine, the series was expanded through modular drive technology to include larger clamping forces. As a result, at Fakuma 2003, which is being held from October 14 to 18 in Friedrichshafen/ Germany, the ALLROUNDER 420 A will for the first time be accompanied by its big brother, the ALLROUNDER 520 A with a clamping force of 1,600 kN. 

plastic molding
plastic molding

The Good injection molding machine A concept

The main functions of the injection molding machine – opening and closing moulds, injection and dosing – have been designed with electric drives as the basic structure. The other movements such as ejection and moving the nozzle and mould functions can either be electric or hydraulic, depending on the operating requirements. 

The movement of the mould closing operation is initiated by rotation of the servomotor to the five-point toggle system via a threaded spindle. This has been specially configured to the dynamic behaviour of the electronic drive.

The injection and dosing movements are converted with high torque via a gear position and a threaded pinion. To operate the movements with optimised use of time and low maintenance, the spindles are equipped with a special cool lubrication system. This ensures a high level of efficiency with low service costs and the longest possible service life. 

The machine series are modular in design due to the choice of auxiliary axes with electric or hydraulic drive. In this way, for example, the eject function can be carried out electrically, extremely accurately and dynamically with a spindle, or it can be carried out conventionally (‘softly’) with a hydraulic cylinder.

The nozzle advance movement, which in essence has a contact force applying function for most applications, is mostly with hydraulics or it can also be carried out electrically.
In ARBURG’s view it is very important that core pulls and specific special movements on the plastic mold, which have previously been integrated hydraulically, continue to be optimally operated with hydraulics in the future. For this reason, a special energy-saving small-accumulator hydraulic system has been developed for the optional hydraulic auxiliary functions on the machine, which can be assembled and dismantled on a modular basis.

Regulation

The basic structure of the electric axes ensures that they are highly dynamic and location-and position-regulated. This produces a reproducible, pin-point procedural sequence. This is mainly used for application with absolute and relative positioning accuracy for the mould and ejection movements.

In this way, for example, stroke-dependent functions such as mould positions in connection with core pull, or final positions when unscrewing, can be achieved extremely accurately.

As all stroke positions are measured absolutely, it is not necessary to carry out a reference movement or set them to a reference point.

On the injection side, the positioning accuracy and the acceleration in conjunction with the position-regulated screw movement can lead to additional accuracy with the injection molded parts. During dosage, the effect of the electric drive can be seen in the accuracy and in the energy requirement. 

When viewed on an individual basis, the options and potential for the improvement described, in conjunction with the well-tried and tested SELOGICA control system, lead to added value in relation to parts production.

The opportunity to operate individual cycle stages simultaneously adds even more importance to the programming of the SELOGICA control system. The appropriate cycle symbols with their comprehensive logistic links are extremely clear and can be used to optimise the procedures.

The synergistic effects of the ALLROUNDER A

During the development of the ALLROUNDER 420 A a great deal of importance was placed on the synthesis between the most up-to-date drive technology and tried and tested injection moulding technology.

In this way the design of the clamping areas ensures continued use of existing moulds. Furthermore, the daily operational practice is taken into account owing to the modular nature and the option of connecting hydraulic core pulls onto the plastic molds.

Flexibility through modular construction

The concept of electrically driven main axes as the basis and the option of freely combinable electrically or hydraulically driven auxiliary axes integrates the advantages of both systems. 

The machines have sufficient hydraulic power at their disposal precisely where it is needed, and they have the highest level of electro-mechanical accuracy coupled with economic energy consumption wherever feasible for the production task.

This means that the ALLROUNDER A machines also represent extremely flexible production systems, which always allow the machines to be equipped within an optimum cost/benefit framework, while at the same time precisely adapting them to the prevailing production requirements.

Injection Molding Equipment

Injection molding equipment is equipment that is very important for the operation of injection molding machines. Indeed, all injection molding machines utilize injection molding equipment that includes a power source, injection unit, mold assembly, and clamping unit to perform the four stages of the process cycle.

injection molding equipment
injection molding equipment

One of injection molding equipments is injection unit. This injection molding equipment is responsible for both heating and injecting the material into the mold. The first part of this unit is the hopper, a large container into which the raw plastic is poured. The hopper has an open bottom, which allows the material to feed into the barrel that contains the mechanism for heating and injecting the material into the mold.

Another injection molding equipment is clamping unit. Prior to the injection of the molten plastic into the plastic mold, the two halves of the mold must first be securely closed by the clamping unit. The hydraulically powered clamping motor actuates clamping bars that push the moveable platen towards the stationary platen and exert sufficient force to keep the mold securely closed while the material is injected and subsequently cools. After the required cooling time, the mold is then opened by the clamping motor.

There are also molds, typically made of steel or aluminum, as the plastic injection mould and molding equipment. The mold has many components, but can be split into two halves. Each half is attached inside the injection molding machine and the rear half is allowed to slide so that the mold can be opened and closed along the mould’s parting line. The two main components of the mold are the mold core and the mold cavity.

When this injection molding equipment is closed, the space between the mold core and the mold cavity forms the part cavity that will be filled with molten plastic to create the desired part. Multiple-cavity molds are sometimes used, in which the two mold halves form several identical part cavities.

Mold base also includes injection molding equipment that is a place where the plastic mold core and cavity are each mounted. Then, the mold base is fixed to the platens inside the injection molding machine. The front half of the mold base includes a support plate, to which the mold cavity is attached, the sprue bushing, into which the material will flow from the nozzle, and a locating ring, in order to align the mold base with the nozzle.

The rear half of the mold base includes the ejection system, to which the mold core is attached, and a support plate. When the clamping unit separates the mold halves, the ejector bar actuates the ejection system. Meanwhile, mold channels are one of injection molding equipment types that is usually integrated into the mold design in order for the molten plastic to flow into the mold cavities.

First, the molten plastic enters the mold through the sprue. Additional channels, called runners, carry the molten plastic from the sprue to all of the cavities that must be filled. At the end of each runner, the molten plastic enters the cavity through a gate which directs the flow. The molten plastic that solidifies inside these runners is attached to the part and must be separated after the part has been ejected from the mold.

Besides using several types of injection molding equipment, there are many types of materials that may be used in the injection molding process. Most polymers may be used, including all thermoplastics, some thermosets, and some elastomers. When these materials are used in the Thermoplastic Injection Molding Process, their raw form is usually small pellets or a fine powder. Also, colourants may be added in the process to control the colour of the final part.

What is Plastic Injection Molding

Injection molding is a molding procedure whereby a heat-softened plastic material is forced from a cylinder into a relatively cool cavity giving the article the desired shape. Injection molding is a manufacturing technique for making parts from the plastic material. Molten plastic is injected at high pressure into a mold, which is the inverse of the desired shape. The mold is made by a Mold Manufacturer China Company from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part. Injection molding is very widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars.

The process of plastic injection molding



An injection molding machine consists of three basic parts, the mold plus the clamping and injection units. The clamping unit is what holds the mold under pressure during the injection and cooling. Basically, it holds the two halves of the injection mold together.

During the injection phase, plastic material, usually in the form of pellets, are loaded into a hopper on top of the injection unit. The pellets feed into the cylinder where they are heated until they reach molten form (think of how a hot glue gun works here). Within the heating cylinder there is a motorized screw that mixes the molten pellets and forces them to end of the cylinder. Once enough material has accumulated in front of the screw, the injection process begins. The molten plastic is inserted into the mold through a sprue, while the screw controls the pressure and speed.

The dwelling phase consists of a pause in the injection process. The molten plastic has been injected into the mold and the pressure is applied to make sure all of the mold cavities are filled.

Then the plastic is allowed to cool to its solid form within the mold. The clamping unit is then opened, which separates the two halves of the mold. An ejecting rod and plate eject the finished piece from the mold.

Extrusion

A machine used to extrude materials is very similar to the injection-moulding machine explained above. A motor turns a thread, which feeds granules of plastic through a heater. The granules melt into a liquid, which is forced through a die, forming a long ‘tube-like’ shape. The extrusion is then cooled and forms a solid shape. The shape of the die determines the shape of the tube.

Advantages of Injection Molding 



– High tolerances are repeatable 

– Wide range of materials can be used 

– Low labour costs

– Minimal scrap losses 

– Little need to finish parts after molding

Plastic Injection molding
Plastic Injection molding

Disadvantages of Injection Molding



– Expensive equipment investment 

– Running costs may be high 

– Parts must be designed with specific molding consideration.

Overview

Injection molding is a relatively new way to manufacture parts. It is a fast process and is used to produce large numbers of identical items from high precision engineering components to disposable consumer goods. Injection molding is often used in mass-production and prototyping. It produces such small products as bottle tops, sinks plugs, children’s toys, containers, model kits, disposable razors and parts of cameras. The process can even mould such large items as dingy hulls and kit car body shell parts.

What to know more about injection molding? Please go to
https://en.wikipedia.org/wiki/Injection_molding to take a look.

Plastic Mold Technology

Plastic mold technology​

Plastic injection mold develops day after day. Each time, on exhibition, we can see that all manufacturers will exhibitor their newest and most advanced mould technology to attract customers. K fair in German is one of the most famous plastic industry exhibitions, there are many famous plastic injection moulds manufacturer will attend the fair and display their newest and most advanced plastic injection moulds. Besides K fair, NPE in America, Italy Milano PLAST, Plastic Magen in Mexico, Brazil last, Canton fair and Chinaplast, they are all world famous plastic injection moulds industry exhibition where can learn a lot of advanced plastic mold technology​.

In recent years, gas assistant molding system and RHCM (Rapid Heat Cycle Molding) are the top two advanced plastic injection moulds technology.

Plastic Mold

plastic mold

The gas assistant molding system

Gas assistant molding is a kind of new technology which brings the high-pressure air into plastic molding parts to let the plastic product with hollow section. Compare to traditional plastic molds​, it can reduce the weight of the product; realize thick wall and thin wall at the same time. The product surface will be more beautiful than traditional mould, without shrink mark, deformation and other molding defects. This kind of molding technology is more and more widely used in commodity products plastic injection moulds, household appliances product plastic injection moulds.

ST after some years’ research and development, it succeeds on gas assistance molding technology on various kinds product, such as for plastic chair, plastic handle and so on. Below is the picture of our design of a gas assistant chair for your reference.

Besides, injection machine and plastic injection mould, gas assistance equipment including Nitrogen Generator, pressure controller unit and air inlet parts.

RHCM (Rapid Heat Cycle Molding)

It is a kind of high speed and high-temperature molding technology. Put some Glass Fiber into plastic raw material to get the plastic product with high hardness and reflective surface. RHCM can remove the molding defects like melt line and flow mark which will appear in traditional plastic molding.

RHCM use high steam to make the mould cavity surface to reach the plastic raw material distortion temperature. Mould with high temperature ensures the good flow of plastic raw material; it makes the material fast flow and filled. It can avoid material to become more solid. This kind technology realizes no cooling molding and product with high glossy appearance without molding defects like deformation, melt line, flow mark, silver line. This kind of mould with short cycle time, reduce around 70% compared to traditional molding.

Plastic molds

plastic molds

RHCM mould have its advantage, it also have some disadvantages

  •  Mould steel will be easy crack
  •  Oil stain – As the mould temperature will be exceeding 130 ℃
  •  Gate area will appear white mark

Even though, RHCM technology is not widely used on market, but it will be a main technology in future as more and more customer require for high quality product, especially for outer parts. Nowadays, RHCM mould is mainly used in outer part product, like TV case and some automotive parts.​

If you want to know more information about plastic mold​​ and plastic mold technology, welcome to go to our mold blog http://mold.world.edu/, there are lots of plastic mold information to help you

Precision Injection Mold Making

Precision Measurement And Injection Mold Making

It is remarkable that it is possible to open a package from Sweden, clean up EDM tool, and install it in an engine lathe spindle made in upstate New York, and indicate the run-out with a dial indicator made in Switzerland, held by a magnetic base made in Japan. This is amazing in itself, but the truly amazing thing is that it all works, quite well!

In this example, which actually happened to me, the run-out was less than .0001in/.0025 mm, right out of the box, first try. This is what precision tool measurement is all about.

The number of precision tools used by an injection mold maker are numerous. A partial list would include:

Precision measurement tools

  • Granite surface plate
  • Surface gage
  • Dial indicator
  • Height master/Cadillac gage
  • Gage blocks
  • Pin gages
  • Sine plate
  • Magnetic squaring block
  • Vee-block
  • Precision micrometers
  • Spin fixture

One of the more challenging aspects of building a mold is to have all of the various measuring tools calibrated to the same standard. This is why the EDM chuck from Sweden fit in the American lathe spindle: the accuracy was traceable to a common standard.

It doesn’t mean much if you are accurate within .0002 in., if your micrometer is off! It just won’t work. Shops need to have a master set of gage blocks that are traceable to the NIST, or National Institute of Standards and Technology. This is not as hard as it sounds, you just need to invest in a good set of gage blocks, not some made by child labor in a developing nation.

The proper care and use of these expensive tools is critical as well. They need to be treated with respect, handled carefully, kept free from rust and grinding grit. They need to have a clean storage place, with a grit-free surface on which to sit.

There are many places that you can cut costs in Plastic mold making, precision measurement tools is not one of them. It simply makes no sense to save money by buying a cheap dial indicator, for example. It is only going to haunt you in the long run. The same holds true for gage blocks, micrometers, squaring blocks, sine plates and so on.

With large items, such as the optical comparator or coordinate measuring machine, it is especially important to obtain a reliable tool. Valuable shop time can be quickly consumed with trouble-shooting a low quality machine. Not only that, but what if the measurements are unreliable? The mistakes can become extremely expensive and will quickly erase the initial savings.

Reliable precision measurement manufacturers

 Starrett Brown-and Sharpe Interapid Girod
 Etalon Mitutoyo Suburban Mahr
 Tesa Hermann Schmidt OGP Magnets
 Harig Micro-Vu Mitutoyo Zeiss

Insert Molding

Insert Molding Advantages

Over the years, the technical advancements have taken place and instead of step-by-step manufacturing of products, there is manufacturing through one full-fledged process called insert molding . Certain industries still manufacture components through processes that include assembling discrete parts such as soldering, connectors, adhesives or fasteners. Molding through inserts is the perfect alternative to all such things and can benefit you in the following ways:

Decreased labour cost and assembly

Simply because various components are being joined or connected through thermoplastics, you can greatly bring down the assembly as well as labour cost with the help of this process.

Decreased weight and size

This process can yield smaller as well as lighter components by eliminating the need for connectors or fasteners. It merely blends the strength of metal inserts and resin.

Increased reliability

This process helps you in avoiding problems such as misalignment, part loosening, and improper termination as well as other problems. Every single part is secured tightly with the thermoplastic.

Design flexibility

Plastic Molding

Insert Plastic Molding

Another advantage of the insert molding process is that it gives you design flexibility. Designers love the unlimited configurations which can be used in insert plastic molding.

This process can literally allow you to reduce cost and experiment with the designs apart from getting other advantages as well. Most of all, it can allow you to save time and faults that might occur in manufacturing components otherwise. In a lot of ways, this process can be used by various industries to produce high quality and efficient components for all the purposes.