Molding

Prototype Stamping Supply

Ming Chiang Precision is your source to get you started when you are beginning your stamping design process. We can assist with your design by providing you with a prototype stamping to prove you stamping and die design is correct.

Prototyping your design also helps us in the development process. When prototype stampings are provided, most of the engineering process has been completed and can easily be transferred to the next step, providing short-run metal stampings and on into progressive die stamping for your long term requirements.

Here at Ming Chiang progressive die and stamping, we can assist you with other rapid prototyping services also. We have partner companies with a variety of services to provide you with a prototype stamping in a timely manner.


Metal Stamping Manufacturer

With one of the most advanced metal fabrication shops in the industry, Ming Jiang Precision has the manufacturing capabilities to produce nearly any metal stamping parts you may need. We have presses running up to 1,700 tons, multiple flat-laser and 5-axis laser systems, and an in-house tool room staffed with dedicated toolmakers to build and maintain all required tooling.

In order to best serve our custom needs, we have become the metal stamping parts manufacturer that companies turn to for precision metal parts as well as secondary forming and finishing services. Stamping, deep drawing, comprehensive fabrication services, and more are available to meet the unique needs of our customers. We also offer design assistance from our skilled engineering staff, who will work with you as needed to maximize your products performance, integrity, and manufacturability.

 


Mold Tooling Introduction

The mold tooling machine was relatively simple compared to machines in use today: it worked like a large hypodermic needle, using a plunger to inject plastic through a heated cylinder into a mold. The industry progressed slowly over the years, producing products such as collar stays, buttons, and hair combs.

Tool and die makers are a class of machinists in the manufacturing industries who make jigs, fixtures, dies, molds, machine tools, cutting tools, gauges, and other tools used in manufacturing processes. Depending on which area of concentration a particular person works in, he or she may be called by variations on the name, including tool maker (toolmaker), die maker (diemaker), mold tooling maker (moldmaker), tool fitter (toolfitter), etc.


Injection Molding Specialist

We have specialized in custom, high volume plastic injection molding, injection molded parts for many years. We excel at partnering with customers who have an annual volume of 500,000 parts per year or greater.

We will be your high volume, small plastic injection molded parts specialist. If you need a precision high-volume molder you have come to the right place. Our company supplies an ISO 9001:2008 certified plastic injection molder. We make billions of parts each year in our 125,000 square foot facility. We offer a turnkey manufacturing solution including mold design, mold building and high volume parts manufacturing. We excel at partnering with customers who have an annual volume of 500,000 parts per year or greater. Our globally competitive prices eliminate the risks of sourcing offshore.


An Overview of Injection Molding

image from www.djmetalrep.com

Injection molding is a fast, automated, versatile process that can produce precise, complex three–dimensional parts from a fraction of a gram to more than a hundred kilograms, in virtually any plastic material. The process starts with feeding small plastic beads into a heated screw and barrel system that melts the plastic into a high–viscosity liquid. The screw then forces the molten plastic into a closed mold that provides the shape, cooling and solidification, and finally ejects the part.

Injection molding is fast and can be economical. But because every part needs its own costly injection molding tool, the process is economically viable only for mass production, usually more than 10,000 parts. Injection molding tools take weeks or months to build. Often, design mistakes become apparent, requiring time–consuming mold corrections. Multiple iterations may go from the producer to the tool builder until the final part design and quality are achieved, increasing costs and product time to market.


The Process of Plastic Injection Molding

image from www.superiorplastics.biz

The Process and Equipment

Because most engineering thermoplastic parts are fabricated by injection molding, it is important for the designer to understand the molding process, its capabilities and its limitations. The basic process is very simple. Thermoplastic supplied in pellet form are dried when necessary, melted, injected into a mold under pressure and allowed to cool. The mold is then opened, the parts removed, the mold closed and the cycle is repeated.

 

The Molding Machine

Melting the plastic and injecting it into the mold are the functions of the plastifying and injection system. The rate of injection and the pressure achieved in the mold are controlled by the machine hydraulic system. 

 

The Mold

Mold design is critical to the quality and economics of the injection molded part. Part appearance, strength, toughness, size, shape, and cost are all dependent on the quality of the mold. Key considerations for Engineering Thermoplastics are:

-Proper design for strength to withstand the high pressure involved.

-Correct materials of construction, especially when reinforced resins are used.

-Properly designed flow paths to convey the resin to the correct location in the part.

-Proper venting of air ahead of the resin entering the mold.

-Carefully designed heat transfer to control the cooling and solidification of the moldings.

-Easy and uniform ejection of the molded parts.

When designing the part, consideration should be given to the effect of gate location and thickness variations upon flow, shrinkage, warpage, cooling, venting, etc. Your DuPont representative will be glad to assist with processing information or mold design suggestions. The overall molding cycle can be as short as two seconds or as long as several minutes, with one part to several dozen ejected each time the mold opens. The cycle time can be limited by the heat transfer capabilities of the mold, except when machine dry cycle or plastifying capabilities are limiting.

 


Molding Process

image from 99-ideas.co

Injection molding utilizes a ram or screw-type plunger to force molten plastic material into a mold cavity; this solidifies into a shape that has conformed to the contour of the mold. It is most commonly used to process both thermoplastic and thermosetting polymers, with the former being considerably more prolific in terms of annual material volumes processed. Thermoplastics are prevalent due to characteristics which make them highly suitable for injection molding, such as the ease with which they may be recycled, their versatility allowing them to be used in a wide variety of applications, and their ability to soften and flow upon heating. Thermoplastics also have an element of safety over thermosets; if a thermosetting polymer is not ejected from the injection barrel in a timely manner, chemical crosslinking may occur causing the screw and check valves to seize and potentially damaging the injection molding machine.

Injection molding consists of high pressure injection of the raw material into a mold which shapes the polymer into the desired shape. Molds can be of a single cavity or multiple cavities. In multiple cavity molds, each cavity can be identical and form the same parts or can be unique and form multiple different geometries during a single cycle. Molds are generally made from tool steels, but stainless steels and aluminum molds are suitable for certain applications. Aluminum molds typically are ill-suited for high volume production or parts with narrow dimensional tolerances, as they have inferior mechanical properties and are more prone to wear, damage, and deformation during the injection and clamping cycles; but are cost effective in low volume applications as mold fabrication costs and time are considerably reduced. Many steel molds are designed to process well over a million parts during their lifetime and can cost hundreds of thousands of dollars to fabricate.


Injection Mold

image from www.mespecialties.com

Material is introduced into the injection molding machine via a Hopper.  The injection moulding machine consists of a heated barrel equipped with a reciprocating screw (driven by a hydraulic or electric motor), which feeds the molten polymer into a temperature controlled split mould via a channel system of gates and runners. 

The screw melts (plasticises) the polymer, and also acts as a ram during the injection phase. The screw action also provides additional heating by virtue of the shearing action on the polymer.

The polymer is injected into a mould tool that defines the shape of the moulded part. 

The pressure of injection is high, dependant on the material being processed; it can be up to one thousand atmospheres.  Tools tend to be manufactured from steels, (which can be hardened and plated), and Aluminium alloys for increased cutting and hand polishing speeds.  The costs associated with tool manufacture means that injection moulding tends to lend itself to high volume manufacture.  Details of process costing can be found at:

The tool can be used to manufacture one consistent part in a repeating process or incorporate multi cavities (a multi impression tool), that is many components can be manufactured on the same tool repeatedly with a single injection. 

It should be noted that, whilst in the animation the flute pitch of the screw is shown as constant along its length, in practice it varies considerably dependent upon the polymer being processed. In particular the root diameter increases from hopper to nozzle to provide compression to the melt.
Source: http://www.bpf.co.uk/plastipedia/processes/injection_moulding.aspx

Injection Molding

image from image.made-in-china.com

Injection Molding (or Moulding to use the UK spelling), along with extrusion ranks as one of the prime processes for producing plastics articles. 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 mouldings count for a significant proportion of all plastics products from micro parts to large components such as bumpers and wheelie bins.  Virtually all sectors of manufacturing use injection moulded parts - the flexibility in size and and shape possible through use of this process have consistently extended the boundaries of design in plastics and enabled significant replacement of traditional materials thanks to light weighting and design freedom.  The table below shows the type of products that can be injection moulded, but is by no means comprehensive.


What Is Thermoplastic Injection Molding?

image from www.rutlandplastics.co.uk

Thermoplastic injection molding is the most common way to manufacture plastic parts. Thermoplastics are polymers that can be heated to soften or melt, and cooled to solidify as a physical change, rather than a chemical change that takes place during molding of thermoset materials.

The thermoplastic injection molding process begins by adding pelletized material to a hopper. In most cases, the material must is dried prior to molding, and frequently requires the addition of a color concentrate before loading. The material is gravity fed into a heated barrel and screw. Rotation of the screw results in shearing action on the raw pellets causing them to melt.  The screw rotation also pushes the molten plastic forward in the barrel toward the mold. The material is then injected into the closed mold at high pressure through a runner system to fill all the cavities. The mold is clamped shut under enough force to keep the mold halves together while the molten plastic is flowing. On a cold runner system, the plastic in the runner solidifies and must be discarded or ground into pellets to be reused, which we refer to as “regrind.” If a hot runner system is used, the plastic in the runner stays molten, and no material is wasted. When the mold cavities are filled, the part cools until rigid enough to be ejected. Part cooling within the mold is accomplished through water lines cut into the mold. At the completion of the cooling cycle, the mold opens and the parts are ejected for part removal.