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How to make plastic injection mold

How to make plastic injection mold

The process of making a plastic injection mould consist of determining what should be the size of
the mold, designing the mold, ordering required materials for the design, creating a rough shape, heating the mold, precision machining, wire cutting, polishing and fitting and trial of the mold.

Step 1: Determining the size of the plastic injection mold.

This process is not hard and does not require a lot of time. The end product, the plastic shape, determines the size of the mold.

Step2: Designing the mold.

Computer CAD design is used to draw the design. First set a 2 dimension layout and make sure you have all the mold
design features marked such as the size of the mold, parting line, the layout of the cavities are all set. Note the information that will be needed such as the mechanical design and the accessories that will be used.

After the two dimension layout made is satisfying and all information is noted make a
detailed 3D design. This will require programming skills to create. It may take some time to complete the designing with regards to the complexity of the mold.After the first 3D design is made it is necessary to assess any need for adjustments and the flow of the mold.

Step 3: Ordering the required molding material

After your design drawing is completed its time to order the required material. This may include desire steel, cutting tools and plastic part samples.

Step 4: Creating a rough shape of the plastic molds

Sizing of the steel then milling and drilling comprises this step. Make the desired steel shape and drill the holes needed as per the design in a rough work machine. Leave polishing and smoothing for later.

Step 5: Heating the mold

Heating is done as a form of treatment after creating the rough shape to harden and balance the created steel shape. Not every type of steel may need heating, an example, the P20.

Step 6: Precision machining.

Precision machining works slower due to the hardened steel properties but will get the design dimension created as per the design drawing.

Step 7: Wire cutting and EDM

Wire cutting is a process where special holes are made in to the design. These holes include pin holes for the ejector, for the lifters and the inserters. EDM helps work on narrow spaces which cannot be machined easily or where the space is too small for the cutting tool to get in.

Step 8: Polishing and fitting
polishing and fitting the created mold in to the mold maker machine follows.
The mold maker machine will collect all parts put into it and will follow the
design drawing to make the finished plastic mold. When the machine work is done further
polishing and engraving follows to complete the design.

Step 9: Trying the mold.

After the mold is created it will be good to try if it will work for the desired plastic shapes. The mode is installed in the plastic injection molding machine and injection parameters are set to work on the plastic samples acquired. If the mold is good enough for the job, well and good, the mold creation process is complete. You can now proceed to create the desired plastic products or sell the design to another company.

Injection Molds

Injection Molds

The world has become very dependent upon plastic products. From household items to industry and aerospace, plastic in its many formulations has transformed modern manufacturing and created conveniences and economies unimagined in the early decades of the 20th century.

Injection Molds
The injection moulding industry took hold in 1946 when James Hendry built a screw injection molding machine. But, his technology was based on an earlier invention by John Wesley Hyatt who, in 1868 injected hot celluloid into a mold to make billiard balls. Hyatt’s method used a plunger to force the ma

terial inside a mold. Hendry’s improvement was revolutionary because it eliminated the plunger and replaced it with an auger-type action that better distributed material and facilitated the use of plastic inside molds.

 

Today’s plastic molds use much the same process and produce a wide variety of products from car panels to outdoor furniture, small toys and tools. Injection molding is ubiquitous in manufacturing and uses many different materials from polymer plastics to aluminum, copper and other metals. The plastic bottles and kitchen implements people use in everyday life are products of the injection process.

Because the metal molds are generally expensive to produce, Plastic molding is most economically used when thousands of pieces are being manufactured. Molds are made of hardened steel or, more recently, aluminum which is less expensive.

The Injection Process
Described very simply, molten plastic is injected into the mold under high heat and pressure. The goal is to have the molten plastic material evenly flow to all parts of the mold, creating an exact, consistent, solid plastic replica of the mold cavity. After a brief cooling cycle, the mold or tooling mechanically ejects the plastic part which then moves on through the manufacturing process. In the injection molding industry, this is a completely automated process that’s very fast and extremely efficient.

Rotational Molding
Rotational molding is yet another method of producing multiple products, most often made with a variety of plastic powders. This process is usually used in making hollow products such as traffic cones, canoes, kayaks, bicycle helmets and giant tanks used for water or chemical storage.

Like Injection molding, rotational molding had its roots in the 1940s. But it was not until the technology was more sophisticated and new polymer and plastic formulations became available that the rotational process became a mainstream manufacturing method.

Rotational Process
The two processes are quite different. Let’s consider, for example, a 300 gallon water storage tank made of polyethylene. Picture a master mold made of aluminum or steel. The plastics manufacturer pours poly resin powder into the mold that is fitted inside an oven. Once sealed, the mold is mechanically turned on at least three axes, moving much like a gyroscope. At the same time, the oven is raised to an appropriate temperature and the polymer – or other material – tumbles inside and slowly coats the inner walls of the mold, melting as it rotates.

Once the optimal temperature is reached, the mold is cooled. As the temperature of the mold itself falls, the product on the inside shrinks away from the inner walls and is easily removed. This is not always the case with injection molds that are often more difficult to successfully remove. The shrinking action of rotational molding is particularly desirable when the product is very large and awkward to handle.

Rotational molding is also more economical for some products because less material is used. In addition, the polymer that is left over from one mold can be used in another. The method itself is more streamlined than injection molding, which requires more interlocking parts.

Materials Improve and Expand
Most products made with the rotational molding method are from the polyethylene family. Other materials include nylons, polypropylene and PVC plastics. Some manufacturers have developed formulas that integrate the use of natural materials such as sand and chips of stone to make products.

Plastic and resin products are now an integral part of everyday life and supply us with items as tiny as paper clips and as big as storage tanks. As the industry developed, so too has environmental awareness about the safety and use of these petrochemical-based products. Today, materials can meet the specifications of FDA requirements, and other health and safety related regulations. Producers are also cooperating to create products that can be recycled.

Custom Injection Molding

Custom Injection Molding

If  your business needs plastic molding products with specific types and dimensions, then you should turn to custom injection molding companies. These manufacturers have the ability to make plastic parts for specific applications – they can customize virtually all plastic components per your requirements. They can stamp your logo or messages, produce unique colors and designs and package them specifically based on what you want and need.

Choosing a custom injection molding company

Most of the custom injection molding companies can produce any plastic product you specify, but not all of them go the extra mile to take care of ‘finishing services’ such as decorating, assembly, labeling and packaging. Some even have a design group that can assist clients with plastic part and mold design. From rapid prototyping and tooling to injection molding, ultrasonic and plastic welding and stamping, these companies can assist you every step of the way. Go for manufacturers that offer these added perks – you will end up saving time, money and effort.

Note that some custom injection molding companies do not do these extras in-house – they hire sub-assemblers and finishers, but are still able to produce products at par with your standards.

Also examine the manufacturing company’s logistics and scheduling system. They should be able to handle your delivery needs no matter how demanding they may be. You should also go for companies that implement strict controls to monitor the whole custom injection molding process. They should have the latest inspection equipment at hand to allow them to match the closest tolerance and thus provide quality consistently.

The custom injection molding company’s plant climate is also very important. They should have facilities that ensure mold cooling system control. You may contact any companies in the internet directory for your custom injection molding needs. injection Molding provides detailed information on Plastic Molds, Injection Molding, Plastic Injection Molding, Injection Molding Machines, Custom Injection Molding and more.

What Is Plastic Molding

What Is Plastic Molding

Plastics are synthetically produced non-metallic compounds. It can be molded into various forms and hardened for commercial use. Plastic molding products can be seen everywhere. Examples are jars, protective caps, plastic tubes, grips, toys, bottles, cases, accessories, kitchen utensils and a lot more.

Even the keyboard and the mouse that you use are made through plastic molding. Even the plastic parts of the chair that you are sitting on are created this way.

The basic idea in plastic molding is inserting molten liquid plastic into a ready shaped mold, for example the mold of a bottle. It will be then allowed to cool, then the mold will be removed to reveal the plastic bottle.

Plastic moulding can also custom-mold a wide variety of plastic products including: garden pots, cabinets, office trays and boxes, barriers, barricades and traffic signage and displays for product and marketing promotions.

If you are planning to go into plastic molding business, you should first know the different processes.  Choose from a plastic molding process that fits your budget, your expertise, and your resources. Here are basic definitions of various methods of plastic molding.

The Plastic Molding Processes:

1.      Injection Molding

In Injection Molding, melted plastic is forced into a mold cavity. Once cooled, the mold can be removed. This plastic molding process is commonly used in mass-production or prototyping of a product. Injection molding machines were made in the 1930’s. These can be used to mass produce toys, kitchen utensils, bottle caps, and cell phone stands to name a few.

2.      Blow Molding

Blow molding is like injection molding except that hot liquid plastic pours out of a barrel vertically in a molten tube. The mold closes on it and forces it outward to conform to the inside shape of the mold. When it is cooled, the hollow part is formed. Examples of blow molding products are bottles, tubes and containers.

Equipments needed in setting-up a blow molding business are relatively higher than injection molding.

3.      Compression Molding

In this type of plastic molds, a slug of hard plastic is pressed between two heated mold halves. Compression molding usually uses vertical presses instead of the horizontal presses used for injection and blow molding. The parts formed are then air-cooled. Prices of equipment used for compression molding are moderate.

4.      Film Insert Molding

This plastic molding technique imbeds an image beneath the surface of a molded part. A material like film or fabric is inserted into a mold. Plastic is then injected.

5.      Gas Assist Molding

Also called gas injection molding is used to create plastic parts with hollow interiors. Partial shot of plastic is then followed by high-pressure gas to fill the mold cavity with plastic.

6.      Rotational Molding

Hollow molds packed with powdered plastic are secured to pipe-like spokes that extend from a central hub. The molds rotate on separate axes at once. The hub swings the whole mold to a closed furnace room causing the powder to melt and stick to the insides of the tools. As the molds turn slowly, the tools move into a cooling room. Here, sprayed water causes the plastic to harden into a hollow part. In this type of plastic molds tooling costs are low and piece prices are high. Cycle time takes about 40-45 minutes.

7.      Structural Foam Molding

Structural foam molding is a process of plastic molding usually used for parts that require thicker walls than standard injection molding. Inserting a small amount of nitrogen or chemical blow agent into the plastic material makes the walls thicker. Foaming happens as the melted plastic material enters the mold cavity. A thin plastic skin forms and solidifies in the mold wall. This type of plastic molding can be used with any thermoplastic that can be injection molded.

8.      Thermoforming

In this plastic molding process, sheets of pre-extruded rigid plastics are horizontally heated and sucked down into hollow one-piece tools. When the hot plastic solidifies, its shape conforms to that of the mold.

Tooling costs are usually low and piece prices vary on the machinery.

Plastic molding is a very technical process. It needs experts in this type of manufacturing business for it to be competitive in the market. Therefore, a very scientific and systematic study should be first made before going into this endeavor, if you want to know more about us, please go to our mean website to know more.