How to Inject Silicone Molds

How to Inject Silicone Molds

·      Often castings of an object are made by injecting material into a mold. The mold may be made up of two or more pieces, which are closed before injection begins. The main benefits of this process are reduced seam lines in the product as well as allowing you to use only as much casting material as you need with little waste. When injecting material into a closed silicone mold, it is essential to take several steps to insure that the casting comes out right. If your mold was designed for this purpose with the holes already in place, begin at Step 6. 

1

Determine the best injection point in your mold. Ideally, this should be a place that is not easily seen on the cast, such as the back or bottom. Mark the point with a marker.

2

Determine the highest points in the cast. Mark these with the marker.

3

Drill a hole in the silicone at the injection point. The drill bit should be the same diameter as the tip of the syringe. Use an extremely sharp drill bit to prevent the rubber from grabbing onto the bit. It's a good idea to have a friend hold the mold in place just in case the bit grabs the silicone; otherwise the entire mold will spin and could cause injuries.

4

Drill small holes in the highest points. Use the smallest bit you have for these as they are simply to allow air to escape as you inject the casting material.

5

Mark the holes in the mold shell and drill it out as well.

6

Apply a thin coat of silicone mold release or hand soap to the entire inner mold surface with a paintbrush. Allow it to dry and buff out the excess with a paper towel.

7

Close the mold and strap or clamp it shut tightly.

8

Mix the casting material according to its instructions.

9

Pour the casting material into the syringe.

10

Insert the tip of the syringe into the injection hole and inject the casting material.

11

Allow the casting material to run out of the air release holes for a few seconds before plugging each one with a bit of clay. This allows any air bubbles in the casting material to escape the mold.

12

Once the mold is filled, remove the syringe and plug the injection hole with clay.

13

Allow the casting material to cure and dry.

14

Remove the cast from the mold.

15

Remove the knobs left by the holes with a razor blade and sandpaper if needed.

skype: lee.ivy66

ivylee886@gmail.com

Free Technology Co., Ltd

http://www.freetech-mould.com

How to Make a Silicone Mold

Silicone molds are most often used in projects that require resin or other plastic casting, and can be seen in the creation of toys, collectible figurines, props, model parts and other small plastic casting projects. Silicone rubber is usually preferred because it can be used with many materials and it does not stick to itself or other objects, negating the need for a mold release agent or a separating wall during the molding process. The most common type of silicone mold is the two-part mold, which creates a seamless end product.

Instructions

1

Build a molding box for the model object you would like to make copies from. For smaller objects, make your box walls from Legos, and roll out a flat piece of modeling clay for the bottom of the box. For larger objects, build the box walls and bottom from sturdy cardboard or wood. Make sure that the box gives your model a clearance of at least 1/4 inch on all sides.

2

Mix together half a batch of silicone RTV rubber and catalyst, following the packaging directions for the brand of rubber you have. Make sure that the catalyst is completely blended into the rubber, creating a pale version of the catalyst's color.

3

Mark the halfway point on your molding box with a pencil or marker. Pour the batch of silicone rubber into the molding box, and stop at this halfway mark.

4

Press the model object into the siliconerubber until it is half covered and does not touch the sides of the molding box. Let this half of the mold cure, or dry, overnight or for 12 hours.

5

Mix together the rest of the silicone RTV rubber, and pour it into the molding box, covering the model object completely. Let the rubber cure overnight.

6

Take the molding box apart and separate the mold halves, removing the model object. Fit the mold halves back together and secure them with rubber bands.

7

Carve a pouring hole in the top of the mold at the joining line with a razor blade or utility knife. Cut the hole deep enough to penetrate through the rubber and reach the inside cavity.

skype: lee.ivy66

ivylee886@gmail.com

Free Technology Co., Ltd

http://www.freetech-mould.com

Injection Blow Molding Basics

Injection blow molding is a manufacturing process that combines the accuracy of injection molding with the minimal waste and rapid processing of blow molding. Injection blow molding can be used with plastics and is generally used to make hollow shapes such as bottles. The manufacturing process is more expensive than other blow molding techniques, so larger containers are generally fabricated using extrusion blow molding. The final products of injection blow molding have no seams, and can be glass clear.

Injection Blow Molding Process

The injection blow molding process has three phases: Injection of the material into the preform mold; blowing of the preform, or parison, into the product mold; and ejection of the product from the machine. A commonly used machine configuration is a three-stage blow molding machine, which rotates through 120 inches for each phase of the process. In the injection phase, molten plastic or glass is injected into the preform mold over a core pin, which forms the interior of the parison and finishes the interior of the neck. At this point, the neck of the container is fully formed. The parison is removed from the mold and inserted into the blow mold. The parison is inflated inside the blow mold by pressurized air. After a cooling period, the product is ejected from the machine, tested for leaks, and moved to another station for labeling or finishing.

Designing for the Injection Blow Molding Process

Designing products to be fabricated using injection blow molding includes selecting a thermoplastic resin for the product application, designing the mold geometry to take into account material shrinkage during cooling, calculating the right amount of material to be injected and choosing the right pressure to inflate the parison in the mold. Tolerances in the core rod and preform mold design are critical so that the core rod sits exactly in the center of the mold and the resulting parison has constant wall thickness prior to blowing.

Products Fabricated Using the Injection Blow Molding Process

Injection blow molding is used to create hollow products such as bottles, and is generally only used for small containers such as medicine bottles or single-serve beverage containers. The injection phase of the process can create a neck with very fine tolerances, with designs such as screw threads or threads for childproof caps. Unlike standard injection molding, undercuts can be incorporated into an injection blow molded design for some products, such as mascara bottles.

Chrome Vs. Nickel Plating

Chrome and nickel are metals used to plate machine parts, such as rollers and cylinders, with a scratch-resistant surface that protects them from wear and tear. They are also used on bathroom and kitchen fixtures.

1.                            Chrome

Chrome comes in standard and hard versions. It is applied in varying thicknesses according to the required purpose. Thinner coatings are used on objects that are not exposed to much abrasion. Thicker coatings offer more protection from abrasion and corrosion. If a machine part is frequently exposed to water, experts at Phoenix Electroplating recommend an undercoat of nickel plating, as chrome is porous.

Nickel

Nickel is used to prevent corrosion, particularly when applied prior to chrome plating on objects. It is also hard-wearing and is widely used on machine parts in the oil and gas industry, the automotive industry, in making molds for plastics and in food processing machines.

Bathroom and Kitchen Fixtures

According to Rejuvenation, suppliers of home fixtures, nickel was the standard finish for kitchen and bathroom fixtures made from the 1800s until the 1930s. Chrome then overtook nickel in popularity. Nickel is warmer in appearance and creates a more authentic, antique look, but Rejuvenation says the two finishes blend harmoniously in one room.

How to Clean Chrome Plated Plastic

Any chrome surfaces actually consist of an extremely thin layer of chrome plated onto another material. Regardless of what that other material is, from plastic to steel to aluminum, this chrome plated is what needs to be addressed when the time comes to clean it. You can always buy a special chrome cleaner, but there are several items in your home that work just as well and are far less expensive.

1.                            Toothpaste Method

1

Spread a thin layer of toothpaste on the surface of the chrome plating. Use the opaque white toothpaste, not one of the gel varieties.

2

Rub the toothpaste-covered chrome plating with a soft, clean cloth in small circular and swirling patterns. There is no need to apply a lot of force.

3

Take a fresh cloth and wipe away the toothpaste, revealing a shining, clean surface.

2.                            Vinegar Method

4

Pour undiluted distilled white vinegar into a spray bottle.

5

Spray the surface of the chrome plating with the undiluted vinegar.

6

Wipe down the surface with a clean cloth.

3.                            Baby Oil Method

7

Dampen a portion of a soft cloth with baby oil.

8

Rub the baby oil into the chrome plating in the same manner as you did with the toothpaste.

9

Wipe off excess baby oil with a fresh cloth or a still fresh portion of the same cloth.

10

Wipe down the newly cleaned area with soapy water to remove any greasy feeling from the baby oil, if desired.

skype: lee.ivy66

ivylee886@gmail.com

Free Technology Co., Ltd

http://www.freetech-mould.com

How to Chrome Plastic Parts

How to Chrome Plastic Parts

1

Take the part down to the bare plastic. You can do this by etching the parts with strong chromic acid, according to Atlas Chrome. This will give you a basic surface to begin working on.

2

Repair any cracks or splits in the plastic part. You can do this by using epoxy glue purchased at your local auto supply store.

3

Dip the plastic parts with silver so that that they will conduct electricity.

4

Layer a conventional plating process such as copper, nickel or chrome onto the plastic parts in several layers. You will most likely need to lightly sand and buff the plastic parts prior this process as well.

5

Apply the chrome plating to the plastic parts for the final revamp. Do this by soaking them in a chrome plating solution for about five minutes

How to Make a Two Part Mold

There are several different ways to make molds. The most common mold types are one-part and two-part molds, with the complex three-part molds used a little less often. One part molds are best suited to flat-backed designs, as they typically require one side of the mold to be completely open at all times. Two part molds are used for most other projects, as they can be taken apart to retrieve a cast object. Three part molds are like two part molds, but have an added inner piece that makes the casting hollow.

Instructions

1

Coat your model with mold release, so that the mold material does not stick to the model.

2

Create an open-top box that will hold your liquid mold material. You can make the box out of pieces of thick cardboard or even wood, although cardboard will be easier to take apart later. Make sure that the box is at least 1/4 inch bigger than the model in all dimensions.

3

Seal the corners, edges and bottom of the box with modeling clay, so that none of the mold material leaks out of the box.

4

Mix together a batch of your mold-making material. Typically, two-part molds are made from either plaster or rubber. Make sure to take the appropriate safety precautions for the material you have chosen.

5

Pour the mold material into the box. Stop pouring once the box is half-filled. Discard the rest of the mixture.

6

Let the mold material sit for several minutes to firm up slightly. When the material is ready, press the model into it so that half of the model has sunken into the material. Let the other half of the model sit above the surface.

7

Let the mold material harden completely. If you have used plaster or rubber, this will set in 12 hours.

8

Coat the top of the mold, which has the model sticking out of it, with mold release. This will make the mold easier to separate later.

9

Make another batch of your mold material. Pour the material into the box, covering the model completely. Fill the box.

10

Let the mold material harden completely. When the material has hardened, take the box apart.

11

Pull each side of the mold apart and remove the model from the inside. Fit the mold back together.

12

Tie the mold together with rubber bands or cording. Carve a hole in the mold, at the seam, that reaches the inside cavity. Use this hole to pour your casting material.

What Is the Blow Molding Process?

Blow molding is used to produce plastic bottles.

Blow molding is a method for making a variety of hollow plastic products. Molten plastic is extruded, in a tube shape, from a die, then a mold closes around it. The plastic is then inflated.

History

Blow molding first appeared late in the 1800s, but modern polyethylene bottle production did not commence until the early 1940s.

Types

The blow molding process can take four forms: reheat and blow molding, injection blow molding, stretch blow molding and extrusion blow molding. The machinery can vary significantly, though the major difference tends to be the point of plastic inflation.

Uses

The various processes are used to create a range of products, including bleach and milk bottles. Stretch blow molding is used in the production of PET (Polyethylene terephthalate) bottles, which are widely employed for carbonated beverages.

Plastics

The plastics used in the various blow molding processes can include HDPE (high density polyethylene), LDPE (low density polyethylene), PP (polypropylene), and PVC (polyvinyl chloride).

Disadvantages of Blow Molding

Blow molding is the process in which hollow, plastic containers are made. Air is blown into molds to form items such as thermoplastic bottles, tubing and milk jugs. While blow molding allows companies to manufacture high volumes of plastic containers, which are significantly cheaper than glass, there are a few disadvantages to the process. Some disadvantages include environmental hazards and a significant dependence on petroleum.

Environmental Disadvantages

Plastic products made by the process of blow molding aren't biodegradable, which presents an obvious environmental hazard, especially when empty containers find their way to landfills. When disposed of in landfills, plastic products are buried and remain in the earth forever. Their oil-based material then becomes part of the soil and runs the risk of threatening plant life, animals and groundwater.

Dependence on Petroleum

Aside from the gasoline industry, plastic manufacturers depend on millions of gallons of petroleum in their quest to produce blow-molded products. Because oil is the most important agent in thermoplastics and blow molding is becoming more streamlined and automated, the process plays an ongoing threat on a diminishing world oil supply.

Process and Material Limitations

Although blow molding has been automated and can produce mass quantities of products, the process is largely limited to hollow forms. These forms are delicate and contain various thicknesses which must be precise, which often results in wasted material in the process of arriving at containers with proper dimensions and specifications. In some cases, thermoplastic is stretched to save on material, which can lead to substandard containers.

      skype: lee.ivy66

      ivylee886@gmail.com

Free Technology Co., Ltd
http://www.freetech-mould.com

Steps of Injection Molding

·                                  

Many popular plastic items are produced by injection molding.

Injection molding has continued to grow since the late 19th century. Capable of producing small items such as combs, it is also used to create parts for airplanes and medical supplies. It is hard to imagine the world without the products it produces. The process was patented by John Wesley Hyatt and his brother Isaiah in 1872. Today, injection molding is used to produce about 30 percent of all plastic products. The process is relatively simple, but expensive. Thus it is usually only used to mass produce items.

Instructions

1

Clamp the mold shut. This will hold the mold in place while the mold is filled with melted plastic. It will also keep the mold still while the plastic cools.

2

Inject the melted plastic into the mold. The plastic starts out as polymer resin pellets which are poured into a large open-bottomed hopper. A motor turns the auger, feeding the pellets into the cylinder where they are melted and turned into molten plastic, then pushed into the mold. The auger injects the melted plastic into the mold at a pressure between 10,000-30,000 pounds per square inch. The auger then holds the plastic, forcing more plastic in to fill the mold completely. This guarantees that the final product will not contain any gaps. A gate closes keeping the plastic inside the mold while it cools. Molds are usually either water ic belting. 35+ years' experience.

3

Drill small holes into the mold, if it is cooled by water or another liquid. The cooling period accounts for about 85 percent of the molding process. The temperature of the water is usually between 33 and 60 degrees Fahrenheit. Water below freezing can be used. However, glycol, or a similar additive, needs to be used to keep the water from freezing. The major disadvantage to using water to cool the mold is the buildup of condensation.

4

Loosen the clamp and open the mold. Remove the plastic part that was just created. Then clean the part, removing any excess plastic.

How to Clean Injection Molds

Injection molding is an industrial plastic-making process.

Injection molding is a production process in which plastics are heated until liquid and sprayed into a mold where they cool and are given the final shape of the manufactured product. As the project cools, it shrinks away from the mold walls, allowing it to be ejected. To keep this process working efficiently, molds need to be systematically and regularly cleaned. Although most molds are cleaned haphazardly and by hand, there are also a number of technological solutions available.

 

Instructions

1.                            Cleaning Molds by Hand

1

Disassemble the mold using a screwdriver to disconnect the parts. Separate the parts that are most susceptible to corrosion and contaminate build-up. These include the front and rear clamp plates, bubbler plates, bushings, water lines and wear plate grease grooves.

2

Spray the pieces of the mold with a cleaning spray, or place them in a solvent bath. More abrasive cleaning chemicals may work more quickly, but they will also cause wear and tear on the mold that can shorten its life.

3

Scrub the mold with a stiff brush to remove the contaminants, then wipe dry.

2.                            Cleaning With Dry Ice Pellets

4

Connect a dry-ice pellet blasting system to an air line near your mold. A double-line system introduces the pellets at the spray nozzle, while single-line systems introduce them at the hopper and offer a more powerful spray.

5

Disassemble the mold and strongly secure the parts to be cleaned. The force of the dry-ice pellet impacts can easily knock over unsecured parts, possibly damaging them.

6

Ensure the area is clear. These guns spray dry ice at 900 feet per second, which can cause severe injury.

7

Put on safety gear. This includes a face mask, gloves and an apron as well as ear protection that can block the 102-decibel noise produced by the sprayer.

8

Turn on the air line and squeeze the trigger to spray the parts. The dry ice will dissolve on impact, taking residue with it. This method, however, may not be very effective at rust removal.

3.                            Cleaning Molds Ultrasonically

9

Disassemble the mold and immerse the parts in a detergent solution. The exact type of detergent depends on what kind of contamination is to be removed. Heavily alkaline solutions like sodium hydroxide are very effective with most contaminants, but are dangerously caustic. Mildly acidic solutions are better for rust, but will turn steel gray.

10

Connect an ultrasonic generator to a shop power line. This generator transforms regular current into the very high frequencies necessary for ultrasonic cleaning.

11

Attach transducers to the bottom and sides of the tank. These transducers will vibrate at the high frequencies coming in from the generator, which produces tiny bubbles in the water that impact the mold pieces with force enough to strip away contaminants, while leaving the metal mold undamaged.

12

Set the timer on the generator, and walk away. The cleaning process will proceed on its own.

http://www.freetech-mould.com/equipment.html