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2014年7月13日星期日

How to Clean Chromed Plastic on Vehicles


How to Clean Chromed Plastic on Vehicles

·                               Chromed plastic is found on many locations of a vehicle such as grills, door handles and body mouldings. It becomes water spotted, can be discolored from acid rain or covered in bug residue. Using a glass cleaner to remove these contaminants is the safest way to clean the plastic without harming the adjacent painted areas. This process can be repeated as needed. However, since the glass cleaner dries to a spotless finish, usually no further cleaning is necessary. 

Instructions

1
Mix a bucket of soapy water using dish detergent and water as if preparing to hand-wash a car. Use the mixture with a kitchen sponge to clean the moulding of all road film and grime. Dry when complete with a chamois or kitchen-type towel.
2
Apply glass cleaner such as Windex to a kitchen towel or directly onto chrome and scrub chromed area with the kitchen towel. Chrome does not scratch easily, so use moderate pressure to scrub stains.
3
Repeat as necessary. Due to the majority of stains, such as tree sap or acid rain spots, being water-based contaminants, a water-based cleaner such as Windex is the best for cleaning. Although glass cleaner should remove all stains, rubbing compound with a terry cloth rag and elbow grease may be used for removing more difficult stains such as dried bird droppings or bug residue.


2014年6月3日星期二

Dangers of Injection Molding


Dangers of Injection Molding

Many plastic products are pressed by an injection molding machine.
Many common plastic items are created using an injection molding machine, and manufacturers point to the machine's efficiency and speed in pressing out plastic products. Much of the injection molding process is automated, and in many cases, the machine operator's role is merely to monitor it. While operation requires minimal training, there are several potential dangers to running an injection molding machine.

Heat

Depending on the type of material used, the melting point for plastic ranges from 250 to 650 degrees Fahrenheit. An injection molding machine will heat up enough to not just melt the plastic, but allow it to flow smoothly into the mold. Burns are a hazard, whether from the machine's heated surfaces, melted plastic or from the freshly molded product. In addition to eye and face protection, heat-resistant gloves may be needed while operating the machine.
Caught In the Press
On an injection molding machine, the platens join together to form the actual mold, and the plastic is molded under pressure before it is ejected. This constant movement creates a hazard, as fingers can be crushed or amputated in the press. Long hair and jewelry can also get hung up in the machinery, severely injuring the operator. Reaching into a molding machine to free up a stuck part is particularly dangerous.
Peripheral Machinery
While not part of the injection molding process, waste plastic is often thrown into a grinder that can shred the scraps--or anything else that gets into the grinder--in seconds.
Fumes
Plastics and polymers are made from different chemical compounds that, when melted, may give off hazardous fumes. An injection molding machine should only be operated in a well-ventilated area.
Flying Objects
While most products made via an injection molding machine are ejected in a controlled manner, there is still the possibility of flying objects. Eye and face protection should be worn when operating the machine.
Slipping and Falling
Good housekeeping is essential when running an injection molding machine. Scraps of plastic can quickly collect on the surrounding floor area quickly, and it is easy to lose your footing and fall. New plastic is often shipped in pellet form, which can be hazardous if spilled.

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2014年5月30日星期五

How to Calculate Molding Machine Sizes


How to Calculate Molding Machine Sizes

Producing quality plastic products requires a molding machine that has been properly sized.
Molding machines come in a wide variety of clamp tonnages. The clamp tonnage refers to the amount of force that the machine can exert on a mold while the molten plastic is being injected. The plastic is injected into the mold at high pressure in order to ensure that the mold is completely filled before the plastic hardens. The pressure of the injection when coupled with the surface area of the mold creates a force that must be counteracted by the molding machine. The molding machine must be sized to handle this force to produce acceptable products.

Instructions

1.                            Sizing a Molding Machine

1
Determine the surface area of the part that is being molded in square inches. If it is a multiple cavity mold, the surface area associated with each cavity along with the runners that feed each cavity should be included in the total surface area.
2
Determine the planned injection pressure in pounds per square inch (psi). The injection pressure will be a function of the material that you are using and the part wall thickness. A material supplier can help determine the injection pressure.
3
Determine the pressintensification ratio for the molding machine. This is a function of the machine's screw and the hydraulic piston that acts upon it. The machine supplier can provide this information if it is not already known.
4
Multiply the injection pressure by the intensification ratio. This provides the plastic packing pressure in psi.
5
Multiply the plastic packing pressure by the part surface area. This results in the total pounds of force that will be exerted on the mold in pounds.
6
Divide the pounds of force by 2,000 (2,000 pounds = 1 ton). This provides the tons of force required to be offset by the molding machine's clamp tonnage. This gives the minimum clamp tonnage size needed for a molding machine for the specific product in question.
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How to Generate Runner Sizes for Plastic Injection Mold Design


How to Generate Runner Sizes for Plastic Injection Mold Design

The runner feeds the molten plastic from an injection machine into the mold to form the desired plastic part. The length of the runner is completely dependent on the part design, so there are no specific rules regarding overall length. It is the diameter of the runner that impacts part quality and cost and therefore it should be sized with some care. Once the runner freezes, no more plastic can be injected into the part. The runner should be sized to make sure that part receives sufficient plastic without excessive fractional heating, while freezing quickly enough to minimize cycle time.

Instructions

1.                            Calculating Runner Diameter

1
Determine thickest cross-section of the desired part.
2
Where part design allows, locate runner nearest to the thickest cross section of the part. If the part is of a uniform thickness, locate the runner near the center or along the longest edge, as part design allows.
3
Runner diameter should be between 75% to 100% of the part thickness where the runner is located.
4
Based on your injection machine type, determine the acceptable pressure drop for an injection cycle.

2.                            Calculate Injection Pressure Drop

5
Calculate runner volume. V = pi x r^2 x L, where pi = 3.14159, r = runner radius and L = runner length.
6
Calculate volumetric flow rate (Q) based upon your pre-determined fill time. The fill time is a function of material type, part thickness, and desired cycle time. The molder must know this independent of this exercise. Q = V/t, where t = seconds of fill time.
7
Calculate shear rate (S). S = 4Q/(pi x r^3)
8
Calculate the pressure drop (P). P = (S x m x 2L)/r, where m = melt viscosity of the plastic. The melt viscosity is a function of S, melt temperature, and the material. The molder must know this independent of this exercise, although many plastic suppliers can help with this.
9
Compare pressure drop to predetermined acceptable pressure drop. If improvement is desired, change the runner diameter and repeat the exercise. Repeat calculation until an acceptable runner diameter is found.
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2014年5月29日星期四

The Plastic Manufacturing Process


The Plastic Manufacturing Process

1.                            Plastic Injection Molding Process


Injection molding is one of the main methods by which parts are manufactured from plastic. The first step in the injection molding process is to feed plastic pellets into the hopper, which then feeds the pellets into the barrel. The barrel is heated and contains a reciprocating screw or a ram injector. A reciprocating screw is typically found in machines that produce smaller parts. The reciprocating screw crushes the pellets, making it easier for the plastic to be liquefied. Toward the front of the barrel, the reciprocating screw propels the liquefied plastic forward, thereby injecting the plastic through a nozzle and into the empty mold. Unlike the barrel, the mold is kept cool to harden the plastic into the correct shape. The mold plates are held closed by a large plate (referred to as a movable platen). The movable platen is attached to a hydraulic piston, which puts pressure on the mold. Clamping the mold shut prevents plastic from leaking out, which would create deformities in the finished pieces.

2.                            Plastic Extrusion Molding Process


Extrusion molding is another method of manufacturing plastic components. Extrusion molding is very similar to injection molding and is used to make pipes, tubes, straws, hoses and other hollow pieces. Plastic resin is fed into a barrel where it is liquefied. A rotating screw propels the liquefied plastic into a mold, which contains a tube-shaped orifice. The size and shape of the tube determines the size and shape of the plastic piece. The liquefied plastic then cools and is fed through an extruder, which flattens the plastic and forms the piece into its final shape.

Issues That Arise in the Plastic Manufacturing Process

A number of complications can arise during the plastic manufacturing process, including burned parts, deformities, surface imperfections and brittle parts. Parts become burned when the molds are not kept cool or if the melting temperature in the barrel is too high. Additionally, if the reciprocating screw becomes jammed or is not rotating fast enough, liquefied resin will remain in the barrel too long and become scorched. Surface imperfections and deformities occur when the surface temperature of the mold is uneven, if the molds are not clamped tightly enough or if the melting temperature is too high. Brittle pieces are formed when not enough liquefied resin is injected into the mold or if the plastic hardens before the mold can be filled. Regular testing and calibration of injection and extrusion molding machines is critical to ensure that the process runs smoothly.
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Two Different Types of Injection Molding


Two Different Types of Injection Molding

Injection molding is a manufacturing process for producing high volumes of finished parts at a low cost per part. Various plastic or rubber parts are produced in a wide range of colors. The injection molding machine injects heated molding material to the part mold through input channels. The two principal types of injection molding machines use either a cold runner channel or a hot runner channel.

Cold Runner Machines

Cold channel injection molding machines cool the entry channel, or runner, after each part is molded and ejected. During each molding cycle a part is produced with material in the runner channel. After the part is ejected, the runner is waste material and must be separated from the molded part. Runner waste is reground and reused or thrown away. Disposed material affects part cost. Reground and reprocessed material may affect part quality. Changing part colors in a cold runner machine is fairly easy since each ejected parts carries the material with it. Cold runner machines offer the advantages of cheaper mold designs, lower maintenance costs and lower operator skills.

Hot Runner Machines

Hot runner injection machines keep the runner portion of the mold hot. This reduces or eliminates runner scrap material, which may reduce part costs. Hot runnermachines are more expensive than cold runner machines. Hot machines require more skilled operators and require costly maintenance. Changing colors in hot runner machines is difficult because material is hard to remove from the runners. Hot runner machines eliminate wasteful runner scrap and the need to separate them from molded parts.

Changing Injection Molding Technology

Until recently, all injection molding machines were hydraulic devices. Newer machines are operated by an all-electric process or a hybrid combination of both technologies. Each injection molding process has an advantage. Hydraulic injectors offer high injection rates. Electric injection machines produce precision parts accurately and consistently. Hybrid machines are best suited to part positioning accuracy and repetitive parts. In a paper presented in May of 2008 to the Energy Technology Conference at New Orleans, Amit Kanungo and Eric Swan, senior engineers for RLW Analytics stated, "though it is a challenge to choose a right machine for molder's processing needs, by most accounts in the near future, all-electric machines will dominate the injection molding industry in the U.S."

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2014年5月25日星期日

What’s hot runner mold?


What’s hot runner mold?

  It use an assembly of heated components in plastic injection molds that inject plastic into the cavities of the mold. There are two general types of runnerless molds  - the insulated system and the hot runner system. Hot runners mold retain the advantages of the insulated 
  runner system over conventional cold runner system and eliminate a number of the disadvantages. Hot runner system is one of the more important enhancements you can incorporate into a mold to improve molded part quality, reduce production times and remain price competitive
  Injection Mold with Hot runner Solution will use reliable hot runner system and mold design tools. Our engineering department work harder and quicker than any other supplier to offer you new design ideas and mold concepts using any kind of hot runner system.with long history of experience and reliability for plastic injection molding and hot runner mold manufacturing,  we can deliver the best solutions. 
  Although there are many hot runner manufactures , a few major components is same:
  1. Hot runner plate (MANIFOLD)
  2. Nozzle
3. Temperature Controller
  4. Auxiliary parts

  Advantage of hot-runner mold in injection molding industry  
 Why some many customer select hot runner to make injection mold .This is mainly due to such injection mold has following salient feature:
  Less plastic raw materials: in the age of expensive oil and raw materials . hot runner technology is the effective way to reduce the materials cost.
  Quickly cycle time for injection molding, Due to no cooling time constrains runner system.
  Plastic can be more uniform state injection into each cavity, the result is consistent quality
  parts. Such injection molding components of good quality and low residual stress after ejection part distortion. reduce product costs, improve product quality

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2014年5月22日星期四

What Is Injection Molding Used for?


What Is Injection Molding Used for?


Injection molding is used for manufacturing plastic, rubber and metal. Materials are fed through a heated barrel in the machine and forced into a mold where it will cool and take its shape. An injection molding machine can stamp out metal car shell parts, rubber valve steam seals, and even plastic toys for kids.

 

Plastic


Injection molds uses plastic to make toys for children, milk containers and movie cases. It also makes other plastic products such as combs, kitchen utensils and dust pans.

Rubber

Injection molds make many rubber automobile parts. It makes valve steam seals and oil seals for the engine. It also makes earplugs, rubber hoses and telecommunications items.

Metal

Injection molds can stamp out small to large items. It can stamp out automobile parts from spark plugs and floor pans to ball bearings. It also can stamp out items like TV hangers and knitting needles.
 
 
 
 
 

2014年5月21日星期三

injection molding (2)

injection molding

 

Injection molding is a plastic manufacturing process whereby granules of plastic are heated until they melt and are then forced into a specially designed mold. Once in the mold the plastic is allowed to cool and hardens into the form of the mold. Injection molding is widely used in industry to produce plastic artifacts like computer casings, toys and cookware.

Barrel

·                                 The key part of an injection molding tool is the barrel. This is a metal cylinder that houses the reciprocating screw. The plastic granules are emptied into the barrel via the hopper and while in the barrel a combination of heat from the heaters and friction from the reciprocating screw liquidizes the plastic pellets. At the end of the barrel is an injection nozzle, through which the molten plastic is injected into the mold.

Reciprocating Screw

·                                 The reciprocating screw sits inside the barrel of the injection molding device. This tool rotates and forces the plastic pellets through the barrel and into the mold. In appearance, the reciprocating screw is roughly cylindrical, tapering slightly to a point at one end. Its outer surface is shaped into a screw thread.

Hopper

·                                 The hopper is a tool used to store the plastic granules before they enter the barrel. It consists of a large funnel into which the plastic granules are deposited before they enter the barrel.

Heater

·                                 The heaters sit around the barrel and raise the temperature of the plastic granules to the point at which they melt. This enables the molten plastic to be injected into the mold. The heaters sit wrapped around the cylinder and are powered by electricity.

Mold

·                                 The mold and the corresponding mold cavity determine the final shape of the injection molded artifact. There are certain limitations on the design of the mold and the design of the molded artifacts caused by the necessity of being able to remove the artifact once it has solidified.

Mobile Platen

·                                 The platen is a mobile flat plate that is used to push the mold and the mold cavity together. This ensures that the molten plastic migrates to every part of the mold and mold cavity. The platen is held in place against the mold by a clamp.

Clamp

·                                 The purpose of the clamp is to hold the mold and the platen as close together as possible while the molten plastic is setting into the final shape of the injection molded artifact. The clamp is often adjustable so the pressure on the platen can be increased to ensure that the molten plastic has reached every part of the mold cavity.

c

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2014年4月13日星期日

development of automobile and motorcycle mold in China


According to reports , automobile, motorcycle industry has an annual demand of more than 450 million molds , and our country large precision mold manufacturing capacity is not enough , China's current high profile car cover mold almost dependent on imports , and medium-sized interior and exterior trim pieces of plastic injection mold is also a great demand . Development of large-scale high-tech precision automobile, motorcycle cover mold and medium-sized interior and exterior trim plastic mold is an important task in the future of the automotive, motorcycle mold.

In China 's mold market , the development of the automobile mold is a top task. Because automobile and motorcycle industry is one of the five pillar industries of the national economy in China .From the economic development law, China's automobile and motorcycle industry into the " economic take-off " stage , so the production and sales , will inevitably bring about strong domestic economy , Auto mold to a huge market .

According molding material web is understood that with the rapid growth of China's automobile, motorcycle exports, plastic injection molds and metal instead of wood , make plastic mold in the automotive and motorcycle industry increased demand , especially new materials and new molding technology development , plastic products such demand in the automotive, motorcycle industry is increasing.

Auto mold -related research reports

2013-2018 domestic automobile mold industry forecast market size and depth profiling report

November 2013

2013-2017 automotive mold industry private equity business plan

China auto mold manufacturing industry investment strategy and depth of research and consulting reports 2013-2018

Chinese automobile mold industry market research and trends forecast report 2013-2018


In a certain extent, automobile, motorcycle plastic products can reflect the amount of a country's level of car and motorcycle industrial development. For example : Germany per vehicle on average use of plastic products has reached nearly 300 kilograms , accounting for about 22% of the total consumption of materials, automobile , motorcycle plastic parts is the largest country in the world uses . The average use per vehicle in Japan has reached about 100 kg of plastic , but they are the instrument panel and other interior trim parts used in all plastic products.

Currently, the automobile , motorcycle plastics applications have been developed by the ordinary decorative pieces to the structure, functional pieces . The use of plastic materials has also been extended to the ordinary plastic with high impact resistance even better composite or plastic alloy , and can appear , along with plastic material and improve the technology and process of forming , plastic products in the automotive, motorcycle application of the car industry will become more common, will inevitably lead to large-scale development of automobile and motorcycle mold.