2023年12月1日发(作者：黑鲨手机官网首页)

各种常用成形工艺英汉对照

塑料成型

injection molding 射出成形 （注塑成型）

extrusion molding 挤出成形 （挤出成型）

calendaring molding 压延成形 （压延成型）

hollow(blow) molding 中空(吹出)成形

matched mould thermal forming 对模热成形

compression molding 压缩成形 （压制成型）

transfer molding 转送成形 （传递模塑成型）

slush molding 凝塑成形 （搪塑）

rotational molding 离心成形 （滚塑）

foam forming 发泡成形 （发泡成型）

dip mold 浸渍成形

encapsulation molding 注入成形 （封装成型）

matched die method 对模成形法

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Plastic Processing Methods

PROCESS DESCRIPTION

An extruded parison tube of heated thermoplastic is

positioned between two halves of an open split mold and

expanded against the sides of the closed mold via air

Blow吹塑

pressure. The mold is opened and the part ejected. Low tool

and die costs, rapid production rates, and ability to mold fairly

complex hollow shapes in one piece.

Dough-consistent thermoplastic mass is formed into a sheet

surface finish, and convenient for low-volume production.

Centrifugal

Reinforcement is placed in mold and is rotated. Resin

casting离心浇

distributed through pipe; impregnates reinforcement through

铸

centrifugal action. Utilized for round objects, particularly pipe

Process methods vary. Both thermoplastics and thermosets

widely used in coating of numerous materials. Roller coating

型 closed (heat and pressure are applied) and the material flows

and fills the mold cavity. Heat completes polymerization and

the part is ejected. The process is sometimes used for

thermoplastics. Little material waste is attainable; large, bulky

parts can be molded; process is adaptable to rapid

automation (racetrack techniques, etc.)

Mixed compound is poured into open molds to surround and

winding filaments, usually glass, in the form of roving are saturated

with resin and machine-wound onto mandrels having shape of

desired finished part. Once winding is completed, part and

mandrel are cured; mandrel can then be removed through

porthole at end of wound part. High-strength reinforcements

can be oriented precisely in direction where strength is

required. Good uniformity of resin distribution in finished part;

finished product; very economical in large production of parts.

A variation of the conventional compression molding this

process employs two metal molds possessing a close-fitting,

telescoping area to seal in the plastic compound being

Matched-die-

molded and to allow trim of the reinforcement. The mat or

molding

preform reinforcement is positioned in the mold and the molds

is closed and heated under pressures of 150-400 psi (1-3

Mpa). The mold is then opened and the part is removed.

predetermined time in order to achieve a specified buildup of

partially cured material on mold walls; mold is opened and

unpolymerized material is poured out; and semifused part is

removed from mold and fully polymerized in oven. Low mold

usually oven-cured without the application of pressure. In

spray molding, a modification, resin systems and chopped

fiber are sprayed simultaneously from a spray gun against the

mold surface. Wet-layup parts are sometimes cured under

pressure, using vacuum bag, pressure bag, or autoclave, and

depending on the method employed, wet-layup can be called

open molding, hand layup, sprayup, vacuum bag, pressure

bag, or autoclave molding. Little equipment required, efficient,

Casting: There are several methods and the most common are discussed

below:

(a) Cold Casting: Liquid plastics or resins are mixed with inert materials such as

clays, limestone or marble chips. The plaster-like material is then trowelled, or

otherwise applied to a thick shape or mold. After air curing the item is removed,

finished by grinding, sawing or filing.

Extrusion: In this process a continuous flow of molten plastic is formed through

a shaped opening called a die, and the plastic is then cooled. Depending onthe

shape of the opening, many different parts can be made. If the opening is like a

ring, a tube or pipe can be made. If the opening is a long thin slit, a sheet may be

formed. While the die determines the shape of the plastic flow, many different

methods are used "down stream" to make different types of parts. In some

instances a cooling bath may be used while at other times air jets, water sprays,

fans, vacuum pulling conveyor is used to pull the extrusion along the line. As the

part leaves the "take off" it may be sawed to special lengths, coiled, spooled,

sheared or punched, depending on the requirements of the piece.

Fabrication

Molding (or Forming): The term "molding" is often applied to operations that

do not involve power presses and probably are more accurately described as

"forming" or "fabrication." Code 4484 applies to the former; code 4452 to the

latter. There are a variety of methods and although not necessarily all-inclusive,

the listing below should describe most that would be encountered:

(a) Blow Molding: This is a modification of injection molding and presently

involves forming in one of two methods. The first involves extruding a tube of

heated soft plastic which is gravity fed into the open mold. The operation is timed

so that the molds are closed over the material, air is injected into it thereby

forcing the plastic to conform to the shape of the mold. The molds are then

the cycle the press is opened and the parts removed either by hand or by an

unloading tray. The parts are finished by cleaning the "flash" at the end of the

mold parting line by tumbling, filing, sanding or machining.

(d) Dip Molding

: This is an outgrowth of the latex dipping industry. Involves

dipping a mold into liquid plastic to form a deposit in the shape of the mold. The

deposit is then blown from the mold, cut to size and finished.

(e) Foam Molding:

A set of molds are mounted in a hydraulic or pneumatic

press. After the mold is closed, partially expanded beads of polystyrene are

amount of liquid is introduced into thin walled metal molds which are then closed

and placed in a heated oven. At the same time the molds are rotated so that the

liquid comes in contact with the entire inner surface of the mold. After sufficient

time, the molds are removed from the oven, opened and the hollow items with

an external shape like the inside of the mold are removed. The items are

through the contours of the mold without interference with the position of inserts

or other mold parts.

(j) Vacuum Molding: Sheets of plastic are softened in an oven, and then placed

over a mold of wood or metal. A vacuum is formed in the space between the

mold and the plastic sheet, and the plastic is drawn down to take the

conformation of the mold. After sufficient cooling time, the piece is removed. The

formed part must then be removed from the rest of the sheet by sawing or

stamping.

Filament Winding

: This method is used to produce tanks that can be quite

large or ducts for the chemical industry. Usually wooden molds are made and

main processes:

(a) High Pressure Laminating: This involves combining together with plastic

resins layers of fibrous materials such as fabric, paper, glass fibers or other

materials to form a sandwich which is fused in a press under high heat and

pressure which serves to cure the plastic and set the laminate into permanent

rigid form.

Plastic Families

There are two basic families of plastics: Thermoplastic materials and

Thermo set materials.

Thermoplastics soften and melt upon the addition of heat.

Upon removal of heat they then again stiffen and harden into a new shape.

The Thermoplastic family is what most people relate to when they think about

plastics because of the many domestic products that are produced from them.

What red blooded American male does not have first hand experience with

this family of plastics when as a child built Revelle models of boats, cars

or other objects and then lit them on fire only to end up with an amorphous

blob?

The injection molding technique was developed to efficiently process

this family of plastics into the many useful products we use everyday. Some

of the commonly used thermoplastics are polyethylene, polypropylene,

polystyrene, PVC, ABS and Nylon to name a few. There are countless other

engineered plastic materials and compounds to suit broad varieties of

applications.

Southwest Plastics

has extensive injection molding capabilities for

thermoplastic materials.

Thermosets harden and cure in the molding process as the molecules actually

crosslink in a chemical reaction and set into a final shape. No addition

of heat will soften or melt the material. As a result, thermosets have

their advantage in any high heat environment where softening or melting

cannot be tolerated. Domestically products such as ash trays, cooking

utensils and cookware handles are produced from thermosets. Industrially

thermosets are used in electrical, electronic and military applications.

Some examples of thermoset materials are phenolics, epoxys, melamines and

diallylphthalates.

Thermosets can be molded using the compression, transfer or injection

molding processes.

Southwest Plastics

has extensive capabilities in molding thermoset

materials using all three of these processes.

Processing Methods

In order to transform plastic materials into usable shapes, many methods

of processing plastics have been developed including the following:

Injection molding, compression molding, transfer molding, blow molding,

thermoforming, vaccu-forming, extrusion, and blown film. Each of these

processes require specific expertice and skill. has

Southwest Plastics

expertise in COMPRESSION, TRANSFER, and INJECTION molding.

Compression Molding is the first technique developed in the early 1900s

to mold Bakelite (phenolic) molding compounds. It is used today to process

many varieties of thermoset plastics and composites including phenolic,

epoxy, melamine, and diallyl phthalate. The compression molding press is

simply a vertically oriented hydraulic press. The compression mold is

clamped into the compression molding press, and is simple in that it

consists of two halves: the cavity and the force or core on the opposite

side. The mold is heated to the temperature as specified by the material

manufacturer which is usually around 300° F, and the material is placed

directly in the cavity. The mold is then closed under pressure compressing

the material and causing it to flow into the void between the cavity and

the core. The mold is held closed for several minutes (depending on the

material used and the wall thickness of the part) while the material is

curing or "setting" into the form of the mold surface. The mold is then

opened and the part ejected from the mold cavity. Compression molding

lends itself to relatively simple parts, but since there are no sprues,

runners or gates through which the material must flow, the material can

be heavily loaded with a composite of fillers and fibrous reinforcements

which remain in a random orientation in the molded part resulting in

superior strength properties.

Transfer Molding is another method for molding thermoset materials where

the design of the part is too complicated or unsuitable for compression

molding. Transfer molding is often used when metal inserts, studs,

connector pins wear plates, electronic components or other parts are molded

into the part. With transfer molding, the mold is clamped closed first.

The material charge is then loaded into a loading "pot" which is connected

to the cavity with a short runner. The material is then "transferred" from

the pot to the cavity via the runner under pressure exerted from a plunger

which is hydraulically actuated against the material which has been loaded

in the pot.

Injection molding is a high production method of producing a vast variety

of thermoplastic parts into shapes ranging from fairly simple to quite

complex. Injection mold cavities are fed with melted plastic material

which is forced under high pressure through a sprue which feeds a runner

system then through a gate into the cavity. The material is then cooled

to the point that the material is solid and then ejected from the mold as

a finished part. Certain thermoset materials can also be injection molded

after several modifications to the standard injection molding machine are

affected. The injection molding machine consists of two basic components:

the clamp unit and the injection unit. The clamp unit holds and clamps

the tool into position while the injection unit plasticizes and injects

the material into the mold which has been positioned by the clamp unit.

The clamp force must be sufficient to hold the mold closed against the

hydraulic pressure of the material being injected under high pressure by

the injection unit. The rule of thumb is that there must be three tons

of clamp force for every square inch of cavity projected area in the mold.

Both units are coordinated by a computer controller on the machine which

is programmed to efficiently to produce high quantities of consistent

quality parts on an automated cycle.

Southwest Plastics has been in business for over 50 years and has

extensive experience in both and materials. We

thermosetthermoplastic

have a state of the art facility and offer molding services using

compression, transferinjection molding

and techniques. Let us work with

you on your next project so we can become your "plastics partner".

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Da/Pro Rubber, Inc. offers compression molding of rubber compounds.

Compression molding consists of a top and bottom plate mold that is machined

to a custom configuration (fig. 1). An elastomer preform is added between the

plates and the plates are compressed under heat and pressure for a specific

amount of time. The Da/Pro process monitors variables closely and adjusts to

compensate for variable differences during each cycle. After the elastomer is

cured properly, the mold is opened, the part is removed, the mold cleaned and

the cycle repeated.

Fig. 1

Da/Pro Rubber, Inc. offers transfer molding of rubber compounds. Transfer

molding consists of a mold cavity similar to a compression mold. In addition, the

Each process has advantages and disadvantages. Our experienced staff of

engineers, chemists and salesmen can answer all of your questions and

concerns with any of your molding needs - contact us

.

Compression Molding

Compression Molding has been used for many years and is a common

method for thermosetting plastics or permanently hardening plastics by

heating them. Compression Molding has been used in the auto industry

desired shape. The two halves of the mold are then opened and the part

created is removed.

Advantages

Compression Molding has many advantages over similar processes. For

example, molds for Compression Molding are often simpler than molds

for injection molding or other comparable molding methods. These

molds also tend to be less expensive, require less maintenance, create

Although less expensive for high volume, Compression Molding

requires a high initial investment. As mentioned before, the metal die

used for the mold may be expensive. However, if produced or acquired

correctly, this cost should be a one-time investment.

Compression Molding can also be labor intensive. Perfecting the mold at

the beginning of operations can be time consuming and require

secondary operations. However, this should only be an initial bother as

the mold will continue to operate as desired once set up properly.

dramatically in price, chances are you have not provided specific

enough information to rule out misunderstandings.

Also, be on the lookout for quotes that do not contain a separate tooling

charge or a non-returnable tooling charge. These red flags could mean

that you do not actually own your tool. To make sure the manufacturing

remains in contact with the liquid Plastisol until the heats penetrates to 1/16 or 1/8"

depth. The heated PVC particles swell, absorb the plasticizer, and then come in contact

with each other. From there, the dip mold is then removed from the plastisol. In slush