PTFE pipe introduction

PTFE pipe introduction

       The forming process of the PTFE pipe has a pressing method, an extrusion method, a hydraulic method, a welding method, a winding method, and the like, and the pressing method is mainly used. Generally, a dispersed PTFE resin having a particle diameter of 500 μm and an apparent density of 0.45 g/ml to 0.55 g/ml is used. The small diameter tube is made of a resin with a relatively large compression, and the large and medium diameter tube is made of a resin with a relatively small compression. The propellant is usually selected from solvent oils No. 200 and No. 260. The PTFE pipe is subjected to secondary processing to obtain a PTFE heat shrinkable pipe, a PTFE spiral pipe, a PTFE steel wire reinforced hydraulic pipe, and the like.

      1.1, Teflon ordinary tube

The Teflon common tube is made by pressing a polytetrafluoroethylene dispersion resin at a normal temperature with an organic solvent as a squeezing agent, and then drying and sintering. According to the size of the pipe diameter, it can be divided into two types: ordinary pipe and micro pipe. Ordinary tube inner diameter > 4mm, micro tube inner diameter ≤ 4mm.

      Typical formulations for the production of PTFE tubes:

      Dispersed PTFE resin: 100 parts by weight

      Squeezing agent: 18~24

      Production process:

      PTFE, squeezing agent → mixing → pressing → drying → sintering → cooling → product.

      Production process parameters:

      Mixing: Temperature ≤19 °C, time 10min~20min, mixing at 25 °C ~ 30 °C for more than 24h.

      Billet: The compression rate is about 50mm/min and the pressure is 0~3MPa.

      Pushing: the temperature of the cavity is 30 °C ~ 50 °C, the die temperature is 50 °C ~ 60 °C, the pushing rate becomes smaller with the increase of the pipe diameter, and accelerates as the wall thickness becomes smaller.

      Drying: below 210 °C, 2h~3h

      Sintering: batch sintering, heating rate 60 °C / h, 375 °C ± 5 °C for 4h.

Continuous sintering, drying zone 100 °C ~ 250 °C, preheating zone 250 °C ~ 330 °C, sintering zone 380 °C ~ 420 °C, cooling zone less than 300 °C.

      Main equipment: mixer, pre-former, vertical pusher, drying and sintering furnace.

Uses: as insulation and conveying fluid conduits.

      1.2, Teflon heat shrinkable tube

      The PTFE heat shrinkable tube has the property of being heat-shrinked, so it can be tightly coated on the surface of other workpieces, making the workpiece corrosion-resistant, electrically insulating and anti-adhesive. Widely used in electrical, chemical, mechanical, printing and other industries. The maximum shrinkage of PTFE heat shrink tubing is reported to be greater than 75%.

      Made of dispersed PTFE resin, the principle is that PTFE is subjected to stress during processing to produce forced high elastic deformation. This deformation is reversible, and the low temperature makes it freeze. If reheated and frozen, the forced high elastic deformation will gradually disappear and Revert to the original state.

      Typical formulations for the production of PTFE heat shrink tubing:

      Dispersed PTFE resin 100 (parts by weight)

Squeezing agent 20～22

   Production process:

PTFE resin, extrusion aid → mixing → storage → preforming → pressing → drying → sintering → cooling → heat treatment → inflation → cooling → product.

Production process parameters:

The front part is the same as a normal PTFE tube.

Heat treatment: The process of quenching the dried and sintered pipe again after further sintering at a high temperature again, the temperature is 390 °C ± 2 °C, and the coolant is - 5 °C.

Inflation: At about 310 °C, it is filled with a compressed gas of 0198 MPa or less, and the inflation rate is 200% to 400%.

Main equipment: Inflator, the other is the same as ordinary PTFE tube.

1.3, PTFE steel wire reinforced hydraulic pipe

       The ordinary PTFE tube will be ruptured under the pressure of about 40kg/cm2. When it is combined with the steel wire, the pressure resistance is greatly improved, and the maximum working pressure in foreign countries reaches 700kg/cm2. Studies have shown that the compressive strength and pulse strength of the hose are not only related to the strength of the steel wire, but also to the size of the braiding angle. When the weaving angle of the single layer weaving is 54° 44′′, the steel wire does not elongate under the internal pressure, and the length and diameter of the hose do not change, and the pressure resistance is the best.

When used as a hose for aerospace industrial hydraulic systems, in order to prevent static breakdown of the inner tube due to the flow of hydraulic oil, a small amount of conductive carbon black must be added during the manufacture of the PTFE inner tube. However, studies have found that the addition of carbon black does not completely prevent static electricity from discharging through the tube wall and increases voids.

       In the 1960s, Attas manufactured a composite tube, in which the inner layer of the tube was a uniform mixture of conductive carbon black and PTFE, and the outer layer of the tube was pure PTFE. This form of inner tube layer has axial electrical conductivity, so it can remove static electricity and prevent seepage.

       Its process:

       Inner layer resin (including conductive carbon black), outer layer resin → compact → push → dry → cooling → inspection → weaving → fitting → inspection.

       PTFE steel wire composite hoses are mainly used in hydraulic systems, air-conditioning systems, fuel systems, and oil systems on aircraft. In the civil industry, it is suitable for rubber, plastic, pharmaceutical, clothing, shipbuilding, automotive, machine tools, motors, diesel, paper and other industries for hydraulic, steam pressure, steam delivery and other soft connectors.

1.4, PTFE spiral tube

PTFE spiral tube, also known as PTFE flexible hose, has flexible properties in addition to all the excellent properties of PTFE. At present, there are two types of pure PTFE spiral tubes and chemical fibers, stainless steel wires and plastic coated glass fibers.

       It is made by PTFE whole secondary processing, which is made by continuously rotating the PTFE thin-walled tube continuously through a combined mold with a temperature of 270 °C ~ 280 °C at a certain speed.

       It is mainly used for the connection of the flexible connection of the corrosion-resistant and high-temperature resistant equipment, the misalignment connection, the serpentine pipeline, the pump engine and other shocking components. Shielded cables and protective cable bushings for aircraft engines.

A Simple Guide To Plastic Molding

So you need a custom plastic part or product, but you don’t know how to get it made.

Is it large or small? Should it be flexible or stiff? Is it round, square, or some weird shape? Do you already have a mold, or do you need to have one made?

This guide will explain the different kinds of molding processes available today to help you discover the ideal process for your product.

What Is Plastic Molding?

Molding, also sometimes spelled moulding, is the process of manufacturing by shaping liquid or pliable material using a rigid frame called a mold or matrix.

When molding plastics, a powder or liquid polymer such as polyethylene or polypropylene is placed into a hollow mold so the polymer can take its shape. Depending on the type of process used, various ranges of heat and pressure are used to create an end product.

The History of Plastic Molding

Plastic molding began in the late 1800’s to fill the need for plastic billiard balls as opposed to the commonly used ivory billiard balls of the time. In 1868, John Wesley Hyatt invented a way to make billiard balls by injecting celluloid into a mold. Four years later, Hyatt and his brother invented and patented a machine to automate the process. This was the first plastic injection molding machine in existence and it used a basic plunger to inject plastic into a mold through a heated cylinder.

In 1946, the screw injection molding machine was invented by James Hendry, which replaced the plunger injection technique. This is the technique most commonly used today.

Modern rotational molding also has a rich history beginning in 1855 when rotation and heat were used to produce metal artillery shells in Britain.

Plastics were introduced into the process in the early 1950’s, when rotational molding was first used to manufacture doll heads. And then in the 1960’s the modern process of rotational molding that allows us to create large hallow containers with low-density polyethylene was developed. In recent history, process improvements, better equipment, and plastic powder developments have sped up the process of creating finished products which has caused rotational molding to grow rapidly in popularity.

The Types of Plastic Molding

The most popular techniques in plastic molding are rotational molding, injection molding, blow molding, compression molding, extrusion molding, and thermoforming. We’ll cover all these techniques in this guide to help you discover the best process to make your part or product.

Rotational Molding

Rotational Molding, also called rotomolding, is a manufacturing process for producing large hollow parts and products by placing a powder or liquid resin into a metal mold and rotating it in an oven until the resin coats the inside of the mold. The constant rotation of the mold creates centrifugal force forming even-walled products. Once the mold cools, the hardened plastic is removed from the mold.

Very little material is wasted during the process, and excess material is often re-used, making it economical and environmentally friendly.

Common Uses for Rotational Molding

Rotational molding is commonly used to make large hollow plastic products like utility carts, storage tanks, car parts, marine buoys, pet houses, recycling bins, road cones, kayak hulls, and playground slides.

Rotational Molds Are Highly Customizable And Cost Effective

The mold itself can be highly intricate to facilitate the molding of a wide range of products. Molds can include inserts, curves, and contours as well as logos and slots for plastic or metal inserts to be placed after a product is molded.

Tooling costs are lower with rotational molds than injection or blow molds. The results are lower start-up costs and cost-effective production runs even when producing as few as 25 items at a time.

Injection Molding

Injection molding is the process of making custom plastic parts by injecting molten plastic material at high pressure into a metal mold. Just like other forms of plastic molding, after the molten plastic is injected into the mold, the mold is cooled and opened to reveal a solid plastic part.

The process is similar to a Jello mold which is filled then cooled to create the final product.

Common Uses for Injection Molding

Injection molding is commonly used for making very high volume custom plastic parts. Large injection molding machines can mold car parts. Smaller machines can produce very precise plastic parts for surgical applications. In addition, there are many types of plastic resins and additives that can be used in the injection molding process, increasing its flexibility for designers and engineers.

Injection molds, which are usually made from steel or aluminum, carry a hefty cost. However, the cost per part is very economical if you need several thousand parts per year.

With injection molding, tooling usually takes 12-16 weeks with up to four more weeks for production.

Blow Molding

Blow molding is a method of making hollow, thin-walled, custom plastic parts. It is primarily used for making products with a uniform wall thickness and where the shape is important. The process is based upon the same principle as glass blowing.

Blow molding machines heat up plastic and inject air blowing up the hot plastic like a balloon. The plastic is blown into a mold and as it expands, it presses against the walls of the mold taking its shape. After the plastic “balloon” fills the mold, it is cooled and hardened, and the part is ejected. The whole process takes less than two minutes so an average 12 hour day can produce around 1440 pieces.

Common Uses for Blow Molding

Blow molding processes generate, in most cases, bottles, plastic drums, and fuel tanks. If you need a hundred thousand plastic bottles, this is the process for you. Blow molding is fast and economical with the mold itself costing less than an injection molding, but more than rotational molding … sometimes as high as 6 to 7 times as much as a roto-molding tool.

Compression Molding

Compression molding is done exactly like the name suggests. A heated plastic material is placed into a heated mold and then pressed into a specific shape. Usually, the plastic comes in sheets, but can also be in bulk. Once the plastic is compressed into the right shape, the heating process ensures that the plastic retains maximum strength. The final steps in this process involve cooling, trimming, and then removing the plastic part from the mold.

Common Uses of Compression Molding

The best use of compression molding is the replacement of metal parts with plastic parts. It is mostly used for small parts and products in very high volume. The automotive industry uses compression molding heavily because the final products are very strong and durable.

The initial cost of a compression mold is substantial, depending on several factors including the number of cavities, the size of the parts, the complexity of the pieces, and the surface finish among other things. But the cost of each individual part is low at high quantities, so large quantities of parts are ideal for this form of molding.

Extrusion Molding

Extrusion molding is similar to injection molding except that a long continuous shape is produced. Another difference in extrusion molding is that the process uses a “die” not a “mold.”

Extruded parts are made by squeezing hot raw material through a custom die. A simplistic visualization would be like squeezing Play Doh through a shaped hole.

While other forms of molding use extrusion to get the plastic resins into a mold, this process extrudes the melted plastic directly into a die. The die shape, not a mold, determines the shape of the final product.

Common Uses of Extrusion Molding

Parts made from extrusion have a fixed cross-sectional profile. Examples of extruded products include PVC piping, straws, and hoses. The parts do not need to be round but they need to have the same shape along the length of the part.

The cost of extrusion molding is relatively low compared to other molding processes because of the simplicity of the die and the machines themselves.

However, the nature of the extrusion molding process limits the kinds of products that can be manufactured with this technique.

Thermoforming

Thermoforming is a manufacturing process where a plastic sheet called thermoplastic is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. Thermoplastic comes in a wide variety of materials, colors, finishes, and thickness.

Thermoforming uses several different types of molds and processes in order to achieve the final product. To create 3D products, the mold is typically a single 3D form made out of aluminum. Because thermoforming uses low pressures, molds can be produced for a low cost using inexpensive materials.

Common Uses of Thermoforming

Thin-gauge thermoforming is commonly used to manufacture disposable cups, containers, lids, trays, blisters, clamshells, and other products for the food and general retail industries. Thick-gauge thermoforming includes parts as diverse as vehicle door and dash panels, refrigerator liners, and utility vehicle beds.

On average, it takes about 8 weeks to get a thermoform mold ready for production. The cost of a thermoform mold is based upon the size of the part that needs to be produced. A mold for a small part can cost as little as $20,000 while the cost of a larger mold can be upwards of $50,000.

Black PTFE rod ordered by Belgian customers to complete production and delivery

Black PTFE rod ordered by Belgian customers to complete production and delivery

A batch of black PTFE rods ordered by Belgian customers has been produced.

Our company can produce extruded rods and molded rods of various sizes according to customers' needs. we can produce different colors, increase the graphite powder of carbon powder, etc. The materials can choose new materials and recycled materials.

Company website：www.sukoptfe.com

Email：info@sukoptfe.com

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