The important features associated with plastic molding

The important features associated with plastic molding

Plastic molding, one of the most vital process required, is required to taken into utilize to shape plastic using a rigid frame or mould. Not to mention the way of using technique that allows for the creation of objects of all shapes and sizes with huge design flexibility for both simple and highly complex designs.

It starts with advanced techniques and placing liquid polymer into a hollow mould so that the polymer can take its shape – mainly with different ranges of pressure and heat required. You will get access to different plastic molding techniques that include rotational molding, injection molding, blow molding and compression molding to name just a few.

Plastic design

Plastic design process is not an easy part of the entire process. It is complicated and need assistance from top engineers and expert – who work in a planned way by focusing on various important things. Professionals who are working for plastic designs also remove uneven wall thickness by digging out material of triangle shape space and adding radius to compensate removed wall to reach even wall thickness.

Parts undercut are important that can’t be released from mold because of the undercut. You have to simply add a hole on top of undercut area. In order to make the plastic design process easier, they work on parts fitment. Original design is vertical tab that insert into plastic parts. Experts change tab into horizontal direction to ensure strong and unmovable fitment. They also provide you functional accuracy as injection molded parts can reach high accuracy

Injection molding machine

Use of injection molding machine is also important that depends on mold overall size, location ring, sprue bush, and ejection connector tap size with machine and a lot more. Waterline layout and nipple size, cavity layout, runner layout and weight, Mold steel type and hardness are some added features associated with it.

The most detailed mold test report is another important feature associated with plastic molding that assures easy and fast setting in mass production at client site.

Reaching the right and reputed plastic mold factory is important where you will get complete solutions for this process that is a popular manufacturing option – responsible for many car parts, containers, signs and other high volume items.

POM Material Injection Molding

POM Material Injection Molding

Polyoxymethylene (POM) is a thermoplastic material also known as acetal. POM-H (polyoxymethylene homopolymer), POM-K (polyoxymethylene copolymer) is a high density, high crystallinity thermoplastic engineering plastic with good physical, mechanical and chemical properties, especially with excellent friction resistance.

POM is a crystalline plastic with a sharp melting point. Once the melting point is reached, the melt viscosity drops rapidly. Decomposition occurs when the
temperature exceeds a certain limit or the melt is heated for too long.

Copper is a POM degradation catalyst. Copper should be avoided where it is in contact with the POM melt.

 1. Plastic processing

POM has a small water absorption, generally 0.2%-0.5%. Under normal circumstances, POM can be processed without drying, but it must be dried for wet
materials. The drying temperature is above 80℃ and the time is more than 2 hours. The specific conditions should be based on the supplier’s data.

The proportion of recycled materials used is generally not more than 20-30%. However, depending on the type of product and the end use, it can sometimes be up to 100%.

2. The selection of plastic machine

In addition to the requirement that the screw has no stagnant area, the POM has no special requirements for the injection molding machine, and generally
can be injection molded.

3. Mold and gate design

The common mold temperature is controlled to 80-90℃, the runner diameter is 3-6 mm, the gate length is 0.5 mm. The gate size depends on the thickness
of the wall, and the circular gate diameter should be at least 0.5-0.6 times the thickness of the product. The width of the rectangular gate is usually 2 times
or more of the thickness, the depth is 0.6 times the wall thickness, and the draft angle is between 40′-1º30′.

Exhaust system

POM-H thickness 0.01-0.02mm width 3mm

POM-K thickness 0.04mm width 3mm

4. Melting temperature

POM-H can be set to 215℃ (190℃ – 230℃)

POM-K can be set to 205℃ (190℃ – 210℃)

5. Injection speed

Medium speed. If too slow, it produces ripples. If too fast, it is easy to produce grain and shear overheating.

6. Back pressure

The lower the better, generally no more than 200bar

7. Stay time in barrel

POM-H can be held at 215℃ for 35 minutes

POM-K can stay in 205℃ for 20 minutes without decomposition.

POM-K can be retained for 7 minutes at 240℃. If the machine is shut down, the barrel temperature should be lowered to 150℃. If you want to stop for a
long time, you must clean the machine and turn off the heater.

8. After machine stops

The cleaning barrel must use PE or PP. Turn off the heating and push the screw in the front position. The barrel and screw must be kept clean. Impurities or dirt can change the thermal stability of the POM (especially POM-H).

9. Post processing

For very warm parts and high quality requirements, heat treatment is required.

The annealing treatment effect can be carried out by immersing the product in a hydrochloric acid solution having a concentration of 30% for 30 minutes,
and then visually discriminating whether cracks have residual stress.

Analysis of uneven color of injection molded products

Analysis of uneven color of injection molded products

The reasons and solutions for the uneven color of injection molded products:

1. The colorant is poorly diffused, and this often causes a pattern to appear near the gate.

2. The plastic or colorant has poor thermal stability. To stabilize the color tone of the part, it is necessary to strictly fix the production conditions, especially the material temperature, the amount of material and the production cycle.

3. For crystalline plastics, try to make the cooling speed of each part of the parts consistent. For parts with large difference in wall thickness, coloring agent can be used to mask the chromatic aberration. For the parts with uniform wall thickness, the temperature and mold temperature should be fixed. .

4. The shape and gate form of the part, the position has an influence on the filling condition of the plastic, so that some parts of the part have chromatic aberration and should be modified if necessary.

Analysis of the causes of color and gloss defects of injection molded products

Under normal circumstances, the gloss of the surface of an injection molded part is mainly determined by the type of plastic, the colorant and the finish of the mold surface. However, due to some other reasons, the surface color and gloss defects of the product and the dark color of the surface are often caused. The reasons for this and the solution are as follows:

1. The mold has poor finish, the surface of the cavity has rust, etc., and the mold is poorly exhausted.

2. The casting system of the mold is defective. The cold material well should be enlarged, the flow channel should be enlarged, the main flow channel should be polished, the runner and the gate should be polished.

3. The material temperature and the mold temperature are low, and the local heating method of the gate can be used if necessary.

4. The processing pressure is too low, the speed is too slow, the injection time is insufficient, and the back pressure is insufficient, resulting in poor compactness and darkening of the surface.

5. The plastic should be fully plasticized, but the degradation of the material should be prevented, the heat should be stable, and the cooling should be sufficient, especially thick-walled.

6. Prevent cold material from entering the part, and if necessary, use a self-locking spring or lower the nozzle temperature.

7. Excessive recycled materials are used, plastic or colorant is of poor quality, mixed with water vapor or other impurities, and the quality of the lubricant used is poor.

8. The clamping force should be sufficient.

Injection Mold Maker for Making Injection Molding Process Easier

Injection Mold Maker for Making Injection Molding Process Easier

Are you looking for high-grade and advanced injection mold machines or complete solutions for injection molds?

Such questions are very common in manufacturing units – mainly those where molding is an important work to give the right shape and design to any machinery, tool or equipment. A selected injection mold maker brings to you a gamut of solutions that are working dedicatedly to bring to you complete solutions. There is no denying the fact that injection mold is so expensive – not only in cost, but also in time. An injection mold maker takes the responsibility of doing everything from very beginning to end.

They provide you complete solutions and injection mold machine – related to mold overall size, location ring, sprue bush, ejection connector tap size with machine and solutions for parts related to gate, parting line and ejection. You will get mold related to waterline layout and nipple size along with cavity layout, runner layout and weight along with mold steel type and hardness.

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Not to mention CAE analysis and know problem a bit early in some case, where CAE is necessary to prevent problems in advanced instead of after mold construction.

You will also get detailed mold test report that assures easy and fast setting in mass production at client site.

Reaching the right company or a selected injection mold maker is important. Online search is one of the time-saving and convenient way to help you in reaching the right one. Among some of the top companies, you will find name of Jazz Mold comes on the top. You have to contact as per your requirement and leave rest of the work on experts working here.

UPVC Injection Molding Setting

UPVC Injection Molding Setting

UPVC, also known as hard PVC, is an amorphous thermoplastic resin made by polymerizing vinyl chloride monomer with certain additives (such as stabilizers, lubricants, fillers, etc.).

In addition to the use of additives, the method of blending and modifying with other resins has been adopted, which has obvious practical value. These resins are CPVC, PE, ABS, EVA, MBS, etc.

UPVC has a high melt viscosity and poor fluidity. Even if the injection pressure and melt temperature are increased, the fluidity does not change much. The molding temperature is very close to the thermal decomposition temperature, so the temperature range is narrow. It is a difficult material of molding.

1. Plastic processing

After 24 hours at room temperature, the amount of water absorption is less than 0.02%, so there is no need to dry. If it must be dried, it can be placed in dryer at 60-70 °C for 3 hours, or at 80 ° C for 1-1.5 hours.

Recycled materials can be mixed with up to 20% of the new material, depending on the end use of the product. Abuse of recycled materials can cause injection molding to fail, not only because there are too many recycled components, but also because the materials are reprocessed many times.

2. Injection molding machine selection

UPVC has a high viscosity and easy decomposition, and the decomposition products have a corrosive effect on iron. The screw and barrel is special designed, and extra fan on barrel may be required.

3. Mold and gate design

The mold temperature can be set 40°C. The length of the flow path is short and the diameter is large to reduce pressure loss and keep holding pressure. The shorter the gate, the better. The gate cross section should be round, the diameter is at least 6 mm, and the shape is conical, and the inner angle is 5° degree.

The runner cross section is also round and 7mm diameter.

The mold is stainless steel with a chromium content of at least 13%, preferably 16%, and a Rockwell hardness of at least 55. The mold can be chrome-plated to form protection against corrosion.

4. Melt temperature

It varies from 185-205 °C. The exact melt temperature of the UPVC can be known from the smoothness of the injected material. If the material is rough,  the material is not uniform (insufficient plasticization), indicating that the temperature is too low; if the foam is emitted after the injection and a large amount of smoke is emitted, the temperature is too high.

5. Injection speed

The injection speed need to be slow, otherwise excessive shearing will degrade the material. When UPVC is used to produce extremely smooth thick-walled products, multi-stage injection molding speed should be used.

6. Screw speed

Should be in accordance with the molding cycle. The screw surface speed should not exceed 0.15-0.2m/s

7. Back pressure

Up to 150 bar, but the lower the better. The common is 5 bar.

8. Material residence time in barrel

At 200 °C, the residence time can not exceed 5 minutes. When the temperature is 210 ° C, the residence time can not exceed 3 minutes.

Reach right plastic mold factory to get services and processes

Reach right plastic mold factory to get services and processes

Plastic molds are important industrial products in order to shape and mold plastic before it results to a more viable and feasible product in the market. It commonly undergoes injection molding in various forms but the most popular technique is forcing a plastic liquid into a metal mold. The molding is made through the use of molten plastic that cools while it is inside the mold.

Plastic molds are used in order to lessen down the costs related to various manufacturing processes. This technology is favored because of the quick turnaround time in the procedure. A variation known as reaction injection molding is also used for fiberglass, epoxy and polymer plastic. Here are ideas on the services, processes and equipment design employed in the manufacture of these products.

Plastic molding services result from rotational molding, blow molding, thermoforming and compression molding. Other services include mold prototyping, insert molding, micro-molding, two- shot injection molding, machining and hot stamping. These services have characteristics that make them distinct from one another.

For instance, machining is that phase where the molds are removed through drilling, milling or turning. Micro-molding is known to use special and mini molding machines in order to produce small parts out of the process. The parts produced out of these services are commonly less than two grams in weight. In a two- shot injection, a plastic product is produced from two sets of raw materials through the use of only one operation.

Plastic molding processes

Plastic molds cannot be completed without undergoing some processes. First on the list is the development of a three-dimensional or 3D CAD model. The making of a computer model is that point when a manufacturer may ask a consumer for concepts and prototypes to see if they are good enough for the production of plastics.

Machines for injection molding, blow molding and thermoplastic injection are a few examples of plastic mold factory equipment designs. The basic outputs from these machines include insulated runners as well as CAM, encapsulating, stack and insert molds. This important aspect in manufacturing plastic molds is the fabrication of machineries to create the output. Barrels, liners, component and feeders are also created out of the equipment design. Along the process, special forms of equipment for different plastic mold services are formed.

Plastic molding, one of the most vital process required, is required to taken into utilize to shape plastic using a rigid frame or mould. Not to mention the way of using technique that allows for the creation of objects of all shapes and sizes with huge design flexibility for both simple and highly complex designs.

Reaching the right and reputed plastic mold factory is important where you will gt complete solutions for this process that is a popular manufacturing option – responsible for many car parts, containers, signs and other high volume items. There are a number of added features and benefits associated with it that will surely persuade you to reach the right factory that is involved in offering you complete and comprehensive solutions.