Last Saturday is the Beginng of Spring, our factory had a big dinner together.
We made a short summary of 2022 and had awards for our excellent colleagues. Even though the year 2022 was hard, our factory still had good performance. Here we appreciate all our customers trust and support to our factory.
After 10+ years cooperation together, our team is more and more stronger now, I believe we will have a bright future together.
Cheers for our good harvest and progresses! Cheers for the new year 2023!
Injection molding is a popular manufacturing process, which can quickly produce complex-shaped precise parts without wasting a lot of materials.
Many different processes belong to the category of injection molding, including over-molding and two-shot molding. The two processes are similar, but there are some key differences-here are what engineers and designers need to know:
What is two-shot molding?
Two Shot Injection Molds, also known as dual-molds, double-shot molds, or multi-shot molds, are a subcategory of injection molding that allows engineers to create multi-material or multi-colored parts without adding additional assembly steps.
Through the different layers of materials or colors created by the injection molding machine, the two-shot injection molding process is best understood. The first material is injected into the mold to create the substrate, and other materials or materials will be molded around the substrate. After the substrate solidifies and cools, it is transferred by hand, robotic arm, or rotating plane to another cavity of the mold.
From there, the mold opens and rotates 180° with one side of the substrate to meet the other mold chamber and injection molding nozzle. Once the substrate is in place, the second material is injected and combined with the substrate to form a firm hold. Once the second layer has cooled, the last part will be sprayed out.
Engineers should know that Two Shot Mold can be accelerated or slowed down, depending on how the substrate is transferred to another cavity of the mold. Hand and robot arm transfer takes longer than the rotating plane, but the rotating platen molding is more expensive, usually, there are only high-efficiency options, mass production runs.
In addition, it is very important that the material of the mold is easy to bond, and the mold must be aligned to prevent deformation of the parts.
Advantages and disadvantages of two-shot molding
Two-shot injection molding is efficient and economical manufacturing technology. This process also produces highly durable terminal parts and assemblies.
From a design point of view, two-shot molding provides designers with a lot of flexibility, because this process can create complex geometric shapes and adapt to multiple colors to produce more beautiful parts.
In addition, because one machine manufactures the entire part, no post-processing is required, and engineers can greatly reduce manufacturing time, thereby reducing costs. However, it is worth noting that the initial two-shot injection molding machine may be costly, and the two-shot injection molding machine is more expensive than the standard injection molding machine. Fortunately, these costs are usually offset by labor savings and assembly costs for large-scale production runs.
What is over-molding?
Overmolding, like Two Shot Moulding, is a multi-shot injection molding process that produces a single final product from two or more different thermoplastics. This process is ideal for engineers who want to build components that are powerful, functional, beautiful, and that will not separate over time.
At the beginning of the over-molding process, engineers inject the substrate with a harder over-molding material. Then, the substrate is placed in an over-mold tool or an over-mold cavity within the same mold. The molten-over mold material is then sprayed into, onto, or around the substrate. After the molten material is cooled, the substrate and the over-mold are chemically or mechanically combined. The entire over-molding process only takes 30 seconds.
The product team must remember that all thermoplastics used in the over-molding process must be chemically or thermally compatible with each other. Compatibility with metal substrates is usually not a problem, because they can be used with any plastic over mold, but the product team may encounter compatibility issues when using plastic over molds. If the substrate and mold are not compatible, the final product may be deformed or poorly bound.
However, if two less compatible plastics must be used, the team can design mechanical bonding properties for the part after the fact, although this may result in higher costs.
Advantages and disadvantages of over-molding
Overmolding and two-shot injection molding have many of the same advantages. They are ideal for quickly creating durable, reliable, and vibration-resistant parts with complex geometries, but over-molding is best suited for low-volume production runs.
Compared with two-shot molding, over-mold design is also easier, because engineers can use any standard injection molding machine to carry out this process.
In terms of disadvantages, the tolerances of over-molded parts are often lower than those of two-shot injection molding. It is also important to remember that plastic compatibility requirements may constrain designers.
The cooling rate is a decreasing rate from the time the plastic resin enters the mold until the last cavity of the mold is filled.
The cooling process is complete when the temperature is no longer reducing, and any additional time spent to cool the part is useless.
When the cooling process is complete, it is safe to remove the part from the mold.
Factors that affect the cooling rate and the final molded part
Mold Cavity Pressure
The cooling rate is monitored, measured, and displayed on a pressure curve. It is displayed this way because as the plastic resin cools, it shrinks, which reduces the mold cavity pressure.
Mold Temperature
In plastic injection molding, the temperature of the mold itself can be a factor in the cooling rate process. Aside from affecting mold cooling lines, mold temperature can affect part blemishes, like:
Mold Warpage
Sink Marks
Jetting
Improper mold temperature can also impact properties, such as:
Molded-in Stress
Fatigue Resistance
Wear Resistance
Creep Resistance
Molecular Weight
Dimensional Stability
The cooling rate can also be affected by the use of metals that conduct heat away.
The cooling process is complete when the temperature is no longer reducing and any additional time spent to cool the part is useless.
When the cooling process is complete, it is safe to remove the part from the mold.
TIP: During the plastic mold design phase, you must consider the best possible cooling channels for the mold. Using a plastic molder with a deep knowledge of cooling rate process optimization will allow for better control over the mold temperature, and thus, the cooling rate. It will also provide the best cycle time and the best outcome for a good, stress-reduced molded part.
How to Calculate Cooling Time?
Cooling time in injection molding is a critical part of the production process. It is the amount of time the molten plastic takes to solidify. An adequate cooling system is required to transfer heat away from the mold and maintain a stable cooling rate, ensuring the highest quality final products.
One of the quickest methods for estimating the cooling time is using a formula that accounts for the thickness of the part in an equation based on the effective thermal diffusivity. The thermal diffusivity estimates the transfer of heat in and out of material.
Since its establishment, WIT MOLD has successfully exported more than 2000 sets of molds with different types of structures and designs, which are applied to a variety of industries.
Many people are not aware of the advantages of thermoset materials. This guide describes the thermoset molding process and how it can benefit you.
*Thermoset Molding
Thermoset molding is an irreversible molding process by which malleable forms of plastic are forced into a heated mold and formed into their final shape.
Thermoplastic molding is the reverse process where heated material is injected into a cool mold. The material is then cooled to maintain the final shape of the part.
*Why Use Thermoset Molding?
Thermoset materials are generally stronger than thermoplastic materials due to the catalysts that are added to the base compound that cause chemical reactions at the molecular level, forming a harder, irreversible final form. Thermoset plastics cannot be re-melted, only ground and recycled as filler for different applications.
Thermoset molded products have electrical and thermal insulation properties, which make them ideal for electrical and electronic applications. They are resistant to corrosion and have high impact strength, depending on the resin, and are cost competitive with engineered thermoplastics. Using thermoset molding allows producers to maintain tighter tolerances during the molding process compared to similar thermoplastic materials.
*Pros of Thermoset Injection Molding
Injection molded pieces may be the best fit for a piece for several reasons:
Many different types of materials may be used in injection molding, including thermoplastic and thermosetting resins, polymers, and elastomers. This offers the engineer a great deal of control over which blend of materials will yield the best outcome, especially when needing to meet specific property requirements.
Fantastic for high-volume runs.
Precision and low waste. Because of the specific tooling and material mix, there is less waste with injection-molded parts than with other processes.
Short cooling time – Injection molded pieces cool quickly, reducing the time required to release the injected piece from the mold.
*Cons of Thermoset Injection Molding
While injection molding is a fantastic process for the reasons mentioned above, there are certain limitations and drawbacks. A few of these drawbacks include:
Tooling costs – These costs can be significant as precision crafted molds are required.
Flash – Flash is unavoidable when injection molding thermosets. Once the part has been created and ejected from the mold, an automated or manual next step is necessary to remove the flash (excess material). Flash isn’t an issue with thermoplastics due to the higher viscosity of the liquid plastic.
Part size – The size of the piece being created definitely matters when it comes to the molding process. Typically, smaller part sizes (0.1 lbs to 6 lbs) are injection molded, while larger parts are transfer or compression molded. The volume of the order will also dictate which molding process will be the best fit for the project. Compression molding would likely be used for larger parts with a low (or high) volume, while transfer molding would be used for medium to high volume projects. Injection molding would be ideal for high volume runs with smaller pieces.
WIT offers Custom Plastic Molding services. If you are interested in it, please contact us now!
Weighing the pros and cons of the molding process for your composites can help you determine whether it is the right choice for your project needs. Manufacturing plastic or composite parts requires heating and pouring the raw materials into a mold that has been specially made for the part. The four most common molding processes are:
ㆍCompression
ㆍInjection
ㆍTransfer
ㆍExtrusion
Different molding processes are used to create different works. In this article, we will weigh the pros and cons of the injection molding process for thermoset composites.
Injection-molded parts may be the most suitable one for several reasons:
ㆍMany different types of materials can be used for injection molding, including thermoplastics and thermosetting resins, polymers, and elastomers. This provides engineers with a lot of control over which hybrid material will produce the best results, especially when it is necessary to meet specific performance requirements.
ㆍVery suitable for high-volume operation.
ㆍPrecision and low waste. Due to the specific mold and material combination, compared with other processes, there is less waste of injection molded parts.
ㆍShort cooling time-the injection molded parts cool quickly, reducing the time required for the injection molded parts to be released from the mold.
Thermoset Injection Molding
Disadvantages of thermoset injection molding
For the above reasons, injection molding is an excellent process, but it also has certain limitations and defects. These disadvantages include:
ㆍMold costs – these costs can be very important because precision-made molds are required.
ㆍFlash – Flash is inevitable when injection molding thermoset plastics. Once the part is created and ejected from the mold, the next step is to automatically or manually remove the flash (excess material). Due to the high viscosity of liquid plastics, a flash of thermoplastics is not a problem.
ㆍPart size – The size of the part being created is very important in the molding process. Typically, smaller part sizes (0.1 lb to 6 lb) are injection molded, while larger parts are transfer or compression molded. The number of orders will also determine which molding process is best for the project. Compression molding may be used for smaller parts with a low (or high) volume, while transfer molding may be used for medium to high volume projects. Injection molding will be ideal for large-volume running smaller pieces.
Finally, when choosing a molding process for your part, it is always recommended to talk to a thermoset composite or thermoplastic engineer. After assessing your needs, they will be the most capable and able to make suggestions for your work and provide the highest quality products at the most reasonable cost.
We are a thermoset injection molding supplier. Please feel free to contact us if you are interested in our thermoset injection molding or other products.
If you need a plastic part molded with extreme precision—for example, to ensure there’s no air leak between two molded sections or to be certain there’s no visible seal gap line—you likely require precision molding. The difference between a typical injection molded part and a precision molded part is the tolerance, or acceptable range of variation in dimension: While the majority of injection molded parts have a tolerance of +/- .005″, precision molding holds tolerances between +/- .002″ and +/- .001″ (or less, in some cases).
Let’s say, for example, you’re planning to manufacture a military projectile. In order for the projectile to fit properly in the firearm, handle the acceleration when it’s launched, and explode on impact, it requires very high precision.
If your application requires precision molding, you can’t leave anything to chance—so you’ll want to ask yourself the following three questions before you begin the process:
1. Have you selected a plastic material with low shrinkage?
The plastic material you select for your part makes a big difference in whether you’ll be able to do precision molding. For example, polypropylene has a shrinkage range of +/- .014″ to +/- .022″, with an average of +/- .018″. This is a wide range for shrinkage, which makes hitting a specific tolerance extremely difficult. If you’re molding a toothbrush (which commonly uses polypropylene), dealing with shrinkage isn’t a big concern, as the toothbrush will function appropriately regardless of whether it’s slightly bigger or smaller than its counterparts. Acrylonitrile butadiene styrene (ABS)—another common thermoplastic polymer—has a much narrower shrinkage average of +/- .006″. That gives you a much better chance of hitting a tighter tolerance, but it still won’t reach the +/- .001″ or +/- .002″ tolerance needed for a precision part.
One way to hit high tolerances with your plastic material is to add glass or another filler resin (like carbon fiber or mica) into the material. This can minimize shrinkage and warp by providing more structure in the material. For example, if you include long glass fibers in a polymer material, the part will shrink more perpendicular to those fibers.
2. Have you determined which areas of the mold require precision?
Because precision molding is more expensive than typical injection molding, be certain which aspects of your part require tight tolerances—and whether those tolerances can be achieved through injection molding—before moving forward. For example, a surgical handle may only require precision for the piece that will connect with a pin, not the entire handle. Identifying your precision requirements from the get-go ensures you’ll get what you need without wasting money. In the case of the surgical handle, your injection molding partner may advise you to add the tolerances you need through tooling after the injection molding process is complete.
3. Can the mold manufacturer you’ve selected tool with high precision?
The process of creating plastic parts with tight tolerances begins with a high-precision mold. If each plastic part you create is not identical, you won’t have a precise product—and a precise mold ensures there’s no variation for each part. Because of this, it’s extremely important to select a mold manufacturer who understands the slow, steady process of building a high-precision tool. Keep in mind that selecting a mold manufacturer that specializes in rapid tooling is likely not your best option, as the goal of rapid tooling is to finish the mold quickly—but not necessarily precisely.
Let’s get your precision molding project started
We have years of experience in precision molding, and would love to answer any and all of your questions. You can either contact us with those questions, or, if you’re ready to get your project started now, simply contact us and request a free quote.
Two-shot injection molding is a multi-material injection molding process. The molded plastic part can be a combination of two different materials or a combination of different colors of the same material.
Two-shot molding can also be called 2k injection molding, double shot molding, multiple injection molding (sequential injection molding).
When Is The Use of Two-shot Molding?
ㆍProduct function requirements
For example, power switches, phone buttons, keyboard indicators, car switches, etc. Portion with an LED capable of transmitting light.
ㆍImprove the handle feeling
Some handheld products require the use of rubber in hand-held parts, which makes the hand feel more comfortable. For example, walkie-talkie housing, power tool handle, wrench, screwdriver handle, toothbrush handle, thermos, etc.
ㆍEnhance beauty
For example, some plastic parts have a logo. If you use two-shot injection molding, you don’t have to worry about it being erased.
ㆍA localized area of the product that needs to be plated
In the plastic range, only ABS and PSUsurfaces can be plated. If it is necessary to plate a part or a single side of the product, the plating area should be injected into the ABS. Areas that do not require plating are injected with other materials such as PC.
7 Suggestions for Product Design
Two-shot molding frees the designer’s creativity. However, the following factors should also be noted in the product design process.
No.1
Choose the right material. The figure below shows the compatibility of different plastics.
1 ) The core material can use low viscosity materials to reduce the injection pressure.
2) Consider from the perspective of environmental protection. The recycled material can be used as a core material.
3) Optimize the product according to the characteristics of different materials. For thick parts, the finished skin layer uses soft materials. The core material uses hard or foamed plastic to reduce weight.
No.2
If the material is not chemically compatible, the two materials can be integrated by mechanical interlocking.
The hard plastic is molded for the first time, and the soft plastic is molded for the second time. Transparent for the first time, non-transparent for the second time. The plastic with high molding temperature is molded for the first time, and the plastic with low molding temperature is used for the second molding.
No.2
Before the official production, test the mold to produce a complete product.
No.3
Identify all possible defects in the process and eliminate them before the mold is manufactured.
No.4
Consider the shrinkage of the two materials.In general, shrinkage is determined by the material that is first formed.
No.5
A second injection can only be made after the first injection has been completely completed.
No.6
Consider the molded position, to prevent damage in the process.
No.7
Allow the edge of the first injection molded part to be too large. This ensures a higher pressure during the second injection.
No.8
Ensure that the parameters of the injection unit provide the required pressure, flow rate and cooling capacity.
No.9
Ensure that the structural strength of the first molded part can withstand the injection pressure of the second molding.
Check for loose or damaged fastening parts of the double shot mold. The solution is to find parts of the same specification for replacement.
No.2
After the mold has been used for a long time, the cutting edge must be cleaned and ground. After grinding, the surface of the cutting edge must be demagnetized, otherwise it will easily block the material.
No.3
Elastic parts such as springs of the two-shot mold are most susceptible to damage during use. Breakage and deformation usually occur.
No.4
The method adopted is to replace, and the specifications and model of the spring must be paid attention to during the replacement process.
No.5
Two-shotmold punch during use prone to breakage or bending. Damage to the punch and the sleeve is generally replaced with parts of the same specification. The parameters of the punch mainly include the working part size, the mounting part size, and the length size.
No.6
Check the pressure plate, top plate and other parts of the double shot mold. During maintenance, check the accessories of each part and whether there is any damage, and repair the damaged parts. Pneumatic ejector check for air leaks, and specific measures taken.
Conclusion
Two-shot molding increases the added value and productivity of the product. At the same time, plastics are becoming more and more colorful.
Correspondingly, the cost of two-shot molding is higher. Master the design points and avoid risks in advance. Avoid cost waste.
If you have any questions about two-shot injection molds, please contact us directly. Get a free quote.
The tolerance stated in the plastic injection mold is an engineering requirement. In basic terms, they are allowable variants to the initial dimensions of the parts or the base dimension. As it is impossible to generate a product that purely abides by the base measurements, some leeway obtains factored into the design of items.
This margin ensures that all measurements for molded products fit the setting up demands. For example, you may wish to produce products with a size of 2.8 mm. Nevertheless, attempting to produce them might end up with some of them gauging 2.6 mm.
What tolerances do is to establish minimum as well as optimum values for the production process in a way that ensures the product fits. In this case, the reduced limit can be evaluated 0mm while the ceiling is readied to 0.3 mm. By doing this, you are assured products whose diameters range between 2.8 mm and also 3.1 mm.
The important of tolerances
Generating plastic parts for your products calls for that their measurements fit perfectly. It’s very easy to offer dimensions for the type of components you want; obtaining them to have similar measurements to your requirements is a virtually impossible venture to achieve.
The type of making procedure you go for also has a terrific bearing on the high quality of completion product. Injection molding is among the most effective processes you can experience with standards like hubbub 16901 to name a few, but it’s still unable to produce parts with the right fit.
The only escape of such a scenario where it’s impossible to get an exact suit is to leave area for some distinctions in dimension. They don’t need to be major; they simply require not interfere with the item style. This is where tolerances are available in.
What Influences Tolerance?
The kind of polymer utilized throughout the creation of your items substantially identifies whether the tolerances are within acceptable limitations. As distinct polymers obtain injected into the plastic mold, they cool as well as shrink at different prices.
Despite the fact that these shrinkage rates can be quickly represented, completion product will certainly have different tolerance ranges and also discrepancies from the acceptable varieties. The array is a dimension of the difference between the biggest as well as tiniest measurements of measurements in the created batch.
Various other aspects that figure out tolerance consist of the style of the product, the intricacy of the style along with the atmosphere the injection molded parts will certainly be running in.
Minimum/Good Tolerances for Plastic molds
The great, or rather, minimal tolerances are established by the plastic polymer you choose to use for your products. These tolerances also can be found in various forms. For one, there are dimensional, straightness/flatness, and also hole diameter tolerances. They are also divided right into business tolerances and precision tolerances, which are greater in price.
Considered that an injection-molded physical tightening is a result of the cooling, the facet of temperature level decrease is influenced by various other aspects as well. They include the thaw thermal reading, the cooling price, the thickness of the part, the dimensions of eviction, as well as much more.
Furthermore, a section of the molded product that is thicker than an additional will certainly experience even more shrinking. All these variables are since even though it is possible to forecast the behavior of the plastic polymer you wish to be molded; the material will never ever act as anticipated 100% of the time.
The polymer concerned might likewise experience warpage. This is particularly real with parts that are non-uniform as they shrink at various rates in comparison to components that have uniform wall surface thickness. These non-uniform components can happen whenever the part’s design has a concern.
The final words
WIT MOLD has become one of the best molds in the industry because we combine the essence of the latest technology with proven traditional methods.
With an expert team composed of experienced and knowledgeable experts, we are able to complete custom orders for Custom Plastic Molds and parts that may exceed the capabilities of our competitors. We are also unremittingly committed to improving customer satisfaction, which includes providing comprehensive end-to-end quality assurance for every product we produce.
There are a variety of manufacturing methods used to create products using plastic polymers, including two-shot injection molding, compression thermoset molding and extrusion. While all of these are viable manufacturing processes, there are several advantages to this process that make it the top choice for many plastics manufacturers. The process is relatively simple; one material is injected into a mold in order to make the initial section of the product, followed by a second injection of a secondary material that is compatible with the original material. There are three good reasons many manufacturers use this method of manufacturing plastics or polymers.
Advantages of two-shot injection molding
Two-shot injection molding is cost-effective
The two-step process needs only one machine cycle, rotating the initial mold out of the way and putting the secondary mold around the product so that the second, compatible thermoplastic can be inserted into the second mold. Because the technique uses only one cycle instead of separate machine cycles, it costs less for any production run and requires fewer employees to make the finished product while delivering more items per run. It also ensures a strong bond between the materials without the need for further assembly down the line.
Enhanced product quality
Two-shot injection molding enhances the quality of most thermoplastic items in several ways:
ㆍImproved esthetics. Items look better and are more appealing to the consumer when they are crafted of different colored plastics or polymers. The merchandise looks more expensive if it utilizes more than one color or texture
ㆍImproved ergonomics. Because the process allows for the use of soft-touch surfaces, the resulting items can have ergonomically designed handles or other parts. This is particularly important for tools, medical devices, and other hand-held items.
ㆍIt provides for a better seal when silicone plastics and other rubbery materials are used for gaskets and other parts that require a strong seal.
ㆍIt lets you combine both hard and soft polymers for outstanding comfort and utility for even the smallest of products.
ㆍIt can greatly reduce the number of misalignments when compared to over-molding or more traditional insert processes.
ㆍIt enables manufacturers to create more complex mold designs using multiple materials that can’t be effectively bonded using other processes.
ㆍThe bond created is exceptionally strong, creating a product that is more durable, more reliable, and with longer life.
Versatility
Product manufacturers favor a wide range of applications for two-shot injection molding, including automotive interior parts, medical equipment, tools, and toys. It allows manufacturers to combine various materials and colors to create a strong and attractive final product. Some materials can be effectively combined with this process, including silicone and thermoplastics, nylon and thermoplastic elastomers, or hard nylon and soft-touch materials.
Two-shot injection molding can solve your company’s product production difficulties. An experienced plastic manufacturer can guide you from concept to finished product and ensure a cost-effective solution.
Producing an assembly with multiple components
Compared to other methods of plastic molding, two-shot is ultimately a more cost-efficient way of producing an assembly with multiple components. Here’s why:
Part Consolidation: Two-shot injection molding reduces the number of components in a finished assembly, eliminating an average of $40K in development, engineering, and validation costs associated with each additional part number.
Improved Efficiency: Two-shot molding allows multiple components to be molded with a single tool, reducing the amount of labor needed to run your parts and eliminating the need to weld or join components after the molding process.
Improved Quality: Two-shot is carried out within a single tool, allowing for lower tolerances than other molding processes, a high level of accuracy and repeat-ability, and reduced scrap rates.
Complex Moldings: Two-shot injection molding allows for the creation of complex mold designs that incorporate multiple materials for functionality that cannot be achieved through other molding processes.
Disadvantages of two-shot injection molding
1) High tooling costs and long setup lead times. Up-front costs are high due to the design, testing, and tooling required. There is the initial design and prototyping (probably via CNC or 3D printing), then the design of a prototype mold tool to produce replicas of the part in volume. Lastly, and only after extensive testing during both stages, you can finally inject mold apart.
2) Part design restrictions. Plastic parts must be designed with injection molding consideration and must follow the basic rules of injection molding, for example:
Avoid undercuts and sharp edges as much as possible
Use uniform wall thicknesses to prevent inconsistencies in the cooling process resulting in defects like sink marks.
Draft angles are encouraged for better de-molding.
Don’t forget, because tools are typically made from steel or aluminum, it can be difficult to make design changes. If you need to add plastic to the part, you can make the tool cavity larger by cutting away steel or aluminum. But in order to take away plastic, you need to decrease the size of the tool cavity by adding aluminum or metal to it. This is extremely difficult and in many cases might mean scrapping the tool (or part of it) and starting over.
Also, the weight and size of the part will determine the tool size and necessary press size. The larger the part, the more difficult and expensive it will be.
3) Small runs of parts can be costly. Due to the complexity of tooling, and the necessity to rid the machine of all previous material before the next product can be made, the setup time can be quite lengthy. Therefore small runs of parts have traditionally always been thought of as too expensive to injection mold.
Precision injection molding machine refers to the molding machinery and equipment that is suitable for molding and producing precision plastic products. For a precision injection molding machine, how should we measure or judge it?
Many precision injection molding also requires injection molding machines with
① High injection pressure and high injection speed.
②Mold clamping system with sufficient rigidity and clamping accuracy. The so-called clamping accuracy refers to the uniformity, adjustability, stability and repeatability of the clamping force, and high accuracy of the opening and closing position of the mold.
③The pressure, flow, temperature and metering can be controlled precisely to the corresponding accuracy, and multi-stage injection can be used to ensure the reproduction of the molding process and the repetition accuracy of the products, etc.
The benefits of high-pressure molding that can be realized by precision injection molding machine
A. Improve the precision and quality of precision products.
The injection pressure has the most obvious effect on the shrinkage rate of the product molding. When the injection pressure reaches 392 MPa, the shrinkage rate of the product molding is almost zero. And the precision of the products at this time is only affected by the mold control or environment. Experimental evidence: injection pressure from 98 to 392 MPa, the mechanical strength of the parts can be increased by 3 to 33%.
B. The wall thickness of precision products can be reduced and the molding length can be improved.
Take PC as an example, ordinary machine injection pressure of 177 Mpa can mold 0.8mm wall thickness products, while precision machine injection pressure of 392 MPa can mold products with thickness of 0.45mm or more. Ultra-high pressure injection machine can obtain products with greater flow length ratio.
C. Increase the injection pressure can fully develop the efficacy of injection rate.
The performance of injection molding machine to achieve precision injection molding
Injection molded products have been applied to various fields and widely used to replace metal parts with high precision, thus putting forward strict requirements on the dimensional accuracy, quality accuracy, apparent quality and mechanical properties of injection molded parts. At the same time, the process factors affecting the quality of injection molded products have also put forward higher requirements.
The ideal state of injection molding machine control is to directly control the product size, quality, apparent quality, mechanical properties of the variables as feedback signals for feedback control. However, for the time being, direct measurement and conversion of these non-electrical quantities into electrical signals has not been solved, so it can only be solved by controlling the controllable variables of the injection molding machine that affect the quality of the above mentioned products.
