Silicone Mixing for Custom Industrial Silicone Parts
Connect material preparation with the part you need to manufacture. Send the drawing, application, colour requirement and order plan so the material stage can be reviewed together with molding, extrusion, calendering or die cutting.
Products supported by controlled silicone mixing
These five existing product lines have direct material-mixing or colour-matching evidence. The mixing route is reviewed together with the final part, compound ratio and downstream manufacturing process.
Calculator Silicone Buttons
Round Silicone Jar Opener
Cap Style Silicone Dice Mold
Marble Color Silicone Wristbands
Transparent Gel Silicone Logo Patch
Silicone mixing is one decision inside a complete manufacturing route
Mixing is where silicone, colour and other required ingredients are prepared for the next production stage. The useful starting point is not a generic formula. It is the finished part, its working environment and the route needed to make it.
Legensilico supports custom silicone gaskets, seals, hoses, sheets, cords, membranes and other components. Material preparation should therefore be discussed together with part geometry, application and production method.
- Part drawing or sample
- Application environment
- Colour and appearance
- Expected quantity
What to send before material preparation is discussed
These inputs help separate what is already defined from what still needs engineering or purchasing clarification.
Drawing, dimensions or sample
Shows part geometry, interfaces and the production route that may need review.
Application and working environment
Clarifies the performance questions that matter to the finished component.
Colour and surface expectations
Provides a clear starting point for colour and appearance discussion.
Quantity and packaging plan
Aligns manufacturing and delivery discussion with the intended order.
Use a clear route from project requirements to production planning
The exact formulation and process parameters depend on the project. The practical sequence is to define the requirement, review material preparation and then connect it with the downstream process.
Define the part
Review geometry, use conditions, appearance and expected volume.
Clarify material needs
Identify the silicone, colour and performance questions that require confirmation.
Prepare and evaluate
Discuss how mixing, dispersion and handling relate to the project.
Connect the next process
Move the approved direction into molding, extrusion, calendering or die cutting.
See where silicone mixing can support your custom part
The final route depends on part geometry, material form and project requirements. Explore the related processes below.
Compression Molding
For custom molded silicone parts where the compound is shaped in a mold.
Silicone Extrusion
For continuous profiles such as silicone tubing, cords and sealing sections.
Silicone Calendering
For sheet materials and continuous flat silicone forms requiring a sheet-making route.
Die Cutting
For converting silicone sheet into gaskets, pads and profile-cut components.
Resolve the questions that can affect the next production stage
Mixing quality is connected with colour distribution, dispersion, trapped air, material temperature and the way the compound behaves in the next process. These points should be reviewed against the actual part instead of treated as isolated technical terms.
- Colour uniformity
- Dispersion of ingredients
- Air and deaeration
- Time and temperature
Information that makes the first discussion more useful
| Project input | What it helps clarify | Useful format |
|---|---|---|
| Part geometry | Likely manufacturing route and key interfaces | 2D/3D drawing or sample photos |
| Application | Working environment and required performance questions | Use description or existing specification |
| Colour and appearance | Visual target before production planning | Colour reference, sample or image |
| Quantity | Suitable project and delivery discussion | Prototype and expected order volume |
| Packaging | Handling and shipment requirements | Bag, tray, label or carton instructions |
Exact material, tolerance, testing, MOQ and lead time must be confirmed against the drawing and project requirements.
Silicone mixing equipment, preparation and process factors
The original technical content is preserved below as a detailed reference, while the main page now leads with the information a custom-part buyer needs first.
Open the complete silicone mixing technical guide
Silicone mixing is the foundation and key to producing high-quality silicone products. There are many details that determine success or failure in the silicone mixing. This article will provide a detailed explanation from several aspects, including the mixing tools, the preparations and steps of mixing, and effect factors of silicone mixing. If you want to customize silicone products, this article can help you better understand the role of silicone mixing in silicone manufacturing.
Equipment and Tools of Silicone Mixing
Evenly mixed silicone is a crucial step towards an excellent product. The uniform mixing of silicone cannot do without professional equipment and tools. Now I will introduce to you the essential tools for silicone mixing and the importance of these tools.
Mixer
For silicone mixing, it is very important to choose the right mixer. Manufacturers need to choose different mixers for materials with different characteristics. If the production volumes of your products vary greatly, different mixers are necessary based on your production volumes.The mixer is mainly divided into four categories, which are the high-shear mixer, the dynamic mixer, the static mixer and the metering mixer. The common mixers we often used mainly include open mill mixer,intensive mixer,and internal mixer.
The main function of the mixer is to let the curing agent,and other additives evenly distributed in the entire compound. This can greatly keep the consistency of your products performance. A professional mixer can efficiently achieve uniform mixing. Moreover, it can be combined with a stirring and temperature control system to prevent the local temperature of the compound from being too high, which could accelerate the reaction. In addition, the mixer can also promote the deaeration of the compound, obtaining a dense and high-quality compound.
Blades
In the silicone mixture, the blades and the mixer work together to form a strong shearing force. This shear force can achieve the microscopic uniform dispersion of fillers within the compound. The rotating blades can stir the compound and prevent local curing. In addition, it can also break the air inside the compound, improving its strength and toughness. At the same time, the heat energy generated during the mixing of the compound also provides better conditions for the uniform mixing of the compound.
Different blades have different shapes and rotational speeds, which will have a direct impact on the production process. For instance, helical blades are suitable for processing high-viscosity silicone because they have better shearing and conveying capabilities. The turbine blades can quickly disperse the compound. In addition, the processing capabilities of high-speed and low-speed blades for compounds are also different. Therefore, when purchasing blades, manufacturers need to make an appropriate choice based on the characteristics of the materials you produce.
Container
In silicone mixing, the mixing container determines the physical mixing and chemical reaction environment of the silicone and various additives. A good container can improve the stability and controllability of the reaction environment. When purchasing a mixed container, manufacturers should consider its functions and whether it is compatible with the raw materials of your products.
Generally speaking, professional silicone manufacturers usually choose stainless steel containers with precision-polished interior surfaces. It has high mechanical strength, is resistant to wear and impact, has a smooth surface that is easy to clean, and does not react with silicone and other additives.Therefore, it has become the first choice for silicone manufacturers, whether from food grade silicone, medical grade silicone is able to use.
Use stainless steel containers should periodically check the clearance between the wall-scraping impeller and interior wall, to avoid mixing dead zones. It is also needed to regularly check the interior walls and the inlet and outlet of the container for any residues. Timely cleaning of residues can guarantee your products consistency and boost production efficiency.
QC Facility
Professional quality inspection equipment is indispensable in the silicone mixing stage. It can determine in real time whether the compound is mixed evenly, and monitor the viscosity of the mixture, curing speed, and the mixing ratio of additives and raw materials.Once the detection equipment finds abnormalities, workers can immediately adjust the parameters of the materials, effectively avoiding the waste of raw materials and reducing the overall production cost.
The equipment can also test the mixed compound to make sure that it meets the production standards and the customized requirements of your standards. In addition, the detection equipment can also retain processing data, facilitating continuous optimization of the production process.
Rotational rheometers are typically used to test the viscosity, curing speed and other properties of compounds, and can provide comprehensive data. Infrared spectrometers and scanning calorimeters can analyze the mixing ratio and curing degree of compounds. A colorimeter can monitor whether there are defects such as bubbles inside the compound, whether the color paste is uniform, and whether there are impurities inside the compound. These instruments can better help you test the quality of the compound and improve the quality of your products.
Mixing Preparation
Raw Material
Choosing the right raw materials is the most important step in production. Before mixing, it needs to stir and homogenize the mixed raw materials. During the production and transportation of raw materials, some impurities may be drawn, so filtering the raw materials is essential to safeguard the purity of your products.
Besides, manufacturers should choose the appropriate raw materials based on the performance of your final product. The raw materials should have high stability. This can make your production process smoother. In addition, it is also necessary to consider whether the raw materials are compatible with the processing equipment. In other words, whether the equipment can process raw materials smoothly.These are the necessary conditions for your successful production activities.
Storage
The storage of silicone raw materials must pay attention to issues such as storage environmental conditions and packaging.If the silicone is not stored properly, the raw material is easy to deteriorate. The first thing to do when storing silicone is to choose a dry and cool warehouse. It is recommended that the storage temperature be between 0℃ and 25℃, and the temperature should be kept as stable as possible.It is suggested that factory should be equipped with temperature monitoring device and dehumidifier, which can better keep the stability of raw materials and avoid moisture absorption and stickiness of raw materials.
Moreover, different raw materials should be stored in different areas to prevent cross-contamination and misuse. We also suggest that when storing raw materials, all raw materials should be clearly marked with batch numbers, storage periods, etc. This can better help them manage the inventory, prevent raw materials from being stored for too long, and promptly clear out expired raw materials.
Select Mixing Container
As mentioned above, when choosing a container, one should not only consider its functionality but also its compatibility with the raw materials. The preferred containers are made of 304 or 316L stainless steel. This type of container is the best choice for the vast majority of silicone mixing. It is scratch-resistant and wear-resistant, chemically stable and easy to clean. Therefore, manufacturers are always considering purchasing this kind of mixing container.
You should be aware that there are also many taboos when choosing containers. For instance, if your products use silicone with extremely strong additives, plastic containers can not be used.If your products use acid curing silicone, stainless steel that hasn’t been professionally treated can not be used. You should choose dedicated containers for the raw materials of your different products, so that factories can better avoid cross pollution and guarantee the quality of your products. Before using the container, it is also needed to clean it to guarantee there is no residue inside. Besides, regular inspection and maintenance are also indispensable.
Precise Measuring
Accurate measurement is the most critical part of silicone mixing. It directly affects the uniformity and consistency of the material. Therefore, precise weighing equipment must be used to accurately weigh and measure the raw materials.Professional equipment can have precise control of blending ratio, fundamentally guarantee the correct chemical reaction. Accurate measurement can also help you save expensive raw materials and prevent greater losses caused by substandard products.
Pre-mixing
Pre-mixing is to create better conditions for the final mixing. Pre-mixing can form a uniform slurry by using small batch and high shear rates, which can significantly improve the uniformity of material dispersion. Pre-mixing can also shorten the time of main mixing, reduce the difficulty of main mixing and improve production efficiency.
However, it should be noted that not all silicone mixtures require pre-mixing. Usually, pre-mixing is only carried out for large-scale production and complex formulas. For instance, if your products use a formula with multiple additives or need to carry out large-scale production, pre-mixing can be conducted. Or if your silicone products have high specifications, such as medical-grade silicone that requires extremely high uniformity, pre-mixing can be carried out. For small-scale, simple formula production, pre-mixing is unnecessary.
Steps of Silicone Mixing
The main mixing requires putting the materials into a mixing machine for high-speed mixing. Throughout the entire mixing process, it is necessary to make sure that the wall-scraper impeller scrapes the tank walls and bottom, scraping the materials at the edges into the main mixing zone. This approach is the key to ensuring high-quality mixing of materials.
Factories need to stir the materials to the specified time according to the characteristics of the materials you produce. If your products still need to add color paste or other fillers, it can do so at this stage. Stir until the color and texture of the material are completely uniform to the naked eye. Through high-speed mixing, the curing agent and filler can be mixed at the molecular level, avoiding local curing.
Next, vacuum is needed to exhaust the air in the mixed material. Using a vacuum pump to continuously stir the material under vacuum conditions until no bubbles emerge on the compound. Vacuum exhaust can remove the air entrained during the mixing process, resulting in a dense compound. Such compounds can greatly improve the performance and appearance of your products.
Finally, cut the material. Cut the material to a specific width and make sure the width is correct. Then, the cut material is laminated with the film to prevent material contamination. Don’t forget to clean the equipment after using it.
Factors Affecting Silicone Mixing
Mixing silicone is actually not difficult. But it’s not easy to achieve good product performance.The reason is that there are many details that need to be paid attention to in the silicone mixing process. These details are often the key to success or failure.
Characteristics of Raw Materials
The raw material is the basis for the mixture of silicone.The degree of difficulty and method of mixing different raw materials are different.
Viscosity is one of the important factors affecting the mixing of silicone. Generally speaking, high-viscosity silicone requires equipment with higher shear force. This type of equipment usually has a larger mixed power and consumes more energy. And it is easy to incorporate air when mixed.Therefore, more demanding deaeration systems are required.Relatively, low viscosity silicone is easier to mix and deaerating. However, its good fluidity requires equipment with better sealing performance.
Besides, the proportion and the characteristics of the filler also need to be taken into consideration.Blending ratio difference, the greater the precision for the measurement of the material and the requirements of the dispersion efficiency is higher.Some filler reunites easily, it is difficult to disperse. Uneven dispersion can lead to abnormal viscosity, strength and smoothness of the material.
Therefore, for silicone mixing, it is necessary to precisely understand the characteristics of raw materials and fillers, and be able to correctly adjust the mixing parameters. In this way, the mixing effect will be guaranteed.
Temperature Control
Temperature is an important factor affecting the silicone during the mixing process. Temperature is also a controllable and optimized factor in the production process.
Temperature affects the viscosity and reaction efficiency of silicone. The viscosity of silicone will decrease when the temperature is too high. Conversely, the viscosity will increase. Similarly, the higher the temperature will get the faster the rate of the chemical reaction. Therefore, a higher temperature means that the time available for pouring is shorter. Excessively high temperatures can also lead to different hardness levels of your products and affect their appearance. Too low temperature not only affects the viscosity of the material but also reduces production efficiency.
Therefore, manufacturers must pay attention to the control of temperature during the mixing process. During the production process, the environmental temperature in the production workshop must also be controlled. Only through systematic temperature control can we achieve more stable, efficient and high-quality production.
Mixing Time and Speed
For silicone mixing, the mixing time and speed are not two separate parameters. Time and speed need to be coordinated to achieve the best mixing effect.
Generally speaking, if the mixing time is too short or the speed is too slow, it will lead to uneven distribution of fillers and curing agents. Ultimately, it will lead to poor local curing of your products and a decline in its strength and other properties. If the time is too long or the speed is too fast, it will cause the material temperature to be too high and damage the structure of the material.It also draws in too much air, leading to decreased production efficiency and increased unnecessary energy consumption.
Therefore, it is important to determine the optimal mixing time and speed for each product. The optimal parameters can be found through experiments, or a mixed strategy of starting with low speed and then high speed can be adopted. It is indispensable to adjust the parameters according to the characteristics of the material, and use professional testing equipment to guarantee that the mixture is in place. This can help you achieve the best quality while realizing higher production efficiency and the lowest energy consumption.
Final Thoughts
Silicone mixing is a simple yet complex project. It is the inevitable path to obtaining high-quality products. Legensilico has many years of experience in silicone production and is committed to providing you with high-quality silicone products. If you want to customize or purchase high-quality silicone products, please feel free to contact us.
Common silicone mixing questions
Why do some parts of the silicone appear color stripes after curing?
The root cause of this problem lies in the fact that the raw materials and additives were not mixed evenly. There are many reasons for this problem. Insufficient shearing force of the mixer, too large a gap between the wall-scraping impeller and the tank wall, too short a mixing time, etc., can all cause this trouble. Therefore, to solve the problem, it needs to check whether the power of the mixer is sufficient, whether there are mixing dead zones, and whether the mixing time and speed have reached the optimal parameters. What’s more, it also needs to check whether the workers are operating in accordance with the standard procedures and so on.
Why are there bubbles inside and on the surface of the cured products?
Bubble is associated with two parts, respectively is mixing and deaeration.The formation of bubbles might be due to an overly fast mixing speed, which causes a large amount of air to be drawn into the compound. Or it could be caused by insufficient deaeration time or an inadequate vacuum system.
To solve the problem, it needs to optimize the stirring program and upgrade the vacuum deaeration system. Adopting a mixed strategy of starting low and then fast can effectively help you reduce air intake. It also needs to check the integrity of the vacuum pipelines and seals. Besides, slowly stirring the compound under vacuum conditions can also help you solve this problem.
Why does the evenly mixed compound appear to be layered up and down before pouring?
There are many reasons for this phenomenon. This might be due to the low viscosity of the raw materials, or the mismatch between the density of the filler and that of the raw materials, or the material is left for too long after being mixed.
Once the cause of the problem is understood, it will be very easy to solve. Select raw materials with higher viscosity or complete the pouring before the material settles. Within the allowable range of the formula, appropriate additives are allowed to change the thixotropy of the compound and improve its anti-settling ability.
How can cross-contamination be effectively avoided when changing the production of different types of silicone?
To effectively avoid cross-contamination, it needs to keep equipment clean. To achieve this, following a standard cleaning procedure is essential.Choose a professional silicone cleaning agent, its cleaning efficiency and effect is far better than the ordinary solvent, and then rinse the equipment.
You can also use no dead zone and easy disassembly cleaning equipment. This can help keep the equipment better and effectively prevent cross-contamination.
Why do products made from well-mixed compounds have a sticky surface?
Well mixed compound but sticky surface, the cause of this problem may be the chemical reaction rather than the problem of uniform mixing. You should focus on checking three aspects: the mixing ratio, the purity of the raw materials, and whether the curing environment is suitable.Too low or ineffective curing agent can cause this problem. Cross-contamination can also cause this problem, which could be equipment contamination, material contamination or environmental pollution. Excessively high environmental humidity or too low curing temperature may also cause this phenomenon.
If this problem occurs, please check the production records of this batch of products and keep the samples of this batch for testing. Then, the possible causes of the above-mentioned phenomenon need to be investigated step by step.Or you can also contact the supplier and ask the manufacturer to use professional equipment to help you find the cause.
Send the drawing, application and order plan for a project review
Legensilico can use those inputs to discuss material preparation together with the downstream manufacturing route.
