If you’re a silicone straw distributor, a retail seller, or a food service owner, you know uneven wall thickness of silicone straws can negatively affect your business. It can lead to customer complaints and poor service delivery, which in turn can affect brand image, among other things. So why do some silicone straws have uneven thickness? Is it an avoidable problem? Let's find answers to these questions.
How Silicone Straws are Molded and Produced
Silicone drinking straws are produced through molding. Here are the two (2) major types of molding used:
Injection Molding
Injection molding is a type of production where raw silicone material is passed into a heated compartment to be melted. Then, a plunger injects the melted silicone at high pressure through small openings to fill a shaped cavity. When it cools or cures, the final product is ejected from that cavity.
Extrusion Molding
For the extrusion molding process, raw silicone material is melted by a rotating screw that also pushes the molten material through a shaped opening ( often called a die). The die is shaped in the form of the desired end product. After cooling, the extruded product can be cut into the desired length.
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Injection Molding |
Extrusion Molding |
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Uses cases
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Used for making silicone straws with special features or designs such as sharp tips, collapsible sections, logos, and other intricate decorations. Used for producing branded silicone straws.
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Commonly used for producing silicone straws of regular shapes and designs.
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Advantages |
It's an excellent technique to make designs that require high precision Suitable for automated and fast production. |
It's as fast as the mold continuously pushes out tube after tube. Then the tube can be cut into the preferred length. It's ideal for long and uniform-shaped straws. |
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Limitations |
It's not economical for small-scale production. Complex design setup process. |
It's not suitable for 3D designs or special features / designs requiring high precision. Extrusion molding is less precise in wall thickness compared to injection molding. |
Keep in mind that there are other types of molding processes, but they are not suitable for manufacturing silicone straws. For example, rotational molding and compression are other molding techniques popular in the manufacturing world, but they are not practical for silicone straw production.
What are the Causes of Uneven Wall Thickness in Silicone Straws
Uneven wall thickness occurs due to many reasons. Some of these reasons are unique to each molding technique used.
Mold / Die Misalignment and Defect
In extrusion, if the die has maligned parts or worn-out surfaces, the straws made with it may have uneven thickness. For example, if the inner pin, also known as mandre, is not at the center, one side of the straw wall will be thicker than the other. Additionally, a defective die can also affect the flow and formation processes.
As for injection molding, if the mold has air trapped in it, the molten silicone may not fill the mold completely and accurately. Also, if the injection pressure is low, the silicone may not fill up as it should, resulting in an uneven wall thickness.
Temperature Imbalance
Temperature imbalance can cause inconsistent flow and formation in both molding methods.
Inconsistent Cooling
In the extrusion molding process, if the cooling isn't uniform, such that one side cools faster, the final product may likely have an uneven wall thickness.
Material Impurities
Impurities tend to block or obstruct smooth flow through the channels, affecting the flow rate of the material, thereby causing uneven thickness in any molding method used.
How Expert Manufacturers Prevent Silicone Straw Uneven Wall Thickness or Eccentricity
Top silicone straw manufacturers almost never face uneven thickness problems due to the preventive steps they take. For example, renowned silicone manufacturers like KEAN follow these preventive measures:
Proper Equipment Maintenance
Proper equipment maintenance is a practice used by manufacturing giants to keep their straw molding machines in excellent shape and free of any defects. The practice prevents wear and tear that often affects the production of silicon straws, especially the uneven wall thickness.
Professional Tool Alignment Check
To prevent defective silicone straws, established and reputable manufacturers have dedicated professionals who constantly check the alignment of molding tools. With this approach, mechanical errors are avoided, and straw production is free of defects. Apart from errors, such professionals ensure the molds and other components are properly positioned and well set before use.
Temperature Check
Temperature is an important part of the straw molding process, be it injection or extrusion technique. The temperature is set to a consistent rate that keeps heating the material at a consistent rate and in the right proportion. However, it goes beyond that. Temperature checks also help to ascertain the even distribution of heat across the mold. The even distribution of heat across the mold prevents eccentricity.
Pressure Check
Pressure, just like temperature, is important and must be properly monitored. So, before each production, the pressure system needs to be inspected, as an inconsistency in pressure can easily ruin the final product. If the pressure is stronger at any point than at others, a lot can go wrong. One part of the straw may have thicker walls than others.
Material Assessment
Material assessment is an essential preventative measure. In its raw state before undergoing heat, silicone should be checked for debris. This prevents foreign bodies from contaminating the raw material and disrupting the molding process.
High Quality Material Usage
Premium and high-quality materials prevent defects during production. When heated, it melts in its entirety evenly. The consistency in viscosity is maintained, and this allows proper flow, preventing thin spots and weak areas in the straw.
Silicone Straws Vs. Paper Straws
Silicone and paper straws differ in composition and applications. Here's a detailed comparison:
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Characteristics |
Silicone Straws |
Paper Straws |
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Material and Safety |
Silicone straws are food grade, non-toxic, and can withstand temperatures between -40°C and 220°C. They do not release harmful substances or react with hot liquids.
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Paper straws are food-grade and sometimes have edible, waterproof adhesive coating. Under high temperatures, paper straws may soften or degrade when soaked in liquid of any temperature for too long. |
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Cleaning and Hygiene |
Silicone straws are easy to clean. Cleaning can be done with a soft brush. Silicone straws do not retain stains. |
Paper straws are designed for one-off use. Cleaning will make such straws soggy and unusable.
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Durability |
Silicone straws are durable and reusable. They do not get damaged easily despite repeated use, biting, and long hours in liquid. |
Paper straws have low durability since they are designed for one-time use. Within 15 to 30 minutes of being in liquid, the paper material starts to soften. |
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Use cases |
Silicone straw is soft and safe to use. It can be carried around and reused at another time. For example, some keep it as a personal straw they use everywhere. In some cases, silicone straws are used with flasks and portable cups. |
Paper straws are often softer than the silicone type. Paper straws are common at restaurants, fast food, and tea shops. |
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Environmental Friendliness |
Since silicone straws are reusable, they are considered environmentally friendly. A user can keep a silicone straw for a long time. This makes it safe for the environment as only a few are disposed of. While the few disposed of can remain in landfills for many years, they don't react to form toxic waste that contaminates the environment. |
Paper straws are also environmentally friendly as they are biodegradable, and the raw material sources are renewable. However, the resources and carbon emissions for a single-use production raise concerns. |
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Cost |
The production cost is high, but the long-term use compensates for it. |
The production cost is significantly low. However, due to its one-time use nature, more needs to be produced, thereby raising its long-term cost for businesses. |
How KEAN Delivers High-quality Reusable Silicone Straws
KEAN is a silicone manufacturer that produces high-quality silicone straws that have uniform wall thickness, excellent ergonomic design, and durable yet food-safe composition.
For example, the company does mass production of reusable BPA-free and non-toxic silicone straws for babies. These types of safe silicone straws can be carried around and used with baby bottles, cups, and many drinking materials. The straws come with a lightweight, collapsible case that can be squeezed into the pocket, attached to a key chain, and fitted into a purse.
Apart from baby silicone straws, businesses can also request any other types and forms of food-grade silicone straws. Using advanced production tools and implementing preventive measures that eliminate defects, KEAN can manufacture custom silicone straw designs in high volume.
Final Thoughts
Uneven wall thickness in silicone straws is a problem that affects the brand and quality of service of a business, as it lowers durability and impacts usage. Thankfully, it's an avoidable problem that renowned manufacturers deal with by using precision based techniques and tools, and putting adequate measures in place to ensure machines are without defects, properly maintained, and production processes are adequately supervised.